Author: "Akhperjanian, A. G." - Searchworks@Jio Institute Digital Library Search Results

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807 results on '"Akhperjanian, A. G."'

1. H.E.S.S. discovery of very high energy gamma-ray emission from PKS 0625-354

Author: Collaboration, H. E. S. S., Abdalla, H., Abramowski, A., Aharonian, F., Benkhali, F. Ait, Akhperjanian, A. G., Andersson, T., Angüner, E. O., Arrieta, M., Aubert, P., Backes, M., Balzer, A., Barnard, M., Becherini, Y., Tjus, J. Becker, Berge, D., Bernhard, S., Bernlöhr, K., Blackwell, R., Böttcher, M., Boisson, C., Bolmont, J., Bordas, P., Bregeon, J., Brun, F., Brun, P., Bryan, M., Bulik, T., Capasso, M., Carr, J., Casanova, S., Cerruti, M., Chakraborty, N., Chalme-Calvet, R., Chaves, R. C. G., Chen, A., Chevalier, J., Chrétien, M., Colafrancesco, S., Cologna, G., Condon, B., Conrad, J., Cui, Y., Davids, I. D., Decock, J., Degrange, B., Deil, C., Devin, J., deWilt, P., Dirson, L., Djannati-Ataï, A., Domainko, W., Donath, A., Drury, L. O'C., Dubus, G., Dutson, K., Dyks, J., Dyrda, M., Edwards, T., Egberts, K., Eger, P., Ernenwein, J. -P., Eschbach, S., Farnier, C., Fegan, S., Fernandes, M. V., Fiasson, A., Fontaine, G., Förster, A., Funk, S., Füßling, M., Gabici, S., Gajdus, M., Gallant, Y. A., Garrigoux, T., Giavitto, G., Giebels, B., Glicenstein, J. F., Gottschall, D., Goyal, A., Grondin, M. -H., Hadasch, D., Hahn, J., Haupt, M., Hawkes, J., Heinzelmann, G., Henri, G., Hermann, G., Hervet, O., Hinton, J. A., Hofmann, W., Hoischen, C., Holler, M., Horns, D., Ivascenko, A., Jacholkowska, A., Jamrozy, M., Janiak, M., Jankowsky, D., Jankowsky, F., Jingo, M., Jogler, T., Jouvin, L., Jung-Richardt, I., Kastendieck, M. A., Katarzyński, K., Katz, U., Kerszberg, D., Khélifi, B., Kieffer, M., King, J., Klepser, S., Klochkov, D., Kluźniak, W., Kolitzus, D., Komin, Nu., Kosack, K., Krakau, S., Kraus, M., Krayzel, F., Krüger, P. P., Laffon, H., Lamanna, G., Lau, J., Lees, J. -P., Lefaucheur, J., Lefranc, V., Lemière, A., Lemoine-Goumard, M., Lenain, J. -P., Leser, E., Lohse, T., Lorentz, M., Liu, R., López-Coto, R., Lypova, I., Marandon, V., Marcowith, A., Mariaud, C., Marx, R., Maurin, G., Maxted, N., Mayer, M., Meintjes, P. J., Meyer, M., Mitchell, A. M. W., Moderski, R., Mohamed, M., Mohrmann, L., Morå, K., Moulin, E., Murach, T., de Naurois, M., Niederwanger, F., Niemiec, J., Oakes, L., O'Brien, P., Odaka, H., Öttl, S., Ohm, S., Ostrowski, M., Oya, I., Padovani, M., Panter, M., Parsons, R. D., Pekeur, N. W., Pelletier, G., Perennes, C., Petrucci, P. -O., Peyaud, B., Piel, Q., Pita, S., Poon, H., Prokhorov, D., Prokoph, H., Pühlhofer, G., Punch, M., Quirrenbach, A., Raab, S., Reimer, A., Reimer, O., Renaud, M., Reyes, R. de los, Rieger, F., Romoli, C., Rosier-Lees, S., Rowell, G., Rudak, B., Rulten, C. B., Sahakian, V., Salek, D., Sanchez, D. A., Santangelo, A., Sasaki, M., Schlickeiser, R., Schüssler, F., Schulz, A., Schwanke, U., Schwemmer, S., Settimo, M., Seyffert, A. S., Shafi, N., Shilon, I., Simoni, R., Sol, H., Spanier, F., Spengler, G., Spies, F., Stawarz, Ł., Steenkamp, R., Stegmann, C., Stinzing, F., Stycz, K., Sushch, I., Tavernet, J. -P., Tavernier, T., Taylor, A. M., Terrier, R., Tibaldo, L., Tiziani, D., Tluczykont, M., Trichard, C., Tuffs, R., Uchiyama, Y., van der Walt, D. J., van Eldik, C., van Rensburg, C., van Soelen, B., Vasileiadis, G., Veh, J., Venter, C., Viana, A., Vincent, P., Vink, J., Voisin, F., Völk, H. J., Vuillaume, T., Wadiasingh, Z., Wagner, S. J., Wagner, P., Wagner, R. M., White, R., Wierzcholska, A., Willmann, P., Wörnlein, A., Wouters, D., Yang, R., Zabalza, V., Zaborov, D., Zacharias, M., Zanin, R., Zdziarski, A. A., Zech, A., Zefi, F., Ziegler, A., and Żywucka, N.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: PKS 0625-354 (z=0.055) was observed with the four H.E.S.S. telescopes in 2012 during 5.5 hours. The source was detected above an energy threshold of 200 GeV at a significance level of 6.1$\sigma$. No significant variability is found in these observations. The source is well described with a power-law spectrum with photon index $\Gamma =2.84 \pm 0.50_{stat} \pm 0.10_{syst}$ and normalization (at $E_0$=1.0 TeV) $N_0(E_0)=(0.58 \pm 0.22_{stat} \pm 0.12_{syst})\times10^{-12}$ TeV$^{-1}$cm$^{-2}$s$^{-1}$. Multi-wavelength data collected with Fermi-LAT, Swift-XRT, Swift-UVOT, ATOM and WISE are also analysed. Significant variability is observed only in the Fermi-LAT $\gamma$-ray and Swift-XRT X-ray energy bands. Having a good multi-wavelength coverage from radio to very high energy, we performed a broadband modelling from two types of emission scenarios. The results from a one zone lepto-hadronic, and a multi-zone leptonic models are compared and discussed. On the grounds of energetics, our analysis favours a leptonic multi-zone model. Models associated to the X-ray variability constraint supports previous results suggesting a BL Lac nature of PKS 0625-354, with, however, a large-scale jet structure typical of a radio galaxy., Comment: 13 pages, 6 figures, accepted for publication in MNRAS
Published: 2018
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2. A search for new supernova remnant shells in the Galactic plane with H.E.S.S

Author: Collaboration, H. E. S. S., Abdalla, H., Abramowski, A., Aharonian, F., Benkhali, F. Ait, Akhperjanian, A. G., Andersson, T., Angüner, E. O., Arakawa, M., Arrieta, M., Aubert, P., Backes, M., Balzer, A., Barnard, M., Becherini, Y., Tjus, J. Becker, Berge, D., Bernhard, S., Bernlöhr, K., Blackwell, R., Böttcher, M., Boisson, C., Bolmont, J., Bonnefoy, S., Bordas, P., Bregeon, J., Brun, F., Brun, P., Bryan, M., Büchele, M., Bulik, T., Capasso, M., Carr, J., Casanova, S., Cerruti, M., Chakraborty, N., Chaves, R. C. G., Chen, A., Chevalier, J., Coffaro, M., Colafrancesco, S., Cologna, G., Condon, B., Conrad, J., Cui, Y., Davids, I. D., Decock, J., Degrange, B., Deil, C., Devin, J., deWilt, P., Dirson, L., Djannati-Ataï, A., Domainko, W., Donath, A., Drury, L. O'C., Dutson, K., Dyks, J., Edwards, T., Egberts, K., Eger, P., Ernenwein, J. -P., Eschbach, S., Farnier, C., Fegan, S., Fernandes, M. V., Fiasson, A., Fontaine, G., Förster, A., Funk, S., Füßling, M., Gabici, S., Gajdus, M., Gallant, Y. A., Garrigoux, T., Giavitto, G., Giebels, B., Glicenstein, J. F., Gottschall, D., Goyal, A., Grondin, M. -H., Hahn, J., Haupt, M., Hawkes, J., Heinzelmann, G., Henri, G., Hermann, G., Hervet, O., Hinton, J. A., Hofmann, W., Hoischen, C., Holch, T. L., Holler, M., Horns, D., Ivascenko, A., Iwasaki, H., Jacholkowska, A., Jamrozy, M., Janiak, M., Jankowsky, D., Jankowsky, F., Jingo, M., Jogler, T., Jouvin, L., Jung-Richardt, I., Kastendieck, M. A., Katarzyński, K., Katsuragawa, M., Katz, U., Kerszberg, D., Khangulyan, D., Khélifi, B., King, J., Klepser, S., Klochkov, D., Kluźniak, W., Kolitzus, D., Komin, Nu., Kosack, K., Krakau, S., Kraus, M., Krüger, P. P., Laffon, H., Lamanna, G., Lau, J., Lees, J. -P., Lefaucheur, J., Lefranc, V., Lemière, A., Lemoine-Goumard, M., Lenain, J. -P., Leser, E., Lohse, T., Lorentz, M., Liu, R., López-Coto, R., Lypova, I., Marandon, V., Marcowith, A., Mariaud, C., Marx, R., Maurin, G., Maxted, N., Mayer, M., Meintjes, P. J., Meyer, M., Mitchell, A. M. W., Moderski, R., Mohamed, M., Mohrmann, L., Morå, K., Moulin, E., Murach, T., Nakashima, S., de Naurois, M., Niederwanger, F., Niemiec, J., Oakes, L., O'Brien, P., Odaka, H., Öttl, S., Ohm, S., Ostrowski, M., Oya, I., Padovani, M., Panter, M., Parsons, R. D., Pekeur, N. W., Pelletier, G., Perennes, C., Petrucci, P. -O., Peyaud, B., Piel, Q., Pita, S., Poon, H., Prokhorov, D., Prokoph, H., Pühlhofer, G., Punch, M., Quirrenbach, A., Raab, S., Reimer, A., Reimer, O., Renaud, M., Reyes, R. de los, Richter, S., Rieger, F., Romoli, C., Rowell, G., Rudak, B., Rulten, C. B., Sahakian, V., Saito, S., Salek, D., Sanchez, D. A., Santangelo, A., Sasaki, M., Schlickeiser, R., Schüssler, F., Schulz, A., Schwanke, U., Schwemmer, S., Seglar-Arroyo, M., Settimo, M., Seyffert, A. S., Shafi, N., Shilon, I., Simoni, R., Sol, H., Spanier, F., Spengler, G., Spies, F., Stawarz, Ł., Steenkamp, R., Stegmann, C., Stycz, K., Sushch, I., Takahashi, T., Tavernet, J. -P., Tavernier, T., Taylor, A. M., Terrier, R., Tibaldo, L., Tiziani, D., Tluczykont, M., Trichard, C., Tsuji, N., Tuffs, R., Uchiyama, Y., van der Walt, D. J., van Eldik, C., van Rensburg, C., van Soelen, B., Vasileiadis, G., Veh, J., Venter, C., Viana, A., Vincent, P., Vink, J., Voisin, F., Völk, H. J., Vuillaume, T., Wadiasingh, Z., Wagner, S. J., Wagner, P., Wagner, R. M., White, R., Wierzcholska, A., Willmann, P., Wörnlein, A., Wouters, D., Yang, R., Zabalza, V., Zaborov, D., Zacharias, M., Zanin, R., Zdziarski, A. A., Zech, A., Zefi, F., Ziegler, A., Żywucka, N., Bamba, A., Fukui, Y., Sano, H., and Yoshiike, S.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: A search for new supernova remnants (SNRs) has been conducted using TeV gamma-ray data from the H.E.S.S. Galactic plane survey. As an identification criterion, shell morphologies that are characteristic for known resolved TeV SNRs have been used. Three new SNR candidates were identified in the H.E.S.S. data set with this method. Extensive multiwavelength searches for counterparts were conducted. A radio SNR candidate has been identified to be a counterpart to HESS J1534-571. The TeV source is therefore classified as a SNR. For the other two sources, HESS J1614-518 and HESS J1912+101, no identifying counterparts have been found, thus they remain SNR candidates for the time being. TeV-emitting SNRs are key objects in the context of identifying the accelerators of Galactic cosmic rays. The TeV emission of the relativistic particles in the new sources is examined in view of possible leptonic and hadronic emission scenarios, taking the current multiwavelength knowledge into account., Comment: Accepted for publication in A&A, 24 pages, 13 figures. Minor corrections in v2
Published: 2018
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3. Constraints on particle acceleration in SS433/W50 from MAGIC and H.E.S.S. observations

Author: MAGIC Collaboration, Ahnen, M. L., Ansoldi, S., Antonelli, L. A., Arcaro, C., Babić, A., Banerjee, B., Bangale, P., de Almeida, U. Barres, Barrio, J. A., González, J. Becerra, Bednarek, W., Bernardini, E., Berti, A., Biasuzzi, B., Biland, A., Blanch, O., Bonnefoy, S., Bonnoli, G., Borracci, F., Carosi, R., Carosi, A., Chatterjee, A., Colin, P., Colombo, E., Contreras, J. L., Cortina, J., Covino, S., Cumani, P., Da Vela, P., Dazzi, F., De Angelis, A., De Lotto, B., Wilhelmi, E. de Oña, Di Pierro, F., Doert, M., Domínguez, A., Prester, D. Dominis, Dorner, D., Doro, M., Einecke, S., Glawion, D. Eisenacher, Elsaesser, D., Engelkemeier, M., Ramazani, V. Fallah, Fernández-Barral, A., Fidalgo, D., Fonseca, M. V., Font, L., Fruck, C., Galindo, D., López, R. J. García, Garczarczyk, M., Gaug, M., Giammaria, P., Godinović, N., Gora, D., Griffiths, S., Guberman, D., Hadasch, D., Hahn, A., Hassan, T., Hayashida, M., Herrera, J., Hose, J., Hrupec, D., Hughes, G., Ishio, K., Konno, Y., Kubo, H., Kushida, J., dić, D. Kuvež, Lelas, D., Lindfors, E., Lombardi, S., Longo, F., López, M., López-Oramas, A., Majumdar, P., Makariev, M., Maneva, G., Manganaro, M., Mannheim, K., Maraschi, L., Mariotti, M., Martínez, M., Mazin, D., Menzel, U., Minev, M., Mirzoyan, R., Moralejo, A., Moreno, V., Moretti, E., Munar-Adrover, P., Neustroev, V., Niedzwiecki, A., Rosillo, M. Nievas, Nilsson, K., Nishijima, K., Noda, K., Nogués, L., Paiano, S., Palacio, J., Paneque, D., Paoletti, R., Paredes, J. M., Paredes-Fortuny, X., Pedaletti, G., Peresano, M., Perri, L., Persic, M., Moroni, P. G. Prada, Prandini, E., Puljak, I., Garcia, J. R., Reichardt, I., Rhode, W., Ribó, M., Rico, J., Saito, T., Satalecka, K., Schroeder, S., Schweizer, T., Shore, S. N., Sillanpää, A., Sitarek, J., Šnidarić, I., Sobczynska, D., Stamerra, A., Strzys, M., Surić, T., Takalo, L., Tavecchio, F., Temnikov, P., Terzić, T., Tescaro, D., Teshima, M., Torres, D. F., Torres-Albá, N., Treves, A., Vanzo, G., Acosta, M. Vazquez, Vovk, I., Ward, J. E., Will, M., Wu, M. H., Zarić, D., Collaboration, H. E. S. S., Abdalla, H., Abramowski, A., Aharonian, F., Benkhali, F. Ait, Akhperjanian, A. G., Andersson, T., Angüner, E. O., Arakawa, M., Arrieta, M., Aubert, P., Backes, M., Balzer, A., Barnard, M., Becherini, Y., Tjus, J. Becker, Berge, D., Bernhard, S., Bernlöhr, K., Blackwell, R., Böttcher, M., Boisson, C., Bolmont, J., Bordas, P., Bregeon, J., Brun, F., Brun, P., Bryan, M., Büchele, M., Bulik, T., Capasso, M., Carr, J., Casanova, S., Cerruti, M., Chakraborty, N., Chalme-Calvet, R., Chaves, R. C. G., Chen, A., Chevalier, J., Chrétien, M., Coffaro, M., Colafrancesco, S., Cologna, G., Condon, B., Conrad, J., Cui, Y., Davids, I. D., Decock, J., Degrange, B., Deil, C., Devin, J., deWilt, P., Dirson, L., Djannati-Ataï, A., Domainko, W., Donath, A., Drury, L. O'C., Dutson, K., Dyks, J., Edwards, T., Egberts, K., Eger, P., Ernenwein, J. P., Eschbach, S., Farnier, C., Fegan, S., Fernandes, M. V., Fiasson, A., Fontaine, G., Förster, A., Funk, S., ling, M. Füß, Gabici, S., Gajdus, M., Gallant, Y. A., Garrigoux, T., Giavitto, G., Giebels, B., Glicenstein, J. F., Gottschall, D., Goyal, A., Grondin, M. H., Hahn, J., Haupt, M., Hawkes, J., Heinzelmann, G., Henri, G., Hermann, G., Hervet, O., Hinton, J. A., Hofmann, W., Hoischen, C., Holler, M., Horns, D., Ivascenko, A., Iwasaki, H., Jacholkowska, A., Jamrozy, M., Janiak, M., Jankowsky, D., Jankowsky, F., Jingo, M., Jogler, T., Jouvin, L., Jung-Richardt, I., Kastendieck, M. A., Katarzyński, K., Katsuragawa, M., Katz, U., Kerszberg, D., Khangulyan, D., Khélifi, B., Kieffer, M., King, J., Klepser, S., Klochkov, D., Kluźniak, W., Kolitzus, D., Komin, Nu., Kosack, K., Krakau, S., Kraus, M., Krüger, P. P., Laffon, H., Lamanna, G., Lau, J., Lees, J. P., Lefaucheur, J., Lefranc, V., Lemiére, A., Lemoine-Goumard, M., Lenain, J. P., Leser, E., Lohse, T., Lorentz, M., Liu, R., López-Coto, R., Lypova, I., Marandon, V., Marcowith, A., Mariaud, C., Marx, R., Maurin, G., Maxted, N., Mayer, M., Meintjes, P. J., Meyer, M., Mitchell, A. M. W., Moderski, R., Mohamed, M., Mohrmann, L., Morå, K., Moulin, E., Murach, T., Nakashima, S., de Naurois, M., Niederwanger, F., Niemiec, J., Oakes, L., O'Brien, P., Odaka, H., Öttl, S., Ohm, S., Ostrowski, M., Oya, I., Padovani, M., Panter, M., Parsons, R. D., Pekeur, N. W., Pelletier, G., Perennes, C., Petrucci, P. O., Peyaud, B., Piel, Q., Pita, S., Poon, H., Prokhorov, D., Prokoph, H., Pühlhofer, G., Punch, M., Quirrenbach, A., Raab, S., Reimer, A., Reimer, O., Renaud, M., Reyes, R. de los, Richter, S., Rieger, F., Romoli, C., Rowell, G., Rudak, B., Rulten, C. B., Safi-Harb, S., Sahakian, V., Saito, S., Salek, D., Sanchez, D. A., Santangelo, A., Sasaki, M., Schlickeiser, R., Schüssler, F., Schulz, A., Schwanke, U., Schwemmer, S., Seglar-Arroyo, M., Settimo, M., Seyffert, A. S., Shafi, N., Shilon, I., Simoni, R., Sol, H., Spanier, F., Spengler, G., Spies, F., Stawarz, L., Steenkamp, R., Stegmann, C., Stycz, K., Sushch, I., Takahashi, T., Tavernet, J. P., Tavernier, T., Taylor, A. M., Terrier, R., Tibaldo, L., Tiziani, D., Tluczykont, M., Trichard, C., Tsuji, N., Tuffs, R., Uchiyama, Y., van der Walt, D. J., van Eldik, C., van Rensburg, C., van Soelen, B., Vasileiadis, G., Veh, J., Venter, C., Viana, A., Vincent, P., Vink, J., Voisin, F., Völk, H. J., Vuillaume, T., Wadiasingh, Z., Wagner, S. J., Wagner, P., Wagner, R. M., White, R., Wierzcholska, A., Willmann, P., Wörnlein, A., Wouters, D., Yang, R., Zabalza, V., Zaborov, D., Zacharias, M., Zanin, R., Zdziarski, A. A., Zech, A., Zefi, F., Ziegler, A., and Żywucka, N.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: The large jet kinetic power and non-thermal processes occurring in the microquasar SS 433 make this source a good candidate for a very high-energy (VHE) gamma-ray emitter. Gamma-ray fluxes have been predicted for both the central binary and the interaction regions between jets and surrounding nebula. Also, non-thermal emission at lower energies has been previously reported. We explore the capability of SS 433 to emit VHE gamma rays during periods in which the expected flux attenuation due to periodic eclipses and precession of the circumstellar disk periodically covering the central binary system is expected to be at its minimum. The eastern and western SS433/W50 interaction regions are also examined. We aim to constrain some theoretical models previously developed for this system. We made use of dedicated observations from MAGIC and H.E.S.S. from 2006 to 2011 which were combined for the first time and accounted for a total effective observation time of 16.5 h. Gamma-ray attenuation does not affect the jet/medium interaction regions. The analysis of a larger data set amounting to 40-80 h, depending on the region, was employed. No evidence of VHE gamma-ray emission was found. Upper limits were computed for the combined data set. We place constraints on the particle acceleration fraction at the inner jet regions and on the physics of the jet/medium interactions. Our findings suggest that the fraction of the jet kinetic power transferred to relativistic protons must be relatively small to explain the lack of TeV and neutrino emission from the central system. At the SS433/W50 interface, the presence of magnetic fields greater 10$\mu$G is derived assuming a synchrotron origin for the observed X-ray emission. This also implies the presence of high-energy electrons with energies up to 50 TeV, preventing an efficient production of gamma-ray fluxes in these interaction regions., Comment: Accepted for publication in A&A, 9 pages, 2 figures
Published: 2017
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4. Systematic search for very-high-energy gamma-ray emission from bow shocks of runaway stars

Author: Collaboration, H. E. S. S., Abdalla, H., Abramowski, A., Aharonian, F., Benkhali, F. Ait, Akhperjanian, A. G., Andersson, T., Angüner, E. O., Arakawa, M., Arrieta, M., Aubert, P., Backes, M., Balzer, A., Barnard, M., Becherini, Y., Tjus, J. Becker, Berge, D., Bernhard, S., Bernlöhr, K., Blackwell, R., Böttcher, M., Boisson, C., Bolmont, J., Bordas, P., Bregeon, J., Brun, F., Brun, P., Bryan, M., Büchele, M., Bulik, T., Capasso, M., Carr, J., Casanova, S., Cerruti, M., Chakraborty, N., Chalme-Calvet, R., Chaves, R. C. G., Chen, A., Chevalier, J., Chrétien, M., Coffaro, M., Colafrancesco, S., Cologna, G., Condon, B., Conrad, J., Cui, Y., Davids, I. D., Decock, J., Degrange, B., Deil, C., Devin, J., deWilt, P., Dirson, L., Djannati-Ataï, A., Domainko, W., Donath, A., Drury, L. O'C., Dutson, K., Dyks, J., Edwards, T., Egberts, K., Eger, P., Ernenwein, J. -P., Eschbach, S., Farnier, C., Fegan, S., Fernes, M. V., Fiasson, A., Fontaine, G., örster, A. F, Funk, S., Füßling, M., Gabici, S., Gajdus, M., Gallant, Y. A., Garrigoux, T., Giavitto, G., Giebels, B., Glicenstein, J. F., Gottschall, D., Goyal, A., Grondin, M. -H., Hahn, J., Haupt, M., Hawkes, J., Heinzelmann, G., Henri, G., Hermann, G., Hervet, O., Hinton, J. A., Hofmann, W., Hoischen, C., Holler, M., Horns, D., Ivascenko, A., Iwasaki, H., Jacholkowska, A., Jamrozy, M., Janiak, M., Jankowsky, D., Jankowsky, F., Jingo, M., Jogler, T., Jouvin, L., Jung-Richardt, I., Kastendieck, M. A., Katarzyński, K., Katsuragawa, M., Katz, U., Kerszberg, D., Khangulyan, D., Khélifi, B., Kieffer, M., King, J., Klepser, S., Klochkov, D., Kluźniak, W., Kolitzus, D., Komin, Nu., Kosack, K., Krakau, S., Kraus, M., Krüger, P. P., Laffon, H., Lamanna, G., Lau, J., Lees, J. -P., Lefaucheur, J., Lefranc, V., Lemière, A., Lemoine-Goumard, M., Lenain, J. -P., Leser, E., Lohse, T., Lorentz, M., Liu, R., López-Coto, R., Lypova, I., Maron, V., Marcowith, A., Mariaud, C., Marx, R., Maurin, G., Maxted, N., Mayer, M., Meintjes, P. J., Meyer, M., Mitchell, A. M. W., Moderski, R., Mohamed, M., Mohrmann, L., Morå, K., Moulin, E., Murach, T., Nakashima, S., de Naurois, M., Niederwanger, F., Niemiec, J., Oakes, L., O'Brien, P., Odaka, H., Öttl, S., Ohm, S., Ostrowski, M., Oya, I., Padovani, M., Panter, M., Parsons, R. D., Pekeur, N. W., Pelletier, G., Perennes, C., Petrucci, P. -O., Peyaud, B., Piel, Q., Pita, S., Poon, H., Prokhorov, D., Prokoph, H., Pühlhofer, G., Punch, M., Quirrenbach, A., Raab, S., Reimer, A., Reimer, O., Renaud, M., Reyes, R. de los, Richter, S., Rieger, F., Romoli, C., Rowell, G., Rudak, B., Rulten, C. B., Sahakian, V., Saito, S., Salek, D., Sanchez, D. A., Santangelo, A., Sasaki, M., Schlickeiser, R., Schüssler, F., Schulz, A., Schwanke, U., Schwemmer, S., Seglar-Arroyo, M., Settimo, M., Seyffert, A. S., Shafi, N., Shilon, I., Simoni, R., Sol, H., Spanier, F., Spengler, G., Spies, F., Stawarz, Ł., Steenkamp, R., Stegmann, C., Stycz, K., Sushch, I., Takahashi, T., Tavernet, J. -P., Tavernier, T., Taylor, A. M., Terrier, R., Tibaldo, L., Tiziani, D., Tluczykont, M., Trichard, C., Tsuji, N., Tuffs, R., Uchiyama, Y., van der Walt, D. J., van Eldik, C., van Rensburg, C., van Soelen, B., Vasileiadis, G., Veh, J., Venter, C., Viana, A., Vincent, P., Vink, J., Voisin, F., Völk, H. J., Vuillaume, T., Wadiasingh, Z., Wagner, S. J., Wagner, P., Wagner, R. M., White, R., Wierzcholska, A., Willmann, P., Wörnlein, A., Wouters, D., Yang, R., Zabalza, V., Zaborov, D., Zacharias, M., Zanin, R., Zdziarski, A. A., Zech, A., Zefi, F., Ziegler, A., and Żywucka, N.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: Runaway stars form bow shocks by ploughing through the interstellar medium at supersonic speeds and are promising sources of non-thermal emission of photons. One of these objects has been found to emit non-thermal radiation in the radio band. This triggered the development of theoretical models predicting non-thermal photons from radio up to very-high-energy (VHE, E $\geq 0.1$TeV) gamma rays. Subsequently, one bow shock was also detected in X-ray observations. However, the data did not allow discrimination between a hot thermal and a non-thermal origin. Further observations of different candidates at X-ray energies showed no evidence for emission at the position of the bow shocks either. A systematic search in the \textit{Fermi}-LAT energy regime resulted in flux upper limits for 27 candidates listed in the E-BOSS catalogue. Here we perform the first systematic search for VHE gamma-ray emission from bow shocks of runaway stars. Using all available archival H.E.S.S. data we search for very-high-energy gamma-ray emission at the positions of bow shock candidates listed in the second E-BOSS catalogue release. Out of the 73 bow shock candidates in this catalogue, 32 have been observed with H.E.S.S. None of the observed 32 bow shock candidates in this population study show significant emission in the H.E.S.S. energy range. Therefore, flux upper limits are calculated in five energy bins and the fraction of the kinetic wind power that is converted into VHE gamma rays is constrained. Emission from stellar bow shocks is not detected in the energy range between 0.14 and 18 TeV. The resulting upper limits constrain the level of VHE gamma-ray emission from these objects down to 0.1-1 % of the kinetic wind energy., Comment: 7 pages, 2 figures, 1 table. Accepted for publication in A&A
Published: 2017
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5. The population of TeV pulsar wind nebulae in the H.E.S.S. Galactic Plane Survey

Author: Collaboration, H. E. S. S., Abdalla, H., Abramowski, A., Aharonian, F., Benkhali, F. Ait, Akhperjanian, A. G., Andersson, T., Angüner, E. O., Arrieta, M., Aubert, P., Backes, M., Balzer, A., Barnard, M., Becherini, Y., Tjus, J. Becker, Berge, D., Bernhard, S., Bernlöhr, K., Blackwell, R., Böttcher, M., Boisson, C., Bolmont, J., Bordas, P., Bregeon, J., Brun, F., Brun, P., Bryan, M., Bulik, T., Capasso, M., Carr, J., Carrigan, S., Casanova, S., Cerruti, M., Chakraborty, N., Chalme-Calvet, R., Chaves, R. C. G., Chen, A., Chevalier, J., Chrétien, M., Colafrancesco, S., Cologna, G., Condon, B., Conrad, J., Couturier, C., Cui, Y., Davids, I. D., Degrange, B., Deil, C., Devin, J., deWilt, P., Dirson, L., Djannati-Ataï, A., Domainko, W., Donath, A., Drury, L. O'C., Dubus, G., Dutson, K., Dyks, J., Edwards, T., Egberts, K., Eger, P., Ernenwein, J. -P., Eschbach, S., Farnier, C., Fegan, S., Fernandes, M. V., Fiasson, A., Fontaine, G., Förster, A., Funk, S., Füßling, M., Gabici, S., Gajdus, M., Gallant, Y. A., Garrigoux, T., Giavitto, G., Giebels, B., Glicenstein, J. F., Gottschall, D., Goyal, A., Grondin, M. -H., Hadasch, D., Hahn, J., Haupt, M., Hawkes, J., Heinzelmann, G., Henri, G., Hermann, G., Hervet, O., Hillert, A., Hinton, J. A., Hofmann, W., Hoischen, C., Holler, M., Horns, D., Ivascenko, A., Jacholkowska, A., Jamrozy, M., Janiak, M., Jankowsky, D., Jankowsky, F., Jingo, M., Jogler, T., Jouvin, L., Jung-Richardt, I., Kastendieck, M. A., Katarzyński, K., Katz, U., Kerszberg, D., Khélifi, B., Kieffer, M., King, J., Klepser, S., Klochkov, D., Kluźniak, W., Kolitzus, D., Komin, Nu., Kosack, K., Krakau, S., Kraus, M., Krayzel, F., Krüger, P. P., Laffon, H., Lamanna, G., Lau, J., Lees, J. -P., Lefaucheur, J., Lefranc, V., Lemière, A., Lemoine-Goumard, M., Lenain, J. -P., Leser, E., Lohse, T., Lorentz, M., Liu, R., López-Coto, R., Lypova, I., Marandon, V., Marcowith, A., Mariaud, C., Marx, R., Maurin, G., Maxted, N., Mayer, M., Meintjes, P. J., Meyer, M., Mitchell, A. M. W., Moderski, R., Mohamed, M., Mohrmann, L., Morå, K., Moulin, E., Murach, T., de Naurois, M., Niederwanger, F., Niemiec, J., Oakes, L., O'Brien, P., Odaka, H., Öttl, S., Ohm, S., Wilhelmi, E. de Oña, Ostrowski, M., Oya, I., Padovani, M., Panter, M., Parsons, R. D., Arribas, M. Paz, Pekeur, N. W., Pelletier, G., Perennes, C., Petrucci, P. -O., Peyaud, B., Pita, S., Poon, H., Prokhorov, D., Prokoph, H., Pühlhofer, G., Punch, M., Quirrenbach, A., Raab, S., Reimer, A., Reimer, O., Renaud, M., Reyes, R. de los, Rieger, F., Romoli, C., Rosier-Lees, S., Rowell, G., Rudak, B., Rulten, C. B., Sahakian, V., Salek, D., Sanchez, D. A., Santangelo, A., Sasaki, M., Schlickeiser, R., Schüssler, F., Schulz, A., Schwanke, U., Schwemmer, S., Settimo, M., Seyffert, A. S., Shafi, N., Shilon, I., Simoni, R., Sol, H., Spanier, F., Spengler, G., Spies, F., Stawarz, Ł., Steenkamp, R., Stegmann, C., Stinzing, F., Stycz, K., Sushch, I., Tavernet, J. -P., Tavernier, T., Taylor, A. M., Terrier, R., Tibaldo, L., Tiziani, D., Tluczykont, M., Trichard, C., Tuffs, R., Uchiyama, Y., Valerius, K., van der Walt, D. J., van Eldik, C., van Soelen, B., Vasileiadis, G., Veh, J., Venter, C., Viana, A., Vincent, P., Vink, J., Voisin, F., Völk, H. J., Vuillaume, T., Wadiasingh, Z., Wagner, S. J., Wagner, P., Wagner, R. M., White, R., Wierzcholska, A., Willmann, P., Wörnlein, A., Wouters, D., Yang, R., Zabalza, V., Zaborov, D., Zacharias, M., Zdziarski, A. A., Zech, A., Zefi, F., Ziegler, A., and Żywucka, N.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: The nine-year H.E.S.S. Galactic Plane Survey (HGPS) yielded the most uniform observation scan of the inner Milky Way in the TeV gamma-ray band to date. The sky maps and source catalogue of the HGPS allow for a systematic study of the population of TeV pulsar wind nebulae found throughout the last decade. To investigate the nature and evolution of pulsar wind nebulae, for the first time we also present several upper limits for regions around pulsars without a detected TeV wind nebula. Our data exhibit a correlation of TeV surface brightness with pulsar spin-down power $\dot{E}$. This seems to be caused both by an increase of extension with decreasing $\dot{E}$, and hence with time, compatible with a power law $R_\mathrm{PWN}(\dot{E}) \sim \dot{E}^{-0.65 \pm 0.20}$, and by a mild decrease of TeV gamma-ray luminosity with decreasing $\dot{E}$, compatible with $L_{1-10\,\mathrm{TeV}} \sim \dot{E}^{0.59 \pm 0.21}$. We also find that the offsets of pulsars with respect to the wind nebula centres with ages around 10 kyr are frequently larger than can be plausibly explained by pulsar proper motion and could be due to an asymmetric environment. In the present data, it seems that a large pulsar offset is correlated with a high apparent TeV efficiency $L_{1-10\,\mathrm{TeV}}/\dot{E}$. In addition to 14 HGPS sources considered as firmly identified pulsar wind nebulae and 5 additional pulsar wind nebulae taken from literature, we find 10 HGPS sources that form likely TeV pulsar wind nebula candidates. Using a model that subsumes the present common understanding of the very high-energy radiative evolution of pulsar wind nebulae, we find that the trends and variations of the TeV observables and limits can be reproduced to a good level, drawing a consistent picture of present-day TeV data and theory., Comment: 28 pages, 12 figures, 8 tables. Accepted for publication in A&A
Published: 2017
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6. Gamma-ray blazar spectra with H.E.S.S. II mono analysis: the case of PKS 2155-304 and PG 1553+113

Author: Collaboration, H. E. S. S., Abdalla, H., Abramowski, A., Aharonian, F., Benkhali, F. Ait, Akhperjanian, A. G., Andersson, T., Angüner, E. O., Arrieta, M., Aubert, P., Backes, M., Balzer, A., Barnard, M., Becherini, Y., Tjus, J. Becker, Berge, D., Bernhard, S., Bernlöhr, K., Blackwell, R., Böttcher, M., Boisson, C., Bolmont, J., Bordas, P., Brun, F., Brun, P., Bryan, M., Bulik, T., Capasso, M., Carr, J., Casanova, S., Cerruti, M., Chakraborty, N., Chalme-Calvet, R., Chaves, R. C. G., Chen, A., Chevalier, J., Chrétien, M., Colafrancesco, S., Cologna, G., Condon, B., Conrad, J., Couturier, C., Cui, Y., Davids, I. D., Degrange, B., Deil, C., Devin, J., deWilt, P., Dirson, L., Djannati-Ataï, A., Domainko, W., Donath, A., Drury, L. O'C., Dubus, G., Dutson, K., Dyks, J., Edwards, T., Egberts, K., Eger, P., Ernenwein, J. -P., Eschbach, S., Farnier, C., Fegan, S., Fern, M. V., Fiasson, A., Fontaine, G., Förster, A., Funk, S., Füßling, M., Gabici, S., Gajdus, M., Gallant, Y. A., Garrigoux, T., Giavitto, G., Giebels, B., Glicenstein, J. F., Gottschall, D., Goyal, A., Grondin, M. -H., Hadasch, D., Hahn, J., Haupt, M., Hawkes, J., Heinzelmann, G., Henri, G., Hermann, G., Hervet, O., Hillert, A., Hinton, J. A., Hofmann, W., Hoischen, C., Holler, M., Horns, D., Ivascenko, A., Jacholkowska, A., Jamrozy, M., Janiak, M., Jankowsky, D., Jankowsky, F., Jingo, M., Jogler, T., Jouvin, L., Jung-Richardt, I., Kastendieck, M. A., Katarzyński, K., Katz, U., Kerszberg, D., Khélifi, B., Kieffer, M., King, J., Klepser, S., Klochkov, D., Kluźniak, W., Kolitzus, D., Komin, Nu., Kosack, K., Krakau, S., Kraus, M., Krayzel, F., Krüger, P. P., Laffon, H., Lamanna, G., Lau, J., Lees, J. -P., Lefaucheur, J., Lefranc, V., Lemière, A., Lemoine-Goumard, M., Lenain, J. -P., Leser, E., Lohse, T., Lorentz, M., Liu, R., López-Coto, R., Lypova, I., Mar, V., Marcowith, A., Mariaud, C., Marx, R., Maurin, G., Maxted, N., Mayer, M., Meintjes, P. J., Meyer, M., Mitchell, A. M. W., Moderski, R., Mohamed, M., Mohrmann, L., Morå, K., Moulin, E., Murach, T., de Naurois, M., Niederwanger, F., Niemiec, J., Oakes, L., O'Brien, P., Odaka, H., Öttl, S., Ohm, S., Ostrowski, M., Oya, I., Padovani, M., Panter, M., Parsons, R. D., Arribas, M. Paz, Pekeur, N. W., Pelletier, G., Perennes, C., Petrucci, P. -O., Peyaud, B., Pita, S., Poon, H., Prokhorov, D., Prokoph, H., Pühlhofer, G., Punch, M., Quirrenbach, A., Raab, S., Reimer, A., Reimer, O., Renaud, M., Reyes, R. de los, Rieger, F., Romoli, C., Rosier-Lees, S., Rowell, G., Rudak, B., Rulten, C. B., Sahakian, V., Salek, D., Sanchez, D. A., Santangelo, A., Sasaki, M., Schlickeiser, R., Schüssler, F., Schulz, A., Schwanke, U., Schwemmer, S., Settimo, M., Seyffert, A. S., Shafi, N., Shilon, I., Simoni, R., Sol, H., Spanier, F., Spengler, G., Spies, F., Stawarz, Ł., Steenkamp, R., Stegmann, C., Stinzing, F., Stycz, K., Sushch, I., Tavernet, J. -P., Tavernier, T., Taylor, A. M., Terrier, R., Tibaldo, L., Tiziani, D., Tluczykont, M., Trichard, C., Tuffs, R., Uchiyama, Y., van der Walt, D. J., van Eldik, C., van Soelen, B., Vasileiadis, G., Veh, J., Venter, C., Viana, A., Vincent, P., Vink, J., Voisin, F., Völk, H. J., Vuillaume, T., Wadiasingh, Z., Wagner, S. J., Wagner, P., Wagner, R. M., White, R., Wierzcholska, A., Willmann, P., Wörnlein, A., Wouters, D., Yang, R., Zabalza, V., Zaborov, D., Zacharias, M., Zdziarski, A. A., Zech, A., Zefi, F., Ziegler, A., Żywucka, N., Collaboration, LAT, Ackermann, M., Ajello, M., Baldini, L., Barbiellini, G., Bellazzini, R., Bl, R. D., Bonino, R., Bregeon, J., Bruel, P., Buehler, R., Cali, G. A., Cameron, R. A., Caragiulo, M., Caraveo, P. A., Cavazzuti, E., Cecchi, C., Chiang, J., Chiaro, G., Ciprini, S., Cohen-Tanugi, J., Costanza, F., Cutini, S., D'Amm, F., de Palma, F., Desiante, R., Di Lalla, N., Di Mauro, M., Di Venere, L., Donaggio, B., Favuzzi, C., Focke, W. B., Fusco, P., Gargano, F., Gasparrini, D., Giglietto, N., Giordano, F., Giroletti, M., Guillemot, L., Guiriec, S., Horan, D., Jóhannesson, G., Kamae, T., Kensei, S., Kocevski, D., Larsson, S., Li, J., Longo, F., Loparco, F., Lovellette, M. N., Lubrano, P., Maldera, S., Manfreda, A., Mazziotta, M. N., Michelson, P. F., Mizuno, T., Monzani, M. E., Morselli, A., Negro, M., Nuss, E., Orienti, M., Orl, E., Paneque, D., Perkins, J. S., Pesce-Rollins, M., Piron, F., Pivato, G., Porter, T. A., Principe, G., Rainò, S., Razzano, M., Simone, D., Siskind, E. J., Spada, F., Spinelli, P., Thayer, J. B., Torres, D. F., Torresi, E., Troja, E., Vianello, G., and Wood, K. S.
Subjects: Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Instrumentation and Methods for Astrophysics
Abstract: The addition of a 28 m Cherenkov telescope (CT5) to the H.E.S.S. array extended the experiment's sensitivity to lower energies. The lowest energy threshold is obtained using monoscopic analysis of data taken with CT5, providing access to gamma-ray energies below 100 GeV. Such an extension of the instrument's energy range is particularly beneficial for studies of Active Galactic Nuclei with soft spectra, as expected for those at a redshift > 0.5. The high-frequency peaked BL Lac objects PKS 2155-304 (z = 0.116) and PG 1553+113 (0.43 < z < 0.58) are among the brightest objects in the gamma-ray sky, both showing clear signatures of gamma-ray absorption at E > 100 GeV interpreted as being due to interactions with the extragalactic background light (EBL). Multiple observational campaigns of PKS 2155-304 and PG 1553+113 were conducted during 2013 and 2014 using the full H.E.S.S. II instrument. A monoscopic analysis of the data taken with the new CT5 telescope was developed along with an investigation into the systematic uncertainties on the spectral parameters. The energy spectra of PKS 2155-304 and PG 1553+113 were reconstructed down to energies of 80 GeV for PKS 2155-304, which transits near zenith, and 110 GeV for the more northern PG 1553+113. The measured spectra, well fitted in both cases by a log-parabola spectral model (with a 5.0 sigma statistical preference for non-zero curvature for PKS 2155-304 and 4.5 sigma for PG 1553+113), were found consistent with spectra derived from contemporaneous Fermi-LAT data, indicating a sharp break in the observed spectra of both sources at E ~ 100 GeV. When corrected for EBL absorption, the intrinsic H.E.S.S. II mono and Fermi-LAT spectrum of PKS 2155-304 was found to show significant curvature. For PG 1553+113, however, no significant detection of curvature in the intrinsic spectrum could be found within statistical and systematic uncertainties., Comment: 13 pages, 9 figures, accepted for publication in A&A
Published: 2016
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7. First limits on the very-high energy gamma-ray afterglow emission of a fast radio burst: H.E.S.S. observations of FRB 150418

Author: Collaboration, H. E. S. S., Abdalla, H., Abramowski, A., Aharonian, F., Benkhali, F. Ait, Akhperjanian, A. G., Andersson, T., Angüner, E. O., Arakawa, M., Arrieta, M., Aubert, P., Backes, M., Balzer, A., Barnard, M., Becherini, Y., Tjus, J. Becker, Berge, D., Bernhard, S., Bernlöhr, K., Blackwell, R., Böttcher, M., Boisson, C., Bolmont, J., Bordas, P., Bregeon, J., Brun, F., Brun, P., Bryan, M., Büchele, M., Bulik, T., Capasso, M., Carr, J., Casanova, S., Cerruti, M., Chakraborty, N., Chalme-Calvet, R., Chaves, R. C. G., Chen, A., Chevalier, J., Chrétien, M., Coffaro, M., Colafrancesco, S., Cologna, G., Condon, B., Conrad, J., Cui, Y., Davids, I. D., Decock, J., Degrange, B., Deil, C., Devin, J., deWilt, P., Dirson, L., Djannati-Ataï, A., Domainko, W., Donath, A., Drury, L. O'C., Dutson, K., Dyks, J., Edwards, T., Egberts, K., Eger, P., Ernenwein, J. -P., Eschbach, S., Farnier, C., Fegan, S., Fern, M. V., Fiasson, A., Fontaine, G., Förster, A., Funk, S., Füßling, M., Gabici, S., Gajdus, M., Gallant, Y. A., Garrigoux, T., Giavitto, G., Giebels, B., Glicenstein, J. F., Gottschall, D., Goyal, A., Grondin, M. -H., Hahn, J., Haupt, M., Hawkes, J., Heinzelmann, G., Henri, G., Hermann, G., Hervet, O., Hinton, J. A., Hofmann, W., Hoischen, C., Holler, M., Horns, D., Ivascenko, A., Iwasaki, H., Jacholkowska, A., Jamrozy, M., Janiak, M., Jankowsky, D., Jankowsky, F., Jingo, M., Jogler, T., Jouvin, L., Jung-Richardt, I., Kastendieck, M. A., Katarzyński, K., Katsuragawa, M., Katz, U., Kerszberg, D., Khangulyan, D., Khélifi, B., Kieffer, M., King, J., Klepser, S., Klochkov, D., Kluźniak, W., Kolitzus, D., Komin, Nu., Kosack, K., Krakau, S., Kraus, M., Krüger, P. P., Laffon, H., Lamanna, G., Lau, J., Lees, J. -P., Lefaucheur, J., Lefranc, V., Lemière, A., Lemoine-Goumard, M., Lenain, J. -P., Leser, E., Lohse, T., Lorentz, M., Liu, R., López-Coto, R., Lypova, I., Mar, V., Marcowith, A., Mariaud, C., Marx, R., Maurin, G., Maxted, N., Mayer, M., Meintjes, P. J., Meyer, M., Mitchell, A. M. W., Moderski, R., Mohamed, M., Mohrmann, L., Morå, K., Moulin, E., Murach, T., Nakashima, S., de Naurois, M., Niederwanger, F., Niemiec, J., Oakes, L., O'Brien, P., Odaka, H., Öttl, S., Ohm, S., Ostrowski, M., Oya, I., Padovani, M., Panter, M., Parsons, R. D., Arribas, M. Paz, Pekeur, N. W., Pelletier, G., Perennes, C., Petrucci, P. -O., Peyaud, B., Piel, Q., Pita, S., Poon, H., Prokhorov, D., Prokoph, H., Pühlhofer, G., Punch, M., Quirrenbach, A., Raab, S., Reimer, A., Reimer, O., Renaud, M., Reyes, R. de los, Richter, S., Rieger, F., Romoli, C., Rowell, G., Rudak, B., Rulten, C. B., Sahakian, V., Saito, S., Salek, D., Sanchez, D. A., Santangelo, A., Sasaki, M., Schlickeiser, R., Schüssler, F., Schulz, A., Schwanke, U., Schwemmer, S., Seglar-Arroyo, M., Settimo, M., Seyffert, A. S., Shafi, N., Shilon, I., Simoni, R., Sol, H., Spanier, F., Spengler, G., Spies, F., Stawarz, Ł., Steenkamp, R., Stegmann, C., Stycz, K., Sushch, I., Takahashi, T., Tavernet, J. -P., Tavernier, T., Taylor, A. M., Terrier, R., Tibaldo, L., Tiziani, D., Tluczykont, M., Trichard, C., Tsuji, N., Tuffs, R., Uchiyama, Y., van der Walt, D. J., van Eldik, C., van Rensburg, C., van Soelen, B., Vasileiadis, G., Veh, J., Venter, C., Viana, A., Vincent, P., Vink, J., Voisin, F., Völk, H. J., Vuillaume, T., Wadiasingh, Z., Wagner, S. J., Wagner, P., Wagner, R. M., White, R., Wierzcholska, A., Willmann, P., Wörnlein, A., Wouters, D., Yang, R., Zabalza, V., Zaborov, D., Zacharias, M., Zanin, R., Zdziarski, A. A., Zech, A., Zefi, F., Ziegler, A., Żywucka, N., Collaboration, SUPERB, Jankowski, F., Keane, E. F., and Petroff, E.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: Aims: Following the detection of the fast radio burst FRB150418 by the SUPERB project at the Parkes radio telescope, we aim to search for very-high energy gamma-ray afterglow emission. Methods: Follow-up observations in the very-high energy gamma-ray domain were obtained with the H.E.S.S. imaging atmospheric Cherenkov telescope system within 14.5 hours of the radio burst. Results: The obtained 1.4 hours of gamma-ray observations are presented and discussed. At the 99 % C.L. we obtained an integral upper limit on the gamma-ray flux of (E>350 GeV) < 1.33 x 10^-8 m^-2s^-1. Differential flux upper limits as function of the photon energy were derived and used to constrain the intrinsic high-energy afterglow emission of FRB 150418. Conclusions: No hints for high-energy afterglow emission of FRB 150418 were found. Taking absorption on the extragalactic background light into account and assuming a distance of z = 0.492 based on radio and optical counterpart studies and consistent with the FRB dispersion, we constrain the gamma-ray luminosity at 1 TeV to L < 5.1 x 10^47 erg/s at 99% C.L., Comment: accepted for publication in A&A
Published: 2016
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8. Deeper H.E.S.S. observations of Vela Junior (RX J0852.0$-$4622): Morphology studies and resolved spectroscopy

Author: Collaboration, H. E. S. S., Abdalla, H., Abramowski, A., Aharonian, F., Benkhali, F. Ait, Akhperjanian, A. G., Andersson, T., Angüner, E. O., Arakawa, M., Arrieta, M., Aubert, P., Backes, M., Balzer, A., Barnard, M., Becherini, Y., Tjus, J. Becker, Berge, D., Bernhard, S., Bernlöhr, K., Blackwell, R., Böttcher, M., Boisson, C., Bolmont, J., Bordas, P., Bregeon, J., Brun, F., Brun, P., Bryan, M., Büchele, M., Bulik, T., Capasso, M., Carr, J., Casanova, S., Cerruti, M., Chakraborty, N., Chalme-Calvet, R., Chaves, R. C. G., Chen, A., Chevalier, J., Chrétien, M., Coffaro, M., Colafrancesco, S., Cologna, G., Condon, B., Conrad, J., Cui, Y., Davids, I. D., Decock, J., Degrange, B., Deil, C., Devin, J., deWilt, P., Dirson, L., Djannati-Ataï, A., Domainko, W., Donath, A., Drury, L. O'C., Dutson, K., Dyks, J., Edwards, T., Egberts, K., Eger, P., Ernenwein, J. -P., Eschbach, S., Farnier, C., Fegan, S., Fern, M. V., Fiasson, A., Fontaine, G., Förster, A., Funk, S., Füßling, M., Gabici, S., Gajdus, M., Gallant, Y. A., Garrigoux, T., Giavitto, G., Giebels, B., Glicenstein, J. F., Gottschall, D., Goyal, A., Grondin, M. -H., Hahn, J., Haupt, M., Hawkes, J., Heinzelmann, G., Henri, G., Hermann, G., Hervet, O., Hinton, J. A., Hofmann, W., Hoischen, C., Holler, M., Horns, D., Ivascenko, A., Iwasaki, H., Jacholkowska, A., Jamrozy, M., Janiak, M., Jankowsky, D., Jankowsky, F., Jingo, M., Jogler, T., Jouvin, L., Jung-Richardt, I., Kastendieck, M. A., Katarzyński, K., Katsuragawa, M., Katz, U., Kerszberg, D., Khangulyan, D., Khélifi, B., Kieffer, M., King, J., Klepser, S., Klochkov, D., Kluźniak, W., Kolitzus, D., Komin, Nu., Kosack, K., Krakau, S., Kraus, M., Krüger, P. P., Laffon, H., Lamanna, G., Lau, J., Lees, J. -P., Lefaucheur, J., Lefranc, V., Lemière, A., Lemoine-Goumard, M., Lenain, J. -P., Leser, E., Lohse, T., Lorentz, M., Liu, R., López-Coto, R., Lypova, I., Mar, V., Marcowith, A., Mariaud, C., Marx, R., Maurin, G., Maxted, N., Mayer, M., Meintjes, P. J., Meyer, M., Mitchell, A. M. W., Moderski, R., Mohamed, M., Mohrmann, L., Morå, K., Moulin, E., Murach, T., Nakashima, S., de Naurois, M., Niederwanger, F., Niemiec, J., Oakes, L., O'Brien, P., Odaka, H., Öttl, S., Ohm, S., Ostrowski, M., Oya, I., Padovani, M., Panter, M., Parsons, R. D., Arribas, M. Paz, Pekeur, N. W., Pelletier, G., Perennes, C., Petrucci, P. -O., Peyaud, B., Piel, Q., Pita, S., Poon, H., Prokhorov, D., Prokoph, H., Pühlhofer, G., Punch, M., Quirrenbach, A., Raab, S., Reimer, A., Reimer, O., Renaud, M., Reyes, R. de los, Richter, S., Rieger, F., Romoli, C., Rowell, G., Rudak, B., Rulten, C. B., Sahakian, V., Saito, S., Salek, D., Sanchez, D. A., Santangelo, A., Sasaki, M., Schlickeiser, R., Schüssler, F., Schulz, A., Schwanke, U., Schwemmer, S., Seglar-Arroyo, M., Settimo, M., Seyffert, A. S., Shafi, N., Shilon, I., Simoni, R., Sol, H., Spanier, F., Spengler, G., Spies, F., Stawarz, Ł., Steenkamp, R., Stegmann, C., Stycz, K., Sushch, I., Takahashi, T., Tavernet, J. -P., Tavernier, T., Taylor, A. M., Terrier, R., Tibaldo, L., Tiziani, D., Tluczykont, M., Trichard, C., Tsuji, N., Tuffs, R., Uchiyama, Y., van der Walt, D. J., van Eldik, C., van Rensburg, C., van Soelen, B., Vasileiadis, G., Veh, J., Venter, C., Viana, A., Vincent, P., Vink, J., Voisin, F., Völk, H. J., Vuillaume, T., Wadiasingh, Z., Wagner, S. J., Wagner, P., Wagner, R. M., White, R., Wierzcholska, A., Willmann, P., Wörnlein, A., Wouters, D., Yang, R., Zabalza, V., Zaborov, D., Zacharias, M., Zanin, R., Zdziarski, A. A., Zech, A., Zefi, F., Ziegler, A., and Żywucka, N.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: Aims. We study gamma-ray emission from the shell-type supernova remnant (SNR) RX J0852.0$-$4622 to better characterize its spectral properties and its distribution over the SNR. Methods. The analysis of an extended High Energy Spectroscopic System (H.E.S.S.) data set at very high energies (E > 100 GeV) permits detailed studies, as well as spatially resolved spectroscopy, of the morphology and spectrum of the whole RX J0852.0$-$4622 region. The H.E.S.S. data are combined with archival data from other wavebands and interpreted in the framework of leptonic and hadronic models. The joint Fermi-LAT-H.E.S.S. spectrum allows the direct determination of the spectral characteristics of the parent particle population in leptonic and hadronic scenarios using only GeV-TeV data. Results. An updated analysis of the H.E.S.S. data shows that the spectrum of the entire SNR connects smoothly to the high-energy spectrum measured by Fermi-LAT. The increased data set makes it possible to demonstrate that the H.E.S.S. spectrum deviates significantly from a power law and is well described by both a curved power law and a power law with an exponential cutoff at an energy of $E_\mathrm{cut} = (6.7 \pm 1.2_\mathrm{stat} \pm 1.2_\mathrm{syst})$ TeV. The joint Fermi-LAT-H.E.S.S. spectrum allows the unambiguous identification of the spectral shape as a power law with an exponential cutoff. No significant evidence is found for a variation of the spectral parameters across the SNR, suggesting similar conditions of particle acceleration across the remnant. A simple modeling using one particle population to model the SNR emission demonstrates that both leptonic and hadronic emission scenarios remain plausible. It is also shown that at least a part of the shell emission is likely due to the presence of a pulsar wind nebula around PSR J0855$-$4644., Comment: 14 pages, 5 figures, 8 tables. Published in A&A
Published: 2016
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9. H.E.S.S. observations of RX J1713.7-3946 with improved angular and spectral resolution; evidence for gamma-ray emission extending beyond the X-ray emitting shell

Author: Collaboration, H. E. S. S., Abdalla, H., Abramowski, A., Aharonian, F., Benkhali, F. Ait, Akhperjanian, A. G., Andersson, T., Angüner, E. O., Arrieta, M., Aubert, P., Backes, M., Balzer, A., Barnard, M., Becherini, Y., Tjus, J. Becker, Berge, D., Bernhard, S., Bernlöhr, K., Blackwell, R., Böttcher, M., Boisson, C., Bolmont, J., Bordas, P., Bregeon, J., Brun, F., Brun, P., Bryan, M., Büchele, M., Bulik, T., Capasso, M., Carr, J., Casanova, S., Cerruti, M., Chakraborty, N., Chalme-Calvet, R., Chaves, R. C. G., Chen, A., Chevalier, J., Chrétien, M., Coffaro, M., Colafrancesco, S., Cologna, G., Condon, B., Conrad, J., Cui, Y., Davids, I. D., Decock, J., Degrange, B., Deil, C., Devin, J., deWilt, P., Dirson, L., Djannati-Ataï, A., Domainko, W., Donath, A., Drury, L. O'C., Dutson, K., Dyks, J., Edwards, T., Egberts, K., Eger, P., Ernenwein, J. -P., Eschbach, S., Farnier, C., Fegan, S., Fern, M. V., Fiasson, A., Fontaine, G., Förster, A., Funk, S., Füßling, M., Gabici, S., Gajdus, M., Gallant, Y. A., Garrigoux, T., Giavitto, G., Giebels, B., Glicenstein, J. F., Gottschall, D., Goyal, A., Grondin, M. -H., Hadasch, D., Hahn, J., Haupt, M., Hawkes, J., Heinzelmann, G., Henri, G., Hermann, G., Hervet, O., Hinton, J. A., Hofmann, W., Hoischen, C., Holler, M., Horns, D., Ivascenko, A., Jacholkowska, A., Jamrozy, M., Janiak, M., Jankowsky, D., Jankowsky, F., Jingo, M., Jogler, T., Jouvin, L., Jung-Richardt, I., Kastendieck, M. A., Katarzyński, K., Katz, U., Kerszberg, D., Khélifi, B., Kieffer, M., King, J., Klepser, S., Klochkov, D., Kluźniak, W., Kolitzus, D., Komin, Nu., Kosack, K., Krakau, S., Kraus, M., Krüger, P. P., Laffon, H., Lamanna, G., Lau, J., Lees, J. -P., Lefaucheur, J., Lefranc, V., Lemière, A., Lemoine-Goumard, M., Lenain, J. -P., Leser, E., Lohse, T., Lorentz, M., Liu, R., López-Coto, R., Lypova, I., Mar, V., Marcowith, A., Mariaud, C., Marx, R., Maurin, G., Maxted, N., Mayer, M., Meintjes, P. J., Meyer, M., Mitchell, A. M. W., Moderski, R., Mohamed, M., Mohrmann, L., Morå, K., Moulin, E., Murach, T., de Naurois, M., Niederwanger, F., Niemiec, J., Oakes, L., O'Brien, P., Odaka, H., Öttl, S., Ohm, S., Ostrowski, M., Oya, I., Padovani, M., Panter, M., Parsons, R. D., Pekeur, N. W., Pelletier, G., Perennes, C., Petrucci, P. -O., Peyaud, B., Piel, Q., Pita, S., Poon, H., Prokhorov, D., Prokoph, H., Pühlhofer, G., Punch, M., Quirrenbach, A., Raab, S., Reimer, A., Reimer, O., Renaud, M., Reyes, R. de los, Rieger, F., Romoli, C., Rowell, G., Rudak, B., Rulten, C. B., Sahakian, V., Salek, D., Sanchez, D. A., Santangelo, A., Sasaki, M., Schlickeiser, R., Schüssler, F., Schulz, A., Schwanke, U., Schwemmer, S., Seglar-Arroyo, L., Settimo, M., Seyffert, A. S., Shafi, N., Shilon, I., Simoni, R., Sol, H., Spanier, F., Spengler, G., Spies, F., Stawarz, Ł., Steenkamp, R., Stegmann, C., Stycz, K., Sushch, I., Tavernet, J. -P., Tavernier, T., Taylor, A. M., Terrier, R., Tibaldo, L., Tiziani, D., Tluczykont, M., Trichard, C., Tuffs, R., Uchiyama, Y., van der Walt, D. J., van Eldik, C., van Rensburg, C., van Soelen, B., Vasileiadis, G., Veh, J., Venter, C., Viana, A., Vincent, P., Vink, J., Voisin, F., Völk, H. J., Vuillaume, T., Wadiasingh, Z., Wagner, S. J., Wagner, P., Wagner, R. M., White, R., Wierzcholska, A., Willmann, P., Wörnlein, A., Wouters, D., Yang, R., Zabalza, V., Zaborov, D., Zacharias, M., Zanin, R., Zdziarski, A. A., Zech, A., Zefi, F., Ziegler, A., and Żywucka, N.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: Supernova remnants exhibit shock fronts (shells) that can accelerate charged particles up to very high energies. In the past decade, measurements of a handful of shell-type supernova remnants in very-high-energy gamma rays have provided unique insights into the acceleration process. Among those objects, RX$~$J1713.7-3946 (also known as G347.3-0.5) has the largest surface brightness, allowing us in the past to perform the most comprehensive study of morphology and spatially resolved spectra of any such very-high-energy gamma-ray source. Here we present extensive new H.E.S.S. measurements of RX$~$J1713.7-3946, almost doubling the observation time compared to our previous publication. Combined with new improved analysis tools, the previous sensitivity is more than doubled. The H.E.S.S. angular resolution of $0.048^\circ$ ($0.036^\circ$ above 2 TeV) is unprecedented in gamma-ray astronomy and probes physical scales of 0.8 (0.6) parsec at the remnant's location. The new H.E.S.S. image of RX$~$J1713.7-3946 allows us to reveal clear morphological differences between X-rays and gamma rays. In particular, for the outer edge of the brightest shell region, we find the first ever indication for particles in the process of leaving the acceleration shock region. By studying the broadband energy spectrum, we furthermore extract properties of the parent particle populations, providing new input to the discussion of the leptonic or hadronic nature of the gamma-ray emission mechanism., Comment: 32 pages, 12 figures, accepted for publication in A&A, v2 is final accepted version
Published: 2016
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10. H.E.S.S. limits on line-like dark matter signatures in the 100 GeV to 2 TeV energy range close to the Galactic Centre

Author: Collaboration, H. E. S. S., Abdalla, H., Abramowski, A., Aharonian, F., Benkhali, F. Ait, Akhperjanian, A. G., Andersson, T., Angüner, E. O., Arrieta, M., Aubert, P., Backes, M., Balzer, A., Barnard, M., Becherini, Y., Tjus, J. Becker, Berge, D., Bernhard, S., Bernlöhr, K., Birsin, E., Blackwell, R., Böttcher, M., Boisson, C., Bolmont, J., Bordas, P., Bregeon, J., Brun, F., Brun, P., Bryan, M., Bulik, T., Capasso, M., Carr, J., Casanova, S., Chakraborty, N., Chalme-Calvet, R., Chaves, R. C. G., Chen, A., Chevalier, J., Chrétien, M., Colafrancesco, S., Cologna, G., Condon, B., Conrad, J., Couturier, C., Cui, Y., Davids, I. D., Degrange, B., Deil, C., Devin, J., deWilt, P., Djannati-Ata\", A., Domainko, W., Donath, A., Drury, L. O'C., Dubus, G., Dutson, K., Dyks, J., Dyrda, M., Edwards, T., Egberts, K., Eger, P., Ernenwein, J. -P., Eschbach, S., Farnier, C., Fegan, S., Fernandes, M. V., Fiasson, A., Fontaine, G., Förster, A., Funk, S., Füßling, M., Gabici, S., Gajdus, M., Gallant, Y. A., Garrigoux, T., Giavitto, G., Giebels, B., Glicenstein, J. F., Gottschall, D., Goyal, 18 A., Grondin, M. -H., Grudzińska, M., Hadasch, D., Hahn, J., Hawkes, J., Heinzelmann, G., Henri, G., Hermann, G., Hervet, O., Hillert, A., Hinton, J. A., Hofmann, W., Hoischen, C., Holler, M., Horns, D., Ivascenko, A., Jacholkowska, A., Jamrozy, M., Janiak, M., Jankowsky, D., Jankowsky, F., Jingo, M., Jogler, T., Jouvin, L., Jung-Richardt, I., Kastendieck, M. A., Katarzyński, K., Katz, U., Kerszberg, D., Khélifi, B., Kieffer, M., King, J., Klepser, S., Klochkov, D., Kluźniak, W., Kolitzus, D., Komin, Nu., Kosack, K., Krakau, S., Kraus, M., Krayzel, F., Krüger, P. P., Laffon, H., Lamanna, G., Lau, J., Lees, J. -P., Lefaucheur, J., Lefranc, V., Lemière, A., Lemoine-Goumard, M., Lenain, J. -P., Leser, E., Liu, R., Lohse, T., Lorentz, M., Lypova, I., Marandon, V., Marcowith, A., Mariaud, C., Marx, R., Maurin, G., Maxted, N., Mayer, M., Meintjes, P. J., Meyer, M., Mitchell, A. M. W., Moderski, R., Mohamed, M., Morå, K., Moulin, E., Murach, T., de Naurois, M., Niederwanger, F., Niemiec, J., Oakes, L., O'Brien, P., Odaka, H., Ohm, S., Ostrowski, M., Öttl, S., Oya, I., Padovani, M., Panter, M., Parsons, R. D., Arribas, M. Paz, Pekeur, N. W., Pelletier, G., Perennes, C., Petrucci, P. -O., Peyaud, B., Pita, S., Poon, H., Prokhorov, D., Prokoph, H., Pühlhofer, G., Punch, M., Quirrenbach, A., Raab, S., Reimer, A., Reimer, O., Renaud, M., Reyes, R. de los, Rieger, F., Romoli, C., Rosier-Lees, S., Rowell, G., Rudak, B., Rulten, C. B., Sahakian, V., Salek, D., Sanchez, D. A., Santangelo, A., Sasaki, M., Schlickeiser, R., Schüssler, F., Schulz, A., Schwanke, U., Schwemmer, S., Settimo, M., Seyffert, A. S., Shafi, N., Shilon, I., Simoni, R., Sol, H., Spanier, F., Spengler, G., Spies, F., Stawarz, L., Steenkamp, R., Stegmann, C., Stinzing, F., Stycz, K., Sushch, I., Tavernet, J. -P., Tavernier, T., Taylor, A. M., Terrier, R., Tibaldo, L., Tluczykont, M., Trichard, C., Tuffs, R., van der Walt, J., van Eldik, C., van Soelen, B., Vasileiadis, G., Veh, J., Venter, C., Viana, A., Vincent, P., Vink, J., Voisin, F., Vuillaume, H. J. Völk. T., Wadiasingh, Z., Wagner, S. J., Wagner, P., Wagner, R. M., White, R., Wierzcholska, A., Willmann, P., Wörnlein, A., Wouters, D., Yang, R., Zabalza, V., Zaborov, D., Zacharias, M., Zdziarski, A. A., Zech, A., Zefi, F., Ziegler, A., and Żywucka, N.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: A search for dark matter line-like signals was performed in the vicinity of the Galactic Centre by the H.E.S.S. experiment on observational data taken in 2014. An unbinned likelihood analysis was developed to improve the sensitivity to line-like signals. The upgraded analysis along with newer data extend the energy coverage of the previous measurement down to 100 GeV. The 18 h of data collected with the H.E.S.S. array allow one to rule out at 95% CL the presence of a 130 GeV line (at $l = -1.5^{\circ}, b = 0^{\circ}$ and for a dark matter profile centered at this location) previously reported in Fermi-LAT data. This new analysis overlaps significantly in energy with previous Fermi-LAT and H.E.S.S. results. No significant excess associated with dark matter annihilations was found in the energy range 100 GeV to 2 TeV and upper limits on the gamma-ray flux and the velocity weighted annihilation cross-section are derived adopting an Einasto dark matter halo profile. Expected limits for present and future large statistics H.E.S.S. observations are also given., Comment: Accepted by PRL. 7 pages, 3 figures, 1 table
Published: 2016
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11. The supernova remnant W49B as seen with H.E.S.S. and Fermi-LAT

Author: Collaboration, H. E. S. S., Abdalla, H., Abramowski, A., Aharonian, F., Benkhali, F. Ait, Akhperjanian, A. G., Andersson, T., Angüner, E. O., Arrieta, M., Aubert, P., Backes, M., Balzer, A., Barnard, M., Becherini, Y., Tjus, J. Becker, Berge, D., Bernhard, S., Bernlöhr, K., Blackwell, R., Böttcher, M., Boisson, C., Bolmont, J., Bordas, P., Bregeon, J., Brun, F., Brun, P., Bryan, M., Bulik, T., Capasso, M., Carr, J., Casanova, S., Cerruti, M., Chakraborty, N., Chalme-Calvet, R., Chaves, R. C. G., Chen, A., Chevalier, J., Chrétien, M., Colafrancesco, S., Cologna, G., Condon, B., Conrad, J., Cui, Y., Davids, I. D., Decock, J., Degrange, B., Deil, C., Devin, J., deWilt, P., Dirson, L., Djannati-Ataï, A., Domainko, W., Donath, A., Drury, L. O'C., Dubus, G., Dutson, K., Dyks, J., Edwards, T., Egberts, K., Eger, P., Ernenwein, J. -P., Eschbach, S., Farnier, C., Fegan, S., Fernandes, M. V., Fiasson, A., Fontaine, G., Förster, A., Funk, S., Füßling, M., Gabici, S., Gajdus, M., Gallant, Y. A., Garrigoux, T., Giavitto, G., Giebels, B., Glicenstein, J. F., Gottschall, D., Goyal, A., Grondin, M. -H., Hadasch, D., Hahn, J., Haupt, M., Hawkes, J., Heinzelmann, G., Henri, G., Hermann, G., Hervet, O., Hinton, J. A., Hofmann, W., Hoischen, C., Holler, M., Horns, D., Ivascenko, A., Jacholkowska, A., Jamrozy, M., Janiak, M., Jankowsky, D., Jankowsky, F., Jingo, M., Jogler, T., Jouvin, L., Jung-Richardt, I., Kastendieck, M. A., Katarzyński, K., Katz, U., Kerszberg, D., Khélifi, B., Kieffer, M., King, J., Klepser, S., Klochkov, D., Kluźniak, W., Kolitzus, D., Komin, Nu., Kosack, K., Krakau, S., Kraus, M., Krayzel, F., Krüger, P. P., Laffon, H., Lamanna, G., Lau, J., Lees, J. -P., Lefaucheur, J., Lefranc, V., Lemière, A., Lemoine-Goumard, M., Lenain, J. -P., Leser, E., Lohse, T., Lorentz, M., Liu, R., López-Coto, R., Lypova, I., Marandon, V., Marcowith, A., Mariaud, C., Marx, R., Maurin, G., Maxted, N., Mayer, M., Meintjes, P. J., Meyer, M., Mitchell, A. M. W., Moderski, R., Mohamed, M., Mohrmann, L., Morå, K., Moulin, E., Murach, T., de Naurois, M., Niederwanger, F., Niemiec, J., Oakes, L., O'Brien, P., Odaka, H., Öttl, S., Ohm, S., Ostrowski, M., Oya, I., Padovani, M., Panter, M., Parsons, R. D., Pekeur, N. W., Pelletier, G., Perennes, C., Petrucci, P. -O., Peyaud, B., Piel, Q., Pita, S., Poon, H., Prokhorov, D., Prokoph, H., Pühlhofer, G., Punch, M., Quirrenbach, A., Raab, S., Reimer, A., Reimer, O., Renaud, M., Reyes, R. de los, Rieger, F., Romoli, C., Rosier-Lees, S., Rowell, G., Rudak, B., Rulten, C. B., Sahakian, V., Salek, D., Sanchez, D. A., Santangelo, A., Sasaki, M., Schlickeiser, R., Schüssler, F., Schulz, A., Schwanke, U., Schwemmer, S., Settimo, M., Seyffert, A. S., Shafi, N., Shilon, I., Simoni, R., Sol, H., Spanier, F., Spengler, G., Spies, F., Stawarz, Ł., Steenkamp, R., Stegmann, C., Stinzing, F., Stycz, K., Sushch, I., Tavernet, J. -P., Tavernier, T., Taylor, A. M., Terrier, R., Tibaldo, L., Tiziani, D., Tluczykont, M., Trichard, C., Tuffs, R., Uchiyama, Y., van der Walt, D. J., van Eldik, C., van Rensburg, C., van Soelen, B., Vasileiadis, G., Veh, J., Venter, C., Viana, A., Vincent, P., Vink, J., Voisin, F., Völk, H. J., Vuillaume, T., Wadiasingh, Z., Wagner, S. J., Wagner, P., Wagner, R. M., White, R., Wierzcholska, A., Willmann, P., Wörnlein, A., Wouters, D., Yang, R., Zabalza, V., Zaborov, D., Zacharias, M., Zdziarski, A. A., Zech, A., Zefi, F., Ziegler, A., Żywucka, N., Collaboration, Fermi-LAT, and Katsuta, J.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: The supernova remnant (SNR) W49B originated from a core-collapse supernova that occurred between one and four thousand years ago, and subsequently evolved into a mixed-morphology remnant, which is interacting with molecular clouds (MC). $\gamma$-ray observations of SNR/MC associations are a powerful tool to constrain the origin of Galactic cosmic-rays, as they can probe the acceleration of hadrons through their interaction with the surrounding medium and subsequent emission of non-thermal photons. The detection of a $\gamma$-ray source coincident with W49B at very high energies (VHE; E > 100 GeV) with the H.E.S.S. Cherenkov telescopes is reported together with a study of the source with 5 years of Fermi-LAT high energy $\gamma$-ray (0.06 - 300 GeV) data. The smoothly-connected combined source spectrum, measured from 60 MeV to multi-TeV energies, shows two significant spectral breaks at $304\pm20$ MeV and $8.4_{-2.5}^{+2.2}$ GeV, the latter being constrained by the joint fit from the two instruments. The detected spectral features are similar to those observed in several other SNR/MC associations and are found to be indicative of $\gamma$-ray emission produced through neutral-pion decay., Comment: 10 pages, 6 figures. Accepted for publication in A&A
Published: 2016
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12. Search for dark matter annihilations towards the inner Galactic halo from 10 years of observations with H.E.S.S

Author: Collaboration, H. E. S. S., Abdallah, H., Abramowski, A., Aharonian, F., Benkhali, F. Ait, Akhperjanian, A. G., Angüner, E., Arrieta, M., Aubert, P., Backes, M., Balzer, A., Barnard, M., Becherini, Y., Tjus, J. Becker, Berge, D., Bernhard, S., Bernlöhr, K., Birsin, E., Blackwell, R., Böttcher, M., Boisson, C., Bolmont, J., Bordas, P., Bregeon, J., Brun, F., Brun, P., Bryan, M., Bulik, T., Capasso, M., Carr, J., Casanova, S., Chadwick, P. M., Chakraborty, N., Chalme-Calvet, R., Chaves, R. C. G., Chen, A., Chevalier, J., Chrétien, M., Colafrancesco, S., Cologna, G., Condon, B., Conrad, J., Couturier, C., Cui, Y., Davids, I. D., Degrange, B., Deil, C., deWilt, P., Dickinson, H. J., Djannati-Ataï, A., Domainko, W., Donath, A., Drury, L. O'C., Dubus, G., Dutson, K., Dyks, J., Dyrda, M., Edwards, T., Egberts, K., Eger, P., Ernenwein, J. -P., Eschbach, S., Farnier, C., Fegan, S., Fernandes, M. V., Fiasson, A., Fontaine, G., Förster, A., Funk, S., Füßling, M., Gabici, S., Gajdus, M., Gallant, Y. A., Garrigoux, T., Giavitto, G., Giebels, B., Glicenstein, J. F., Gottschall, D., Goyal, A., Grondin, M. -H., Grudzińska, M., Hadasch, D., Hahn, J., Hawkes, J., Heinzelmann, G., Henri, G., Hermann, G., Hervet, O., Hillert, A., Hinton, J. A., Hofmann, W., Hoischen, C., Holler, M., Horns, D., Ivascenko, A., Jacholkowska, A., Jamrozy, M., Janiak, M., Jankowsky, D., Jankowsky, F., Jingo, M., Jogler, T., Jouvin, L., Jung-Richardt, I., Kastendieck, M. A., Katarzyński, K., Katz, U., Kerszberg, D., Khélifi, B., Kieffer, M., King, J., Klepser, S., Klochkov, D., Kluźniak, W., Kolitzus, D., Komin, Nu., Kosack, K., Krakau, S., Kraus, M., Krayzel, F., Krüger, P. P., Laffon, H., Lamanna, G., Lau, J., Lees, J. -P., Lefaucheur, J., Lefranc, V., Lemière, A., Lemoine-Goumard, M., Lenain, J. -P., Leser, E., Lohse, T., Lorentz, M., Liu, R., Lypova, I., Marandon, V., Marcowith, A., Mariaud, C., Marx, R., Maurin, G., Maxted, N., Mayer, M., Meintjes, P. J., Menzler, U., Meyer, M., Mitchell, A. M. W., Moderski, R., Mohamed, M., Morå, K., Moulin, E., Murach, T., de Naurois, M., Niederwanger, F., Niemiec, J., Oakes, L., Odaka, H., Ohm, S., Öttl, S., Ostrowski, M., Oya, I., Padovani, M., Panter, M., Parsons, R. D., Arribas, M. Paz, Pekeur, N. W., Pelletier, G., Petrucci, P. -O., Peyaud, B., Pita, S., Poon, H., Prokhorov, D., Prokoph, H., Pühlhofer, G., Punch, M., Quirrenbach, A., Raab, S., Reimer, A., Reimer, O., Renaud, M., Reyes, R. de los, Rieger, F., Romoli, C., Rosier-Lees, S., Rowell, G., Rudak, B., Rulten, C. B., Sahakian, V., Salek, D., Sanchez, D. A., Santangelo, A., Sasaki, M., Schlickeiser, R., Schüssler, F., Schulz, A., Schwanke, U., Schwemmer, S., Seyffert, A. S., Shafi, N., Shilon, I., Simoni, R., Sol, H., Spanier, F., Spengler, G., Spies, F., Stawarz, Ł., Steenkamp, R., Stegmann, C., Stinzing, F., Stycz, K., Sushch, I., Tavernet, J. -P., Tavernier, T., Taylor, A. M., Terrier, R., Tluczykont, M., Trichard, C., Tuffs, R., van der Walt, J., van Eldik, C., van Soelen, B., Vasileiadis, G., Veh, J., Venter, C., Viana, A., Vincent, P., Vink, J., Voisin, F., Völk, H. J., Vuillaume, T., Wadiasingh, Z., Wagner, S. J., Wagner, P., Wagner, R. M., White, R., Wierzcholska, A., Willmann, P., Wörnlein, A., Wouters, D., Yang, R., Zabalza, V., Zaborov, D., Zacharias, M., Zdziarski, A. A., Zech, A., Zefi, F., Ziegler, A., and Zywucka, N.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: The inner region of the Milky Way halo harbors a large amount of dark matter (DM). Given its proximity, it is one of the most promising targets to look for DM. We report on a search for the annihilations of DM particles using $\gamma$-ray observations towards the inner 300 parsecs of the Milky Way, with the H.E.S.S. array of ground-based Cherenkov telescopes. The analysis is based on a 2D maximum likelihood method using Galactic center (GC) data accumulated by H.E.S.S. over the last 10 years (2004-2014), and does not show any significant $\gamma$-ray signal above background. Assuming Einasto and Navarro-Frenk-White DM density profiles at the GC, we derive upper limits on the annihilation cross section $\langle \sigma v\rangle$. These constraints are the strongest obtained so far in the TeV DM mass range and improve upon previous limits by a factor 5. For the Einasto profile, the constraints reach $\langle \sigma v\rangle$ values of $\rm 6\times10^{-26} cm^3s^{-1}$ in the $W^+W^-$ channel for a DM particle mass of 1.5 TeV, and $\rm 2\times10^{-26} cm^3s^{-1}$ in the $\tau^+\tau^-$ channel for 1 TeV mass. For the first time, ground-based $\gamma$-ray observations have reached sufficient sensitivity to probe $\langle \sigma v\rangle$ values expected from the thermal relic density for TeV DM particles., Comment: Accepted by PRL. Includes Supplemental Material. 7+4 pages, 2+4 figures, 1 table
Published: 2016
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13. A search for very high-energy flares from the microquasars GRS 1915+105, Circinus X-1, and V4641 Sgr using contemporaneous H.E.S.S. and RXTE observations

Author: Collaboration, H. E. S. S., Abdalla, H., Abramowski, A., Aharonian, F., Benkhali, F. Ait, Akhperjanian, A. G., Angüner, E. O., Arrieta, M., Aubert, P., Backes, M., Balzer, A., Barnard, M., Becherini, Y., Tjus, J. Becker, Berge, D., Bernhard, S., Bernlöhr, K., Birsin, E., Blackwell, R., Böttcher, M., Boisson, C., Bolmont, J., Bordas, P., Bregeon, J., Brun, F., Brun, P., Bryan, M., Bulik, T., Capasso, M., Carr, J., Casanova, S., Chadwick, P. M., Chakraborty, N., Chalme-Calvet, R., Chaves, R. C. G., Chen, A., Chevalier, J., Chrétien, M., Colafrancesco, S., Cologna, G., Condon, B., Conrad, J., Couturier, C., Cui, Y., Davids, I. D., Degrange, B., Deil, C., deWilt, P., Dickinson, H. J., Djannati-Ataï, A., Domainko, W., Donath, A., Drury, L. O'C., Dubus, G., Dutson, K., Dyks, J., Dyrda, M., Edwards, T., Egberts, K., Eger, P., Ernenwein, J. -P., Eschbach, S., Farnier, C., Fegan, S., Fernandes, M. V., Fiasson, A., Fontaine, G., Förster, A., Funk, S., Füßling, M., Gabici, S., Gajdus, M., Gallant, Y. A., Garrigoux, T., Giavitto, G., Giebels, B., Glicenstein, J. F., Gottschall, D., Goyal, A., Grondin, M. -H., Grudzińska, M., Hadasch, D., Hahn, J., Hawkes, J., Heinzelmann, G., Henri, G., Hermann, G., Hervet, O., Hillert, A., Hinton, J. A., Hofmann, W., Hoischen, C., Holler, M., Horns, D., Ivascenko, A., Jacholkowska, A., Jamrozy, M., Janiak, M., Jankowsky, D., Jankowsky, F., Jingo, M., Jogler, T., Jouvin, L., Jung-Richardt, I., Kastendieck, M. A., Katarzyński, K., Katz, U., Kerszberg, D., Khélifi, B., Kieffer, M., King, J., Klepser, S., Klochkov, D., Kluźniak, W., Kolitzus, D., Komin, Nu., Kosack, K., Krakau, S., Kraus, M., Krayzel, F., Krüger, P. P., Laffon, H., Lamanna, G., Lau, J., -P., J., Lefaucheur, J., Lefranc, V., Lemière, A., Lemoine-Goumard, M., Lenain, J. -P., Leser, E., Lohse, T., Lorentz, M., Liu, R., Lypova, I., Marandon, V., Marcowith, A., Mariaud, C., Marx, R., Maurin, G., Maxted, N., Mayer, M., Meintjes, P. J., Menzler, U., Meyer, M., Mitchell, A. M. W., Moderski, R., Mohamed, M., Morå, K., Moulin, E., Murach, T., de Naurois, M., Niederwanger, F., Niemiec, J., Oakes, L., Odaka, H., Öttl, S., Ohm, S., Ostrowski, M., Oya, I., Padovani, M., Panter, M., Parsons, R. D., Arribas, M. Paz, Pekeur, N. W., Pelletier, G., Petrucci, P. -O., Peyaud, B., Pita, S., Poon, H., Prokhorov, D., Prokoph, H., Pühlhofer, G., Punch, M., Quirrenbach, A., Raab, S., Reimer, A., Reimer, O., Renaud, M., Reyes, R. de los, Rieger, F., Romoli, C., Rosier-Lees, S., Rowell, G., Rudak, B., Rulten, C. B., Sahakian, V., Salek, D., Sanchez, D. A., Santangelo, A., Sasaki, M., Schlickeiser, R., Schüssler, F., Schulz, A., Schwanke, U., Schwemmer, S., Seyffert, A. S., Shafi, N., Shilon, I., Simoni, R., Sol, H., Spanier, F., Spengler, G., Spies, F., Stawarz, Ł., Steenkamp, R., Stegmann, C., Stinzing, F., Stycz, K., Sushch, I., Tavernet, J. -P., Tavernier, T., Taylor, A. M., Terrier, R., Tluczykont, M., Trichard, C., Tuffs, R., van der Walt, J., van Eldik, C., van Soelen, B., Vasileiadis, G., Veh, J., Venter, C., Viana, A., Vincent, P., Vink, J., Voisin, F., Völk, H. J., Vuillaume, T., Wadiasingh, Z., Wagner, S. J., Wagner, P., Wagner, R. M., White, R., Wierzcholska, A., Willmann, P., Wörnlein, A., Wouters, D., Yang, R., Zabalza, V., Zaborov, D., Zacharias, M., Zdziarski, A. A., Zech, A., Zefi, F., Ziegler, A., and Żywucka, N.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: Microquasars are potential $\gamma$-ray emitters. Indications of transient episodes of $\gamma$-ray emission were recently reported in at least two systems: Cyg X-1 and Cyg X-3. The identification of additional $\gamma$-ray-emitting microquasars is required to better understand how $\gamma$-ray emission can be produced in these systems. Theoretical models have predicted very high-energy (VHE) $\gamma$-ray emission from microquasars during periods of transient outburst. Observations reported herein were undertaken with the objective of observing a broadband flaring event in the $\gamma$-ray and X-ray bands. Contemporaneous observations of three microquasars, GRS 1915+105, Circinus X-1, and V4641 Sgr, were obtained using the High Energy Spectroscopic System (H.E.S.S.) telescope array and the Rossi X-ray Timing Explorer (RXTE) satellite. X-ray analyses for each microquasar were performed and VHE $\gamma$-ray upper limits from contemporaneous H.E.S.S. observations were derived. No significant $\gamma$-ray signal has been detected in any of the three systems. The integral $\gamma$-ray photon flux at the observational epochs is constrained to be $I(> 560 {\rm\ GeV}) < 7.3\times10^{-13}$ cm$^{-2}$ s$^{-1}$, $I(> 560 {\rm\ GeV}) < 1.2\times10^{-12}$ cm$^{-2}$ s$^{-1}$, and $I(> 240 {\rm\ GeV}) < 4.5\times10^{-12}$ cm$^{-2}$ s$^{-1}$ for GRS 1915+105, Circinus X-1, and V4641 Sgr, respectively. The $\gamma$-ray upper limits obtained using H.E.S.S. are examined in the context of previous Cherenkov telescope observations of microquasars. The effect of intrinsic absorption is modelled for each target and found to have negligible impact on the flux of escaping $\gamma$-rays. When combined with the X-ray behaviour observed using RXTE, the derived results indicate that if detectable VHE $\gamma$-ray emission from microquasars is commonplace, then it is likely to be highly transient., Comment: 23 pages, 12 figures, accepted for publication by A&A
Published: 2016
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14. Extended VHE gamma-ray emission towards SGR1806-20, LBV1806-20, and stellar cluster Cl*1806-20

Author: Abdalla, H., Abramowski, A., Aharonian, F., Benkhali, F. Ait, Akhperjanian, A. G., Angüner, E. O., Arrieta, M., Aubert, P., Backes, M., Balzer, A., Barnard, M., Becherini, Y., Tjus, J. Becker, Berge, D., Bernhard, S., Bernlöhr, K., Birsin, E., Blackwell, R., Böttcher, M., Boisson, C., Bolmont, J., Bordas, P., Bregeon, J., Brun, F., Brun, P., Bryan, M., Bulik, T., Capasso, M., Carr, J., Casanova, S., Chakraborty, N., Chalme-Calvet, R., Chaves, R. C. G., Chen, A., Chevalier, J., Chrétien, M., Colafrancesco, S., Cologna, G., Condon, B., Conrad, J., Couturier, C., Cui, Y., Davids, I. D., Degrange, B., Deil, C., deWilt, P., Djannati-Ataï, A., Domainko, W., Donath, A., Drury, L. O'C., Dubus, G., Dutson, K., Dyks, J., Dyrda, M., Edwards, T., Egberts, K., Eger, P., Ernenwein, J. -P., Eschbach, S., Farnier, C., Fegan, S., Fernandes, M. V., Fiasson, A., Fontaine, G., Förster, A., Funk, S., Füßling, M., Gabici, S., Gajdus, M., Gallant, Y. A., Garrigoux, T., Giavitto, G., Giebels, B., Glicenstein, J. F., Gottschall, D., Goyal, A., Grondin, M. -H., Grudzińska, M., Hadasch, D., Hahn, J., Hawkes, J., Heinzelmann, G., Henri, G., Hermann, G., Hervet, O., Hillert, A., Hinton, J. A., Hofmann, W., Hoischen, C., Holler, M., Horns, D., Ivascenko, A., Jacholkowska, A., Jamrozy, M., Janiak, M., Jankowsky, D., Jankowsky, F., Jingo, M., Jogler, T., Jouvin, L ., Jung-Richardt, I., Kastendieck, M. A., Katarzyński, K., Katz, U., Kerszberg, D., Khélifi, B., Kieffer, M., King, J., Klepser, S., Klochkov, D., Kluźniak, W., Kolitzus, D., Komin, Nu., Kosack, K., Krakau, S., Kraus, M., Krayzel, F., Krüger, P. P., Laffon, H., Lamanna, G., Lau, J., Lees, J. -P., Lefaucheur, J., Lefranc, V., Lemière, A., Lemoine-Goumard, M., Lenain, J. -P., Leser, E., Lohse, T., Lorentz, M., Liu, R., Lypova, I., Marandon, V., Marcowith, A., Mariaud, C., Marx, R., Maurin, G., Maxted, N., Mayer, M., Meintjes, P. J., Menzler, U., Meyer, M., Mitchell, A. M. W., Moderski, R., Mohamed, M., Morå, K., Moulin, E., Murach, T., de Naurois, M., Niederwanger, F., Niemiec, J., Oakes, L., Odaka, H., Öttl, S., Ohm, S., Ostrowski, M., Oya, I., Padovani, M., Panter, M., Parsons, R. D., Arribas, M. Paz, Pekeur, N. W., Pelletier, G., Petrucci, P. -O., Peyaud, B., Pita, S., Poon, H., Prokhorov, D., Prokoph, H., Pühlhofer, G., Punch, M., Quirrenbach, A., Raab, S., Reimer, A., Reimer, O., Renaud, M., Reyes, R. de los, Rieger, F., Romoli, C., Rosier-Lees, S., Rowell, G., Rudak, B., Rulten, C. B., Sahakian, V., Salek, D., Sanchez, D. A., Santangelo, A., Sasaki, M., Schlickeiser, R., Schüssler, F., Schulz, A., Schwanke, U., Schwemmer, S., Seyffert, A. S., Shafi, N., Shilon, I., Simoni, R., Sol, H., Spanier, F., Spengler, G., Spies, F., Stawarz, L., Steenkamp, R., Stegmann, C., Stinzing, F., Stycz, K., Sushch, I., Tavernet, J. -P., Tavernier, T., Taylor, A. M., Terrier, R., Tluczykont, M., Trichard, C., Tuffs, R., van der Walt, J., van Eldik, C., van Soelen, B., Vasileiadis, G., Veh, J., Venter, C., Viana, A., Vincent, P., Vink, J., Voisin, F., Völk, H. J., Vuillaume, T., Wadiasingh, Z., Wagner, S. J., Wagner, P., Wagner, R. M., White, R., Wierzcholska, A., Willmann, P., Wörnlein, A., Wouters, D., Yang, R., Zabalza, V., Zaborov, D., Zacharias, M., Zdziarski, A. A., Zech, A., Zefi, F., Ziegler, A., and Zywucka, N.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: Using the High Energy Spectroscopic System (H.E.S.S.) telescopes we have discovered a steady and extended very high-energy (VHE) gamma-ray source towards the luminous blue variable candidate LBV1806-20, massive stellar cluster Cl*1806-20, and magnetar SGR1806-20. The new VHE source, HESSJ1808-204, was detected at a statistical significance of >6sigma (post-trial) with a photon flux normalisation $(2.9 \pm 0.4_{\rm stat} \pm 0.5_{\rm sys})\times 10^{-13}$\,ph\,cm$^{-2}$\,s$^{-1}$\,TeV$^{-1}$ at 1TeV and a power-law photon index of $2.3\pm0.2_{\rm stat}\pm 0.3_{\rm sys}$. The luminosity of this source (0.2 to 10 TeV; scaled to distance d=8.7kpc) is $L_{\rm VHE}\sim1.6 \times 10^{34}(d/{8.7kpc})^2$\,erg\,s$^{-1}$. The VHE gamma-ray emission is extended and is well fit by a single Gaussian with statistical standard deviation of $0.095^\circ \pm 0.015^\circ$. This extension is similar to that of the synchrotron radio nebula G10.0-0.3, which is thought to be powered by LBV1806-20. The VHE gamma-ray luminosity could be provided by the stellar wind luminosity of LBV1806-20 by itself and/or the massive star members of Cl*1806-20. Alternatively, magnetic dissipation (e.g. via reconnection) from SGR1806-20 can potentially account for the VHE luminosity. The origin and hadronic and/or leptonic nature of the accelerated particles responsible for HESSJ1808-204 is not yet clear. If associated with SGR1806-20, the potentially young age of the magnetar (650yr) can be used to infer the transport limits of these particles to match the VHE source size. This discovery provides new interest in the potential for high-energy particle acceleration from magnetars, massive stars, and/or stellar clusters., Comment: Accepted for publication in A&A (This version reduced some latex in the title and abstract)
Published: 2016
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15. Acceleration of petaelectronvolt protons in the Galactic Centre

Author: collaboration, H. E. S. S., Abramowski, A., Aharonian, F., Benkhali, F. Ait, Akhperjanian, A. G., Angüner, E. O., Backes, M., Balzer, A., Becherini, Y., Tjus, J. Becker, Berge, D., Bernhard, S., Bernlöhr, K., Birsin, E., Blackwell, R., Böttcher, M., Boisson, C., Bolmont, J., Bordas, P., Bregeon, J., Brun, F., Brun, P., Bryan, M., Bulik, T., Carr, J., Casanova, S., Chakraborty, N., Chalme-Calvet, R., Chaves, R. C. G., Chen, A., Chrétien, M., Colafrancesco, S., Cologna, G., Conrad, J., Couturier, C., Cui, Y., Davids, I. D., Degrange, B., Deil, C., deWilt, P., Djannati-Ataï, A., Domainko, W., Donath, A., Drury, L. O'C., Dubus, G., Dutson, K., Dyks, J., Dyrda, M., Edwards, T., Egberts, K., Eger, P., Ernenwein, J. -P., Espigat, P., Farnier, C., Fegan, S., Feinstein, F., Fernandes, M. V., Fernandez, D., Fiasson, A., Fontaine, G., Förster, A., Füßling, M., Gabici, S., Gajdus, M., Gallant, Y. A., Garrigoux, T., Giavitto, G., Giebels, B., Glicenstein, J. F., Gottschall, D., Goyal, A., Grondin, M. -H., Grudzińska, M., Hadasch, D., Häffner, S., Hahn, J., Hawkes, J., Heinzelmann, G., Henri, G., Hermann, G., Hervet, O., Hillert, A., Hinton, J. A., Hofmann, W., Hofverberg, P., Hoischen, C., Holler, M., Horns, D., Ivascenko, A., Jacholkowska, A., Jamrozy, M., Janiak, M., Jankowsky, F., Jung-Richardt, I., Kastendieck, M. A., Katarzyński, K., Katz, U., Kerszberg, D., Khélifi, B., Kieffer, M., Klepser, S., Klochkov, D., Kluźniak, W., Kolitzus, D., Komin, Nu., Kosack, K., Krakau, S., Krayzel, F., Krüger, P. P., Laffon, H., Lamanna, G., Lau, J., Lefaucheur, J., Lefranc, V., Lemiére, A., Lemoine-Goumard, M., Lenain, J. -P., Lohse, T., Lopatin, A., Lu, C. -C., Lui, R., Marandon, V., Marcowith, A., Mariaud, C., Marx, R., Maurin, G., Maxted, N., Mayer, M., Meintjes, P. J., Menzler, U., Meyer, M., Mitchell, A. M. W., Moderski, R., Mohamed, M., Morå, K., Moulin, E., Murach, T., de Naurois, M., Niemiec, J., Oakes, L., Odaka, H., Öttl, S., Ohm, S., Opitz, B., Ostrowski, M., Oya, I., Panter, M., Parsons, R. D., Arribas, M. Paz, Pekeur, N. W., Pelletier, G., Petrucci, P. -O., Peyaud, B., Pita, S., Poon, H., Prokoph, H., Pühlhofer, G., Punch, M., Quirrenbach, A., Raab, S., Reichardt, I., Reimer, A., Reimer, O., Renaud, M., Reyes, R. de los, Rieger, F., Romoli, C., Rosier-Lees, S., Rowell, G., Rudak, B., Rulten, C. B., Sahakian, V., Salek, D., Sanchez, D. A., Santangelo, A., Sasaki, M., Schlickeiser, R., Schüssler, F., Schulz, A., Schwanke, U., Schwemmer, S., Seyffert, A. S., Simoni, R., Sol, H., Spanier, F., Spengler, G., Spies, F., Stawarz, Ł., Steenkamp, R., Stegmann, C., Stinzing, F., Stycz, K., Sushch, I., Tavernet, J. -P., Tavernier, T., Taylor, A. M., Terrier, R., Tluczykont, M., Trichard, C., Tuffs, R., Valerius, K., van der Walt, J., van Eldik, C., van Soelen, B., Vasileiadis, G., Veh, J., Venter, C., Viana, A., Vincent, P., Vink, J., Voisin, F., Völk, H. J., Vuillaume, T., Wagner, S. J., Wagner, P., Wagner, R. M., Weidinger, M., Weitzel, Q., White, R., Wierzcholska, A., Willmann, P., Wörnlein, A., Wouters, D., Yang, R., Zabalza, V., Zaborov, D., Zacharias, M., Zdziarski, A. A., Zech, A., Zefi, F., and Żywucka, N.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: Galactic cosmic rays reach energies of at least a few Peta-electronvolts (1 PeV =$10^\mathbf{15}$ electron volts). This implies our Galaxy contains PeV accelerators (PeVatrons), but all proposed models of Galactic cosmic-ray accelerators encounter non-trivial difficulties at exactly these energies. Tens of Galactic accelerators capable of accelerating particle to tens of TeV (1 TeV =$10^\mathbf{12}$ electron volts) energies were inferred from recent gamma-ray observations. None of the currently known accelerators, however, not even the handful of shell-type supernova remnants commonly believed to supply most Galactic cosmic rays, have shown the characteristic tracers of PeV particles: power-law spectra of gamma rays extending without a cutoff or a spectral break to tens of TeV. Here we report deep gamma-ray observations with arcminute angular resolution of the Galactic Centre regions, which show the expected tracer of the presence of PeV particles within the central 10~parsec of the Galaxy. We argue that the supermassive black hole Sagittarius A* is linked to this PeVatron. Sagittarius A* went through active phases in the past, as demonstrated by X-ray outbursts and an outflow from the Galactic Centre. Although its current rate of particle acceleration is not sufficient to provide a substantial contribution to Galactic cosmic rays, Sagittarius A* could have plausibly been more active over the last $\gtrsim 10^{6-7}$ years, and therefore should be considered as a viable alternative to supernova remnants as a source of PeV Galactic cosmic rays., Comment: 29 pages, 7 figures, 3 tables, in press, for official published article see http://www.nature.com/nature/journal/v531/n7595/full/nature17147.html
Published: 2016
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16. Detailed spectral and morphological analysis of the shell type SNR RCW 86

Author: Collaboration, H. E. S. S., Abramowski, A., Aharonian, F., Benkhali, F. Ait, Akhperjanian, A. G., Angüner, E. O., Backes, M., Balzer, A., Becherini, Y., Tjus, J. Becker, Berge, D., Bernhard, S., Bernlöhr, K., Birsin, E., Blackwell, R., Böttcher, M., Boisson, C., Bolmont, J., Bordas, P., Bregeon, J., Brun, F., Brun, P., Bryan, M., Bulik, T., Carr, J., Casanova, S., Chakraborty, N., Chalme-Calvet, R., Chaves, R. C. G., Chen, A., Chevalier, J., Chretien, M., Colafrancesco, S., Cologna, G., Condon, B., Conrad, J., Couturier, C., Cui, Y., Davids, I. D., Degrange, B., Deil, C., deWilt, P., Djannati-Atai, A., Domainko, W., Donath, A., Drury, L. O'C., Dubus, G., Dutson, K., Dyks, J., Dyrda, M., Edwards, T., Egberts, K., Eger, P., Ernenwein, J. -P., Espigat, P., Farnier, C., Fegan, S., Feinstein, F., Fernandes, M. V., Fernandez, D., Fiasson, A., Fontaine, G., Förster, A., Füßling, M., Gabici, S., Gajdus, M., Gallant, Y. A., Garrigoux, T., Giavitto, G., Giebels, B., Glicenstein, J. F., Gottschall, D., Goyal, A., Grondin, M. -H., Grudzińska, M., Hadasch, D., Häffner, S., Hahn, J., Hawkes, J., Heinzelmann, G., Henri, G., Hermann, G., Hervet, O., Hillert, A., Hinton, J. A., Hofmann, W., Hofverberg, P., Hoischen, C., Holler, M., Horns, D., Ivascenko, A., Jacholkowska, A., Jamrozy, M., Janiak, M., Jankowsky, F., Jung-Richardt, I., Kastendieck, M. A., Katarzynski, K., Katz, U., Kerszberg, D., Khelifi, B., Kieffer, M., Klepser, S., Klochkov, D., Kluzniak, W., Kolitzus, D., Komin, Nu., Kosack, K., Krakau, S., Krayzel, F., Krüger, P. P., Laffon, H., Lamanna, G., Lau, J., Lefaucheur, J., Lefranc, V., Lemiere, A., Lemoine-Goumard, M., Lenain, J. -P., Lohse, T., Lopatin, A., Lorentz, M., Lu, C. -C., Lui, R., Marandon, V., Marcowith, A., Mariaud, C., Marx, R., Maurin, G., Maxted, N., Mayer, M., Meintjes, P. J., Menzler, U., Meyer, M., Mitchell, A. M. W., Moderski, R., Mohamed, M., Moraa, K., Moulin, E., Murach, T., de Naurois, M., Niemiec, J., Oakes, L., Odaka, H., Öttl, Ohm, S., Opitz, B., Ostrowski, M., Oya, I., Panter, M., Parsons, R. D., Arribas, M. Paz, Pekeur, N. W., Pelletier, G., Petrucci, P. -O., Peyaud, B., Pita, S., Poon, H., Prokhorov, D., Prokoph, H., Pühlhofer, G., Punch, M., Quirrenbach, A., Raab, S., Reichardt, I., Reimer, A., Reimer, O., Renaud, M., Reyes, R. de los, Rieger, F., Romoli, C., Rosier-Lees, S., Rowell, G., Rudak, B., Rulten, C. B., Sahakian, V., Salek, D., Sanchez, D. A., Santangelo, A., Sasaki, M., Schlickeiser, R., Schüssler, F., Schulz, A., Schwanke, U., Schwemmer, S., Seyffert, A. S., Simoni, R., Sol, H., Spanier, F., Spengler, G., Spies, F., Stawarz, L., Steenkamp, R., Stegmann, C., Stinzing, F., Stycz, K., Sushch, I., Tavernet, J. -P., Tavernier, T., Taylor, A. M., Terrier, R., Tluczykont, M., Trichard, C., Tuffs, R., Valerius, K., van der Walt, J., van Eldik, C., van Soelen, B., Vasileiadis, G., Veh, J., Venter, C., Viana, A., Vincent, P., Vink, J., Voisin, F., Völk, H. J., Vuillaume, T., Wagner, S. J., Wagner, P., Wagner, R. M., Weidinger, M., White, R., Wierzcholska, A., Willmann, P., Wörnlein, A., Wouters, D., Yang, R., Zabalza, V., Zaborov, D., Zacharia, M., Zdziarski, A. A., Zech, A., Zefi, F., and Zywucka, N.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: Aims: We aim for an understanding of the morphological and spectral properties of the supernova remnant RCW~86 and for insights into the production mechanism leading to the RCW~86 very high-energy gamma-ray emission. Methods: We analyzed High Energy Spectroscopic System data that had increased sensitivity compared to the observations presented in the RCW~86 H.E.S.S. discovery publication. Studies of the morphological correlation between the 0.5-1~keV X-ray band, the 2-5~keV X-ray band, radio, and gamma-ray emissions have been performed as well as broadband modeling of the spectral energy distribution with two different emission models. Results:We present the first conclusive evidence that the TeV gamma-ray emission region is shell-like based on our morphological studies. The comparison with 2-5~keV X-ray data reveals a correlation with the 0.4-50~TeV gamma-ray emission.The spectrum of RCW~86 is best described by a power law with an exponential cutoff at $E_{cut}=(3.5\pm 1.2_{stat})$ TeV and a spectral index of $\Gamma$~$1.6\pm 0.2$. A static leptonic one-zone model adequately describes the measured spectral energy distribution of RCW~86, with the resultant total kinetic energy of the electrons above 1 GeV being equivalent to $\sim$0.1\% of the initial kinetic energy of a Type I a supernova explosion. When using a hadronic model, a magnetic field of $B$~100$\mu$G is needed to represent the measured data. Although this is comparable to formerly published estimates, a standard E$^{-2}$ spectrum for the proton distribution cannot describe the gamma-ray data. Instead, a spectral index of $\Gamma_p$~1.7 would be required, which implies that ~$7\times 10^{49}/n_{cm^{-3}}$erg has been transferred into high-energy protons with the effective density $n_{cm^{-3}}=n/ 1$ cm^-3. This is about 10\% of the kinetic energy of a typical Type Ia supernova under the assumption of a density of 1~cm^-3., Comment: accepted for publication by A&A
Published: 2016
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17. Discovery of variable VHE gamma-ray emission from the binary system 1FGL J1018.6-5856

Author: Collaboration, H. E. S. S., Abramowski, A., Aharonian, F., Benkhali, F. Ait, Akhperjanian, A. G., Angüner, E. O., Backes, M., Balzer, A., Becherini, Y., Tjus, J. Becker, Berge, D., Bernhard, S., Bernlöhr, K., Birsin, E., Blackwell, R., Böttcher, M., Boisson, C., Bolmont, J., Bordas, P., Bregeon, J., Brun, F., Brun, P., Bryan, M., Bulik, T., Carr, J., Casanova, S., Chakraborty, N., Chalme-Calvet, R., Chaves, R. C. G., Chen, A., Chrétien, M., Colafrancesco, S., Cologna, G., Conrad, J., Couturier, C., Cui, Y., Davids, I. D., Degrange, B., Deil, C., deWilt, P., Djannati-Ataï, A., Domainko, W., Donath, A., Drury, L. O'C., Dubus, G., Dutson, K., Dyks, J., Dyrda, M., Edwards, T., Egberts, K., Eger, P., Ernenwein, J. -P., Espigat, P., Farnier, C., Fegan, S., Feinstein, F., Fernandes, M. V., Fernandez, D., Fiasson, A., Fontaine, G., Förster, A., Füßling, M., Gabici, S., Gajdus, M., Gallant, Y. A., Garrigoux, T., Giavitto, G., Giebels, B., Glicenstein, J. F., Gottschall, D., Goyal, A., Grondin, M. -H., Grudzińska, M., Hadasch, D., Häffner, S., Hahn, J., Hawkes, J., Heinzelmann, G., Henri, G., Hermann, G., Hervet, O., Hillert, A., Hinton, J. A., Hofmann, W., Hofverberg, P., Hoischen, C., Holler, M., Horns, D., Ivascenko, A., Jacholkowska, A., Jahn, C., Jamrozy, M., Janiak, M., Jankowsky, F., Jung-Richardt, I., Kastendieck, M. A., Katarzyński, K., Katz, U., Kerszberg, D., Khélifi, B., Kieffer, M., Klepser, S., Klochkov, D., Kluźniak, W., Kolitzus, D., Komin, Nu., Kosack, K., Krakau, S., Krayzel, F., Krüger, P. P., Laffon, H., Lamanna, G., Lau, J., Lefaucheur, J., Lefranc, V., Lemière, A., Lemoine-Goumard, M., Lenain, J. -P., Lohse, T., Lopatin, A., Lu, C. -C., Lui, R., Marandon, V., Marcowith, A., Mariaud, C., Marx, R., Maurin, G., Maxted, N., Mayer, M., Meintjes, P. J., Menzler, U., Meyer, M., Mitchell, A. M. W., Moderski, R., Mohamed, M., Morå, K., Moulin, E., Murach, T., de Naurois, M., Niemiec, J., Oakes, L., Odaka, H., Öttl, S., Ohm, S., Wilhelmi, E. de Oña, Opitz, B., Ostrowski, M., Oya, I., Panter, M., Parsons, R. D., Arribas, M. Paz, Pekeur, N. W., Pelletier, G., Petrucci, P. -O., Peyaud, B., Pita, S., Poon, H., Prokoph, H., Pühlhofer, G., Punch, M., Quirrenbach, A., Raab, S., Reichardt, I., Reimer, A., Reimer, O., Renaud, M., Reyes, R. de los, Rieger, F., Romoli, C., Rosier-Lees, S., Rowell, G., Rudak, B., Rulten, C. B., Sahakian, V., Salek, D., Sanchez, D. A., Santangelo, A., Sasaki, M., Schlickeiser, R., Schüssler, F., Schulz, A., Schwanke, U., Schwemmer, S., Seyffert, A. S., Simoni, R., Sol, H., Spanier, F., Spengler, G., Spies, F., Stawarz, Ł., Steenkamp, R., Stegmann, C., Stinzing, F., Stycz, K., Sushch, I., Tavernet, J. -P., Tavernier, T., Taylor, A. M., Terrier, R., Tluczykont, M., Trichard, C., Valerius, K., van der Walt, J., van Eldik, C., van Soelen, B., Vasileiadis, G., Veh, J., Venter, C., Viana, A., Vincent, P., Vink, J., Voisin, F., Völk, H. J., Vuillaume, T., Wagner, S. J., Wagner, P., Wagner, R. M., Weidinger, M., Weitzel, Q., White, R., Wierzcholska, A., Willmann, P., Wörnlein, A., Wouters, D., Yang, R., Zabalza, V., Zaborov, D., Zacharias, M., Zdziarski, A. A., Zech, A., Zefi, F., and Żywucka, N.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: Re-observations with the H.E.S.S. telescope array of the very-high-energy (VHE) source HESS J1018-589 A coincident with the Fermi-LAT $\gamma$-ray binary 1FGL J1018.6-5856 have resulted in a source detection significance of more than 9$\sigma$, and the detection of variability ($\chi^2$/$\nu$ of 238.3/155) in the emitted $\gamma$-ray flux. This variability confirms the association of HESS J1018-589 A with the high-energy $\gamma$-ray binary detected by Fermi-LAT, and also confirms the point-like source as a new very-high-energy binary system. The spectrum of HESS J1018-589 A is best fit with a power-law function with photon index $\Gamma = 2.20 \pm 0.14_{\rm stat} \pm 0.2_{\rm sys}$. Emission is detected up to ~20 TeV. The mean differential flux level is $(2.9 \pm 0.4)\times10^{-13}$ TeV$^{-1}$ cm$^{-2}$ s$^{-1}$ at 1 TeV, equivalent to ~1% of the flux from the Crab Nebula at the same energy. Variability is clearly detected in the night-by-night lightcurve. When folded on the orbital period of 16.58 days, the rebinned lightcurve peaks in phase with the observed X-ray and high-energy phaseograms. The fit of the H.E.S.S. phaseogram to a constant flux provides evidence of periodicity at the level of 3$\sigma$. The shape of the VHE phaseogram and measured spectrum suggest a low inclination, low eccentricity system with a modest impact from VHE $\gamma$-ray absorption due to pair production ($\tau$ < 1 at 300 GeV)., Comment: Accepted for publication in A&A
Published: 2015
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18. Constraints on an Annihilation Signal from a Core of Constant Dark Matter Density around the Milky Way Center with H.E.S.S

Author: HESS Collaboration, Abramowski, A., Aharonian, F., Benkhali, F. Ait, Akhperjanian, A. G., Angüner, E. O., Backes, M., Balenderan, S., Balzer, A., Barnacka, A., Becherini, Y., Tjus, J. Becker, Berge, D., Bernhard, S., Bernlöhr, K., Birsin, E., Biteau, J., Böttcher, M., Boisson, C., Bolmont, J., Bordas, P., Bregeon, J., Brun, F., Brun, P., Bryan, M., Bulik, T., Carrigan, S., Casanova, S., Chadwick, P. M., Chakraborty, N., Chalme-Calvet, R., Chaves, R. C. G., Chrétien, M., Colafrancesco, S., Cologna, G., Conrad, J., Couturier, C., Cui, Y., Davids, I. D., Degrange, B., Deil, C., deWilt, P., Djannati-Ataï, A., Domainko, W., Donath, A., Drury, L. O'C., Dubus, G., Dutson, K., Dyks, J., Dyrda, M., Edwards, T., Egberts, K., Eger, P., Espigat, P., Farnier, C., Fegan, S., Feinstein, F., Fernandes, M. V., Fernandez, D., Fiasson, A., Fontaine, G., Förster, A., Füßling, M., Gabici, S., Gajdus, M., Gallant, Y. A., Garrigoux, T., Giavitto, G., Giebels, B., Glicenstein, J. F., Gottschall, D., Grondin, M. -H., Grudzińska, M., Hadasch, D., Häffner, S., Hahn, J., Harris, J., Heinzelmann, G., Henri, G., Hermann, G., Hervet, O., Hillert, A., Hinton, J. A., Hofmann, W., Hofverberg, P., Holler, M., Horns, D., Ivascenko, A., Jacholkowska, A., Jahn, C., Jamrozy, M., Janiak, M., Jankowsky, F., Jung-Richardt, I., Kastendieck, M. A., Katarzyński, K., Katz, U., Kaufmann, S., Khélifi, B., Kieffer, M., Klepser, S., Klochkov, D., Kluźniak, W., Kolitzus, D., Komin, Nu., Kosack, K., Krakau, S., Krayzel, F., Krüger, P. P., Laffon, H., Lamanna, G., Lefaucheur, J., Lefranc, V., Lemière, A., Lemoine-Goumard, M., Lenain, J. -P., Lohse, T., Lopatin, A., Lu, C. -C., Marandon, V., Marcowith, A., Marx, R., Maurin, G., Maxted, N., Mayer, M., McComb, T. J. L., Méhault, J., Meintjes, P. J., Menzler, U., Meyer, M., Mitchell, A. M. W., Moderski, R., Mohamed, M., Morå, K., Moulin, E., Murach, T., de Naurois, M., Niemiec, J., Nolan, S. J., Oakes, L., Odaka, H., Ohm, S., Opitz, B., Ostrowski, M., Oya, I., Panter, M., Parsons, R. D., Arribas, M. Paz, Pekeur, N. W., Pelletier, G., Petrucci, P. -O., Peyaud, B., Pita, S., Poon, H., Pühlhofer, G., Punch, M., Quirrenbach, A., Raab, S., Reichardt, I., Reimer, A., Reimer, O., Renaud, M., Reyes, R. de los, Rieger, F., Romoli, C., Rosier-Lees, S., Rowell, G., Rudak, B., Rulten, C. B., Sahakian, V., Salek, D., Sanchez, D. A., Santangelo, A., Schlickeiser, R., Schüssler, F., Schulz, A., Schwanke, U., Schwarzburg, S., Schwemmer, S., Sol, H., Spanier, F., Spengler, G., Spies, F., Stawarz, Ł., Steenkamp, R., Stegmann, C., Stinzing, F., Stycz, K., Sushch, I., Tavernet, J. -P., Tavernier, T., Taylor, A. M., Terrier, R., Tluczykont, M., Trichard, C., Valerius, K., van Eldik, C., van Soelen, B., Vasileiadis, G., Veh, J., Venter, C., Viana, A., Vincent, P., Vink, J., Völk, H. J., Volpe, F., Vorster, M., Vuillaume, T., Wagner, S. J., Wagner, P., Wagner, R. M., Ward, M., Weidinger, M., Weitzel, Q., White, R., Wierzcholska, A., Willmann, P., Wörnlein, A., Wouters, D., Yang, R., Zabalza, V., Zaborov, D., Zacharias, M., Zdziarski, A. A., Zech, A., and Zechlin, H. -S.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: An annihilation signal of dark matter is searched for from the central region of the Milky Way. Data acquired in dedicated ON/OFF observations of the Galactic center region with H.E.S.S. are analyzed for this purpose. No significant signal is found in a total of $\sim 9$ h of ON/OFF observations. Upper limits on the velocity averaged cross section, $<\sigma v >$, for the annihilation of dark matter particles with masses in the range of $\sim 300$ GeV to $\sim 10$ TeV are derived. In contrast to previous constraints derived from observations of the Galactic center region, the constraints that are derived here apply also under the assumption of a central core of constant dark matter density around the center of the Galaxy. Values of $<\sigma v >$ that are larger than $3\cdot 10^{-24}\:\mathrm{cm^3/s}$ are excluded for dark matter particles with masses between $\sim 1$ and $\sim 4$ TeV at 95% CL if the radius of the central dark matter density core does not exceed $500$ pc. This is the strongest constraint that is derived on $<\sigma v>$ for annihilating TeV mass dark matter without the assumption of a centrally cusped dark matter density distribution in the search region., Comment: Accepted for publication by Physical Review Letters, contact authors: Ullrich Schwanke (schwanke@physik.hu-berlin.de, Humboldt Universitaet zu Berlin, Berlin) and Gerrit Spengler (gerrit.spengler@fysik.su.se, Oscar Klein Centre for Cosmoparticle Physics, Stockholm)
Published: 2015
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19. The exceptionally powerful TeV gamma-ray emitters in the Large Magellanic Cloud

Author: Collaboration, H. E. S. S., Abramowski, A., Aharonian, F., Benkhali, F. Ait, Akhperjanian, A. G., Angüner, E. O., Backes, M., Balenderan, S., Balzer, A., Barnacka, A., Becherini, Y., Becker-Tjus, J., Berge, D., Bernhard, S., Bernlöhr, K., Birsin, E., Biteau, J., Böttcher, M., Boisson, C., Bolmont, J., Bordas, P., Bregeon, J., Brun, F., Brun, P., Bryan, M., Bulik, T., Carrigan, S., Casanova, S., Chadwick, P. M., Chakraborty, N., Chalme-Calvet, R., Chaves, R. C. G., Chrétien, M., Colafrancesco, S., Cologna, G., Conrad, J., Couturier, C., Cui, Y., Dalton, M., Davids, I. D., Degrange, B., Deil, C., de Wilt, P., Djannati-Ataï, A., Domainko, W., Donath, A., Drury, L. O'C., Dubus, G., Dutson, K., Dyks, J., Dyrda, M., Edwards, T., Egberts, K., Eger, P., Espigat, P., Farnier, C., Fegan, S., Feinstein, F., Fernandes, M. V., Fernandez, D., Fiasson, A., Fontaine, G., Förster, A., Füßling, M., Gabici, S., Gajdus, M., Gallant, Y. A., Garrigoux, T., Giavitto, G., Giebels, B., Glicenstein, J. F., Gottschall, D., Grondin, M. -H., Grudzińska, M., Hadasch, D., Häffner, S., Hahn, J., Harris, J., Heinzelmann, G., Henri, G., Hermann, G., Hervet, O., Hillert, A., Hinton, J. A., Hofmann, W., Hofverberg, P., Holler, M., Horns, D., Ivascenko, A., Jacholkowska, A., Jahn, C., Jamrozy, M., Janiak, M., Jankowsky, F., Jung, I., Kastendieck, M. A., Katarzyński, K., Katz, U., Kaufmann, S., Khélifi, B., Kieffer, M., Klepser, S., Klochkov, D., Kluźniak, W., Kolitzus, D., Komin, Nu., Kosack, K., Krakau, S., Krayzel, F., Krüger, P. P., Laffon, H., Lamanna, G., Lefaucheur, J., Lefranc, V., Lemière, A., Lemoine-Goumard, M., Lenain, J. -P., Lohse, T., Lopatin, A., Lu, C. -C., Marandon, V., Marcowith, A., Marx, R., Maurin, G., Maxted, N., Mayer, M., McComb, T. J. L., Méhault, J., Meintjes, P. J., Menzler, U., Meyer, M., Mitchell, A. M. W., Moderski, R., Mohamed, M., Morå, K., Moulin, E., Murach, T., de Naurois, M., Niemiec, J., Nolan, S. J., Oakes, L., Odaka, H., Ohm, S., Opitz, B., Ostrowski, M., Oya, I., Panter, M., Parsons, R. D., Arribas, M. Paz, Pekeur, N. W., Pelletier, G., Perez, J., Petrucci, P. -O., Peyaud, B., Pita, S., Poon, H., Pühlhofer, G., Punch, M., Quirrenbach, A., Raab, S., Reichardt, I., Reimer, A., Reimer, O., Renaud, M., Reyes, R. de los, Rieger, F., Rob, L., Romoli, C., Rosier-Lees, S., Rowell, G., Rudak, B., Sahakian, C. B. Rulten V., Salek, D., Sanchez, D. A., Santangelo, A., Schlickeiser, R., Schüssler, F., Schulz, A., Schwanke, U., Schwarzburg, S., Schwemmer, S., Sol, H., Spanier, F., Spengler, G., Spies, F., Stawarz, Ł., Steenkamp, R., Stegmann, C., Stinzing, F., Stycz, K., Sushch, I., Tavernet, J. -P., Tavernier, T., Taylor, A. M., Terrier, R., Tluczykont, M., Trichard, C., Valerius, K., van Eldik, C., van Soelen, B., Vasileiadis, G., Veh, J., Venter, C., Viana, A., Vincent, P., Vink, J., Völk, H. J., Volpe, F., Vorster, M., Vuillaume, T., Wagner, S. J., Wagner, P., Wagner, R. M., Ward, M., Weidinger, M., Weitzel, Q., White, R., Wierzcholska, A., Willmann, P., Wörnlein, A., Wouters, D., Yang, R., Zabalza, V., Zaborov, D., Zacharias, M., Zdziarski, A. A., Zech, A., and Zechlin, H. -S.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: The Large Magellanic Cloud, a satellite galaxy of the Milky Way, has been observed with the High Energy Stereoscopic System (H.E.S.S.) above an energy of 100 billion electron volts for a deep exposure of 210 hours. Three sources of different types were detected: the pulsar wind nebula of the most energetic pulsar known N 157B, the radio-loud supernova remnant N 132D and the largest non-thermal X-ray shell - the superbubble 30 Dor C. The unique object SN 1987A is, surprisingly, not detected, which constrains the theoretical framework of particle acceleration in very young supernova remnants. These detections reveal the most energetic tip of a gamma-ray source population in an external galaxy, and provide via 30 Dor C the unambiguous detection of gamma-ray emission from a superbubble., Comment: Published in Science Magazine (Jan. 23, 2015). This ArXiv version has the supplementary online material incorporated as an appendix to the main paper
Published: 2015
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20. The 2012 flare of PG 1553+113 seen with H.E.S.S. and Fermi-LAT

Author: Abramowski, A., Aharonian, F., Benkhali, F. Ait, Akhperjanian, A. G., Angüner, E. O., Backes, M., Balenderan, S., Balzer, A., Barnacka, A., Becherini, Y., Tjus, J. Becker, Berge, D., Bernhard, S., Bernlöhr, K., Birsin, E., Biteau, J., Böttcher, M., Boisson, C., Bolmont, J., Bordas, P., Bregeon, J., Brun, F., Brun, P., Bryan, M., Bulik, T., Carrigan, S., Casanova, S., Chadwick, P. M., Chakraborty, N., Chalme-Calvet, R., Chaves, R. C. G., Chrétien, M., Colafrancesco, S., Cologna, G., Conrad, J., Couturier, C., Cui, Y., Dalton, M., Davids, I. D., Degrange, B., Deil, C., deWilt, P., Djannati-Ataï, A., Domainko, W., Donath, A., Drury, L. O'C., Dubus, G., Dutson, K., Dyks, J., Dyrda, M., Edwards, T., Egberts, K., Eger, P., Espigat, P., Farnier, C., Fegan, S., Feinstein, F., Fernandes, M. V., Fernandez, D., Fiasson, A., Fontaine, G., Förster, A., Füßling, M., Gabici, S., Gajdus, M., Gallant, Y. A., Garrigoux, T., Giavitto, G., Giebels, B., Glicenstein, J. F., Gottschall, D., Grondin, M. -H., Grudzińska, M., Hadsch, D., Häffner, S., Hahn, J., Harris, J., Heinzelmann, G., Henri, G., Hermann, G., Hervet, O., Hillert, A., Hinton, J. A., Hofmann, W., Hofverberg, P., Holler, M., Horns, D., Ivascenko, A., Jacholkowska, A., Jahn, C., Jamrozy, M., Janiak, M., Jankowsky, F., Jung, I., Kastendieck, M. A., Katarzyński, K., Katz, U., Kaufmann, S., Khélifi, B., Kieffer, M., Klepser, S., Klochkov, D., Kluźniak, W., Kolitzus, D., Komin, Nu., Kosack, K., Krakau, S., Krayzel, F., Krüger, P. P., Laffon, H., Lamanna, G., Lefaucheur, J., Lefranc, V., Lemière, A., Lemoine-Goumard, M., Lenain, J. -P., Lohse, T., Lopatin, A., Lu, C. -C., Marandon, V., Marcowith, A., Marx, R., Maurin, G., Maxted, N., Mayer, M., McComb, T. J. L., Méhault, J., Meintjes, P. J., Menzler, U., Meyer, M., Mitchell, A. M. W., Moderski, R., Mohamed, M., Morå, K., Moulin, E., Murach, T., de Naurois, M., Niemiec, J., Nolan, S. J., Oakes, L., Odaka, H., Ohm, S., Opitz, B., Ostrowski, M., Oya, I., Panter, M., Parsons, R. D., Arribas, M. Paz, Pekeur, N. W., Pelletier, G., Perez, J., Petrucci, P. -O., Peyaud, B., Pita, S., Poon, H., Pühlhofer, G., Punch, M., Quirrenbach, A., Raab, S., Reichardt, I., Reimer, A., Reimer, O., Renaud, M., Reyes, R. de los, Rieger, F., Rob, L., Romoli, C., Rosier-Lees, S., Rowell, G., Rudak, B., Rulten, C. B., Sahakian, V., Salek, D., Sanchez, D. A., Santangelo, A., Schlickeiser, R., Schüssler, F., Schulz, A., Schwanke, U., Schwarzburg, S., Schwemmer, S., Sol, H., Spanier, F., Spengler, G., Spies, F., Stawarz, Ł., Steenkamp, R., Stegmann, C., Stinzing, F., Stycz, K., Sushch, I., Tavernet, J. -P., Tavernier, T., Taylor, A. M., Terrier, R., Tluczykont, M., Trichard, C., Valerius, K., van Eldik, C., van Soelen, B., Vasileiadis, G., Veh, J., Venter, C., Viana, A., Vincent, P., Vink, J., Völk, H. J., Volpe, F., Vorster, M., Vuillaume, T., Wagner, P., Wagner, R. M., Ward, M., Weidinger, M., Weitzel, Q., White, R., Wierzcholska, A., Willmann, P., Wörnlein, A., Wouters, D., Yang, R., Zabalza, V., Zaborov, D., Zacharias, M., Zdziarski, A. A., Zech, A., and Zechlin, H. -S.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: Very high energy (VHE, $E>$100 GeV) $\gamma$-ray flaring activity of the high-frequency peaked BL Lac object \pg\ has been detected by the \hess\ telescopes. The flux of the source increased by a factor of 3 during the nights of 2012 April 26 and 27 with respect to the archival measurements with hint of intra-night variability. No counterpart of this event has been detected in the \fla\ data. This pattern is consistent with VHE $\gamma$ ray flaring being caused by the injection of ultrarelativistic particles, emitting $\gamma$ rays at the highest energies. The dataset offers a unique opportunity to constrain the redshift of this source at \bestz\ using a novel method based on Bayesian statistics. The indication of intra-night variability is used to introduce a novel method to probe for a possible Lorentz Invariance Violation (LIV), and to set limits on the energy scale at which Quantum Gravity (QG) effects causing LIV may arise. For the subluminal case, the derived limits are $\textrm{E}_{\rm QG,1}>4.10\times 10^{17}$ GeV and $\textrm{E}_{\rm QG,2}>2.10\times 10^{10}$ GeV for linear and quadratic LIV effects, respectively., Comment: 39 pages, 9 figures
Published: 2015
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21. H.E.S.S. reveals a lack of TeV emission from the supernova remnant Puppis A

Author: Collaboration, H. E. S. S., Abramowski, A., Aharonian, F., Benkhali, F. Ait, Akhperjanian, A. G., Angüner, E. O., Backes, M., Balenderan, S., Balzer, A., Barnacka, A., Becherini, Y., Tjus, J. Becker, Berge, D., Bernhard, S., Bernlöhr, K., Birsin, E., Biteau, J., Böttcher, M., Boisson, C., Bolmont, J., Bordas, P., Bregeon, J., Brun, F., Brun, P., Bryan, M., Bulik, T., Carrigan, S., Casanova, S., Chadwick, P. M., Chakraborty, N., Chalme-Calvet, R., Chaves, R. C. G., Chrétien, M., Colafrancesco, S., Cologna, G., Conrad, J., Couturier, C., Cui, Y., Davids, I. D., Degrange, B., Deil, C., deWilt, P., Djannati-Ataï, A., Domainko, W., Donath, A., Drury, L. O'C., Dubus, G., Dutson, K., Dyks, J., Dyrda, M., Edwards, T., Egberts, K., Eger, P., Espigat, P., Farnier, C., Fegan, S., Feinstein, F., Fernandes, M. V., Fernandez, D., Fiasson, A., Fontaine, G., Förster, A., Füßling, M., Gabici, S., Gajdus, M., Gallant, Y. A., Garrigoux, T., Giavitto, G., Giebels, B., Glicenstein, J. F., Gottschall, D., Grondin, M. -H., Grudzińska, M., Hadasch, D., Häffner, S., Hahn, J., Harris, J., Heinzelmann, G., Henri, G., Hermann, G., Hervet, O., Hillert, A., Hinton, J. A., Hofmann, W., Hofverberg, P., Holler, M., Horns, D., Ivascenko, A., Jacholkowska, A., Jahn, C., Jamrozy, M., Janiak, M., Jankowsky, F., Jung-Richardt, I., Kastendieck, M. A., Katarzyński, K., Katz, U., Kaufmann, S., Khélifi, B., Kieffer, M., Klepser, S., Klochkov, D., Kluźniak, W., Kolitzus, D., Komin, Nu., Kosack, K., Krakau, S., Krayzel, F., Krüger, P. P., Laffon, H., Lamanna, G., Lefaucheur, J., Lefranc, V., Lemière, A., Lemoine-Goumard, M., Lenain, J. -P., Lohse, T., Lopatin, A., Lu, C. -C., Marandon, V., Marcowith, A., Marx, R., Maurin, G., Maxted, N., Mayer, M., McComb, T. J. L., Méhault, J., Meintjes, P. J., Menzler, U., Meyer, M., Mitchell, A. M. W., Moderski, R., Mohamed, M., Morå, K., Moulin, E., Murach, T., de Naurois, M., Niemiec, J., Nolan, S. J., Oakes, L., Odaka, H., Ohm, S., Opitz, B., Ostrowski, M., Oya, I., Panter, M., Parsons, R. D., Arribas, M. Paz, Pekeur, N. W., Pelletier, G., Petrucci, P. -O., Peyaud, B., Pita, S., Poon, H., Pühlhofer, G., Punch, M., Quirrenbach, A., Raab, S., Reichardt, I., Reimer, A., Reimer, O., Renaud, M., Reyes, R. de los, Rieger, F., Romoli, C., Rosier-Lees, S., Rowell, G., Rudak, B., Rulten, C. B., Sahakian, V., Salek, D., Sanchez, D. A., Santangelo, A., Schlickeiser, R., Schüssler, F., Schulz, A., Schwanke, U., Schwarzburg, S., Schwemmer, S., Sol, H., Spanier, F., Spengler, G., Spies, F., Stawarz, Ł., Steenkamp, R., Stegmann, C., Stinzing, F., Stycz, K., Sushch, I., Tavernet, J. -P., Tavernier, T., Taylor, A. M., Terrier, R., Tluczykont, M., Trichard, C., Valerius, K., van Eldik, C., van Soelen, B., Vasileiadis, G., Veh, J., Venter, C., Viana, A., Vincent, P., Vink, J., Völk, H. J., Volpe, F., Vorster, M., Vuillaume, T., Wagner, S. J., Wagner, P., Wagner, R. M., Ward, M., Weidinger, M., Weitzel, Q., White, R., Wierzcholska, A., Willmann, P., Wörnlein, A., Wouters, D., Yang, R., Zabalza, V., Zaborov, D., Zacharias, M., Zdziarski, A. A., Zech, A., and Zechlin, H. -S.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: Puppis A is an interesting ~4 kyr-old supernova remnant (SNR) that shows strong evidence of interaction between the forward shock and a molecular cloud. It has been studied in detail from radio frequencies to high-energy (HE, 0.1-100 GeV) gamma-rays. An analysis of the Fermi-LAT data has shown an extended HE gamma-ray emission with a 0.2-100 GeV spectrum exhibiting no significant deviation from a power law, unlike most of the GeV-emitting SNRs known to be interacting with molecular clouds. This makes it a promising target for imaging atmospheric Cherenkov telescopes (IACTs) to probe the gamma-ray emission above 100 GeV. Very-high-energy (VHE, E >= 0.1 TeV) gamma-ray emission from Puppis A is for the first time searched for with the High Energy Stereoscopic System (H.E.S.S.). The analysis of the H.E.S.S. data does not reveal any significant emission towards Puppis A. The derived upper limits on the differential photon flux imply that its broadband gamma-ray spectrum must exhibit a spectral break or cutoff. By combining Fermi-LAT and H.E.S.S. measurements, the 99% confidence level upper limits on such a cutoff are found to be 450 and 280 GeV, assuming a power law with a simple exponential and a sub-exponential cutoff, respectively. It is concluded that none of the standard limitations (age, size, radiative losses) on the particle acceleration mechanism, assumed to be still on-going at present, can explain the lack of VHE signal. The scenario in which particle acceleration has ceased some time ago is considered as an alternative explanation. The HE/VHE spectrum of Puppis A could then exhibit a break of non-radiative origin, (as observed in several other interacting SNRs, albeit at somewhat higher energies) owing to the interaction with dense and neutral material in particular towards the northeastern region., Comment: Published in A&A 27 Jan 2015. 7 pages, 2 figures, 1 table
Published: 2014
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22. H.E.S.S. detection of TeV emission from the interaction region between the supernova remnant G349.7+0.2 and a molecular cloud

Author: Collaboration, H. E. S. S., Abramowski, A., Aharonian, F., Benkhali, F. Ait, Akhperjanian, A. G., Angüner, E. O., Backes, M., Balenderan, S., Balzer, A., Barnacka, A., Becherini, Y., Tjus, J. Becker, Berge, D., Bernhard, S., Bernlöhr, K., Birsin, E., Biteau, J., Böttcher, M., Boisson, C., Bolmont, J., Bordas, P., Bregeon, J., Brun, F., Brun, P., Bryan, M., Bulik, T., Carrigan, S., Casanova, S., Chadwick, P. M., Chakraborty, N., Chalme-Calvet, R., Chaves, R. C. G., Chrétien, M., Colafrancesco, S., Cologna, G., Conrad, J., Couturier, C., Cui, Y., Davids, I. D., Degrange, B., Deil, C., deWilt, P., Djannati-Ataï, A., Domainko, W., Donath, A., Drury, L. O'C., Dubus, G., Dutson, K., Dyks, J., Dyrda, M., Edwards, T., Egberts, K., Eger, P., Espigat, P., Farnier, C., Fegan, S., Feinstein, F., Fernandes, M. V., Fernandez, D., Fiasson, A., Fontaine, G., Förster, A., Füßling, M., Gabici, S., Gajdus, M., Gallant, Y. A., Garrigoux, T., Giavitto, G., Giebels, B., Glicenstein, J. F., Gottschall, D., Grondin, M. -H., Grudzińska, M., Hadasch, D., Häffner, S., Hahn, J., Harris, J., Heinzelmann, G., Henri, G., Hermann, G., Hervet, O., Hillert, A., Hinton, J. A., Hofmann, W., Hofverberg, P., Holler, M., Horns, D., Ivascenko, A., Jacholkowska, A., Jahn, C., Jamrozy, M., Janiak, M., Jankowsky, F., Jung-Richardt, I., Kastendieck, M. A., Katarzyński, K., Katz, U., Kaufmann, S., Khélifi, B., Kieffer, M., Klepser, S., Klochkov, D., Kluźniak, W., Kolitzus, D., Komin, Nu., Kosack, K., Krakau, S., Krayzel, F., Krüger, P. P., Laffon, H., Lamanna, G., Lefaucheur, J., Lefranc, V., Lemière, A., Lemoine-Goumard, M., Lenain, J. -P., Lohse, T., Lopatin, A., Lu, C. -C., Marandon, V., Marcowith, A., Marx, R., Maurin, G., Maxted, N., Mayer, M., McComb, T. J. L., Méhault, J., Meintjes, P. J., Menzler, U., Meyer, M., Mitchell, A. M. W., Moderski, R., Mohamed, M., Morå, K., Moulin, E., Murach, T., de Naurois, M., Niemiec, J., Nolan, S. J., Oakes, L., Odaka, H., Ohm, S., Opitz, B., Ostrowski, M., Oya, I., Panter, M., Parsons, R. D., Arribas, M. Paz, Pekeur, N. W., Pelletier, G., Petrucci, P. -O., Peyaud, B., Pita, S., Poon, H., Pühlhofer, G., Punch, M., Quirrenbach, A., Raab, S., Reichardt, I., Reimer, A., Reimer, O., Renaud, M., Reyes, R. de los, Rieger, F., Romoli, C., Rosier-Lees, S., Rowell, G., Rudak, B., Rulten, C. B., Sahakian, V., Salek, D., Sanchez, D. A., Santangelo, A., Schlickeiser, R., Schüssler, F., Schulz, A., Schwanke, U., Schwarzburg, S., Schwemmer, S., Sol, H., Spanier, F., Spengler, G., Spies, F., Stawarz, Ł., Steenkamp, R., Stegmann, C., Stinzing, F., Stycz, K., Sushch, I., Tavernet, J. -P., Tavernier, T., Taylor, A. M., Terrier, R., Tluczykont, M., Trichard, C., Valerius, K., van Eldik, C., van Soelen, B., Vasileiadis, G., Veh, J., Venter, C., Viana, A., Vincent, P., Vink, J., Völk, H. J., Volpe, F., Vorster, M., Vuillaume, T., Wagner, S. J., Wagner, P., Wagner, R. M., Ward, M., Weidinger, M., Weitzel, Q., White, R., Wierzcholska, A., Willmann, P., Wörnlein, A., Wouters, D., Yang, R., Zabalza, V., Zaborov, D., Zacharias, M., Zdziarski, A. A., Zech, A., and Zechlin, H. -S.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: G349.7+0.2 is a young Galactic supernova remnant (SNR) located at the distance of 11.5 kpc and observed across the entire electromagnetic spectrum from radio to high energy (HE) Gamma-rays. Radio and infrared observations indicate that the remnant is interacting with a molecular cloud. In this paper, the detection of very high energy (VHE) Gamma-ray emission coincident with this SNR with the High Energy Stereoscopic System (H.E.S.S.) is reported. An integral flux F(E>400GeV)=(6.5 +-1.1stat +-1.3syst) x 10^{-13} ph/cm/s corresponding to 0.7% of that of the Crab Nebula and to a luminosity of 10^34 erg/s above the same energy threshold, and a steep photon index Gamma_VHE = 2.8 +-0.27stat +-0.20syst are measured. The analysis of more than 5 yr of Fermi-LAT data towards this source shows a power-law like spectrum with a best-fit photon index Gamma_HE = 2.2 +-0.04stat +0.13-0.31syst. The combined Gamma-ray spectrum of G349.7+0.2 can be described by either a broken power-law (BPL) or a power-law with exponential (or sub-exponential) cutoff (PLC). In the former case, the photon break energy is found at E_br,gamma = 55 +70-30 GeV, slightly higher than what is usually observed in the HE/VHE Gamma-ray emitting middle-aged SNRs known to be interacting with molecular clouds. In the latter case, the exponential (respectively sub-exponential) cutoff energy is measured at E_cut,gamma = 1.4 +1.6-0.55 (respectively 0.35 +0.75-0.21) TeV. A pion-decay process resulting from the interaction of the accelerated protons and nuclei with the dense surrounding medium is clearly the preferred scenario to explain the Gamma-ray emission. The BPL with a spectral steepening of 0.5-1 and the PLC provide equally good fits to the data. The product of the average gas density and the total energy content of accelerated protons and nuclei amounts to nH Wp ~ 5 x 10^51 erg/cm3., Comment: Accepted for publication in A&A on November 24, 2014
Published: 2014
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23. Diffuse Galactic gamma-ray emission with H.E.S.S

Author: Collaboration, H. E. S. S., Abramowski, A., Aharonian, F., Benkhali, F. Ait, Akhperjanian, A. G., Angüner, E. O., Backes, M., Balenderan, S., Balzer, A., Barnacka, A., Becherini, Y., Tjus, J. Becker, Berge, D., Bernhard, S., Bernlöhr, K., Birsin, E., Biteau, J., Böttcher, M., Boisson, C., Bolmont, J., Bordas, P., Bregeon, J., Brun, F., Brun, P., Bryan, M., Bulik, T., Carrigan, S., Casanova, S., Chadwick, P. M., Chakraborty, N., Chalme-Calvet, R., Chaves, R. C. G., Chrétien, M., Colafrancesco, S., Cologna, G., Conrad, J., Couturier, C., Cui, Y., Davids, I. D., Degrange, B., Deil, C., deWilt, P., Djannati-Ataï, A., Domainko, W., Donath, A., Drury, L. O'C., Dubus, G., Dutson, K., Dyks, J., Dyrda, M., Edwards, T., Egberts, K., Eger, P., Espigat, P., Farnier, C., Fegan, S., Feinstein, F., Fernandes, M. V., Fernandez, D., Fiasson, A., Fontaine, G., Förster, A., Füßling, M., Gabici, S., Gajdus, M., Gallant, Y. A., Garrigoux, T., Giavitto, G., Giebels, B., Glicenstein, J. F., Gottschall, D., Grondin, M. -H., Grudzińska, M., Hadasch, D., Häffner, S., Hahn, J., Harris, J., Heinzelmann, G., Henri, G., Hermann, G., Hervet, O., Hillert, A., Hinton, J. A., Hofmann, W., Hofverberg, P., Holler, M., Horns, D., Ivascenko, A., Jacholkowska, A., Jahn, C., Jamrozy, M., Janiak, M., Jankowsky, F., Jung-Richardt, I., Kastendieck, M. A., Katarzyński, K., Katz, U., Kaufmann, S., Khélifi, B., Kieffer, M., Klepser, S., Klochkov, D., Kluźniak, W., Kolitzus, D., Komin, Nu., Kosack, K., Krakau, S., Krayzel, F., Krüger, P. P., Laffon, H., Lamanna, G., Lefaucheur, J., Lefranc, V., Lemière, A., Lemoine-Goumard, M., Lenain, J. -P., Lohse, T., Lopatin, A., Lu, C. -C., Marandon, V., Marcowith, A., Marx, R., Maurin, G., Maxted, N., Mayer, M., McComb, T. J. L., Méhault, J., Meintjes, P. J., Menzler, U., Meyer, M., Mitchell, A. M. W., Moderski, R., Mohamed, M., Morå, K., Moulin, E., Murach, T., de Naurois, M., Niemiec, J., Nolan, S. J., Oakes, L., Odaka, H., Ohm, S., Opitz, B., Ostrowski, M., Oya, I., Panter, M., Parsons, R. D., Arribas, M. Paz, Pekeur, N. W., Pelletier, G., Petrucci, P. -O., Peyaud, B., Pita, S., Poon, H., Pühlhofer, G., Punch, M., Quirrenbach, A., Raab, S., Reichardt, I., Reimer, A., Reimer, O., Renaud, M., Reyes, R. de los, Rieger, F., Romoli, C., Rosier-Lees, S., Rowell, G., Rudak, B., Rulten, C. B., Sahakian, V., Salek, D., Sanchez, D. A., Santangelo, A., Schlickeiser, R., Schüssler, F., Schulz, A., Schwanke, U., Schwarzburg, S., Schwemmer, S., Sol, H., Spanier, F., Spengler, G., Spies, F., Stawarz, Ł., Steenkamp, R., Stegmann, C., Stinzing, F., Stycz, K., Sushch, I., Tavernet, J. -P., Tavernier, T., Taylor, A. M., Terrier, R., Tluczykont, M., Trichard, C., Valerius, K., van Eldik, C., van Soelen, B., Vasileiadis, G., Veh, J., Venter, C., Viana, A., Vincent, P., Vink, J., Völk, H. J., Volpe, F., Vorster, M., Vuillaume, T., Wagner, S. J., Wagner, P., Wagner, R. M., Ward, M., Weidinger, M., Weitzel, Q., White, R., Wierzcholska, A., Willmann, P., Wörnlein, A., Wouters, D., Yang, R., Zabalza, V., Zaborov, D., Zacharias, M., Zdziarski, A. A., Zech, A., Zechlin, H. -S., and Fukui, Y.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: Diffuse $\gamma$-ray emission is the most prominent observable signature of celestial cosmic-ray interactions at high energies. While already being investigated at GeV energies over several decades, assessments of diffuse $\gamma$-ray emission at TeV energies remain sparse. After completion of the systematic survey of the inner Galaxy, the H.E.S.S. experiment is in a prime position to observe large-scale diffuse emission at TeV energies. Data of the H.E.S.S. Galactic Plane Survey are investigated in regions off known $\gamma$-ray sources. Corresponding $\gamma$-ray flux measurements were made over an extensive grid of celestial locations. Longitudinal and latitudinal profiles of the observed $\gamma$-ray fluxes show characteristic excess emission not attributable to known $\gamma$-ray sources. For the first time large-scale $\gamma$-ray emission along the Galactic Plane using imaging atmospheric Cherenkov telescopes has been observed. While the background subtraction technique limits the ability to recover modest variation on the scale of the H.E.S.S. field of view or larger, which is characteristic of the inverse Compton scatter-induced Galactic diffuse emission, contributions of neutral pion decay as well as emission from unresolved $\gamma$-ray sources can be recovered in the observed signal to a large fraction. Calculations show that the minimum $\gamma$-ray emission from $\pi^0$-decay represents a significant contribution to the total signal. This detection is interpreted as a mix of diffuse Galactic $\gamma$-ray emission and unresolved sources., Comment: 8 pages, 2 figures, accepted for publication in Physical Review D
Published: 2014
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24. Discovery of the VHE gamma-ray source HESS J1832-093 in the vicinity of SNR G22.7-0.2

Author: Collaboration, H. E. S. S., Abramowski, A., Aharonian, F., Benkhali, F. Ait, Akhperjanian, A. G., Angüner, E., Anton, G., Balenderan, S., Balzer, A., Barnacka, A., Becherini, Y., Tjus, J. Becker, Bernlöhr, K., Birsin, E., Bissaldi, E., Biteau, J., Böttcher, M., Boisson, C., Bolmont, J., Bordas, P., Brucker, J., Brun, F., Brun, P., Bulik, T., Carrigan, S., Casanova, S., Cerruti, M., Chadwick, P. M., Chalme-Calvet, R., Chaves, R. C. G., Cheesebrough, A., Chrétien, M., Colafrancesco, S., Cologna, G., Conrad, J., Couturier, C., Cui, Y., Dalton, M., Daniel, M. K., Davids, I. D., Degrange, B., Deil, C., deWilt, P., Dickinson, H. J., Djannati-Ataï, A., Domainko, W., Drury, L. O'C., Dubus, G., Dutson, K., Dyks, J., Dyrda, M., Edwards, T., Egberts, K., Eger, P., Espigat, P., Farnier, C., Fegan, S., Feinstein, F., Fernandes, M. V., Fernandez, D., Fiasson, A., Fontaine, G., Förster, A., Füßling, M., Gajdus, M., Gallant, Y. A., Garrigoux, T., Giavitto, G., Giebels, B., Glicenstein, J. F., Grondin, M. -H., Grudzińska, M., Häffner, S., Hahn, J., Harris, J., Heinzelmann, G., Henri, G., Hermann, G., Hervet, O., Hillert, A., Hinton, J. A., Hofmann, W., Hofverberg, P., Holler, M., Horns, D., Jacholkowska, A., Jahn, C., Jamrozy, M., Janiak, M., Jankowsky, F., Jung, I., Kastendieck, M. A., Katarzyński, K., Katz, U., Kaufmann, S., Khélifi, B., Kieffer, M., Klepser, S., Klochkov, D., Kluźniak, W., Kneiske, T., Kolitzus, D., Komin, Nu., Kosack, K., Krakau, S., Krayzel, F., Krüger, P. P., Laffon, H., Lamanna, G., Lefaucheur, J., Lemière, A., Lemoine-Goumard, M., Lenain, J. -P., Lennarz, D., Lohse, T., Lopatin, A., Lu, C. -C., Marandon, V., Marcowith, A., Marx, R., Maurin, G., Maxted, N., Mayer, M., McComb, T. J. L., Méhault, J., Meintjes, P. J., Menzler, U., Meyer, M., Moderski, R., Mohamed, M., Moulin, E., Murach, T., Naumann, C. L., de Naurois, M., Niemiec, J., Nolan, S. J., Oakes, L., Ohm, S., Wilhelmi, E. de O na, Opitz, B., Ostrowski, M., Oya, I., Panter, M., Parsons, R. D., Arribas, M. Paz, Pekeur, N. W., Pelletier, G., Perez, J., Petrucci, P. -O., Peyaud, B., Pita, S., Poon, H., Pühlhofer, G., Punch, M., Quirrenbach, A., Raab, S., Raue, M., Reimer, A., Reimer, O., Renaud, M., Reyes, R. de los, Rieger, F., Rob, L., Romoli, C., Rosier-Lees, S., Rowell, G., Rudak, B., Rulten, C. B., Sahakian, V., Sanchez, D. A., Santangelo, A., Schlickeiser, R., Schüssler, F., Schulz, A., Schwanke, U., Schwarzburg, S., Schwemmer, S., Sol, H., Spengler, G., Spies, F., Stawarz, L., Steenkamp, R., Stegmann, C., Stinzing, F., Stycz, K., Sushch, I., Szostek, A., Tavernet, J. -P., Tavernier, T., Taylor, A. M., Terrier, R., Tluczykont, M., Trichard, C., Valerius, K., van Eldik, C., van Soelen, B., Vasileiadis, G., Venter, C., Viana, A., Vincent, P., Völk, H. J., Volpe, F., Vorster, M., Vuillaume, T., Wagner, S. J., Wagner, P., Ward, M., Weidinger, M., Weitzel, Q., White, R., Wierzcholska, A., Willmann, P., Wörnlein, A., Wouters, D., Zabalza, V., Zacharias, M., Zajczyk, A., Zdziarski, A. A., Zech, A., and Zechlin, H. -S.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: The region around the supernova remnant (SNR) W41 contains several TeV sources and has prompted the H.E.S.S. Collaboration to perform deep observations of this field of view. This resulted in the discovery of the new very high energy (VHE) source HESS J1832-093, at the position $\rm RA=18^h 32^m 50^s \pm 3^s_{stat} \pm 2^s_{syst}, \rm Dec=-9^\circ 22' 36'' \pm 32''_{stat} \pm 20''_{syst} (J2000)$, spatially coincident with a part of the radio shell of the neighboring remnant G22.7-0.2. The photon spectrum is well described by a power-law of index $\Gamma = 2.6 \pm 0.3_{\rm stat} \pm 0.1_{\rm syst}$ and a normalization at 1 TeV of $\Phi_0=(4.8 \pm 0.8_{\rm stat}\pm 1.0_{\rm syst})\,\times\,10^{-13}\,\rm{cm} ^{-2}\,s^{-1}\,TeV^{-1}$. The location of the gamma-ray emission on the edge of the SNR rim first suggested a signature of escaping cosmic-rays illuminating a nearby molecular cloud. Then a dedicated XMM-Newton observation led to the discovery of a new X-ray point source spatially coincident with the TeV excess. Two other scenarios were hence proposed to identify the nature of HESS J1832-093. Gamma-rays from inverse Compton radiation in the framework of a pulsar wind nebula scenario or the possibility of gamma-ray production within a binary system are therefore also considered. Deeper multi-wavelength observations will help to shed new light on this intriguing VHE source., Comment: 6 pages, 4 figures
Published: 2014
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25. Search for dark matter annihilation signatures in H.E.S.S. observations of Dwarf Spheroidal Galaxies

Author: Collaboration, H. E. S. S., Abramowski, A., Aharonian, F., Benkhali, F. Ait, Akhperjanian, A. G., Angüner, E., Backes, M., Balenderan, S., Balzer, A., Barnacka, A., Becherini, Y., Tjus, J. Becker, Berge, D., Bernhard, S., Bernlöhr, K., Birsin, E., Biteau, J., Böttcher, M., Boisson, C., Bolmont, J., Bordas, P., Bregeon, J., Brun, F., Brun, P., Bryan, M., Bulik, T., Carrigan, S., Casanova, S., Chadwick, P. M., Chakraborty, N., Chalme-Calvet, R., Chaves, R. C. G., Chrétien, M., Colafrancesco, S., Cologna, G., Conrad, J., Couturier, C., Cui, Y., Dalton, M., Davids, I. D., Degrange, B., Deil, C., deWilt, P., Djannati-Ataï, A., Domainko, W., Donath, A., Drury, L. O'C., Dubus, G., Dutson, K., Dyks, J., Dyrda, M., Edwards, T., Egberts, K., Eger, P., Espigat, P., Farnier, C., Fegan, S., Feinstein, F., Fernandes, M. V., Fernandez, D., Fiasson, A., Fontaine, G., Förster, A., Füßling, M., Gabici, S., Gajdus, M., Gallant, Y. A., Garrigoux, T., Giavitto, G., Giebels, B., Glicenstein, J. F., Gottschall, D., Goudelis, A., Grondin, M. -H., Grudzińska, M., Hadsch, D., Häffner, S., Hahn, J., Harris, J., Heinzelmann, G., Henri, G., Hermann, G., Hervet, O., Hillert, A., Hinton, J. A., Hofmann, W., Hofverberg, P., Holler, M., Horns, D., Ivascenko, A., Jacholkowska, A., Jahn, C., Jamrozy, M., Janiak, M., Jankowsky, F., Jung, I., Kastendieck, M. A., Katarzyński, K., Katz, U., Kaufmann, S., Khélifi, B., Kieffer, M., Klepser, S., Klochkov, D., Kluźniak, W., Kolitzus, D., Komin, Nu., Kosack, K., Krakau, S., Krayzel, F., Krüger, P. P., Laffon, H., Lamanna, G., Lefaucheur, J., Lefranc, V., Lemiére, A., Lemoine-Goumard, M., Lenain, J. -P., Lohse, T., Lopatin, A., Lu, C. -C., Marandon, V., Marcowith, A., Marx, R., Maurin, G., Maxted, N., Mayer, M., McComb, T. J. L., Méhault, J., Meintjes, P. J., Menzler, U., Meyer, M., Mitchell, A. M. W., Moderski, R., Mohamed, M., Morå, K., Moulin, E., Murach, T., de Naurois, M., Niemiec, J., Nolan, S. J., Oakes, L., Odaka, H., Ohm, S., Opitz, B., Ostrowski, M., Oya, I., Panter, M., Parsons, R. D., Arribas, M. Paz, Pekeur, N. W., Pelletier, G., Perez, J., Petrucci, P. -O., Peyaud, B., Pita, S., Poon, H., Pühlhofer, G., Punch, M., Quirrenbach, A., Raab, S., Reichardt, I., Reimer, A., Reimer, O., Renaud, M., Reyes, R. de los, Rieger, F., Rob, L., Romoli, C., Rosier-Lees, S., Rowell, G., Rudak, B., Rulten, C. B., Sahakian, V., Salek, D., Sanchez, D. A., Santangelo, A., Schlickeiser, R., Schüssler, F., Schulz, A., Schwanke, U., Schwarzburg, S., Schwemmer, S., Serpico, P., Sol, H., Spanier, F., Spengler, G., Spieß, F., Stawarz, L., Steenkamp, R., Stegmann, C., Stinzing, F., Stycz, K., Sushch, I., Tavernet, J. -P., Tavernier, T., Taylor, A. M., Terrier, R., Tluczykont, M., Trichard, C., Valerius, K., van Eldik, C., van Soelen, B., Vasileiadis, G., Veh, J., Venter, C., Viana, A., Vincent, P., Vink, J., Völk, H. J., Volpe, F., Vorster, M., Vuillaume, T., Wagner, S. J., Wagner, P., Wagner, R. M., Ward, M., Weidinger, M., Weitzel, Q., White, R., Wierzcholska, A., Willmann, P., Wörnlein, A., Wouters, D., Yang, R., Zabalza, V., Zaborov, D., Zacharias, M., Zdziarski, A. A., Zech, A., and Zechlin, H. -S.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: Dwarf spheroidal galaxies of the Local Group are close satellites of the Milky Way characterized by a large mass-to-light ratio and are not expected to be the site of non-thermal high-energy gamma-ray emission or intense star formation. Therefore they are amongst the most promising candidates for indirect dark matter searches. During the last years the High Energy Stereoscopic System (H.E.S.S.) of imaging atmospheric Cherenkov telescopes observed five of these dwarf galaxies for more than 140 hours in total, searching for TeV gamma-ray emission from annihilation of dark matter particles. The new results of the deep exposure of the Sagittarius dwarf spheroidal galaxy, the first observations of the Coma Berenices and Fornax dwarves and the re-analysis of two more dwarf spheroidal galaxies already published by the H.E.S.S. Collaboration, Carina and Sculptor, are presented. In the absence of a significant signal new constraints on the annihilation cross-section applicable to Weakly Interacting Massive Particles (WIMPs) are derived by combining the observations of the five dwarf galaxies. The combined exclusion limit depends on the WIMP mass and the best constraint is reached at 1-2 TeV masses with a cross-section upper bound of ~3.9x10-24 cm^3 s-1 at a 95% confidence level., Comment: to be published in Physical Review D journal; Contact authors: E. Birsin, C. Farnier, G. Lamanna
Published: 2014
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26. Long-term monitoring of PKS 2155$-$304 with ATOM and H.E.S.S.: investigation of optical/$\gamma$-ray correlations in different spectral states

Author: Abramowski, A., Aharonian, F., Benkhali, F. Ait, Akhperjanian, A. G., Angüner, E. O., Backes, M., Balenderan, S., Balzer, A., Barnacka, A., Becherini, Y., Tjus, J. Becker, Berge, D., Bernhard, S., Bernlöhr, K., Birsin, E., Biteau, J., Böttcher, M., Boisson, C., Bolmont, J., Bordas, P., Bregeon, J., Brun, F., Brun, P., Bryan, M., Bulik, T., Carrigan, S., Casanova, S., Chadwick, P. M., Chakraborty, N., Chalme-Calvet, R., Chaves, R. C. G., Chrétien, M., Colafrancesco, S., Cologna, G., Conrad, J., Couturier, C., Cui, Y., Dalton, M., Davids, I. D., Degrange, B., Deil, C., deWilt, P., Djannati-Ataï, A., Domainko, W., Donath, A., Drury, L. O'C., Dubus, G., Dutson, K., Dyks, J., Dyrda, M., Edwards, T., Egberts, K., Eger, P., Espigat, P., Farnier, C., Fegan, S., Feinstein, F., Fernandes, M. V., Fernandez, D., Fiasson, A., Fontaine, G., Förster, A., Füßling, M., Gabici, S., Gajdus, M., Gallant, Y. A., Garrigoux, T., Giavitto, G., Giebels, B., Glicenstein, J. F., Gottschall, D., Grondin, M. -H., Grudzińska, M., Hadsch, D., Häffner, S., Hahn, J., Harris, J., Heinzelmann, G., Henri, G., Hermann, G., Hervet, O., Hillert, A., Hinton, J. A., Hofmann, W., Hofverberg, P., Holler, M., Horns, D., Ivascenko, A., Jacholkowska, A., Jahn, C., Jamrozy, M., Janiak, M., Jankowsky, F., Jung, I., Kastendieck, M. A., Katarzyński, K., Katz, U., Kaufmann, S., Khélifi, B., Kieffer, M., Klepser, S., Klochkov, D., Kluźniak, W., Kolitzus, D., Komin, Nu., Kosack, K., Krakau, S., Krayzel, F., Krüger, P. P., Laffon, H., Lamanna, G., Lefaucheur, J., Lefranc, V., Lemière, A., Lemoine-Goumard, M., Lenain, J. -P., Lohse, T., Lopatin, A., Lu, C. -C., Marandon, V., Marcowith, A., Marx, R., Maurin, G., Maxted, N., Mayer, M., McComb, T. J. L., Méhault, J., Meintjes, P. J., Menzler, U., Meyer, M., Mitchell, A. M. W., Moderski, R., Mohamed, M., Morå, K., Moulin, E., Murach, T., de Naurois, M., Niemiec, J., Nolan, S. J., Oakes, L., Odaka, H., Ohm, S., Opitz, B., Ostrowski, M., Oya, I., Panter, M., Parsons, R. D., Arribas, M. Paz, Pekeur, N. W., Pelletier, G., Perez, J., Petrucci, P. -O., Peyaud, B., Pita, S., Poon, H., Pühlhofer, G., Punch, M., Quirrenbach, A., Raab, S., Reichardt, I., Reimer, A., Reimer, O., Renaud, M., Reyes, R. de los, Rieger, F., Rob, L., Romoli, C., Rosier-Lees, S., Rowell, G., Rudak, B., Rulten, C. B., Sahakian, V., Salek, D., Sanchez, D. A., Santangelo, A., Schlickeiser, R., Schüssler, F., Schulz, A., Schwanke, U., Schwarzburg, S., Schwemmer, S., Sol, H., Spanier, F., Spengler, G., Spies, F., Stawarz, Ł., Steenkamp, R., Stegmann, C., Stinzing, F., Stycz, K., Sushch, I., Tavernet, J. -P., Tavernier, T., Taylor, A. M., Terrier, R., Tluczykont, M., Trichard, C., Valerius, K., van Eldik, C., van Soelen, B., Vasileiadis, G., Veh, J., Venter, C., Viana, A., Vincent, P., Vink, J., Völk, H. J., Volpe, F., Vorster, M., Vuillaume, T., Wagner, S. J., Wagner, P., Wagner, R. M., Ward, M., Weidinger, M., Weitzel, Q., White, R., Wierzcholska, A., Willmann, P., Wörnlein, A., Wouters, D., Yang, R., Zabalza, V., Zaborov, D., Zacharias, M., Zdziarski, A. A., Zech, A., and Zechlin, H. -S.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: In this paper we report on the analysis of all the available optical and very high-energy $\gamma$-ray ($>$200 GeV) data for the BL Lac object PKS 2155$-$304, collected simultaneously with the ATOM and H.E.S.S. telescopes from 2007 until 2009. This study also includes X-ray (RXTE, Swift) and high-energy $\gamma$-ray (Fermi-LAT) data. During the period analysed, the source was transitioning from its flaring to quiescent optical states,and was characterized by only moderate flux changes at different wavelengths on the timescales of days and months. A flattening of the optical continuum with an increasing optical flux can be noted in the collected dataset, but only occasionally and only at higher flux levels. We did not find any universal relation between the very high-energy $\gamma$-ray and optical flux changes on the timescales from days and weeks up to several years. On the other hand, we noted that at higher flux levels the source can follow two distinct tracks in the optical flux-colour diagrams, which seem to be related to distinct $\gamma$-ray states of the blazar. The obtained results therefore indicate a complex scaling between the optical and $\gamma$-ray emission of PKS 2155$-$304, with different correlation patterns holding at different epochs, and a $\gamma$-ray flux depending on the combination of an optical flux and colour rather than a flux alone., Comment: 10 pages, 5 figures, Accepted for publication in Astronomy & Astrophysics
Published: 2014
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27. Discovery of the hard spectrum VHE gamma-ray source HESS J1641-463

Author: Collaboration, H. E. S. S., Abramowski, A., Aharonian, F., Benkhali, F. Ait, Akhperjanian, A. G., Angüner, E. O., Backes, M., Balenderan, S., Balzer, A., Barnacka, A., Becherini, Y., Tjus, J. Becker, Berge, D., Bernhard, S., Bernlöhr, K., Birsin, E., Biteau, J., Böttcher, M., Boisson, C., Bolmont, J., Bordas, P., Bregeon, J., Brun, F., Brun, P., Bryan, M., Bulik, T., Carrigan, S., Casanova, S., Chadwick, P. M., Chakraborty, N., Chalme-Calvet, R., Chaves, R. C. G., Chrétien, M., Colafrancesco, S., Cologna, G., Conrad, J., Couturier, C., Cui, Y., Dalton, M., Davids, I. D., Degrange, B., Deil, C., deWilt, P., Djannati-Ataï, A., Domainko, W., Donath, A., Drury, L. O'C., Dubus, G., Dutson, K., Dyks, J., Dyrda, M., Edwards, T., Egberts, K., Eger, P., Espigat, P., Farnier, C., Fegan, S., Feinstein, F., Fernandes, M. V., Fernandez, D., Fiasson, A., Fontaine, G., Förster, A., Füßling, M., Gabici, S., Gajdus, M., Gallant, Y. A., Garrigoux, T., Giavitto, G., Giebels, B., Glicenstein, J. F., Gottschall, D., Grondin, M. -H., Grudzińska, M., Hadasch, D., Häffner, S., Hahn, J., Harris, J., Heinzelmann, G., Henri, G., Hermann, G., Hervet, O., Hillert, A., Hinton, J. A., Hofmann, W., Hofverberg, P., Holler, M., Horns, D., Ivascenko, A., Jacholkowska, A., Jahn, C., Jamrozy, M., Janiak, M., Jankowsky, F., Jung-Richardt, I., Kastendieck, M. A., Katarzyński, K., Katz, U., Kaufmann, S., Khélifi, B., Kieffer, M., Klepser, S., Klochkov, D., Kluźniak, W., Kolitzus, D., Komin, Nu., Kosack, K., Krakau, S., Krayzel, F., Krüger, P. P., Laffon, H., Lamanna, G., Lau, J., Lefaucheur, J., Lefranc, V., Lemière, A., Lemoine-Goumard, M., Lenain, J. -P., Lohse, T., Lopatin, A., Lu, C. -C., Marandon, V., Marcowith, A., Marx, R., Maurin, G., Maxted, N., Mayer, M., McComb, T. J. L., Méhault, J., Meintjes, P. J., Menzler, U., Meyer, M., Mitchell, A. M. W., Moderski, R., Mohamed, M., Morå, K., Moulin, E., Murach, T., de Naurois, M., Niemiec, J., Nolan, S. J., Oakes, L., Odaka, H., Ohm, S., Opitz, B., Ostrowski, M., Oya, I., Panter, M., Parsons, R. D., Arribas, M. Paz, Pekeur, N. W., Pelletier, G., Petrucci, P. -O., Peyaud, B., Pita, S., Poon, H., Pühlhofer, G., Punch, M., Quirrenbach, A., Raab, S., Reichardt, I., Reimer, A., Reimer, O., Renaud, M., Reyes, R. de los, Rieger, F., Romoli, C., Rosier-Lees, S., Rowell, G., Rudak, B., Rulten, C. B., Sahakian, V., Salek, D., Sanchez, D. A., Santangelo, A., Schlickeiser, R., Schüssler, F., Schulz, A., Schwanke, U., Schwarzburg, S., Schwemmer, S., Sol, H., Spanier, F., Spengler, G., Spies, F., Stawarz, Ł., Steenkamp, R., Stegmann, C., Stinzing, F., Stycz, K., Sushch, I., Tavernet, J. -P., Tavernier, T., Taylor, A. M., Terrier, R., Tluczykont, M., Trichard, C., Valerius, K., van Eldik, C., van Soelen, B., Vasileiadis, G., Veh, J., Venter, C., Viana, A., Vincent, P., Vink, J., Völk, H. J., Volpe, F., Vorster, M., Vuillaume, T., Wagner, S. J., Wagner, P., Wagner, R. M., Ward, M., Weidinger, M., Weitzel, Q., White, R., Wierzcholska, A., Willmann, P., Wörnlein, A., Wouters, D., Yang, R., Zabalza, V., Zaborov, D., Zacharias, M., Zdziarski, A. A., Zech, A., Zechlin, H. -S., Fukui, Y., Sano, H., Fukuda, T., and Yoshiike, S.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: This letter reports the discovery of a remarkably hard spectrum source, HESS J1641-463, by the High Energy Stereoscopic System (H.E.S.S.) in the very-high energy (VHE) domain. HESS J1641-463 remained unnoticed by the usual analysis techniques due to confusion with the bright nearby source HESS J1640-465. It emerged at a significance level of 8.5 standard deviations after restricting the analysis to events with energies above 4 TeV. It shows a moderate flux level of F(E > 1 TeV) = (3.64 +/- 0.44_stat +/- 0.73_sys) x 10^-13 cm^-2s-1, corresponding to 1.8% of the Crab Nebula flux above the same energy, and a hard spectrum with a photon index of Gamma = 2.07 +/- 0.11_stat +/- 0.20_sys. It is a point-like source, although an extension up to Gaussian width of sigma = 3 arcmin cannot be discounted due to uncertainties in the H.E.S.S. PSF. The VHE gamma-ray flux of HESS J1641-463 is found to be constant over the observed period when checking time binnings from year-by-year to the 28 min exposures timescales. HESS J1641-463 is positionally coincident with the radio supernova remnant SNR G338.5+0.1. No X-ray candidate stands out as a clear association, however Chandra and XMM-Newton data reveal some potential weak counterparts. Various VHE gamma-ray production scenarios are discussed. If the emission from HESS J1641-463 is produced by cosmic ray protons colliding with the ambient gas, then their spectrum must extend close to 1 PeV. This object may represent a source population contributing significantly to the galactic cosmic ray flux around the knee., Comment: 24 pages, 4 figures. Published version
Published: 2014
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28. Probing the gamma-ray emission from HESS J1834-087 using H.E.S.S. and Fermi LAT observations

Author: Collaboration, The H. E. S. S., Abramowski, A., Aharonian, F., Benkhali, F. Ait, Akhperjanian, A. G., Angüner, E., Anton, G., Backes, M., Balenderan, S., Balzer, A., Barnacka, A., Becherini, Y., Tjus, J. Becker, Bernlöhr, K., Birsin, E., Bissaldi, E., Biteau, J., Böttcher, M., Boisson, C., Bolmont, J., Bordas, P., Brucker, J., Brun, F., Brun, P., Bulik, T., Carrigan, S., Casanova, S., Chadwick, P. M., Chalme-Calvet, R., Chaves, R. C. G., Cheesebrough, A., Chrétien, M., Colafrancesco, S., Cologna, G., Conrad, J., Couturier, C., Cui, Y., Dalton, M., Daniel, M. K., Davids, I. D., Degrange, B., Deil, C., deWilt, P., Dickinson, H. J., Djannati-Ataï, A., Domainko, W., Drury, L. O'C., Dubus, G., Dutson, K., Dyks, J., Dyrda, M., Edwards, T., Egberts, K., Eger, P., Espigat, P., Farnier, C., Fegan, S., Feinstein, F., Fernandes, M. V., Fernandez, D., Fiasson, A., Fontaine, G., Förster, A., Füßling, M., Gajdus, M., Gallant, Y. A., Garrigoux, T., Giavitto, G., Giebels, B., Glicenstein, J. F., Grondin, M. -H., Grudzińska, M., Häffner, S., Hahn, J., Harris, J., Heinzelmann, G., Henri, G., Hermann, G., Hervet, O., Hillert, A., Hinton, J. A., Hofmann, W., Hofverberg, P., Holler, M., Horns, D., Jacholkowska, A., Jahn, C., Jamrozy, M., Janiak, M., Jankowsky, F., Jung, I., Kastendieck, M. A., Katarzyński, K., Katz, U., Kaufmann, S., Khélifi, B., Kieffer, M., Klepser, S., Klochkov, D., Kluźniak, W., Kneiske, T., Kolitzus, D., Komin, Nu., Kosack, K., Krakau, S., Krayzel, F., Krüger, P. P., Laffon, H., Lamanna, G., Lefaucheur, J., Lemière, A., Lemoine-Goumard, M., Lenain, J. -P., Lohse, T., Lopatin, A., Lu, C. -C., Marandon, V., Marcowith, A., Marx, R., Maurin, G., Maxted, N., Mayer, M., McComb, T. J. L., Méhault, J., Meintjes, P. J., Menzler, U., Meyer, M., Moderski, R., Mohamed, M., Moulin, E., Murach, T., Naumann, C. L., de Naurois, M., Niemiec, J., Nolan, S. J., Oakes, L., Odaka, H., Ohm, S., Wilhelmi, E. de Oña, Opitz, B., Ostrowski, M., Oya, I., Panter, M., Parsons, R. D., Arribas, M. Paz, Pekeur, N. W., Pelletier, G., Perez, J., Petrucci, P. -O., Peyaud, B., Pita, S., Poon, H., Pühlhofer, G., Punch, M., Quirrenbach, A., Raab, S., Raue, M., Reichardt, I., Reimer, A., Reimer, O., Renaud, M., Reyes, R. de los, Rieger, F., Rob, L., Romoli, C., Rosier-Lees, S., Rowell, G., Rudak, B., Rulten, C. B., Sahakian, V., Sanchez, D. A., Santangelo, A., Schlickeiser, R., Schüssler, F., Schulz, A., Schwanke, U., Schwarzburg, S., Schwemmer, S., Sol, H., Spengler, G., Spies, F., Stawarz, Ł., Steenkamp, R., Stegmann, C., Stinzing, F., Stycz, K., Sushch, I., Tavernet, J. -P., Tavernier, T., Taylor, A. M., Terrier, R., Tluczykont, M., Trichard, C., Valerius, K., van Eldik, C., van Soelen, B., Vasileiadis, G., Venter, C., Viana, A., Vincent, P., Völk, H. J., Volpe, F., Vorster, M., Vuillaume, T., Wagner, S. J., Wagner, P., Wagner, R. M., Ward, M., Weidinger, M., Weitzel, Q., White, R., Wierzcholska, A., Willmann, P., Wörnlein, A., Wouters, D., Yang, R., Zabalza, V., Zacharias, M., Zdziarski, A. A., Zech, A., Zechlin, H. -S., Collaboration, Fermi-LAT, Acero, F., Casandjian, J. M., Cohen-Tanugi, J., Giordano, F., Guillemot, L., Lande, J., Pletsch, H., and Uchiyama, Y.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: Previous observations with HESS have revealed the existence of an extended very-high-energy (VHE; E>100 GeV) gamma-ray source, HESS J1834-087, coincident with the SNR W41. The origin of the gamma-ray emission has been further investigated with HESS and the Fermi-LAT. The gamma-ray data provided by 61h (HESS) and 4 yrs (Fermi LAT) of observations cover over 5 decades in energy (1.8GeV - 30TeV). The morphology and spectrum of the TeV and GeV sources have been studied and multi-wavelength data have been used to investigate the origin of the observed emission. The TeV source can be modeled with a sum of two components: one point-like and one significantly extended (sig_TeV = 0.17{\deg}), both centered on SNR W41 and exhibiting spectra described by a power law of index 2.6. The GeV source detected with Fermi is extended (sig_GeV =0.15{\deg}) and morphologically matches the VHE emission. Its spectrum can be described by a power-law with index 2.15 and joins smoothly the one of the whole TeV source. A break appears in the spectra around 100 GeV. Two main scenarios are proposed to explain the emission: a pulsar wind nebula (PWN) or the interaction of SNR W41 with a molecular cloud. X-ray observations suggest the presence of a point-like source (pulsar candidate) near the center of the SNR and non-thermal X-ray diffuse emission which could arise from a potential PWN. The PWN scenario is supported by the match of of the TeV and GeV positions with the putative pulsar. However, the overall spectrum is reproduced by a 1-zone leptonic model only if an excess of low-energy electrons is injected by a high spin-down power pulsar. This low-energy component is not needed if the point-like TeV source is unrelated to the extended GeV and TeV sources. The interacting SNR scenario is supported by the spatial coincidence between the gamma-ray sources, the detection of OH maser lines and the hadronic modeling., Comment: 12 pages, 8 figures, Accepted for publication in Astronomy & Astrophysics
Published: 2014
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29. Search for TeV Gamma-ray Emission from GRB 100621A, an extremely bright GRB in X-rays, with H.E.S.S

Author: Collaboration, H. E. S. S., Abramowski, A., Aharonian, F., Benkhali, F. Ait, Akhperjanian, A. G., Angüner, E., Anton, G., Balenderan, S., Balzer, A., Barnacka, A., Becherini, Y., Tjus, J. Becker, Bernlöhr, K., Birsin, E., Bissaldi, E., Biteau, J., Böttcher, M., Boisson, C., Bolmont, J., Bordas, P., Brucker, J., Brun, F., Brun, P., Bulik, T., Carrigan, S., Casanova, S., Cerruti, M., Chadwick, P. M., Chalme-Calvet, R., Chaves, R. C. G., Cheesebrough, A., Chrétien, M., Colafrancesco, S., Cologna, G., Conrad, J., Couturier, C., Dalton, M., Daniel, M. K., Davids, I. D., Degrange, B., Deil, C., deWilt, P., Dickinson, H. J., Djannati-Ataï, A., Domainko, W., Drury, L. O'C., Dubus, G., Dutson, K., Dyks, J., Dyrda, M., Edwards, T., Egberts, K., Eger, P., Espigat, P., Farnier, C., Fegan, S., Feinstein, F., Fernandes, M. V., Fernandez, D., Fiasson, A., Fontaine, G., Förster, A., Füßling, M., Gajdus, M., Gallant, Y. A., Garrigoux, T., Giebels, B., Glicenstein, J. F., Grondin, M. -H., Grudzińska, M., Häffner, S., Hahn, J., Harris, J., Heinzelmann, G., Henri, G., Hermann, G., Hervet, O., Hillert, A., Hinton, J. A., Hofmann, W., Hofverberg, P., Holler, M., Horns, D., Jacholkowska, A., Jahn, C., Jamrozy, M., Janiak, M., Jankowsky, F., Jung, I., Kastendieck, M. A., Katarzyński, K., Katz, U., Kaufmann, S., Khélifi, B., Kieffer, M., Klepser, S., Klochkov, D., Kluźniak, W., Kneiske, T., Kolitzus, D., Komin, Nu., Kosack, K., Krakau, S., Krayzel, F., Krüger, P. P., Laffon, H., Lamanna, G., Lefaucheur, J., Lemière, A., Lemoine-Goumard, M., Lenain, J. -P., Lennarz, D., Lohse, T., Lopatin, A., Lu, C. -C., Marandon, V., Marcowith, A., Marx, R., Maurin, G., Maxted, N., Mayer, M., McComb, T. J. L., Méhault, J., Menzler, U., Meyer, M., Moderski, R., Mohamed, M., Moulin, E., Murach, T., Naumann, C. L., de Naurois, M., Niemiec, J., Nolan, S. J., Oakes, L., O'Brien, P. T., Ohm, S., Wilhelmi, E. de Oña, Opitz, B., Ostrowski, M., Oya, I., Panter, M., Parsons, R. D., Arribas, M. Paz, Pekeur, N. W., Pelletier, G., Perez, J., Petrucci, P. -O., Peyaud, B., Pita, S., Poon, H., Pühlhofer, G., Punch, M., Quirrenbach, A., Raab, S., Raue, M., Reimer, A., Reimer, O., Renaud, M., Reyes, R. de los, Rieger, F., Rob, L., Romoli, C., Rosier-Lees, S., Rowell, G., Rudak, B., Rulten, C. B., Sahakian, V., Sanchez, D. A., Santangelo, A., Schlickeiser, R., Schüssler, F., Schulz, A., Schwanke, U., Schwarzburg, S., Schwemmer, S., Sol, H., Spengler, G., Spies, F., Stawarz, Ł., Steenkamp, R., Stegmann, C., Stinzing, F., Stycz, K., Sushch, I., Szostek, A., Tam, P. H. T., Tavernet, J. -P., Tavernier, T., Taylor, A. M., Terrier, R., Tluczykont, M., Trichard, C., Valerius, K., van Eldik, C., Vasileiadis, G., Venter, C., Viana, A., Vincent, P., Völk, H. J., Volpe, F., Vorster, M., Wagner, S. J., Wagner, P., Ward, M., Weidinger, M., Weitzel, Q., White, R., Wierzcholska, A., Willmann, P., Wörnlein, A., Wouters, D., Zacharias, M., Zajczyk, A., Zdziarski, A. A., Zech, A., and Zechlin, H. -S.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: The long gamma-ray burst (GRB) 100621A, at the time the brightest X-ray transient ever detected by Swift-XRT in the $0.3\textrm{--}10$ keV range, has been observed with the H.E.S.S. imaging air Cherenkov telescope array, sensitive to gamma radiation in the very-high-energy (VHE, $>100$ GeV) regime. Due to its relatively small redshift of $z\sim0.5$, the favourable position in the southern sky and the relatively short follow-up time ($<700 \rm{s}$ after the satellite trigger) of the H.E.S.S. observations, this GRB could be within the sensitivity reach of the H.E.S.S. instrument. The analysis of the H.E.S.S. data shows no indication of emission and yields an integral flux upper limit above $\sim$380 GeV of $4.2\times10^{-12} \rm cm^{-2}s^{-1}$ (95 % confidence level), assuming a simple Band function extension model. A comparison to a spectral-temporal model, normalised to the prompt flux at sub-MeV energies, constraints the existence of a temporally extended and strong additional hard power law, as has been observed in the other bright X-ray GRB 130427A. A comparison between the H.E.S.S. upper limit and the contemporaneous energy output in X-rays constrains the ratio between the X-ray and VHE gamma-ray fluxes to be greater than 0.4. This value is an important quantity for modelling the afterglow and can constrain leptonic emission scenarios, where leptons are responsible for the X-ray emission and might produce VHE gamma rays., Comment: 8 pages, 2 figures. Published in A&A
Published: 2014
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30. TeV {\gamma}-ray observations of the young synchrotron-dominated SNRs G1.9+0.3 and G330.2+1.0 with H.E.S.S

Author: Collaboration, H. E. S. S., Abramowski, A., Aharonian, F., Benkhali, F. Ait, Akhperjanian, A. G., Angüner, E., Anton, G., Balenderan, S., Balzer, A., Barnacka, A., Becherini, Y., Tjus, J. Becker, Bernlöhr, K., Birsin, E., Bissaldi, E., Biteau, J., Böttcher, M., Boisson, C., Bolmont, J., Bordas, P., Brucker, J., Brun, F., Brun, P., Bulik, T., Carrigan, S., Casanova, S., Cerruti, M., Chadwick, P. M., Chalme-Calvet, R., Chaves, R. C. G., Cheesebrough, A., Chrétien, M., Colafrancesco, S., Cologna, G., Conrad, J., Couturier, C., Cui, Y., Dalton, M., Daniel, M. K., Davids, I. D., Degrange, B., Deil, C., deWilt, P., Dickinson, H. J., Djannati-Ataï, A., Domainko, W., Drury, L. O'C., Dubus, G., Dutson, K., Dyks, J., Dyrda, M., Edwards, T., Egberts, K., Eger, P., Espigat, P., Farnier, C., Fegan, S., Feinstein, F., Fernandes, M. V., Fernandez, D., Fiasson, A., Fontaine, G., Förster, A., Füßling, M., Gajdus, M., Gallant, Y. A., Garrigoux, T., Giavitto, G., Giebels, B., Glicenstein, J. F., Grondin, M. -H., Grudzińska, M., Häffner, S., Hahn, J., Harris, J., Heinzelmann, G., Henri, G., Hermann, G., Hervet, O., Hillert, A., Hinton, J. A., Hofmann, W., Hofverberg, P., Holler, M., Horns, D., Jacholkowska, A., Jahn, C., Jamrozy, M., Janiak, M., Jankowsky, F., Jung, I., Kastendieck, M. A., Katarzyński, K., Katz, U., Kaufmann, S., Khélifi, B., Kieffer, M., Klepser, S., Klochkov, D., Kluźniak, W., Kneiske, T., Kolitzus, D., Komin, Nu., Kosack, K., Krakau, S., Krayzel, F., Krüger, P. P., Laffon, H., Lamanna, G., Lefaucheur, J., Lemière, A., Lemoine-Goumard, M., Lenain, J. -P., Lennarz, D., Lohse, T., Lopatin, A., Lu, C. -C., Marandon, V., Marcowith, A., Marx, R., Maurin, G., Maxted, N., Mayer, M., McComb, T. J. L., Méhault, J., Meintjes, P. J., Menzler, U., Meyer, M., Moderski, R., Mohamed, M., Moulin, E., Murach, T., Naumann, C. L., de Naurois, M., Niemiec, J., Nolan, S. J., Oakes, L., Ohm, S., Wilhelmi, E. de Oña, Opitz, B., Ostrowski, M., Oya, I., Panter, M., Parsons, R. D., Arribas, M. Paz, Pekeur, N. W., Pelletier, G., Perez, J., Petrucci, P. -O., Peyaud, B., Pita, S., Poon, H., Pühlhofer, G., Punch, M., Quirrenbach, A., Raab, S., Raue, M., Reimer, A., Reimer, O., Renaud, M., Reyes, R. de los, Rieger, F., Rob, L., Romoli, C., Rosier-Lees, S., Rowell, G., Rudak, B., Rulten, C. B., Sahakian, V., Sanchez, D. A., Santangelo, A., Schlickeiser, R., Schüssler, F., Schulz, A., Schwanke, U., Schwarzburg, S., Schwemmer, S., Sol, H., Spengler, G., Spies, F., Stawarz, Ł., Steenkamp, R., Stegmann, C., Stinzing, F., Stycz, K., Sushch, I., Szostek, A., Tavernet, J. -P., Tavernier, T., Taylor, A. M., Terrier, R., Tluczykont, M., Trichard, C., Valerius, K., van Eldik, C., van Soelen, B., Vasileiadis, G., Venter, C., Viana, A., Vincent, P., Völk, H. J., Volpe, F., Vorster, M., Vuillaume, T., Wagner, S. J., Wagner, P., Ward, M., Weidinger, M., Weitzel, Q., White, R., Wierzcholska, A., Willmann, P., Wörnlein, A., Wouters, D., Zabalza, V., Zacharias, M., Zajczyk, A., Zdziarski, A. A., Zech, A., and Zechlin, H. -S.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: The non-thermal nature of the X-ray emission from the shell-type supernova remnants (SNRs) G1.9+0.3 and G330.2+1.0 is an indication of intense particle acceleration in the shock fronts of both objects. This suggests that the SNRs are prime candidates for very-high-energy (VHE; E $>$ 0.1 TeV) {\gamma}-ray observations. G1.9+0.3, recently established as the youngest known SNR in the Galaxy, also offers a unique opportunity to study the earliest stages of SNR evolution in the VHE domain. The purpose of this work is to probe the level of VHE {\gamma}-ray emission from both SNRs and use this to constrain their physical properties. Observations were conducted with the H.E.S.S. (High Energy Stereoscopic System) Cherenkov telescope array over a more than six-year period spanning 2004-2010. The obtained data have effective livetimes of 67 h for G1.9+0.3 and 16 h for G330.2+1.0. The data are analyzed in the context of the multi-wavelength observations currently available and in the framework of both leptonic and hadronic particle acceleration scenarios. No significant {\gamma}-ray signal from G1.9+0.3 or G330.2+1.0 was detected. Upper limits (99% confidence level) to the TeV flux from G1.9+0.3 and G330.2+1.0 for the assumed spectral index {\Gamma} = 2.5 were set at 5.6 $\times$ 10$^{-13}$ cm$^{-2}$ s$^{-1}$ above 0.26 TeV and 3.2 $\times$ 10$^{-12}$ cm$^{-2}$ s$^{-1}$ above 0.38 TeV, respectively. In a one-zone leptonic scenario, these upper limits imply lower limits on the interior magnetic field to B$_{\mathrm{G1.9}}$ $\gtrsim$ 11 {\mu}G for G1.9+0.3 and to B$_{\mathrm{G330}}$ $\gtrsim$ 8 {\mu}G for G330.2+1.0. In a hadronic scenario, the low ambient densities and the large distances to the SNRs result in very low predicted fluxes, for which the H.E.S.S. upper limits are not constraining., Comment: 9 pages, 2 figures, 4 tables. Accepted for publication in MNRAS
Published: 2014
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31. Flux upper limits for 47 AGN observed with H.E.S.S. in 2004-2011

Author: Collaboration, H. E. S. S., Abramowski, A., Aharonian, F., Benkhali, F. Ait, Akhperjanian, A. G., Angüner, E., Anton, G., Balenderan, S., Balzer, A., Barnacka, A., Becherini, Y., Tjus, J. Becker, Bernlöhr, K., Birsin, E., Bissaldi, E., Biteau, J., Böttcher, M., Boisson, C., Bolmont, J., Bordas, P., Brucker, J., Brun, F., Brun, P., Bulik, T., Carrigan, S., Casanova, S., Cerruti, M., Chadwick, P. M., Chalme-Calvet, R., Chaves, R. C. G., Cheesebrough, A., Chrétien, M., Colafrancesco, S., Cologna, G., Conrad, J., Couturier, C., Cui, Y., Dalton, M., Daniel, M. K., Davids, I. D., Degrange, B., Deil, C., deWilt, P., Dickinson, H. J., Djannati-Ataï, A., Domainko, W., Drury, L. O'C., Dubus, G., Dutson, K., Dyks, J., Dyrda, M., Edwards, T., Egberts, K., Eger, P., Espigat, P., Farnier, C., Fegan, S., Feinstein, F., Fernandes, M. V., Fernandez, D., Fiasson, A., Fontaine, G., Förster, A., Füßling, M., Gajdus, M., Gallant, Y. A., Garrigoux, T., Giavitto, G., Giebels, B., Glicenstein, J. F., Grondin, M. -H., Grudzińska, M., Häffner, S., Hahn, J., Harris, J., Heinzelmann, G., Henri, G., Hermann, G., Hervet, O., Hillert, A., Hinton, J. A., Hofmann, W., Hofverberg, P., Holler, M., Horns, D., Jacholkowska, A., Jahn, C., Jamrozy, M., Janiak, M., Jankowsky, F., Jung, I., Kastendieck, M. A., Katarzyński, K., Katz, U., Kaufmann, S., Khélifi, B., Kieffer, M., Klepser, S., Klochkov, D., Kluźniak, W., Kneiske, T., Kolitzus, D., Komin, Nu., Kosack, K., Krakau, S., Krayzel, F., Krüger, P. P., Laffon, H., Lamanna, G., Lefaucheur, J., Lemière, A., Lemoine-Goumard, M., Lenain, J. -P., Lennarz, D., Lohse, T., Lopatin, A., Lu, C. -C., Marandon, V., Marcowith, A., Marx, R., Maurin, G., Maxted, N., Mayer, M., McComb, T. J. L., Méhault, J., Meintjes, P. J., Menzler, U., Meyer, M., Moderski, R., Mohamed, M., Moulin, E., Murach, T., Naumann, C. L., de Naurois, M., Niemiec, J., Nolan, S. J., Oakes, L., Ohm, S., Wilhelmi, E. de Oña, Opitz, B., Ostrowski, M., Oya, I., Panter, M., Parsons, R. D., Arribas, M. Paz, Pekeur, N. W., Pelletier, G., Perez, J., Petrucci, P. -O., Peyaud, B., Pita, S., Poon, H., Pühlhofer, G., Punch, M., Quirrenbach, A., Raab, S., Raue, M., Reimer, A., Reimer, O., Renaud, M., Reyes, R. de los, Rieger, F., Rob, L., Romoli, C., Rosier-Lees, S., Rowell, G., Rudak, B., Rulten, C. B., Sahakian, V., Sanchez, D. A., Santangelo, A., Schlickeiser, R., Schüssler, F., Schulz, A., Schwanke, U., Schwarzburg, S., Schwemmer, S., Sol, H., Spengler, G., Spies, F., Stawarz, Ł., Steenkamp, R., Stegmann, C., Stinzing, F., Stycz, K., Sushch, I., Szostek, A., Tavernet, J. -P., Tavernier, T., Taylor, A. M., Terrier, R., Tluczykont, M., Trichard, C., Valerius, K., van Eldik, C., van Soelen, B., Vasileiadis, G., Venter, C., Viana, A., Vincent, P., Völk, H. J., Volpe, F., Vorster, M., Vuillaume, T., Wagner, S. J., Wagner, P., Ward, M., Weidinger, M., Weitzel, Q., White, R., Wierzcholska, A., Willmann, P., Wörnlein, A., Wouters, D., Zabalza, V., Zacharias, M., Zajczyk, A., Zdziarski, A. A., Zech, A., and Zechlin, H. -S.
Subjects: Astrophysics - Astrophysics of Galaxies, Astrophysics - Cosmology and Nongalactic Astrophysics, Astrophysics - High Energy Astrophysical Phenomena
Abstract: About 40% of the observation time of the High Energy Stereoscopic System (H.E.S.S.) is dedicated to studying active galactic nuclei (AGN), with the aim of increasing the sample of known extragalactic very-high-energy (VHE, E>100 GeV) sources and constraining the physical processes at play in potential emitters. H.E.S.S. observations of AGN, spanning a period from April 2004 to December 2011, are investigated to constrain their gamma-ray fluxes. Only the 47 sources without significant excess detected at the position of the targets are presented. Upper limits on VHE fluxes of the targets were computed and a search for variability was performed on the nightly time scale. For 41 objects, the flux upper limits we derived are the most constraining reported to date. These constraints at VHE are compared with the flux level expected from extrapolations of Fermi-LAT measurements in the two-year catalog of AGN. The H.E.S.S. upper limits are at least a factor of two lower than the extrapolated Fermi-LAT fluxes for 11 objects. Taking into account the attenuation by the extragalactic background light reduces the tension for all but two of them, suggesting intrinsic curvature in the high-energy spectra of these two AGN. Compilation efforts led by current VHE instruments are of critical importance for target-selection strategies before the advent of the Cherenkov Telescope Array, CTA., Comment: 10 pages, 5 figures, 5 tables, accepted in A&A
Published: 2014
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32. HESS J1640-465 - an exceptionally luminous TeV gamma-ray supernova remnant

Author: Collaboration, H. E. S. S., Abramowski, A., Aharonian, F., Benkhali, F. Ait, Akhperjanian, A. G., Angüner, E., Anton, G., Balenderan, S., Balzer, A., Barnacka, A., Becherini, Y., Tjus, J. Becker, Bernlöhr, K., Birsin, E., Bissaldi, E., Biteau, J., Böttcher, M., Boisson, C., Bolmont, J., Bordas, P., Brucker, J., Brun, F., Brun, P., Bulik, T., Carrigan, S., Casanova, S., Cerruti, M., Chadwick, P. M., Chalme-Calvet, R., Chaves, R. C. G., Cheesebrough, A., Chrétien, M., Colafrancesco, S., Cologna, G., Conrad, J., Couturier, C., Cui, Y., Dalton, M., Daniel, M. K., Davids, I. D., Degrange, B., Deil, C., deWilt, P., Dickinson, H. J., Djannati-Ataï, A., Domainko, W., Drury, L. O'C., Dubus, G., Dutson, K., Dyks, J., Dyrda, M., Edwards, T., Egberts, K., Eger, P., Espigat, P., Farnier, C., Fegan, S., Feinstein, F., Fernandes, M. V., Fernandez, D., Fiasson, A., Fontaine, G., Förster, A., Füßling, M., Gajdus, M., Gallant, Y. A., Garrigoux, T., Giavitto, G., Giebels, B., Glicenstein, J. F., Grondin, M. -H., Grudzińska, M., Häffner, S., Hahn, J., Harris, J., Heinzelmann, G., Henri, G., Hermann, G., Hervet, O., Hillert, A., Hinton, J. A., Hofmann, W., Hofverberg, P., Holler, M., Horns, D., Jacholkowska, A., Jahn, C., Jamrozy, M., Janiak, M., Jankowsky, F., Jung, I., Kastendieck, M. A., Katarzyński, K., Katz, U., Kaufmann, S., Khélifi, B., Kieffer, M., Klepser, S., Klochkov, D., Kluźniak, W., Kneiske, T., Kolitzus, D., Komin, Nu., Kosack, K., Krakau, S., Krayzel, F., Krüger, P. P., Laffon, H., Lamanna, G., Lefaucheur, J., Lemière, A., Lemoine-Goumard, M., Lenain, J. -P., Lennarz, D., Lohse, T., Lopatin, A., Lu, C. -C., Marandon, V., Marcowith, A., Marx, R., Maurin, G., Maxted, N., Mayer, M., McComb, T. J. L., Méhault, J., Meintjes, P. J., Menzler, U., Meyer, M., Moderski, R., Mohamed, M., Moulin, E., Murach, T., Naumann, C. L., de Naurois, M., Niemiec, J., Nolan, S. J., Oakes, L., Ohm, S., Wilhelmi, E. de Oña, Opitz, B., Ostrowski, M., Oya, I., Panter, M., Parsons, R. D., Arribas, M. Paz, Pekeur, N. W., Pelletier, G., Perez, J., Petrucci, P. -O., Peyaud, B., Pita, S., Poon, H., Pühlhofer, G., Punch, M., Quirrenbach, A., Raab, S., Raue, M., Reimer, A., Reimer, O., Renaud, M., Reyes, R. de los, Rieger, F., Rob, L., Romoli, C., Rosier-Lees, S., Rowell, G., Rudak, B., Rulten, C. B., Sahakian, V., Sanchez, D. A., Santangelo, A., Schlickeiser, R., Schüssler, F., Schulz, A., Schwanke, U., Schwarzburg, S., Schwemmer, S., Sol, H., Spengler, G., Spies, F., Stawarz, Ł., Steenkamp, R., Stegmann, C., Stinzing, F., Stycz, K., Sushch, I., Szostek, A., Tavernet, J. -P., Tavernier, T., Taylor, A. M., Terrier, R., Tluczykont, M., Trichard, C., Valerius, K., van Eldik, C., van Soelen, B., Vasileiadis, G., Venter, C., Viana, A., Vincent, P., Vink, J., Völk, H. J., Volpe, F., Vorster, M., Vuillaume, T., Wagner, S. J., Wagner, P., Ward, M., Weidinger, M., Weitzel, Q., White, R., Wierzcholska, A., Willmann, P., Wörnlein, A., Wouters, D., Zabalza, V., Zacharias, M., Zajczyk, A., Zdziarski, A. A., Zech, A., and Zechlin, H. -S.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: The results of follow-up observations of the TeV gamma-ray source HESSJ 1640-465 from 2004 to 2011 with the High Energy Stereoscopic System (H.E.S.S.) are reported in this work. The spectrum is well described by an exponential cut-off power law with photon index Gamma=2.11 +/- 0.09_stat +/- 0.10_sys, and a cut-off energy of E_c = (6.0 +2.0 -1.2) TeV. The TeV emission is significantly extended and overlaps with the north-western part of the shell of the SNR G338.3-0.0. The new H.E.S.S. results, a re-analysis of archival XMM-Newton data, and multi-wavelength observations suggest that a significant part of the gamma-ray emission from HESS J1640-465 originates in the SNR shell. In a hadronic scenario, as suggested by the smooth connection of the GeV and TeV spectra, the product of total proton energy and mean target density could be as high as W_p n_H ~ 4 x 10^52 (d/10kpc)^2 erg cm^-3., Comment: accepted for publication in MNRAS, 9 pages, 5 figures, added Spitzer citation and acknowledgement
Published: 2014
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33. Search for Extended {\gamma}-ray Emission around AGN with H.E.S.S. and Fermi-LAT

Author: Collaboration, H. E. S. S., Abramowski, A., Aharonian, F., Benkhali, F. Ait, Akhperjanian, A. G., Angüner, E., Anton, G., Backes, M., Balenderan, S., Balzer, A., Barnacka, A., Becherini, Y., Tjus, J. Becker, Bernlöhr, K., Birsin, E., Bissaldi, E., Biteau, J., Böttcher, M., Boisson, C., Bolmont, J., Bordas, P., Brucker, J., Brun, F., Brun, P., Bulik, T., Carrigan, S., Casanova, S., Chadwick, P. M., Chalme-Calvet, R., Chaves, R. C. G., Cheesebrough, A., Chrétien, M., Colafrancesco, S., Cologna, G., Conrad, J., Couturier, C., Cui, Y., Dalton, M., Daniel, M. K., Davids, I. D., Degrange, B., Deil, C., deWilt, P., Dickinson, H. J., Djannati-Ataï, A., Domainko, W., Drury, L. O'C., Dubus, G., Dutson, K., Dyks, J., Dyrda, M., Edwards, T., Egberts, K., Eger, P., Espigat, P., Farnier, C., Fegan, S., Feinstein, F., Fernandes, M. V., Fernandez, D., Fiasson, A., Fontaine, G., Förster, A., Füßling, M., Gajdus, M., Gallant, Y. A., Garrigoux, T., Giavitto, G., Giebels, B., Glicenstein, J. F., Grondin, M. -H., Grudzińska, M., Häffner, S., Hahn, J., Harris, J., Heinzelmann, G., Henri, G., Hermann, G., Hervet, O., Hillert, A., Hinton, J. A., Hofmann, W., Hofverberg, P., Holler, M., Horns, D., Jacholkowska, A., Jahn, C., Jamrozy, M., Janiak, M., Jankowsky, F., Jung, I., Kastendieck, M. A., Katarzyński, K., Katz, U., Kaufmann, S., Khélifi, B., Kieffer, M., Klepser, S., Klochkov, D., Kluźniak, W., Kneiske, T., Kolitzus, D., Komin, Nu., Kosack, K., Krakau, S., Krayzel, F., Krüger, P. P., Laffon, H., Lamanna, G., Lefaucheur, J., Lemière, A., Lemoine-Goumard, M., Lenain, J. -P., Lohse, T., Lopatin, A., Lu, C. -C., Marandon, V., Marcowith, A., Marx, R., Maurin, G., Maxted, N., Mayer, M., McComb, T. J. L., Méhault, J., Meintjes, P. J., Menzler, U., Meyer, M., Moderski, R., Mohamed, M., Moulin, E., Murach, T., Naumann, C. L., de Naurois, M., Niemiec, J., Nolan, S. J., Oakes, L., Odaka, H., Ohm, S., Wilhelmi, E. de Oña, Opitz, B., Ostrowski, M., Oya, I., Panter, M., Parsons, R. D., Arribas, M. Paz, Pekeur, N. W., Pelletier, G., Perez, J., Petrucci, P. -O., Peyaud, B., Pita, S., Poon, H., Pühlhofer, G., Punch, M., Quirrenbach, A., Raab, S., Raue, M., Reichardt, I., Reimer, A., Reimer, O., Renaud, M., Reyes, R. de los, Rieger, F., Rob, L., Romoli, C., Rosier-Lees, S., Rowell, G., Rudak, B., Rulten, C. B., Sahakian, V., Sanchez, D. A., Santangelo, A., Schlickeiser, R., Schüssler, F., Schulz, A., Schwanke, U., Schwarzburg, S., Schwemmer, S., Sol, H., Spengler, G., Spies, F., Stawarz, Ł., Steenkamp, R., Stegmann, C., Stinzing, F., Stycz, K., Sushch, I., Tavernet, J. -P., Tavernier, T., Taylor, A. M., Terrier, R., Tluczykont, M., Trichard, C., Valerius, K., van Eldik, C., van Soelen, B., Vasileiadis, G., Venter, C., Viana, A., Vincent, P., Völk, H. J., Volpe, F., Vorster, M., Vuillaume, T., Wagner, S. J., Wagner, P., Ward, M., Weidinger, M., Weitzel, Q., White, R., Wierzcholska, A., Willmann, P., Wörnlein, A., Wouters, D., Yang, R., Zabalza, V., Zacharias, M., Zdziarski, A. A., Zech, A., Zechlin, H. -S., and Malyshev, D.
Subjects: Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract: Context: Very-high-energy (VHE; E>100 GeV) {\gamma}-ray emission from blazars inevitably gives rise to electron-positron pair production through the interaction of these {\gamma}-rays with the Extragalactic Background Light (EBL). Depending on the magnetic fields in the proximity of the source, the cascade initiated from pair production can result in either an isotropic halo around an initially beamed source or a magnetically broadened cascade flux. Aims: Both extended pair halo (PH) and magnetically broadened cascade (MBC) emission from regions surrounding the blazars 1ES 1101-232, 1ES 0229+200 and PKS 2155-304 were searched for, using VHE {\gamma}-ray data taken with the High Energy Stereoscopic System (H.E.S.S.), and high energy (HE; 100 MeV 10$^{-12}$G, this limits the production of pair halos developing from electromagnetic cascades. For weaker magnetic fields, in which electromagnetic cascades would result in magnetically broadened cascades, EGMF strengths in the range (0.3 - 3)$\times 10^{-15}$G were excluded for PKS 2155-304 at the 99% confidence level, under the assumption of a 1 Mpc coherence length., Comment: 11 pages, 6 figures. Accepted for publication by Astronomy & Astrophysics
Published: 2014
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34. Long-term TeV and X-ray Observations of the Gamma-ray Binary HESS J0632+057

Author: VERITAS Collaboration, Aliu, E., Archambault, S., Aune, T., Behera, B., Beilicke, M., Benbow, W., Berger, K., Bird, R., Bouvier, A., Buckley, J. H., Bugaev, V., Byrum, K., Cerruti, M., Chen, X., Ciupik, L., Connolly, M. P., Cui, W., Duke, C., Dumm, J., Errando, M., Falcone, A., Federici, S., Feng, Q., Finley, J. P., Fortin, P., Fortson, L., Furniss, A., Galante, N., Gillanders, G. H., Griffin, S., Griffiths, S. T., Grube, J., Gyuk, G., Hanna, D., Holder, J., Hughes, G., Humensky, T. B., Kaaret, P., Kertzman, M., Khassen, Y., Kieda, D., Krawczynski, H., Krennrich, F., Lang, M. J., Madhavan, A. S, Maier, G., Majumdar, P., McCann, A., Moriarty, P., Mukherjee, R., Nieto, D., de Bhróithe, A. O'Faoláin, Ong, R. A., Otte, A. N., Park, N., Perkins, J. S., Pohl, M., Popkow, A., Prokoph, H., Quinn, J., Ragan, K., Rajotte, J., Reyes, L. C., Reynolds, P. T., Richards, G. T., Roache, E., Rousselle, J., Sembroski, G. H., Sheidaei, F., Skole, C., Smith, A. W., Staszak, D., Stroh, M., Telezhinsky, I., Theiling, M., Tucci, J. V., Tyler, J., Varlotta, A., Vincent, S., Wakely, S. P., Weinstein, A., Welsing, R., Williams, D. A., Zajczyk, A., Zitzer, B., Collaboration, H. E. S. S., Abramowski, A., Aharonian, F., Benkhali, F. Ait, Akhperjanian, A. G., Angüner, E., Anton, G., Balenderan, S., Balzer, A., Barnacka, A., Becherini, Y., Tjus, J. Becker, Bernlöhr, K., Birsin, E., Bissaldi, E., Biteau, J., Böttcher, M., Boisson, C., Bolmont, J., Bordas, P., Brucker, J., Brun, F., Brun, P., Bulik, T., Carrigan, S., Casanova, S., Chadwick, P. M., Chalme-Calvet, R., Chaves, R. C. G., Cheesebrough, A., Chrétien, M., Colafrancesco, S., Cologna, G., Conrad, J., Couturier, C., Dalton, M., Daniel, M. K., Davids, I. D., Degrange, B., Deil, C., deWilt, P., Dickinson, H. J., Djannati-Ataï, A., Domainko, W., Drury, L. O'C., Dubus, G., Dutson, K., Dyks, J., Dyrda, M., Edwards, T., Egberts, K., Eger, P., Espigat, P., Farnier, C., Fegan, S., Feinstein, F., Fernandes, M. V., Fernandez, D., Fiasson, A., Fontaine, G., Forster, A., Füßling, M., Gajdus, M., Gallant, Y. A., Garrigoux, T., Giavitto, G., Giebels, B., Glicenstein, J. F., Grondin, M. -H., Grudzińska, M., Häffner, S., Hahn, J., Harris, J., Heinzelmann, G., Henri, G., Hermann, G., Hervet, O., Hillert, A., Hinton, J. A., Hofmann, W., Hofverberg, P., Holler, M., Horns, D., Jacholkowska, A., Jahn, C., Jamrozy, M., Janiak, M., Jankowsky, F., Jung, I., Kastendieck, M. A., Katarzyński, K., Katz, U., Kaufmann, S., Khélifi, B., Kieffer, M., Klepser, S., Klochkov, D., Kluźniak, W., Kneiske, T., Kolitzus, D., Komin, Nu., Kosack, K., Krakau, S., Krayzel, F., Krüger, P. P., Laffon, H., Lamanna, G., Lefaucheur, J., Lemiére, A., Lemoine-Goumard, M., Lenain, J. -P., Lennarz, D., Lohse, T., Lopatin, A., Lu, C. -C., Marandon, V., Marcowith, A., Marx, R., Maurin, G., Maxted, N., Mayer, M., McComb, T. J. L., Méhault, J., Menzler, U., Meyer, M., Moderski, R., Mohamed, M., Moulin, E., Murach, T., Naumann, C. L., de Naurois, M., Niemiec, J., Nolan, S. J., Oakes, L., Ohm, S., Wilhelmi, E. de Onña, Opitz, B., Ostrowski, M., Oya, I., Panter, M., Parsons, R. D., Arribas, M. Paz, Pekeur, N. W., Pelletier, G., Perez, J., Petrucci, P. -O., Peyaud, B., Pita, S., Poon, H., Pühlhofer, G., Punch, M., Quirrenbach, A., Raab, S., Raue, M., Reimer, A., Reimer, O., Renaud, M., Reyes, R. de los, Rieger, F., Rob, L., Romoli, C., Rosier-Lees, S., Rowell, G., Rudak, B., Rulten, C. B., Sahakian, V., Sanchez, D. A., Santangelo, A., Schlickeiser, R., Schüssler, F., Schulz, A., Schwanke, U., Schwarzburg, S., Schwemmer, S., Sol, H., Spengler, G., Spies, F., Stawarz, Ł., Steenkamp, R., Stegmann, C., Stinzing, F., Stycz, K., Sushch, I., Szostek, A., Tavernet, J. -P., Tavernier, T., Taylor, A. M., Terrier, R., Tluczykont, M., Trichard, C., Valerius, K., van Eldik, C., Vasileiadis, G., Venter, C., Viana, A., Vincent, P., Völk, H. J., Volpe, F., Vorster, M., Wagner, S. J., Wagner, P., Ward, M., Weidinger, M., Weitzel, Q., White, R., Wierzcholska, A., Willmann, P., Wörnlein, A., Wouters, D., Zacharias, M., Zdziarski, A. A., Zech, A., and Zechlin, H. -S.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: HESS J0632+057 is the only gamma-ray binary known so far whose position in the sky allows observations with ground-based observatories both in the northern and southern hemispheres. Here we report on long-term observations of HESS J0632+057 conducted with the VERITAS and H.E.S.S. Cherenkov Telescopes and the X-ray Satellite Swift, spanning a time range from 2004 to 2012 and covering most of the system's orbit. The VHE emission is found to be variable, and is correlated with that at X-ray energies. An orbital period of $315 ^{+6}_{-4}$ days is derived from the X-ray data set, which is compatible with previous results, $P = (321 \pm 5$) days. The VHE light curve shows a distinct maximum at orbital phases close to 0.3, or about 100 days after periastron passage, which coincides with the periodic enhancement of the X-ray emission. Furthermore, the analysis of the TeV data shows for the first time a statistically significant ($> 6.5 \sigma$) detection at orbital phases 0.6--0.9. The obtained gamma-ray and X-ray light curves and the correlation of the source emission at these two energy bands are discussed in the context of the recent ephemeris obtained for the system. Our results are compared to those reported for other gamma-ray binaries., Comment: 35 pages, 8 figures, accepted for publication in ApJ
Published: 2013
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35. Constraints on axionlike particles with H.E.S.S. from the irregularity of the PKS 2155-304 energy spectrum

Author: Collaboration, H. E. S. S., Abramowski, A., Acero, F., Aharonian, F., Benkhali, F. Ait, Akhperjanian, A. G., Angüner, E., Anton, G., Balenderan, S., Balzer, A., Barnacka, A., Becherini, Y., Tjus, J. Becker, Bernlöhr, K., Birsin, E., Bissaldi, E., Biteau, J., Boisson, C., Bolmont, J., Bordas, P., Brucker, J., Brun, F., Brun, P., Bulik, T., Carrigan, S., Casanova, S., Cerruti, M., Chadwick, P. M., Chalme-Calvet, R., Chaves, R. C. G., Cheesebrough, A., Chrétien, M., Colafrancesco, S., Cologna, G., Conrad, J., Couturier, C., Dalton, M., Daniel, M. K., Davids, I. D., Degrange, B., Deil, C., deWilt, P., Dickinson, H. J., Djannati-Ataï, A., Domainko, W., Drury, L. O'C., Dubus, G., Dutson, K., Dyks, J., Dyrda, M., Egberts, T. Edwards K., Eger, P., Espigat, P., Farnier, C., Fegan, S., Feinstein, F., Fernandes, M. V., Fernandez, D., Fiasson, A., Fontaine, G., Förster, A., Füssling, M., Gajdus, M., Gallant, Y. A., Garrigoux, T., Gast, H., Giebels, B., Glicenstein, J. F., Göring, D., Grondin, M. -H., Grudzińska, M., Häffner, S., Hague, J. D., Hahn, J., Harris, J., Heinzelmann, G., Henri, G., Hermann, G., Hervet, O., Hillert, A., Hinton, J. A., Hofmann, W., Hofverberg, P., Holler, M., Horns, D., Jacholkowska, A., Jahn, C., Jamrozy, M., Janiak, M., Jankowsky, F., Jung, I., Kastendieck, M. A., Katarzyński, K., Katz, U., Kaufmann, S., Khélifi, B., Kieffer, M., Klepser, S., Klochkov, D., Kluźniak, W., Kneiske, T., Kolitzus, D., Komin, Nu., Kosack, K., Krakau, S., Krayzel, F., Krüger, P. P., Laffon, H., Lamanna, G., Lefaucheur, J., Lemoine-Goumard, M., Lenain, J. -P., Lennarz, D., Lohse, T., Lopatin, A., Lu, C. -C., Marandon, V., Marcowith, A., Marx, R., Maurin, G., Maxted, N., Mayer, M., McComb, T. J. L., Medina, M. C., Méhault, J., Menzler, U., Meyer, M., Moderski, R., Mohamed, M., Moulin, E., Murach, T., Naumann, C. L., de Naurois, M., Nedbal, D., Niemiec, J., Nolan, S. J., Oakes, L., Ohm, S., Wilhelmi, E. de Oña, Opitz, B., Ostrowski, M., Oya, I., Panter, M., Parsons, R. D., Arribas, M. Paz, Pekeur, N. W., Pelletier, G., Perez, J., Petrucci, P. -O., Peyaud, B., Pita, S., Poon, H., Pühlhofer, G., Punch, M., Quirrenbach, A., Raab, S., Raue, M., Reimer, A., Reimer, O., Renaud, M., Reyes, R. de los, Rieger, F., Rob, L., Rosier-Lees, S., Rowell, G., Rudak, B., Rulten, C. B., Sahakian, V., Sanchez, D. A., Santangelo, A., Schlickeiser, R., Schüssler, F., Schulz, A., Schwanke, U., Schwarzburg, S., Schwemmer, S., Sol, H., Spengler, G., Spies, F., Stawarz, L., Steenkamp, R., Stegmann, C., Stinzing, F., Stycz, K., Sushch, I., Szostek, A., Tavernet, J. -P., Terrier, R., Tluczykont, M., Trichard, C., Valerius, K., van Eldik, C., Vasileiadis, G., Venter, C., Viana, A., Vincent, P., Völk, H. J., Volpe, F., Vorster, M., Wagner, S. J., Wagner, P., Ward, M., Weidinger, M., Weitzel, Q., White, R., Wierzcholska, A., Willmann, P., Wörnlein, A., Wouters, D., Zacharias, M., Zajczyk, A., Zdziarski, A. A., Zech, A., and Zechlin, H. -S.
Subjects: Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Cosmology and Extragalactic Astrophysics, High Energy Physics - Experiment
Abstract: Axionlike particles (ALPs) are hypothetical light (sub-eV) bosons predicted in some extensions of the Standard Model of particle physics. In astrophysical environments comprising high-energy gamma rays and turbulent magnetic fields, the existence of ALPs can modify the energy spectrum of the gamma rays for a sufficiently large coupling between ALPs and photons. This modification would take the form of an irregular behavior of the energy spectrum in a limited energy range. Data from the H.E.S.S. observations of the distant BL Lac object PKS 2155-304 (z = 0.116) are used to derive upper limits at the 95% C.L. on the strength of the ALP coupling to photons, $g_{\gamma a} < 2.1\times 10^{-11}$ GeV$^{-1}$ for an ALP mass between 15 neV and 60 neV. The results depend on assumptions on the magnetic field around the source, which are chosen conservatively. The derived constraints apply to both light pseudoscalar and scalar bosons that couple to the electromagnetic field., Comment: 13 pages, 7 figures, to appear in Phys.Rev.D
Published: 2013
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36. H.E.S.S. Observations of the Crab during its March 2013 GeV Gamma-Ray Flare

Author: Collaboration, H. E. S. S., Abramowski, A., Aharonian, F., Benkhali, F. Ait, Akhperjanian, A. G., Angüner, E., Anton, G., Balenderan, S., Balzer, A., Barnacka, A., Becherini, Y., Tjus, J. Becker, Bernlöhr, K., Birsin, E., Bissaldi, E., Biteau, J., Böttcher, M., Boisson, C., Bolmont, J., Bordas, P., Brucker, J., Brun, F., Brun, P., Bulik, T., Carrigan, S., Casanova, S., Cerruti, M., Chadwick, P. M., Chalme-Calvet, R., Chaves, R. C. G., Cheesebrough, A., Chrétien, M., Colafrancesco, S., Cologna, G., Conrad, J., Couturier, C., Cui, Y., Dalton, M., Daniel, M. K., Davids, I. D., Degrange, B., Deil, C., deWilt, P., Dickinson, H. J., Djannati-Ataï, A., Domainko, W., Drury, L. O'C., Dubus, G., Dutson, K., Dyks, J., Dyrda, M., Edwards, T., Egberts, K., Eger, P., Espigat, P., Farnier, C., Fegan, S., Feinstein, F., Fernandes, M. V., Fernandez, D., Fiasson, A., Fontaine, G., Förster, A., Füßling, M., Gajdus, M., Gallant, Y. A., Garrigoux, T., Giavitto, G., Giebels, B., Glicenstein, J. F., Grondin, M. -H., Grudzińska, M., Häffner, S., Hahn, J., Harris, J., Heinzelmann, G., Henri, G., Hermann, G., Hervet, O., Hillert, A., Hinton, J. A., Hofmann, W., Hofverberg, P., Holler, M., Horns, D., Jacholkowska, A., Jahn, C., Jamrozy, M., Janiak, M., Jankowsky, F., Jung, I., Kastendieck, M. A., Katarzyński, K., Katz, U., Kaufmann, S., Khélifi, B., Kieffer, M., Klepser, S., Klochkov, D., Kluźniak, W., Kneiske, T., Kolitzus, D., Komin, Nu., Kosack, K., Krakau, S., Krayzel, F., Krüger, P. P., Laffon, H., Lamanna, G., Lefaucheur, J., Lemière, A., Lemoine-Goumard, M., Lenain, J. -P., Lennarz, D., Lohse, T., Lopatin, A., Lu, C. -C., Marandon, V., Marcowith, A., Marx, R., Maurin, G., Maxted, N., Mayer, M., McComb, T. J. L., Méhault, J., Meintjes, P. J., Menzler, U., Meyer, M., Moderski, R., Mohamed, M., Moulin, E., Murach, T., Naumann, C. L., de Naurois, M., Niemiec, J., Nolan, S. J., Oakes, L., Ohm, S., Wilhelmi, E. de Oña, Opitz, B., Ostrowski, M., Oya, I., Panter, M., Parsons, R. D., Arribas, M. Paz, Pekeur, N. W., Pelletier, G., Perez, J., Petrucci, P. -O., Peyaud, B., Pita, S., Poon, H., Pühlhofer, G., Punch, M., Quirrenbach, A., Raab, S., Raue, M., Reimer, A., Reimer, O., Renaud, M., Reyes, R. de los, Rieger, F., Rob, L., Romoli, C., Rosier-Lees, S., Rowell, G., Rudak, B., Rulten, C. B., Sahakian, V., Sanchez, D. A., Santangelo, A., Schlickeiser, R., Schüssler, F., Schulz, A., Schwanke, U., Schwarzburg, S., Schwemmer, S., Sol, H., Spengler, G., Spies, F., Stawarz, Ł., Steenkamp, R., Stegmann, C., Stinzing, F., Stycz, K., Sushch, I., Szostek, A., Tavernet, J. -P., Tavernier, T., Taylor, A. M., Terrier, R., Tluczykont, M., Trichard, C., Valerius, K., van Eldik, C., van Soelen, B., Vasileiadis, G., Venter, C., Viana, A., Vincent, P., Völk, H. J., Volpe, F., Vorster, M., Vuillaume, T., Wagner, S. J., Wagner, P., Ward, M., Weidinger, M., Weitzel, Q., White, R., Wierzcholska, A., Willmann, P., Wörnlein, A., Wouters, D., Zabalza, V., Zacharias, M., Zajczyk, A., Zdziarski, A. A., Zech, A., and Zechlin, H. -S.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: Context. On March 4, 2013, the Fermi-LAT and AGILE reported a flare from the direction of the Crab Nebula in which the high-energy (HE; E > 100 MeV) flux was six times above its quiescent level. Simultaneous observations in other energy bands give us hints about the emission processes during the flare episode and the physics of pulsar wind nebulae in general. Aims. We search for variability of the emission of the Crab Nebula at very-high energies (VHE; E > 100 GeV), using contemporaneous data taken with the H.E.S.S. array of Cherenkov telescopes. Methods. Observational data taken with the H.E.S.S. instrument on five consecutive days during the flare were analysed concerning the flux and spectral shape of the emission from the Crab Nebula. Night-wise light curves are presented with energy thresholds of 1 TeV and 5 TeV. Results. The observations conducted with H.E.S.S. on 2013 March 6 to March 10 show no significant changes in the flux. They limit the variation on the integral flux above 1 TeV to less than 63% and the integral flux above 5 TeV to less than 78% at a 95% confidence level., Comment: 5 pages, 2 figures. Published in A&A
Published: 2013
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37. HESS J1818-154, a new composite supernova remnant discovered in TeV gamma rays and X-rays

Author: Collaboration, H. E. S. S., Abramowski, A., Aharonian, F., Benkhali, F. Ait, Akhperjanian, A. G., Angüner, E., Anton, G., Balenderan, S., Balzer, A., Barnacka, A., Becherini, Y., Tjus, J. Becker, Bernlöhr, K., Birsin, E., Bissaldi, E., Biteau, J., Böttcher, M., Boisson, C., Bolmont, J., Bordas, P., Brucker, J., Brun, F., Brun, P., Bulik, T., Carrigan, S., Casanova, S., Cerruti, M., Chadwick, P. M., Chalme-Calvet, R., Chaves, R. C. G., Cheesebrough, A., Chrétien, M., Colafrancesco, S., Cologna, G., Conrad, J., Couturier, C., Cui, Y., Dalton, M., Daniel, M. K., Davids, I. D., Degrange, B., Deil, C., de Wilt, P., Dickinson, H. J., Djannati-Ataï, A., Domainko, W., Drury, L. O'C., Dubus, G., Dutson, K., Dyks, J., Dyrda, M., Edwards, T., Egberts, K., Eger, P., Espigat, P., Farnier, C., Fegan, S., Feinstein, F., Fernandes, M. V., Fernandez, D., Fiasson, A., Fontaine, G., Förster, A., Füßling, M., Gajdus, M., Gallant, Y. A., Garrigoux, T., Giavitto, G., Giebels, B., Glicenstein, J. F., Grondin, M. -H., Grudzińska, M., Häffner, S., Hahn, J., Harris, J., Heinzelmann, G., Henri, G., Hermann, G., Hervet, O., Hillert, A., Hinton, J. A., Hofmann, W., Hofverberg, P., Holler, M., Horns, D., Jacholkowska, A., Jahn, C., Jamrozy, M., Janiak, M., Jankowsky, F., Jung, I., Kastendieck, M. A., Katarzynski, K., Katz, U., Kaufmann, S., Khélifi, B., Kieffer, M., Klepser, S., Klochkov, D., Kluźniak, W., Kneiske, T., Kolitzus, D., Komin, Nu., Kosack, K., Krakau, S., Krayzel, F., Krüger, P. P., Laffon, H., Lamanna, G., Lefaucheur, J., Lemière, A., Lemoine-Goumard, M., Lenain, J. -P., Lennarz, D., Lohse, T., Lopatin, A., Lu, C. -C., Marandon, V., Marcowith, A., Marx, R., Maurin, G., Maxted, N., Mayer, M., McComb, T. J. L., Méhault, J., Meintjes, P. J., Menzler, U., Meyer, M., Moderski, R., Mohamed, M., Moulin, E., Murach, T., Naumann, C. L., de Naurois, M., Niemiec, J., Nolan, S. J., Oakes, L., Ohm, S., Wilhelmi, E. de Ona, Opitz, B., Ostrowski, M., Oya, I., Panter, M., Parsons, R. D., Arribas, M. Paz, Pekeur, N. W., Pelletier, G., Perez, J., Petrucci, P. -O., Peyaud, B., Pita, S., Poon, H., Pühlhofer, G., Punch, M., Quirrenbach, A., Raab, S., Raue, M., Reimer, A., Reimer, O., Renaud, M., Reyes, R. de los, Rieger, F., Rob, L., Romoli, C., Rosier-Lees, S., Rowell, G., Rudak, B., Rulten, C. B., Sahakian, V., Sanchez, D. A., Santangelo, A., Schlickeiser, R., Schüssler, F., Schulz, A., Schwanke, U., Schwarzburg, S., Schwemmer, S., Sol, H., Spengler, G., Spies, F., Stawarz, L., Steenkamp, R., Stegmann, C., Stinzing, F., Stycz, K., Sushch, I., Szostek, A., Tavernet, J. -P., Tavernier, T., Taylor, A. M., Terrier, R., Tluczykont, M., Trichard, C., Valerius, K., van Eldik, C., van Soelen, B., Vasileiadis, G., Venter, C., Viana, A., Vincent, P., Völk, H. J., Volpe, F., Vorster, M., Vuillaume, T., Wagner, S. J., Wagner, P., Ward, M., Weidinger, M., Weitzel, Q., White, R., Wierzcholska, A., Willmann, P., Wörnlein, A., Wouters, D., Zabalza, V., Zacharias, M., Zajczyk, A., Zdziarski, A. A., Zech, A., and Zechlin, H. -S.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: Composite supernova remnants (SNRs) constitute a small subclass of the remnants of massive stellar explosions where non-thermal radiation is observed from both the expanding shell-like shock front and from a pulsar wind nebula (PWN) located inside of the SNR. These systems represent a unique evolutionary phase of SNRs where observations in the radio, X-ray, and $\gamma$-ray regimes allow the study of the co-evolution of both these energetic phenomena. In this article, we report results from observations of the shell-type SNR G15.4+0.1 performed with the High Energy Stereoscopic System (H.E.S.S.) and XMM-Newton. A compact TeV $\gamma$-ray source, HESSJ1818-154, located in the center and contained within the shell of G15.4+0.1 is detected by H.E.S.S. and featurs a spectrum best represented by a power-law model with a spectral index of $-2.3 \pm 0.3_{stat} \pm 0.2_{sys}$ and an integral flux of F$(>$0.42$\,\mathrm{TeV}$)=($0.9 \pm 0.3_{\mathrm{stat}} \pm 0.2_{\mathrm{sys}}) \times 10^{-12}$cm$^{-2}$s$^{-1}$. Furthermore, a recent observation with XMM-Newton reveals extended X-ray emission strongly peaked in the center of G15.4+0.1. The X-ray source shows indications of an energy-dependent morphology featuring a compact core at energies above 4 keV and more extended emission that fills the entire region within the SNR at lower energies. Together, the X-ray and VHE $\gamma$-ray emission provide strong evidence of a PWN located inside the shell of G15.4+0.1, and this SNR can therefore be classified as a \emph{composite} based on these observations. The radio, X-ray, and $\gamma$-ray emission from the PWN is compatible with a one-zone leptonic model that requires a low average magnetic field inside the emission region. An unambiguous counterpart to the putative pulsar, which is thought to power the PWN, has been detected neither in radio nor in X-ray observations of G15.4+0.1., Comment: 12 pages, 6 figures
Published: 2013
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38. Discovery of very high energy gamma-ray emission from the BL Lac object PKS 0301-243 with H.E.S.S

Author: Collaboration, H. E. S. S., Abramowski, A., Acero, F., Aharonian, F., Ait, F., Akhperjanian, A. G., Angüner, E., Anton, G., Balenderan, S., Balzer, A., Barnacka, A., Becherini, Y., Becker, J., Bernlöhr, K., Birsin, E., Bissaldi, E., Biteau, J., Böttcher, M., Boisson, C., Bolmont, J., Bordas, P., Brucker, J., Brun, F., Brun, P., Bulik, T., Carrigan, S., Casanova, S., Cerruti, M., Chadwick, P. M., Chalme-Calvet, R., Chaves, R. C. G., Cheesebrough, A., Chrétien, M., Colafrancesco, S., Cologna, G., Conrad, J., Couturier, C., Dalton, M., Daniel, M. K., Davids, I. D., Degrange, B., Deil, C., deWilt, P., Dickinson, H. J., Djannati-Ataï, A., Domainko, W., Drury, L. O'C., Dubus, G., Dutson, K., Dyks, J., Dyrda, M., Edwards, T., Egberts, K., Eger, P., Espigat, P., Farnier, C., Fegan, S., Feinstein, F., Fernandes, M. V., Fernandez, D., Fiasson, A., Fontaine, G., Förster, A., Füssling, M., Gajdus, M., Gallant, Y. A., Garrigoux, T., Giebels, B., Glicenstein, J. F., Grondin, M. -H., Grudzìnska, M., Häffner, S., Hague, J. D., Hahn, J., Harris, J., Heinzelmann, G., Henri, G., Hermann, G., Hervet, O., Hillert, A., Hinton, J. A., Hofmann, W., Hofverberg, P., Holler, M., Horns, D., Jacholkowska, A., Jahn, C., Jamrozy, M., Janiak, M., Jankowsky, F., Jung, I., Kastendieck, M. A., Katarzyński, K., Katz, U., Kaufmann, S., Khélifi, B., Kieffer, M., Klepser, S., Klochkov, D., Kluźniak, W., Kneiske, T., Kolitzus, D., Komin, Nu., Kosack, K., Krakau, S., Krayzel, F., Krüger, P. P., Laffon, H., Lamanna, G., Lefaucheur, J., Lemoine-Goumard, M., Lenain, J. -P., Lennarz, D., Lohse, T., Lopatin, A., Lu, C. -C., Marandon, V., Marcowith, A., Marx, R., Maurin, G., Maxted, N., Mayer, M., McComb, T. J. L., Medina, M. C., Méhault, J., Menzler, U., Meyer, M., Moderski, R., Mohamed, M., Moulin, E., Murach, T., Naumann, C. L., de Naurois, M., Nedbal, D., Niemiec, J., Nolan, S. J., Oakes, L., Ohm, S., Wilhelmi, E. de Oña, Opitz, B., Ostrowski, M., Oya, I., Panter, M., Parsons, R. D., Arribas, M. Paz, Pekeur, N. W., Pelletier, G., Perez, J., Petrucci, P. -O., Peyaud, B., Pita, S., Poon, H., Pühlhofer, G., Punch, M., Quirrenbach, A., Raab, S., Raue, M., Reimer, A., Reimer, O., Renaud, M., Reyes, R. de los, Rieger, F., Rob, L., Rosier-Lees, S., Rowell, G., Rudak, B., Rulten, C. B., Sahakian, V., Sanchez, D. A., Santangelo, A., Schlickeiser, R., Schüssler, F., Schulz, A., Schwanke, U., Schwarzburg, S., Schwemmer, S., Sol, H., Spengler, G., Spies, F., Stawarz, L., Steenkamp, R., Stegmann, C., Stinzing, F., Stycz, K., Sushch, I., Szostek, A., Tavernet, J. -P., Terrier, R., Tluczykont, M., Trichard, C., Valerius, K., van Eldik, C., Vasileiadis, G., Venter, C., Viana, A., Vincent, P., Völk, H. J., Volpe, F., Vorster, M., Wagner, S. J., Wagner, P., Ward, M., Weidinger, M., Weitzel, Q., White, R., Wierzcholska, A., Willmann, P., Wörnlein, A., Wouters, D., Zacharias, M., Zajczyk, A., Zdziarski, A. A., Zech, A., and Zechlin, H. -S.
Subjects: Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract: The active galactic nucleus PKS 0301-243 (z=0.266) is a high-synchrotron-peaked BL Lac object that is detected at high energies (HE, 100 MeV < E < 100 GeV) by Fermi/LAT. This paper reports on the discovery of PKS 0301-243 at very high energies (E>100 GeV) by the High Energy Stereoscopic System (H.E.S.S.) from observations between September 2009 and December 2011 for a total live time of 34.9 hours. Gamma rays above 200 GeV are detected at a significance of 9.4{\sigma}. A hint of variability at the 2.5{\sigma} level is found. An integral flux I(E > 200 GeV) = (3.3 +/- 1.1_stat +/- 0.7_syst)e-12 ph cm^-2s^-1 and a photon index {\Gamma} = 4.6 +/- 0.7_stat +/- 0.2_syst are measured. Multi-wavelength light curves in HE, X-ray and optical bands show strong variability, and a minimal variability timescale of eight days is estimated from the optical light curve. A single-zone leptonic synchrotron self-Compton scenario satisfactorily reproduces the multi-wavelength data. In this model, the emitting region is out of equipartition and the jet is particle dominated. Because of its high redshift compared to other sources observed at TeV energies, the very high energy emission from PKS 0301-243 is attenuated by the extragalactic background light (EBL) and the measured spectrum is used to derive an upper limit on the opacity of the EBL., Comment: 12 pages, 6 figures, to appear in A&A
Published: 2013
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39. H.E.S.S and Fermi-LAT discovery of gamma rays from the blazar 1ES 1312-423

Author: Collaboration, H. E. S. S., Abramowski, A., Acero, F., Aharonian, F., Akhperjanian, A. G., Angüner, E., Anton, G., Balenderan, S., Balzer, A., Barnacka, A., Becherini, Y., Tjus, J. Becker, Bernlöhr, K., Birsin, E., Bissaldi, E., Biteau, J., Boisson, C., Bolmont, J., Bordas, P., Brucker, J., Brun, F., Brun, P., Bulik, T., Carrigan, S., Casanova, S., Cerruti, M., Chadwick, P. M., Chalme-Calvet, R., Chaves, R. C. G., Cheesebrough, A., Chrétien, M., Colafrancesco, S., Cologna, G., Conrad, J., Couturier, C., Dalton, M., Daniel, M. K., Davids, I. D., Degrange, B., Deil, C., deWilt, P., Dickinson, H. J., Djannati-Ataï, A., Domainko, W., Drury, L. O'C., Dubus, G., Dutson, K., Dyks, J., Dyrda, M., Edwards, T., Egberts, K., Eger, P., Espigat, P., Farnier, C., Fegan, S., Feinstein, F., Fernandes, M. V., Fernandez, D., Fiasson, A., Fontaine, G., Förster, A., Füßling, M., Gajdus, M., Gallant, Y. A., Garrigoux, T., Gast, H., Giebels, B., Glicenstein, J. F., Göring, D., Grondin, M. -H., Grudzińska, M., Häffner, S., Hague, J. D., Hahn, J., Harris, J., Heinzelmann, G., Henri, G., Hermann, G., Hervet, O., Hillert, A., Hinton, J. A., Hofmann, W., Hofverberg, P., Holler, M., Horns, D., Jacholkowska, A., Jahn, C., Jamrozy, M., Janiak, M., Jankowsky, F., Jung, I., Kastendieck, M. A., Katarzyński, K., Katz, U., Kaufmann, S., Khélifi, B., Kieffer, M., Klepser, S., Klochkov, D., Kluźniak, W., Kneiske, T., Kolitzus, D., Komin, Nu., Kosack, K., Krakau, S., Krayzel, F., Krüger, P. P., Laffon, H., Lamanna, G., Lefaucheur, J., Lemoine-Goumard, M., Lenain, J. -P., Lennarz, D., Lohse, T., Lopatin, A., Lu, C. -C., Marandon, V., Marcowith, A., Maurin, G., Maxted, N., Mayer, M., McComb, T. J. L., Medina, M. C., Méhault, J., Menzler, U., Meyer, M., Moderski, R., Mohamed, M., Moulin, E., Murach, T., Naumann, C. L., de Naurois, M., Nedbal, D., Niemiec, J., Nolan, S. J., Oakes, L., Ohm, S., de OñaWilhelmi, E., Opitz, B., Ostrowski, M., Oya, I., Panter, M., Parsons, R. D., Arribas, M. Paz, Pekeur, N. W., Pelletier, G., Perez, J., Petrucci, P. -O., Peyaud, B., Pita, S., Poon, H., Pühlhofer, G., Punch, M., Quirrenbach, A., Raab, S., Raue, M., Reimer, A., Reimer, O., Renaud, M., Reyes, R. de los, Rieger, F., Rob, L., Rosier-Lees, S., Rowell, G., Rudak, B., Rulten, C. B., Sahakian, V., Sanchez, D. A., Santangelo, A., Schlickeiser, R., Schüssler, F., Schulz, A., Schwanke, U., Schwarzburg, S., Schwemmer, S., Sol, H., Spengler, G., Spieß, F., Stawarz, {Ł. }, Steenkamp, R., Stegmann, C., Stinzing, F., Stycz, K., Sushch, I., Szostek, A., Tavernet, J. -P., Terrier, R., Tluczykont, M., Trichard, C., Valerius, K., van Eldik, C., Vasileiadis, G., Venter, C., Viana, A., Vincent, P., Völk, H. J., Volpe, F., Vorster, M., Wagner, S. J., Wagner, P., Ward, M., Weidinger, M., White, R., Wierzcholska, A., Willmann, P., Wörnlein, A., Wouters, D., Zacharias, M., Zajczyk, A., Zdziarski, A. A., Zech, A., Zechlin, H. -S., Perkins, J. S., Ojha, R., Stevens, J., Edwards, P. G., and Kadler, M.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: A deep observation campaign carried out by the High Energy Stereoscopic System (H.E.S.S.) on Centaurus A enabled the discovery of gamma rays from the blazar 1ES 1312-423, two degrees away from the radio galaxy. With a differential flux at 1 TeV of (1.9 +/-0.6(stat) +/-0.4(sys)) x 10^{-13} /cm^2 /s /TeV corresponding to 0.5% of the Crab nebula differential flux and a spectral index of 2.9 +/- 0.5 (stat) +/- 0.2 (sys), 1ES 1312-423 is one of the faintest sources ever detected in the very high energy (E>100 GeV) extragalactic sky. A careful analysis using three and a half years of Fermi-LAT data allows the discovery at high energies (E>100 MeV) of a hard spectrum (index of 1.4 +/- 0.4 (stat) +/- 0.2 (sys)) source coincident with 1ES 1312-423. Radio, optical, UV and X-ray observations complete the spectral energy distribution of this blazar, now covering 16 decades in energy. The emission is successfully fitted with a synchrotron self Compton model for the non-thermal component, combined with a black-body spectrum for the optical emission from the host galaxy., Comment: 12 pages, 10 figures, accepted in MNRAS
Published: 2013
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40. H.E.S.S. discovery of VHE gamma-rays from the quasar PKS 1510-089

Author: Collaboration, H. E. S. S., Abramowski, A., Acero, F., Aharonian, F., Akhperjanian, A. G., Anton, G., Balenderan, S., Balzer, A., Barnacka, A., Becherini, Y., Tjus, J. Becker, Behera, B., Bernlöhr, K., Birsin, E., Biteau, J., Bochow, A., Boisson, C., Bolmont, J., Bordas, P., Brucker, J., Brun, F., Brun, P., Bulik, T., Carrigan, S., Casanova, S., Cerruti, M., Chadwick, P. M., Chaves, R. C. G., Cheesebrough, A., Colafrancesco, S., Cologna, G., Conrad, J., Couturier, C., Dalton, M., Daniel, M. K., Davids, I. D., Degrange, B., Deil, C., deWilt, P., Dickinson, H. J., Djannati-Ataï, A., Domainko, W., Drury, L. O'C., Dubus, G., Dutson, K., Dyks, J., Dyrda, M., Egberts, K., Eger, P., Espigat, P., Fallon, L., Farnier, C., Fegan, S., Feinstein, F., Fernandes, M. V., Fernandez, D., Fiasson, A., Fontaine, G., Förster, A., Füßling, M., Gajdus, M., Gallant, Y. A., Garrigoux, T., Gast, H., Giebels, B., Glicenstein, J. F., Glück, B., Göring, D., Grondin, M. -H., Grudzińska, M., Häffner, S., Hague, J. D., Hahn, J., Hampf, D., Harris, J., Hauser, M., Heinz, S., Heinzelmann, G., Henri, G., Hermann, G., Hillert, A., Hinton, J. A., Hofmann, W., Hofverberg, P., Holler, M., Horns, D., Jacholkowska, A., Jahn, C., Jamrozy, M., Jung, I., Kastendieck, M. A., Katarzynski, K., Katz, U., Kaufmann, S., Khélifi, B., Klepser, S., Klochkov, D., Kluźniak, W., Kneiske, T., Kolitzus, D., Komin, Nu., Kosack, K., Kossakowski, R., Krayzel, F., Krüger, P. P., Laffon, H., Lamanna, G., Lefaucheur, J., Lemoine-Goumard, M., Lenain, J. -P., Lennarz, D., Lohse, T., Lopatin, A., Lu, C. -C., Marandon, V., Marcowith, A., Masbou, J., Maurin, G., Maxted, N., Mayer, M., McComb, T. J. L., Medina, M. C., Méhault, J., Menzler, U., Moderski, R., Mohamed, M., Moulin, E., Naumann, C. L., Naumann-Godo, M., de Naurois, M., Nedbal, D., Nguyen, N., Niemiec, J., Nolan, S. J., Ohm, S., Wilhelmi, E. de Ona, Opitz, B., Ostrowski, M., Oya, I., Panter, M., Parsons, R. D., Arribas, M. Paz, Pekeur, N. W., Pelletier, G., Perez, J., Petrucci, P. -O., Peyaud, B., Pita, S., Pühlhofer, G., Punch, M., Quirrenbach, A., Raab, S., Raue, M., Reimer, A., Reimer, O., Renaud, M., Reyes, R. de los, Rieger, F., Ripken, J., Rob, L., Rosier-Lees, S., Rowell, G., Rudak, B., Rulten, C. B., Sahakian, V., Sanchez, D. A., Santangelo, A., Schlickeiser, R., Schulz, A., Schwanke, U., Schwarzburg, S., Schwemmer, S., Sheidaei, F., Skilton, J. L., Sol, H., Spengler, G., Stawarz, Ł., Steenkamp, R., Stegmann, C., Stinzing, F., Stycz, K., Sushch, I., Szostek, A., Tavernet, J. -P., Terrier, R., Tluczykont, M., Trichard, C., Valerius, K., van Eldik, C., Vasileiadis, G., Venter, C., Viana, A., Vincent, P., Völk, H. J., Volpe, F., Vorobiov, S., Vorster, M., Wagner, S. J., Ward, M., White, R., Wierzcholska, A., Wouters, D., Zacharias, M., Zajczyk, A., Zdziarski, A. A., Zech, A., and Zechlin, H. -S.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: The quasar PKS 1510-089 (z=0.361) was observed with the H.E.S.S. array of imaging atmospheric Cherenkov telescopes during high states in the optical and GeV bands, to search for very high energy (VHE, defined as E >= 0.1 TeV) emission. VHE \gamma-rays were detected with a statistical significance of 9.2 standard deviations in 15.8 hours of H.E.S.S. data taken during March and April 2009. A VHE integral flux of I(0.15 TeV < E < 1.0 TeV) = (1.0 +- 0.2 (stat) +- 0.2 (sys) x 10^{-11} cm^{-2}s^{-1} is measured. The best-fit power law to the VHE data has a photon index of \Gamma=5.4 +- 0.7 (stat) +- 0.3 (sys). The GeV and optical light curves show pronounced variability during the period of H.E.S.S. observations. However, there is insufficient evidence to claim statistically significant variability in the VHE data. Because of its relatively high redshift, the VHE flux from PKS 1510-089 should suffer considerable attenuation in the intergalactic space due to the extragalactic background light (EBL). Hence, the measured \gamma-ray spectrum is used to derive upper limits on the opacity due to EBL, which are found to be comparable with the previously derived limits from relatively-nearby BL Lac objects. Unlike typical VHE-detected blazars where the broadband spectrum is dominated by non-thermal radiation at all wavelengths, the quasar PKS 1510-089 has a bright thermal component in the optical to UV frequency band. Among all VHE detected blazars, PKS 1510-089 has the most luminous broad line region (BLR). The detection of VHE emission from this quasar indicates a low level of \gamma-\gamma absorption on the internal optical to UV photon field., Comment: 7 pages, 4 figures, 1 table, accepted for publication in A&A
Published: 2013
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41. Discovery of high and very high-energy emission from the BL Lac object SHBL J001355.9-185406

Author: Collaboration, H. E. S. S., Abramowski, A., Acero, F., Aharonian, F., Akhperjanian, A. G., Angüner, E., Anton, G., Balenderan, S., Balzer, A., Barnacka, A., Becherini, Y., Tjus, J. Becker, Bernlöhr, K., Birsin, E., Bissaldi, E., Biteau, J., Boisson, C., Bolmont, J., Bordas, P., Brucker, J., Brun, F., Brun, P., Bulik, T., Carrigan, S., Casanova, S., Cerruti, M., Chadwick, P. M., Chalme-Calvet, R., Chaves, R. C. G., Cheesebrough, A., Chrétien, M., Colafrancesco, S., Cologna, G., Conrad, J., Couturier, C., Dalton, M., Daniel, M. K., Davids, I. D., Degrange, B., Deil, C., deWilt, P., Dickinson, H. J., Djannati-Ataï, A., Domainko, W., Drury, L. O'C., Dubus, G., Dutson, K., Dyks, J., Dyrda, M., Edwards, T., Egberts, K., Eger, P., Espigat, P., Farnier, C., Fegan, S., Feinstein, F., Fernandes, M. V., Fernandez, D., Fiasson, A., Fontaine, G., Förster, A., Füßling, M., Gajdus, M., Gallant, Y. A., Garrigoux, T., Gast, H., Giebels, B., Glicenstein, J. F., Göring, D., Grondin, M. -H., Grudzińska, M., Häffner, S., Hague, J. D., Hahn, J., Harris, J., Heinzelmann, G., Henri, G., Hermann, G., Hervet, O., Hillert, A., Hinton, J. A., Hofmann, W., Hofverberg, P., Holler, M., Horns, D., Jacholkowska, A., Jahn, C., Jamrozy, M., Janiak, M., Jankowsky, F., Jung, I., Kastendieck, M. A., Katarzyński, K., Katz, U., Kaufmann, S., Khélifi, B., Kieffer, M., Klepser, S., Klochkov, D., Kluźniak, W., Kneiske, T., Kolitzus, D., Komin, Nu., Kosack, K., Krakau, S., Krayzel, F., Krüger, P. P., Laffon, H., Lamanna, G., Lefaucheur, J., Lemoine-Goumard, M., Lenain, J. -P., Lennarz, D., Lohse, T., Lopatin, A., Lu, C. -C., Marandon, V., Marcowith, A., Maurin, G., Maxted, N., Mayer, M., McComb, T. J. L., Medina, M. C., Méhault, J., Menzler, U., Meyer, M., Moderski, R., Mohamed, M., Moulin, E., Murach, T., Naumann, C. L., de Naurois, M., Nedbal, D., Niemiec, J., Nolan, S. J., Oakes, L., Ohm, S., Wilhelmi, E. de Oña, Opitz, B., Ostrowski, M., Oya, I., Panter, M., Parsons, R. D., Arribas, M. Paz, Pekeur, N. W., Pelletier, G., Perez, J., Petrucci, P. -O., Peyaud, B., Pita, S., Poon, H., Pühlhofer, G., Punch, M., Quirrenbach, A., Raab, S., Raue, M., Reimer, A., Reimer, O., Renaud, M., Reyes, R. de los, Rieger, F., Rob, L., Rosier-Lees, S., Rowell, G., Rudak, B., Rulten, C. B., Sahakian, V., Sanchez, D. A., Santangelo, A., Schlickeiser, R., Schüssler, F., Schulz, A., Schwanke, U., Schwarzburg, S., Schwemmer, S., Sol, H., Spengler, G., Spieß, F., Stawarz, Ł., Steenkamp, R., Stegmann, C., Stinzing, F., Stycz, K., Sushch, I., Szostek, A., Tavernet, J. -P., Terrier, R., Tluczykont, M., Trichard, C., Valerius, K., van Eldik, C., Vasileiadis, G., Venter, C., Viana, A., Vincent, P., Völk, H. J., Volpe, F., Vorster, M., Wagner, S. J., Wagner, P., Ward, M., Weidinger, M., White, R., Wierzcholska, A., Willmann, P., Wörnlein, A., Wouters, D., Zacharias, M., Zajczyk, A., Zdziarski, A. A., Zech, A., and Zechlin, H. -S.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: The detection of the high-frequency peaked BL Lac object (HBL) SHBL J001355.9-185406 ($z$=0.095) at high (HE; 100 MeV$<$E$<$300 GeV) and very high-energy (VHE; $E>100\,{\rm GeV}$) with the \fer\ Large Area Telescope (LAT) and the High Energy Stereoscopic System (H.E.S.S.) is reported. Dedicated observations have been performed with the H.E.S.S. telescopes, leading to a detection at the $5.5\,\sigma$ significance level. The measured flux above 310 GeV is $(8.3 \pm 1.7_{\rm{stat}}\pm 1.7_{\rm{sys}})\times 10^{-13}$ photons \cms\ (about 0.6% of that of the Crab Nebula), and the power law spectrum has a photon index of \indexHESS. Using 3.5 years of publicly available \fla\ data, a faint counterpart has been detected in the LAT data at the $5.5\,\sigma$ significance level, with an integrated flux above 300 MeV of $(9.3 \pm 3.4_{\rm stat} \pm 0.8_{\rm sys})\times 10^{-10}$ photons \cms\ and a photon index of $\Gamma = 1.96 \pm 0.20_{\rm stat} \pm 0.08_{\rm sys}$. X-ray observations with \textit{Swift}-XRT allow the synchrotron peak energy in $\nu F_\nu$ representation to be located at $\sim 1.0\,{\rm keV}$. The broadband spectral energy distribution is modelled with a one-zone synchrotron self-Compton (SSC) model and the optical data by a black-body emission describing the thermal emission of the host galaxy. The derived parameters are typical for HBLs detected at VHE, with a particle dominated jet., Comment: 8 pages, 5 figures
Published: 2013
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42. Discovery of TeV gamma-ray emission from PKS 0447-439 and derivation of an upper limit on its redshift

Author: Collaboration, H. E. S. S., Abramowski, A., Acero, F., Akhperjanian, A. G., Anton, G., Balenderan, S., Balzer, A., Barnacka, A., Becherini, Y., Tjus, J. Becker, Behera, B., Bernlöhr, K., Birsin, E., Biteau, J., Bochow, A., Boisson, C., Bolmont, J., Bordas, P., Brucker, J., Brun, F., Brun, P., Bulik, T., Carrigan, S., Casanova, S., Cerruti, M., Chadwick, P. M., Chaves, R. C. G., Cheesebrough, A., Colafrancesco, S., Cologna, G., Conrad, J., Couturier, C., Dalton, M., Daniel, M. K., Davids, I. D., Degrange, B., Deil, C., deWilt, P., Dickinson, H. J., Djannati-Ataï, A., Domainko, W., Drury, L. O'C., Dubus, G., Dutson, K., Dyks, J., Dyrda, M., Egberts, K., Eger, P., Espigat, P., Fallon, L., Farnier, C., Fegan, S., Feinstein, F., Fernandes, M. V., Fernandez, D., Fiasson, A., Fontaine, G., Förster, A., Füßling, M., Gajdus, M., Gallant, Y. A., Garrigoux, T., Gast, H., Giebels, B., Glicenstein, J. F., Glück, B., Göring, D., Grondin, M. -H., Grudzińska, M., Häffner, S., Hague, J. D., Hahn, J., Hampf, D., Harris, J., Heinz, S., Heinzelmann, G., Henri, G., Hermann, G., Hillert, A., Hinton, J. A., Hofmann, W., Hofverberg, P., Holler, M., Horns, D., Jacholkowska, A., Jahn, C., Jamrozy, M., Jung, I., Kastendieck, M. A., Katarzynski, K., Katz, U., Kaufmann, S., Khélifi, B., Klepser, S., Klochkov, D., Kluźniak, W., Kneiske, T., Kolitzus, D., Komin, Nu., Kosack, K., Kossakowski, R., Krayzel, F., Krüger, P. P., Laffon, H., Lamanna, G., Lefaucheur, J., Lemoine-Goumard, M., Lenain, J. -P., Lennarz, D., Lohse, T., Lopatin, A., Lu, C. -C., Marandon, V., Marcowith, A., Masbou, J., Maurin, G., Maxted, N., Mayer, M., McComb, T. J. L., Medina, M. C., Méhault, J., Menzler, U., Moderski, R., Mohamed, M., Moulin, E., Naumann, C. L., Naumann-Godo, M., de Naurois, M., Nedbal, D., Nguyen, N., Niemiec, J., Nolan, S. J., Ohm, S., Wilhelmi, E. de O\ na, Opitz, B., Ostrowski, M., Oya, I., Panter, M., Parsons, R. D., Arribas, M. Paz, Pekeur, N. W., Pelletier, G., Perez, J., Petrucci, P. -O., Peyaud, B., Pita, S., Pühlhofer, G., Punch, M., Quirrenbach, A., Raab, S., Raue, M., Reimer, A., Reimer, O., Renaud, M., Reyes, R. de los, Rieger, F., Ripken, J., Rob, L., Rosier-Lees, S., Rowell, G., Rudak, B., Rulten, C. B., Sahakian, V., Sanchez, D. A., Santangelo, A., Schlickeiser, R., Schulz, A., Schwanke, U., Schwarzburg, S., Schwemmer, S., Sheidaei, F., Skilton, J. L., Sol, H., Spengler, G., Stawarz, Ł., Steenkamp, R., Stegmann, C., Stinzing, F., Stycz, K., Sushch, I., Szostek, A., Tavernet, J. -P., Terrier, R., Tluczykont, M., Trichard, C., Valerius, K., van Eldik, C., Vasileiadis, G., Venter, C., Viana, A., Vincent, P., Völk, H. J., Volpe, F., Vorobiov, S., Vorster, M., Wagner, S. J., Ward, M., White, R., Wierzcholska, A., Wouters, D., Zacharias, M., Zajczyk, A., Zdziarski, A. A., Zech, A., Zechlin, H. -S., and Pelat, D.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: Very high-energy gamma-ray emission from PKS 0447-439 was detected with the H.E.S.S. Cherenkov telescope array in December 2009. This blazar is one of the brightest extragalactic objects in the Fermi Bright Source List and has a hard spectrum in the MeV to GeV range. In the TeV range, a photon index of 3.89 +- 0.37 (stat) +- 0.22 (sys) and a flux normalisation at 1 TeV, Phi(1 TeV) = (3.5 +- 1.1 (stat) +- 0.9 (sys)) x 10^{-13} cm^{-2} s^{-1} TeV^{-1}, were found. The detection with H.E.S.S. triggered observations in the X-ray band with the Swift and RXTE telescopes. Simultaneous UV and optical data from Swift UVOT and data from the optical telescopes ATOM and ROTSE are also available. The spectrum and light curve measured with H.E.S.S. are presented and compared to the multi-wavelength data at lower energies. A rapid flare is seen in the Swift XRT and RXTE data, together with a flux variation in the UV band, at a time scale of the order of one day. A firm upper limit of z < 0.59 on the redshift of PKS 0447-439 is derived from the combined Fermi-LAT and H.E.S.S. data, given the assumptions that there is no upturn in the intrinsic spectrum above the Fermi-LAT energy range and that absorption on the Extragalactic Background Light (EBL) is not weaker than the lower limit provided by current models. The spectral energy distribution is well described by a simple one-zone Synchrotron Self-Compton (SSC) scenario, if the redshift of the source is less than z <~ 0.4., Comment: 14 pages, 10 figures, accepted for publication in A&A
Published: 2013
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43. H.E.S.S. Observations of the Binary System PSR B1259-63/LS 2883 around the 2010/2011 Periastron Passage

Author: Collaboration, H. E. S. S., Abramowski, A., Acero, F., Aharonian, F., Akhperjanian, A. G., Anton, G., Balenderan, S., Balzer, A., Barnacka, A., Becherini, Y., Tjus, J. Becker, Bernlöhr, K., Birsin, E., Biteau, J., Bochow, A., Boisson, C., Bolmont, J., Bordas, P., Brucker, J., Brun, F., Brun, P., Bulik, T., Carrigan, S., Casanova, S., Cerruti, M., Chadwick, P. M., Chaves, R. C. G., Cheesebrough, A., Colafrancesco, S., Cologna, G., Conrad, J., Couturier, C., Dalton, M., Daniel, M. K., Davids, I. D., Degrange, B., Deil, C., deWilt, P., Dickinson, H. J., Djannati-Ataï, A., Domainko, W., Drury, L. O'C., Dubus, G., Dutson, K., Dyks, J., Dyrda, M., Egberts, K., Eger, P., Espigat, P., Fallon, L., Farnier, C., Fegan, S., Feinstein, F., Fernandes, M. V., Fernandez, D., Fiasson, A., Fontaine, G., Förster, A., Füßling, M., Gajdus, M., Gallant, Y. A., Garrigoux, T., Gast, H., Giebels, B., Glicenstein, J. F., Glück, B., Göring, D., Grondin, M. -H., Grudzińska, M., Häffner, S., Hague, J. D., Hahn, J., Hampf, D., Harris, J., Heinz, S., Heinzelmann, G., Henri, G., Hermann, G., Hillert, A., Hinton, J. A., Hofmann, W., Hofverberg, P., Holler, M., Horns, D., Jacholkowska, A., Jahn, C., Jamrozy, M., Jung, I., Kastendieck, M. A., Katarzyński, K., Katz, U., Kaufmann, S., Khélifi, B., Klepser, S., Klochkov, D., Kluźniak, W., Kneiske, T., Kolitzus, D., Komin, Nu., Kosack, K., Kossakowski, R., Krayzel, F., Krüger, P. P., Laffon, H., Lamanna, G., Lefaucheur, J., Lemoine-Goumard, M., Lenain, J. -P., Lennarz, D., Lohse, T., Lopatin, A., Lu, C. -C., Marandon, V., Marcowith, A., Masbou, J., Maurin, G., Maxted, N., Mayer, M., McComb, T. J. L., Medina, M. C., Méhault, J., Menzler, U., Moderski, R., Mohamed, M., Moulin, E., Naumann, C. L., Naumann-Godo, M., de Naurois, M., Nedbal, D., Nguyen, N., Niemiec, J., Nolan, S. J., Ohm, S., Wilhelmi, E. de Oña, Opitz, B., Ostrowski, M., Oya, I., Panter, M., Parsons, R. D., Arribas, M. Paz, Pekeur, N. W., Pelletier, G., Perez, J., Petrucci, P. -O., Peyaud, B., Pita, S., Pühlhofer, G., Punch, M., Quirrenbach, A., Raab, S., Raue, M., Reimer, A., Reimer, O., Renaud, M., Reyes, R. de los, Rieger, F., Ripken, J., Rob, L., Rosier-Lees, S., Rowell, G., Rudak, B., Rulten, C. B., Sahakian, V., Sanchez, D. A., Santangelo, A., Schlickeiser, R., Schulz, A., Schwanke, U., Schwarzburg, S., Schwemmer, S., Sheidaei, F., Skilton, J. L., Sol, H., Spengler, G., Stawarz, Ł., Steenkamp, R., Stegmann, C., Stinzing, F., Stycz, K., Sushch, I., Szostek, A., Tavernet, J. -P., Terrier, R., Tluczykont, M., Trichard, C., Valerius, K., van Eldik, C., Vasileiadis, G., Venter, C., Viana, A., Vincent, P., Völk, H. J., Volpe, F., Vorobiov, S., Vorster, M., Wagner, S. J., Ward, M., White, R., Wierzcholska, A., Wouters, D., Zacharias, M., Zajczyk, A., Zdziarski, A. A., Zech, A., and Zechlin, H. -S.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: Aim. In this paper we present very high energy (VHE; E>100 GeV) data from the \gamma-ray binary system PSR B1259-63/LS 2883 taken around its periastron passage (15th of December 2010) with the High Energy Stereoscopic System (H.E.S.S.) of Cherenkov Telescopes. We aim to search for a possible TeV counterpart of the GeV flare detected by the Fermi LAT. In addition, we aim to study the current periastron passage in the context of previous observations taken at similar orbital phases, testing the repetitive behavior of the source. Methods. Observations at VHE were conducted with H.E.S.S. from 9th to 16th of January 2011. The total dataset amounts to around 6 h of observing time. Results. The source is detected in the 2011 data at a significance level of 11.5\sigma\ revealing an averaged integral flux above 1 TeV of (1.01 \pm 0.18_{stat} \pm 0.20_{sys}) \times 10^{-12} cm^{-2}s^{-1}. The differential energy spectrum follows a power-law shape with a spectral index \Gamma = 2.92 \pm 0.30_{stat} \pm 0.20_{sys} and a flux normalisation at 1 TeV of N_{0} = 1.95 \pm 0.32_{stat} \pm 0.39_{sys}) \times 10^{-12} TeV^{-1} cm^{-2} s^{-1}. The measured lightcurve does not show any evidence for variability of the source on the daily scale. Conclusions. The measured integral flux and the spectral shape of the 2011 data are compatible with the results obtained around previous periastron passages. The absence of variability in the H.E.S.S. data indicates that the GeV flare observed by Fermi LAT in the time period covered also by H.E.S.S. observations originates in a different physical scenario than the TeV emission. Additionaly, new results compared to those obtained in the observations which were performed in 2004 at a similar orbital phase, further support the hypothesis of the repetitive behavior of the source., Comment: 8 pages, 5 figures, 1 table, accepted for publication in A&A
Published: 2013
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44. Search for Very-high-energy \gamma-ray emission from Galactic globular clusters with H.E.S.S

Author: Collaboration, H. E. S. S., Abramowski, A., Acero, F., Aharonian, F., Akhperjanian, A. G., Anton, G., Balenderan, S., Balzer, A., Barnacka, A., Becherini, Y., Tjus, J. Becker, Bernlöhr, K., Birsin, E., Biteau, J., Bochow, A., Boisson, C., Bolmont, J., Bordas, P., Brucker, J., Brun, F., Brun, P., Bulik, T., Carrigan, S., Casanova, S., Cerruti, M., Chadwick, P. M., Chaves, R. C. G., Cheesebrough, A., Colafrancesco, S., Cologna, G., Conrad, J., Couturier, C., Dalton, M., Daniel, M. K., Davids, I. D., Degrange, B., Deil, C., deWilt, P., Dickinson, H. J., Djannati-Ataï, A., Domainko, W., Drury, L. O'C., Dubus, G., Dutson, K., Dyks, J., Dyrda, M., Egberts, K., Eger, P., Espigat, P., Fallon, L., Farnier, C., Fegan, S., Feinstein, F., Fernandes, M. V., Fernandez, D., Fiasson, A., Fontaine, G., Förster, A., Füßling, M., Gajdus, M., Gallant, Y. A., Garrigoux, T., Gast, H., Giebels, B., Glicenstein, J. F., Glück, B., Göring, D., Grondin, M. -H., Grudzińska, M., Häffner, S., Hague, J. D., Hahn, J., Hampf, D., Harris, J., Heinz, S., Heinzelmann, G., Henri, G., Hermann, G., Hillert, A., Hinton, J. A., Hofmann, W., Hofverberg, P., Holler, M., Horns, D., Jacholkowska, A., Jahn, C., Jamrozy, M., Jung, I., Kastendieck, M. A., Katarzyński, K., Katz, U., Kaufmann, S., Khélifi, B., Klepser, S., Klochkov, D., Kluźniak, W., Kneiske, T., Kolitzus, D., Komin, Nu., Kosack, K., Kossakowski, R., Krayzel, F., Krüger, P. P., Laffon, H., Lamanna, G., Lefaucheur, J., Lemoine-Goumard, M., Lenain, J. -P., Lennarz, D., Lohse, T., Lopatin, A., Lu, C. -C., Marandon, V., Marcowith, A., Masbou, J., Maurin, G., Maxted, N., Mayer, M., McComb, T. J. L., Medina, M. C., Méhault, J., Menzler, U., Moderski, R., Mohamed, M., Moulin, E., Naumann, C. L., Naumann-Godo, M., de Naurois, M., Nedbal, D., Nguyen, N., Niemiec, J., Nolan, S. J., Ohm, S., Wilhelmi, E. de Oña, Opitz, B., Ostrowski, M., Oya, I., Panter, M., Parsons, R. D., Arribas, M. Paz, Pekeur, N. W., Pelletier, G., Perez, J., Petrucci, P. -O., Peyaud, B., Pita, S., Pühlhofer, G., Punch, M., Quirrenbach, A., Raab, S., Raue, M., Reimer, A., Reimer, O., Renaud, M., Reyes, R. de los, Rieger, F., Ripken, J., Rob, L., Rosier-Lees, S., Rowell, G., Rudak, B., Rulten, C. B., Sahakian, V., Sanchez, D. A., Santangelo, A., Schlickeiser, R., Schulz, A., Schwanke, U., Schwarzburg, S., Schwemmer, S., Sheidaei, F., Skilton, J. L., Sol, H., Spengler, G., Stawarz, Ł., Steenkamp, R., Stegmann, C., Stinzing, F., Stycz, K., Sushch, I., Szostek, A., Tavernet, J. -P., Terrier, R., Tluczykont, M., Trichard, C., Valerius, K., van Eldik, C., Vasileiadis, G., Venter, C., Viana, A., Vincent, P., Völk, H. J., Volpe, F., Vorobiov, S., Vorster, M., Wagner, S. J., Ward, M., White, R., Wierzcholska, A., Wouters, D., Zacharias, M., Zajczyk, A., Zdziarski, A. A., Zech, A., and Zechlin, H. -S.
Subjects: Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Astrophysics of Galaxies
Abstract: Globular clusters (GCs) are established emitters of high-energy (HE, 100 MeV100 GeV) \gamma-ray regime, judging from the recent detection of a signal from the direction of Terzan 5 with the H.E.S.S. telescope array. We searched for point-like and extended VHE \gamma-ray emission from 15 GCs serendipitously covered by H.E.S.S observations and also performed a stacking analysis combining the data from all GCs to investigate the hypothesis of a population of faint emitters. Assuming IC emission as the origin of the VHE \gamma-ray signal from the direction of Terzan 5, we calculated the expected \gamma-ray flux from each of the 15 GCs, based on their number of millisecond pulsars, their optical brightness and the energy density of background photon fields. We did not detect significant VHE \gamma-ray emission from any of the 15 GCs in either of the two analyses. Given the uncertainties related to the parameter determinations, the obtained flux upper limits allow to rule out the simple IC/msPSR scaling model for NGC 6388 and NGC 7078. The upper limits derived from the stacking analyses are factors between 2 and 50 below the flux predicted by the simple leptonic scaling model, depending on the assumed source extent and the dominant target photon fields. Therefore, Terzan 5 still remains exceptional among all GCs, as the VHE \gamma-ray emission either arises from extra-ordinarily efficient leptonic processes, or from a recent catastrophic event, or is even unrelated to the GC itself., Comment: 8 pages, 1 figure, accepted for publication in Astronomy and Astrophysics
Published: 2013
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45. Search for photon line-like signatures from Dark Matter annihilations with H.E.S.S

Author: Collaboration, H. E. S. S., Abramowski, A., Acero, F., Aharonian, F., Akhperjanian, A. G., Anton, G., Balenderan, S., Balzer, A., Barnacka, A., Becherini, Y., Tjus, J. Becker, Bernlöhr, K., Birsin, E., Biteau, J., Bochow, A., Boisson, C., Bolmont, J., Bordas, P., Brucker, J., Brun, F., Brun, P., Bulik, T., Carrigan, S., Casanova, S., Cerruti, M., Chadwick, P. M., Chaves, R. C. G., Cheesebrough, A., Colafrancesco, S., Cologna, G., Conrad, J., Couturier, C., Dalton, M., Daniel, M. K., Davids, I. D., Degrange, B., Deil, C., deWilt, P., Dickinson, H. J., Djannati-Ataï, A., Domainko, W., Drury, L. O'C., Dubus, G., Dutson, K., Dyks, J., Dyrda, M., Egberts, K., Eger, P., Espigat, P., Fallon, L., Farnier, C., Fegan, S., Feinstein, F., Fernandes, M. V., Fernandez, D., Fiasson, A., Fontaine, G., Förster, A., Füßling, M., Gajdus, M., Gallant, Y. A., Garrigoux, T., Gast, H., Giebels, B., Glicenstein, J. F., Glück, B., Göring, D., Grondin, M. -H., Häffner, S., Hague, J. D., Hahn, J., Hampf, D., Harris, J., Heinz, S., Heinzelmann, G., Henri, G., Hermann, G., Hillert, A., Hinton, J. A., Hofmann, W., Hofverberg, P., Holler, M., Horns, D., Jacholkowska, A., Jahn, C., Jamrozy, M., Jung, I., Kastendieck, M. A., Katarzyński, K., Katz, U., Kaufmann, S., Khélifi, B., Klepser, S., Klochkov, D., Kluźniak, W., Kneiske, T., Komin, Nu., Kosack, K., Kossakowski, R., Krayzel, F., Krüger, P. P., Laffon, H., Lamanna, G., Lefaucheur, J., Lemoine-Goumard, M., Lenain, J. -P., Lennarz, D., Lohse, T., Lopatin, A., Lu, C. -C., Marandon, V., Marcowith, A., Masbou, J., Maurin, G., Maxted, N., Mayer, M., McComb, T. J. L., Medina, M. C., Méhault, J., Menzler, U., Moderski, R., Mohamed, M., Moulin, E., Naumann, C. L., Naumann-Godo, M., de Naurois, M., Nedbal, D., Nekrassov, D., Nguyen, N., Niemiec, J., Nolan, S. J., Ohm, S., Wilhelmi, E. de Oña, Opitz, B., Ostrowski, M., Oya, I., Panter, M., Parsons, R. D., Arribas, M. Paz, Pekeur, N. W., Pelletier, G., Perez, J., Petrucci, P. -O., Peyaud, B., Pita, S., Pühlhofer, G., Punch, M., Quirrenbach, A., Raue, M., Reimer, A., Reimer, O., Renaud, M., Reyes, R. de los, Rieger, F., Ripken, J., Rob, L., Rosier-Lees, S., Rowell, G., Rudak, B., Rulten, C. B., Sahakian, V., Sanchez, D. A., Santangelo, A., Schlickeiser, R., Schulz, A., Schwanke, U., Schwarzburg, S., Schwemmer, S., Sheidaei, F., Skilton, J. L., Sol, H., Spengler, G., Stawarz, Ł., Steenkamp, R., Stegmann, C., Stinzing, F., Stycz, K., Sushch, I., Szostek, A., Tavernet, J. -P., Terrier, R., Tluczykont, M., Trichard, C., Valerius, K., van Eldik, C., Vasileiadis, G., Venter, C., Viana, A., Vincent, P., Völk, H. J., Volpe, F., Vorobiov, S., Vorster, M., Wagner, S. J., Ward, M., White, R., Wierzcholska, A., Wouters, D., Zacharias, M., Zajczyk, A., Zdziarski, A. A., Zech, A., and Zechlin, H. -S.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: Gamma-ray line signatures can be expected in the very-high-energy (VHE; E_\gamma > 100 GeV) domain due to self-annihilation or decay of dark matter (DM) particles in space. Such a signal would be readily distinguishable from astrophysical \gamma-ray sources that in most cases produce continuous spectra which span over several orders of magnitude in energy. Using data collected with the H.E.S.S. \gamma-ray instrument, upper limits on line-like emission are obtained in the energy range between ~500 GeV and ~25 TeV for the central part of the Milky Way halo and for extragalactic observations, complementing recent limits obtained with the Fermi-LAT instrument at lower energies. No statistically significant signal could be found. For monochromatic \gamma-ray line emission, flux limits of (2x10^-7 - 2x10^-5) m^-2 s^-1 sr^-1 and (1x10^-8 - 2x10^-6) m^-2 s^-1 sr^-1 are obtained for the central part of the Milky Way halo and extragalactic observations, respectively. For a DM particle mass of 1 TeV, limits on the velocity-averaged DM annihilation cross section < \sigma v >(\chi\chi -> \gamma\gamma) reach ~10^-27 cm^3 s^-1, based on the Einasto parametrization of the Galactic DM halo density profile., Comment: 6 pages, 4 figures, accepted for publication in Phys. Rev. Lett
Published: 2013
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46. Measurement of the extragalactic background light imprint on the spectra of the brightest blazars observed with H.E.S.S

Author: Collaboration, H. E. S. S., Abramowski, A., Acero, F., Aharonian, F., Akhperjanian, A. G., Anton, G., Balenderan, S., Balzer, A., Barnacka, A., Becherini, Y., Tjus, J. Becker, Bernlöhr, K., Birsin, E., Biteau, J., Bochow, A., Boisson, C., Bolmont, J., Bordas, P., Brucker, J., Brun, F., Brun, P., Bulik, T., Carrigan, S., Casanova, S., Cerruti, M., Chadwick, P. M., Charbonnier, A., Chaves, R. C. G., Cheesebrough, A., Cologna, G., Conrad, J., Couturier, C., Dalton, M., Daniel, M. K., Davids, I. D., Degrange, B., Deil, C., deWilt, P., Dickinson, H. J., Djannati-Ataï, A., Domainko, W., Drury, L. O'C., Dubus, G., Dutson, K., Dyks, J., Dyrda, M., Egberts, K., Eger, P., Espigat, P., Fallon, L., Farnier, C., Fegan, S., Feinstein, F., Fernandes, M. V., Fernandez, D., Fiasson, A., Fontaine, G., Förster, A., Füßling, M., Gajdus, M., Gallant, Y. A., Garrigoux, T., Gast, H., Giebels, B., Glicenstein, J. F., Glück, B., Göring, D., Grondin, M. -H., Häffner, S., Hague, J. D., Hahn, J., Hampf, D., Harris, J., Heinz, S., Heinzelmann, G., Henri, G., Hermann, G., Hillert, A., Hinton, J. A., Hofmann, W., Hofverberg, P., Holler, M., Horns, D., Jacholkowska, A., Jahn, C., Jamrozy, M., Jung, I., Kastendieck, M. A., Katarzyński, K., Katz, U., Kaufmann, S., Khélifi, B., Klochkov, D., Kluźniak, W., Kneiske, T., Komin, Nu., Kosack, K., Kossakowski, R., Krayzel, F., Laffon, H., Lamanna, G., Lenain, J. -P., Lennarz, D., Lohse, T., Lopatin, A., Lu, C. -C., Marandon, V., Marcowith, A., Masbou, J., Maurin, G., Maxted, N., Mayer, M., McComb, T. J. L., Medina, M. C., Méhault, J., Menzler, U., Moderski, R., Mohamed, M., Moulin, E., Naumann, C. L., Naumann-Godo, M., de Naurois, M., Nedbal, D., Nguyen, N., Niemiec, J., Nolan, S. J., Ohm, S., Wilhelmi, E. de Oña, Opitz, B., Ostrowski, M., Oya, I., Panter, M., Parsons, D., Arribas, M. Paz, Pekeur, N. W., Pelletier, G., Perez, J., Petrucci, P. -O., Peyaud, B., Pita, S., Pühlhofer, G., Punch, M., Quirrenbach, A., Raue, M., Reimer, A., Reimer, O., Renaud, M., Reyes, R. de los, Rieger, F., Ripken, J., Rob, L., Rosier-Lees, S., Rowell, G., Rudak, B., Rulten, C. B., Sahakian, V., Sanchez, D. A., Santangelo, A., Schlickeiser, R., Schulz, A., Schwanke, U., Schwarzburg, S., Schwemmer, S., Sheidaei, F., Skilton, J. L., Sol, H., Spengler, G., Stawarz, Ł., Steenkamp, R., Stegmann, C., Stinzing, F., Stycz, K., Sushch, I., Szostek, A., Tavernet, J. -P., Terrier, R., Tluczykont, M., Valerius, K., van Eldik, C., Vasileiadis, G., Venter, C., Viana, A., Vincent, P., Völk, H. J., Volpe, F., Vorobiov, S., Vorster, M., Wagner, S. J., Ward, M., White, R., Wierzcholska, A., Wouters, D., Zacharias, M., Zajczyk, A., Zdziarski, A. A., Zech, A., and Zechlin, H. -S.
Subjects: Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract: The extragalactic background light (EBL) is the diffuse radiation with the second highest energy density in the Universe after the cosmic microwave background. The aim of this study is the measurement of the imprint of the EBL opacity to gamma-rays on the spectra of the brightest extragalactic sources detected with the High Energy Stereoscopic System (H.E.S.S.). The originality of the method lies in the joint fit of the EBL optical depth and of the intrinsic spectra of the sources, assuming intrinsic smoothness. Analysis of a total of ~10^5 gamma-ray events enables the detection of an EBL signature at the 8.8 std dev level and constitutes the first measurement of the EBL optical depth using very-high energy (E>100 GeV) gamma-rays. The EBL flux density is constrained over almost two decades of wavelengths (0.30-17 microns) and the peak value at 1.4 micron is derived as 15 +/- 2 (stat) +/- 3 (sys) nW / m^2 sr., Comment: 11 pages, 9 figures, accepted in A&A
Published: 2012
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47. Identification of HESS J1303-631 as a Pulsar Wind Nebula through gamma-ray, X-ray and radio observations

Author: Collaboration, The H. E. S. S., Abramowski, A., Acero, F., Aharonian, F., Akhperjanian, A. G., Anton, G., Balenderan, S., Balzer, A., Barnacka, A., Becherini, Y., Becker, J., Bernlöhr, K., Birsin, E., Biteau, J., Bochow, A., Boisson, C., Bolmont, J., Bordas, P., Brucker, J., Brun, F., Brun, P., Bulik, T., Büsching, I., Carrigan, S., Casanova, S., Cerruti, M., Chadwick, P. M., Charbonnier, A., Chaves, R. C. G., Cheesebrough, A., Cologna, G., Conrad, J., Couturier, C., Dalton, M., Daniel, M. K., Davids, I. D., Degrange, B., Deil, C., Dickinson, H. J., Djannati-Ataï, A., Domainko, W., Drury, L. O'C., Dubus, G., Dutson, K., Dyks, J., Dyrda, M., Egberts, K., Eger, P., Espigat, P., Fallon, L., Farnier, C., Fegan, S., Feinstein, F., Fernandes, M. V., Fiasson, A., Fontaine, G., Förster, A., Füßling, M., Gajdus, M., Gallant, Y. A., Garrigoux, T., Gast, H., Gérard, L., Giebels, B., Glicenstein, J. F., Glück, B., Göring, D., Grondin, M. -H., Häffner, S., Hague, J. D., Hahn, J., Hampf, D., Harris, J., Hauser, M., Heinz, S., Heinzelmann, G., Henri, G., Hermann, G., Hillert, A., Hinton, J. A., Hofmann, W., Hofverberg, P., Holler, M., Horns, D., Jacholkowska, A., Jahn, C., Jamrozy, M., Jung, I., Kastendieck, M. A., Katarzyński, K., Katz, U., Kaufmann, S., Khélifi, B., Klochkov, D., Kluźniak, W., Kneiske, T., Komin, Nu., Kosack, K., Kossakowski, R., Krayzel, F., Laffon, H., Lamanna, G., Lenain, J. -P., Lennarz, D., Lohse, T., Lopatin, A., Lu, C. -C., Marandon, V., Marcowith, A., Masbou, J., Maurin, G., Maxted, N., Mayer, M., McComb, T. J. L., Medina, M. C., Méhault, J., Menzler, U., Moderski, R., Mohamed, M., Moulin, E., Naumann, C. L., Naumann-Godo, M., de Naurois, M., Nedbal, D., Nekrassov, D., Nguyen, N., Nicholas, B., Niemiec, J., Nolan, S. J., Ohm, S., Wilhelmi, E. de Oña, Opitz, B., Ostrowski, M., Oya, I., Panter, M., Arribas, M. Paz, Pekeur, N. W., Pelletier, G., Perez, J., Petrucci, P. -O., Peyaud, B., Pita, S., Pühlhofer, G., Punch, M., Quirrenbach, A., Raue, M., Reimer, A., Reimer, O., Renaud, M., Reyes, R. de los, Rieger, F., Ripken, J., Rob, L., Rosier-Lees, S., Rowell, G., Rudak, B., Rulten, C. B., Sahakian, V., Sanchez, D. A., Santangelo, A., Schlickeiser, R., Schulz, A., Schwanke, U., Schwarzburg, S., Schwemmer, S., Sheidaei, F., Skilton, J. L., Sol, H., Spengler, G., Stawarz, Ł., Steenkamp, R., Stegmann, C., Stinzing, F., Stycz, K., Sushch, I., Szostek, A., Tavernet, J. -P., Terrier, R., Tluczykont, M., Valerius, K., van Eldik, C., Vasileiadis, G., Venter, C., Viana, A., Vincent, P., Völk, H. J., Volpe, F., Vorobiov, S., Vorster, M., Wagner, S. J., Ward, M., White, R., Wierzcholska, A., Zacharias, M., Zajczyk, A., Zdziarski, A. A., Zech, A., and Zechlin, H. -S.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: The previously unidentified very high-energy (VHE; E > 100 GeV) \gamma-ray source HESS J1303-631, discovered in 2004, is re-examined including new data from the H.E.S.S. Cherenkov telescope array. Archival data from the XMM-Newton X-ray satellite and from the PMN radio survey are also examined. Detailed morphological and spectral studies of VHE \gamma-ray emission as well as of the XMM-Newton X-ray data are performed. Significant energy-dependent morphology of the \gamma-ray source is detected with high-energy emission (E > 10 TeV) positionally coincident with the pulsar PSR J1301-6305 and lower energy emission (E <2 TeV) extending \sim 0.4^{\circ} to the South-East of the pulsar. The spectrum of the VHE source can be described with a power-law with an exponential cut-off N_{0} = (5.6 \pm 0.5) X 10^{-12} TeV^-1 cm^-2 s^-1, \Gamma = 1.5 \pm 0.2) and E_{\rm cut} = (7.7 \pm 2.2) TeV. The PWN is also detected in X-rays, extending \sim 2-3' from the pulsar position towards the center of the \gamma-ray emission region. The spectral energy distribution (SED) is well described by a one zone leptonic scenario which, with its associated caveats, predicts a very low average magnetic field for this source. Significant energy-dependent morphology of this source, as well as the identification of an associated X-ray PWN from XMM-Newton observations enable identification of the VHE source as an evolved PWN associated to the pulsar PSR J1303-6305. However, the large discrepancy in emission region sizes and the low level of synchrotron radiation suggest a multi-population leptonic nature. The low implied magnetic field suggests that the PWN has undergone significant expansion. This would explain the low level of synchrotron radiation and the difficulty in detecting counterparts at lower energies, the reason this source was originally classified as a "dark" VHE \gamma-ray source., Comment: paper accepted for publication in A&A, 12 pages, 10 figures, 3 tables
Published: 2012
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48. Probing the extent of the non-thermal emission from the Vela X region at TeV energies with H.E.S.S

Author: Abramowski, A., Acero, F., Aharonian, F., Akhperjanian, A. G., Anton, G., Balenderan, S., Balzer, A., Barnacka, A., Becherini, Y., Tjus, J. Becker, Bernlöhr, K., Birsin, E., Biteau, J., Bochow, A., Boisson, C., Bolmont, J., Bordas, P., Brucker, J., Brun, F., Brun, P., Bulik, T., Carrigan, S., Casanova, S., Cerruti, M., Chadwick, P. M., Charbonnier, A., Chaves, R. C. G., Cheesebrough, A., Cologna, G., Conrad, J., Couturier, C., Dalton, M., Daniel, M. K., Davids, I. D., Degrange, B., Deil, C., deWilt, P., Dickinson, H. J., Djannati-Ataï, A., Domainko, W., Drury, L. O'C., Dubois, F., Dubus, G., Dutson, K., Dyks, J., Dyrda, M., Egberts, K., Eger, P., Espigat, P., Fallon, L., Farnier, C., Fegan, S., Feinstein, F., Fernandes, M. V., Fernandez, D., Fiasson, A., Fontaine, G., Förster, A., Füßling, M., Gajdus, M., Gallant, Y. A., Garrigoux, T., Gast, H., Giebels, B., Glicenstein, J. F., Glück, B., Göring, D., Grondin, M. -H., Häffner, S., Hague, J. D., Hahn, J., Hampf, D., Harris, J., Heinz, S., Heinzelmann, G., Henri, G., Hermann, G., Hillert, A., Hinton, J. A., Hofmann, W., Hofverberg, P., Holler, M., Horns, D., Jacholkowska, A., Jahn, C., Jamrozy, M., Jung, I., Kastendieck, M. A., ski, K. Katarzyń, Katz, U., Kaufmann, S., Khélifi, B., Klochkov, D., niak, W. Kluź, Kneiske, T., Komin, Nu., Kosack, K., Kossakowski, R., Krayzel, F., Krüger, P. P., Laffon, H., Lamanna, G., Lenain, J. -P., Lennarz, D., Lohse, T., Lopatin, A., Lu, C. -C., Marandon, V., Marcowith, A., Masbou, J., Maurin, G., Maxted, N., Mayer, M., McCom, T. J. L., Medina, M. C., Méhault, J., Menzler, U., Moderski, R., Mohamed, M., Moulin, E., Naumann, C. L., Naumann-Godo, M., deNaurois, M., Nedbal, D., Nguyen, N., Niemiec, J., Nolan, S. J., Ohm, S., aWilhelmi, E. deOñ, Opitz, B., Ostrowski, M., Oya, I., Panter, M., Parsons, D., PazArribas, M., Pekeur, N. W., Pelletier, G., Perez, J., Petrucci, P. -O., Peyaud, B., Pita, S., Pühlhofer, G., Punch, M., Quirrenbach, A., Raue, M., Reimer, A., Reimer, O., Renaud, M., delosReyes, R., Rieger, F., Ripken, J., Rob, L., Rosier-Lees, S., Rowell, G., Rudak, B., Rulten, C. B., Sahakian, V., Sanchez, D. A., Santangelo, A., Schlickeiser, R., Schulz, A., Schwanke, U., Schwarzburg, S., Schwemmer, S., Sheidaei, F., Skilton, J. L., Sol, H., Spengler, G., Stawarz, L., Steenkamp, R., Stegmann, C., Stinzing, F., Stycz, K., Sushch, I., Szostek, A., Tavernet, J. -P., Terrier, R., Tluczykont, M., Trichard, C., Valerius, K., vanEldik, C., Vasileiadis, G., Venter, C., Viana, A., Vincent, P., Völk, H. J., Volpe, F., Vorobiov, S., Vorster, M., Wagner, S. J., Ward, M., White, R., Wierzcholska, A., Wouters, D., Zacharias, M., Zajczyk, A., Zdziarski, A. A., Zech, A., and Zechlin, H. -S.
Subjects: Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Astrophysics of Galaxies
Abstract: Vela X is a region of extended radio emission in the western part of the Vela constellation: one of the nearest pulsar wind nebulae (PWNe), and associated with the energetic Vela pulsar (PSR B0833-45). Extended very-high-energy (VHE) $\gamma$-ray emission (HESS $\mathrm{J0835\mhyphen 455}$) was discovered using the H.E.S.S. experiment in 2004. The VHE $\gamma$-ray emission was found to be coincident with a region of X-ray emission discovered with ${\it ROSAT}$ above 1.5 keV (the so-called \textit{Vela X cocoon}): a filamentary structure extending southwest from the pulsar to the centre of Vela X. A deeper observation of the entire Vela X nebula region, also including larger offsets from the cocoon, has been performed with H.E.S.S. This re-observation was carried out in order to probe the extent of the non-thermal emission from the Vela X region at TeV energies and to investigate its spectral properties. In order to increase the sensitivity to the faint $\gamma$-ray emission from the very extended Vela X region, a multivariate analysis method combining three complementary reconstruction techniques of Cherenkov-shower images is applied for the selection of $\gamma$-ray events. The analysis is performed with the On/Off background method, which estimates the background from separate observations pointing away from Vela X; towards regions free of $\gamma$-ray sources but with comparable observation conditions. The $\gamma$-ray surface brightness over the large Vela X region reveals that the detection of non-thermal VHE $\gamma$-ray emission from the PWN HESS $\mathrm{J0835\mhyphen 455}$ is statistically significant over a region of radius 1.2$^{\circ}$ around the position $\alpha$ = 08$^{\mathrm{h}}$ 35$^{\mathrm{m}}$ 00$^{\mathrm{s}}$, $\delta$ = -45$^{\circ}$ 36$^{\mathrm{\prime}}$ 00$^{\mathrm{\prime}\mathrm{\prime}}$ (J2000).
Published: 2012
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49. Discovery of gamma-ray emission from the extragalactic pulsar wind nebula N157B with the High Energy Stereoscopic System

Author: HESS Collaboration, Abramowski, A., Acero, F., Aharonian, F., Akhperjanian, A. G., Anton, G., Balenderan, S., Balzer, A., Barnacka, A., Becherini, Y., Becker, J., Bernlöhr, K., Birsin, E., Biteau, J., Bochow, A., Boisson, C., Bolmont, J., Bordas, P., Brucker, J., Brun, F., Brun, P., Bulik, T., Carrigan, S., Casanova, S., Cerruti, M., Chadwick, P. M., Charbonnier, A., Chaves, R. C. G., Cheesebrough, A., Cologna, G., Conrad, J., Couturier, C., Dalton, M., Daniel, M. K., Davids, I. D., Degrange, B., Deil, C., Dickinson, H. J., Djannati-Ataï, A., Domainko, W., Drury, L. O'C., Dubus, G., Dutson, K., Dyks, J., Dyrda, M., Egberts, K., Eger, P., Espigat, P., Fallon, L., Farnier, C., Fegan, S., Feinstein, F., Fernandes, M. V., Fernandez, D., Fiasson, A., Fontaine, G., Förster, A., Füßling, M., Gajdus, M., Gallant, Y. A., Garrigoux, T., Gast, H., Gérard, L., Giebels, B., Glicenstein, J. F., Glück, B., Göring, D., Grondin, M. -H., Häffner, S., Hague, J. D., Hahn, J., Hampf, D., Harris, J., Hauser, M., Heinz, S., Heinzelmann, G., Henri, G., Hermann, G., Hillert, A., Hinton, J. A., Hofmann, W., Hofverberg, P., Holler, M., Horns, D., Jacholkowska, A., de Jager, O. C., Jahn, C., Jamrozy, M., Jung, I., Kastendieck, M. A., Katarzyński, K., Katz, U., Kaufmann, S., Khélifi1, B., Klochkov, D., Kluźniak, W., Kneiske, T., Komin, Nu., Kosack, K., Kossakowski, R., Krayzel, F., Laffon, H., Lamanna, G., Lenain, J. -P., Lennarz, D., Lohse, T., Lopatin, A., Lu, C. -C., Marandon, V., Marcowith, A., Masbou, J., Maurin, G., Maxted, N., Mayer, M., McComb, T. J. L., Medina, M. C., Méhault, J., Menzler, U., Moderski, R., Mohamed, M., Moulin, E., Naumann, C. L., Naumann-Godo, M., de Naurois, M., Nedbal, D., Nguyen, N., Nicholas, B., Niemiec, J., Nolan, S. J., Ohm, S., Wilhelmi, E. de Oña, Opitz, B., Ostrowski, M., Oya, I., Panter, M., Arribas, M. Paz, Pekeur, N. W., Pelletier, G., Perez, J., Petrucci, P. -O., Peyaud, B., Pita, S., Pühlhofer, G., Punch, M., Quirrenbach, A., Raue, M., Reimer, A., Reimer, O., Renaud, M., Reyes, R. de los, Rieger, F., Ripken, J., Rob, L., Rosier-Lees, S., Rowell, G., Rudak, B., Rulten, C. B., Sahakian, V., Sanchez, D. A., Santangelo, A., Schlickeiser, R., Schulz, A., Schwanke, U., Schwarzburg, S., Schwemmer, S., Sheidaei, F., Skilton, J. L., Sol, H., Spengler, G., Stawarz, Ł., Steenkamp, R., Stegmann, C., Stinzing, F., Stycz, K., Sushch, I., Szostek, A., Tavernet, J. -P., Terrier, R., Tluczykont, M., Valerius, K., van Eldik, C., Vasileiadis, G., Venter, C., Viana, A., Vincent, P., Völk, H. J., Volpe, F., Vorobiov, S., Vorster, M., Wagner, S. J., Ward, M., White, R., Wierzcholska, A., Zacharias, M., Zajczyk, A., Zdziarski, A. A., Zech, A., and Zechlin, H. -S.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: We present the significant detection of the first extragalactic pulsar wind nebula (PWN) detected in gamma rays, N157B, located in the large Magellanic Cloud (LMC). Pulsars with high spin-down luminosity are found to power energised nebulae that emit gamma rays up to energies of several tens of TeV. N157B is associated with PSRJ0537-6910, which is the pulsar with the highest known spin-down luminosity. The High Energy Stereoscopic System telescope array observed this nebula on a yearly basis from 2004 to 2009 with a dead-time corrected exposure of 46 h. The gamma-ray spectrum between 600 GeV and 12 TeV is well-described by a pure power-law with a photon index of 2.8 \pm 0.2(stat) \pm 0.3(syst) and a normalisation at 1 TeV of (8.2 \pm 0.8(stat) \pm 2.5(syst)) \times 10^-13 cm^-2s^-1TeV^-1. A leptonic multi-wavelength model shows that an energy of about 4 \times 10^49erg is stored in electrons and positrons. The apparent efficiency, which is the ratio of the TeV gamma-ray luminosity to the pulsar's spindown luminosity, 0.08% \pm 0.01%, is comparable to those of PWNe found in the Milky Way. The detection of a PWN at such a large distance is possible due to the pulsar's favourable spin-down luminosity and a bright infrared photon-field serving as an inverse-Compton-scattering target for accelerated leptons. By applying a calorimetric technique to these observations, the pulsar's birth period is estimated to be shorter than 10 ms., Comment: 6 pages, 2 figures, published
Published: 2012
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50. Constraints on the gamma-ray emission from the cluster-scale AGN outburst in the Hydra A galaxy cluster

Author: HESS Collaboration, Abramowski, A., Acero, F., Aharonian, F., Akhperjanian, A. G., Anton, G., Balenderan, S., Balzer, A., Barnacka, A., Becherini, Y., Becker, J., Bernloehr, K., Birsin, E., Biteau, J., Bochow, A., Boisson, C., Bolmont, J., Bordas, P., Brucker, J., Brun, F., Brun, P., Bulik, T., Buesching, I., Carrigan, S., Casanova, S., Cerruti, M., Chadwick, P. M., Charbonnier, A., Chaves, R. C. G., Cheesebrough, A., Cologna, G., Conrad, J., Couturier, C., Daniel, M. K., Davids, I. D., Degrange, B., Deil, C., Dickinson, H. J., Djannati-Atai, A., Domainko, W., Drury, L. O'C., Dubus, G., Dutson, K., Dyks, J., Dyrda, M., Egberts, K., Eger, P., Espigat, P., Fallon, L., Fegan, S., Feinstein, F., Fernandes, M. V., Fiasson, A., Fontaine, G., Foerster, A., Fuessling, M., Gajdus, M., Gallant, Y. A., Garrigoux, T., Gast, H., Gerard, L., Giebels, B., Glicenstein, J. F., Glueck, B., Goering, D., Grondin, M. -H., Haeffner, S., Hague, J. D., Hahn, J., Hampf, D., Harris, J., Hauser, M., Heinz, S., Heinzelmann, G., Henri, G., Hermann, G., Hillert, A., Hinton, J. A., Hofmann, W., Hofverberg, P., Holler, M., Horns, D., Jacholkowska, A., Jahn, C., Jamrozy, M., Jung, I., Kastendieck, M. A., Katarzynski, K., Katz, U., Kaufmann, S., Khelifi, B., Klochkov, D., Kluzniak, W., Kneiske, T., Komin, Nu., Kosack, K., Kossakowski, R., Krayzel, F., Laffon, H., Lamanna, G., Lenain, J. -P., Lennarz, D., Lohse, T., Lopatin, A., Lu, C. -C., Marandon, V., Marcowith, A., Masbou, J., Maurin, G., Maxted, N., Mayer, M., McComb, T. J. L., Medina, M. C., Mehault, J., Moderski, R., Mohamed, M., Moulin, E., Naumann, C. L., Naumann-Godo, M., de Naurois, M., Nedbal, D., Nekrassov, D., Nguyen, N., Nicholas, B., Niemiec, J., Nolan, S. J., Ohm, S., Wilhelmi, E. de Ona, Opitz, B., Ostrowski, M., Oya, I., Panter, M., Arribas, M. Paz, Pekeur, N. W., Pelletier, G., Perez, J., Petrucci, P. -O., Peyaud, B., Pita, S., Puehlhofer, G., Punch, M., Quirrenbach, A., Raue, M., Reimer, A., Reimer, O., Renaud, M., Reyes, R. de los, Rieger, F., Ripken, J., Rob, L., Rosier-Lees, S., Rowell, G., Rudak, B., Rulten, C. B., Sahakian, V., Sanchez, D. A., Santangelo, A., Schlickeiser, R., Schulz, A., Schwanke, U., Schwarzburg, S., Schwemmer, S., Sheidaei, F., Skilton, J. L., Sol, H., Spengler, G., Stawarz, L., Steenkamp, R., Stegmann, C., Stinzing, F., Stycz, K., Sushch, I., Szostek, A., Tavernet, J. -P., Terrier, R., Tluczykont, M., Valerius, K., van Eldik, C., Vasileiadis, G., Venter, C., Viana, A., Vincent, P., Voelk, H. J., Volpe, F., Vorobiov, S., Vorster, M., Wagner, S. J., Ward, M., White, R., Wierzcholska, A., Zacharias, M., Zajczyk, A., Zdziarski, A. A., Zech, A., Zechlin, H. -S., and Ali, M. O.
Subjects: Astrophysics - Cosmology and Nongalactic Astrophysics, Astrophysics - High Energy Astrophysical Phenomena
Abstract: In some galaxy clusters powerful AGN have blown bubbles with cluster scale extent into the ambient medium. The main pressure support of these bubbles is not known to date, but cosmic rays are a viable possibility. For such a scenario copious gamma-ray emission is expected as a tracer of cosmic rays from these systems. Hydra A, the closest galaxy cluster hosting a cluster scale AGN outburst, located at a redshift of 0.0538, is investigated for being a gamma-ray emitter with the High Energy Stereoscopic System (H.E.S.S.) array and the Fermi Large Area Telescope (Fermi-LAT). Data obtained in 20.2 hours of dedicated H.E.S.S. observations and 38 months of Fermi-LAT data, gathered by its usual all-sky scanning mode, have been analyzed to search for a gamma-ray signal. No signal has been found in either data set. Upper limits on the gamma-ray flux are derived and are compared to models. These are the first limits on gamma-ray emission ever presented for galaxy clusters hosting cluster scale AGN outbursts. The non-detection of Hydra A in gamma-rays has important implications on the particle populations and physical conditions inside the bubbles in this system. For the case of bubbles mainly supported by hadronic cosmic rays, the most favorable scenario, that involves full mixing between cosmic rays and embedding medium, can be excluded. However, hadronic cosmic rays still remain a viable pressure support agent to sustain the bubbles against the thermal pressure of the ambient medium. The largest population of highly-energetic electrons which are relevant for inverse-Compton gamma-ray production is found in the youngest inner lobes of Hydra A. The limit on the inverse-Compton gamma-ray flux excludes a magnetic field below half of the equipartition value of 16 muG in the inner lobes., Comment: 8 pages, 4 figures, accepted for publication in A&A
Published: 2012
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