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101. MAGIC observations of the giant radio galaxy M87 in a low-emission state between 2005 and 2007

Author: MAGIC Collaboration, Aleksić, J., Alvarez, E. A., Antonelli, L. A., Antoranz, P., Asensio, M., Backes, M., Barrio, J. A., Bastieri, D., González, J. Becerra, Bednarek, W., Berdyugin, A., Berger, K., Bernardini, E., Biland, A., Blanch, O., Bock, R. K., Boller, A., Bonnoli, G., Tridon, D. Borla, Braun, I., Bretz, T., Cañellas, A., Carmona, E., Carosi, A., Colin, P., Colombo, E., Contreras, J. L., Cortina, J., Cossio, L., Covino, S., Dazzi, F., De Angelis, A., De Caneva, G., del Pozo, E. De Cea, De Lotto, B., Mendez, C. Delgado, Ortega, A. Diago, Doert, M., Domínguez, A., Prester, D. Dominis, Dorner, D., Doro, M., Elsaesser, D., Ferenc, D., Fonseca, M. V., Font, L., Fruck, C., López, R. J. García, Garczarczyk, M., Garrido, D., Gaug, M., Giavitto, G., Godinović, N., Hadasch, D., Häfner, D., Herrero, A., Hildebrand, D., Höhne-Mönch, D., Hose, J., Hrupec, D., Huber, B., Jogler, T., Kellermann, H., Klepser, S., Krähenbühl, T., Krause, J., La Barbera, A., Lelas, D., Leonardo, E., Lindfors, E., Lombardi, S., López, M., López-Oramas, A., Lorenz, E., Makariev, M., Maneva, G., Mankuzhiyil, N., Mannheim, K., Maraschi, L., Mariotti, M., Martínez, M., Mazin, D., Meucci, M., Miranda, J. M., Mirzoyan, R., Miyamoto, H., Moldón, J., Moralejo, A., Munar-Adrover, P., Nieto, D., Nilsson, K., Orito, R., Oya, I., Paneque, D., Paoletti, R., Pardo, S., Paredes, J. M., Partini, S., Pasanen, M., Pauss, F., Perez-Torres, M. A., Persic, M., Peruzzo, L., Pilia, M., Pochon, J., Prada, F., Moroni, P. G. Prada, Prandini, E., Puljak, I., Reichardt, I., Reinthal, R., Rhode, W., Ribó, M., Rico, J., Rügamer, S., Saggion, A., Saito, K., Saito, T. Y., Salvati, M., Satalecka, K., Scalzotto, V., Scapin, V., Schultz, C., Schweizer, T., Shayduk, M., Shore, S. N., Sillanpää, A., Sitarek, J., Snidaric, I., Sobczynska, D., Spanier, F., Spiro, S., Stamatescu, V., Stamerra, A., Steinke, B., Storz, J., Strah, N., Surić, T., Takalo, L., Takami, H., Tavecchio, F., Temnikov, P., Terzić, T., Tescaro, D., Teshima, M., Tibolla, O., Torres, D. F., Treves, A., Uellenbeck, M., Vankov, H., Vogler, P., Wagner, R. M., Weitzel, Q., Zabalza, V., Zandanel, F., Zanin, R., and Ghisellini, G.
Subjects: Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Cosmology and Extragalactic Astrophysics
Abstract: We present the results of a long M87 monitoring campaign in very high energy $\gamma$-rays with the MAGIC-I Cherenkov telescope. We aim to model the persistent non-thermal jet emission by monitoring and characterizing the very high energy $\gamma$-ray emission of M87 during a low state. A total of 150\,h of data were taken between 2005 and 2007 with the single MAGIC-I telescope, out of which 128.6\,h survived the data quality selection. We also collected data in the X-ray and \textit{Fermi}--LAT bands from the literature (partially contemporaneous). No flaring activity was found during the campaign. The source was found to be in a persistent low-emission state, which was at a confidence level of $7\sigma$. We present the spectrum between 100\,GeV and 2\,TeV, which is consistent with a simple power law with a photon index $\Gamma=2.21\pm0.21$ and a flux normalization at 300\,GeV of $(7.7\pm1.3) \times 10^{-8}$ TeV$^{-1}$ s$^{-1}$ m$^{-2}$. The extrapolation of the MAGIC spectrum into the GeV energy range matches the previously published \textit{Fermi}--LAT spectrum well, covering a combined energy range of four orders of magnitude with the same spectral index. We model the broad band energy spectrum with a spine layer model, which can satisfactorily describe our data., Comment: 8 pages, 5 figures, 2 tables; A&A Journal version, fixed typo in the author list
Published: 2012
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102. High zenith angle observations of PKS 2155-304 with the MAGIC-I telescope

Author: The MAGIC Collaboration, Aleksić, J., Antonelli, L. A., Antoranz, P., Asensio, M., de Almeida, U. Barres, Barrio, J. A., González, J. Becerra, Bednarek, W., Berger, K., Bernardini, E., Biland, A., Blanch, O., Bock, R. K., Boller, A., Bonnoli, G., Tridon, D. Borla, Bretz, T., Carmona, E., Carosi, A., Colin, P., Colombo, E., Contreras, J. L., Cortina, J., Cossio, L., Covino, S., Da Vela, P., Dazzi, F., De Angelis, A., De Caneva, G., del Pozo, E. De Cea, De Lotto, B., Mendez, C. Delgado, Ortega, A. Diago, Doert, M., Prester, D. Dominis, Dorner, D., Doro, M., Eisenacher, D., Elsaesser, D., Ferenc, D., Fonseca, M. V., Font, L., Fruck, C., López, R. J. García, Garczarczyk, M., Terrats, D. Garrido, Gaug, M., Giavitto, G., Godinović, N., Muñoz, A. González, Gozzini, S. R., Hadamek, A., Hadasch, D., Häfner, D., Herrero, A., Hose, J., Hrupec, D., Huber, B., Jankowski, F., Jogler, T., Kadenius, V., Klepser, S., Knoetig, M. L., Krähenbühl, T., Krause, J., Kushida, J., La Barbera, A., Lelas, D., Leonardo, E., Lewandowska, N., Lindfors, E., Lombardi, S., López, M., López-Coto, R., López-Oramas, A., Lorenz, E., Makariev, M., Maneva, G., Mankuzhiyil, N., Mannheim, K., Maraschi, L., Marcote, B., Mariotti, M., Martínez, M., Mazin, D., Meucci, M., Miranda, J. M., Mirzoyan, R., Moldón, J., Moralejo, A., Munar-Adrover, P., Niedzwiecki, A., Nieto, D., Nilsson, K., Nowak, N., Orito, R., Paiano, S., Palatiello, M., Paneque, D., Paoletti, R., Paredes, J. M., Partini, S., Persic, M., Pilia, M., Pochon, J., Prada, F., Moroni, P. G. Prada, Prandini, E., Puljak, I., Reichardt, I., Reinthal, R., Rhode, W., Ribó, M., Rico, J., Rügamer, S., Saggion, A., Saito, K., Saito, T. Y., Salvati, M., Satalecka, K., Scalzotto, V., Scapin, V., Schultz, C., Schweizer, T., Shore, S. N., Sillanpää, A., Sitarek, J., Snidaric, I., Sobczynska, D., Spanier, F., Spiro, S., Stamatescu, V., Stamerra, A., Steinke, B., Storz, J., Sun, S., Surić, T., Takalo, L., Takami, H., Tavecchio, F., Temnikov, P., Terzić, T., Tescaro, D., Teshima, M., Tibolla, O., Torres, D. F., Toyama, T., Treves, A., Uellenbeck, M., Vogler, P., Wagner, R. M., Weitzel, Q., Zabalza, V., Zandanel, F., and Zanin, R.
Subjects: Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract: The high frequency peaked BL Lac PKS 2155-304 with a redshift of z=0.116 was discovered in 1997 in the very high energy (VHE, E >100GeV) gamma-ray range by the University of Durham Mark VI gamma-ray Cherenkov telescope in Australia with a flux corresponding to 20% of the Crab Nebula flux. It was later observed and detected with high significance by the Southern Cherenkov observatory H.E.S.S. Detection from the Northern hemisphere is difficult due to challenging observation conditions under large zenith angles. In July 2006, the H.E.S.S. collaboration reported an extraordinary outburst of VHE gamma-emission. During the outburst, the VHE gamma-ray emission was found to be variable on the time scales of minutes and with a mean flux of ~7 times the flux observed from the Crab Nebula. Follow-up observations with the MAGIC-I standalone Cherenkov telescope were triggered by this extraordinary outburst and PKS 2155-304 was observed between 28 July to 2 August 2006 for 15 hours at large zenith angles. Here we present our studies on the behavior of the source after its extraordinary flare and an enhanced analysis method for data taken at high zenith angles. We developed improved methods for event selection that led to a better background suppression. The averaged energy spectrum we derived has a spectral index of -3.5 +/- 0.2 above 400GeV, which is in good agreement with the spectral shape measured by H.E.S.S. during the major flare on MJD 53944. Furthermore, we present the spectral energy distribution modeling of PKS 2155-304. With our observations we increased the duty cycle of the source extending the light curve derived by H.E.S.S. after the outburst. Finally, we find night-by-night variability with a maximal amplitude of a factor three to four and an intranight variability in one of the nights (MJD 53945) with a similar amplitude., Comment: 10 pages, 9 figures; Accepted for publication in A&A
Published: 2012
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103. Detection of VHE \gamma-rays from HESS J0632+057 during the 2011 February X-ray outburst with the MAGIC Telescopes

Author: The MAGIC Collaboration, Aleksić, J., Alvarez, E. A., Antonelli, L. A., Antoranz, P., Asensio, M., Backes, M., de Almeida, U. Barres, Barrio, J. A., Bastieri, D., González, J. Becerra, Bednarek, W., Berger, K., Bernardini, E., Biland, A., Blanch, O., Bock, R. K., Boller, A., Bonnoli, G., Tridon, D. Borla, Bosch-Ramon, V., Bretz, T., Cañellas, A., Carmona, E., Carosi, A., Colin, P., Colombo, E., Contreras, J. L., Cortina, J., Cossio, L., Covino, S., Da Vela, P., Dazzi, F., De Angelis, A., De Caneva, G., del Pozo, E. De Cea, De Lotto, B., Mendez, C. Delgado, Ortega, A. Diago, Doert, M., Domínguez, A., Prester, D. Dominis, Dorner, D., Doro, M., Eisenacher, D., Elsaesser, D., Ferenc, D., Fonseca, M. V., Font, L., Fruck, C., López, R. J. García, Garczarczyk, M., Terrats, D. Garrido, Giavitto, G., Godinović, N., Muñoz, A. González, Gozzini, S. R., Hadasch, D., Häfner, D., Herrero, A., Hildebrand, D., Hose, J., Hrupec, D., Huber, B., Jankowski, F., Jogler, T., Kadenius, V., Kellermann, H., Klepser, S., Krähenbühl, T., Krause, J., La Barbera, A., Lelas, D., Leonardo, E., Lewandowska, N., Lindfors, E., Lombardi, S., López, M., López-Coto, R., López-Oramas, A., Lorenz, E., Makariev, M., Maneva, G., Mankuzhiyil, N., Mannheim, K., Maraschi, L., Mariotti, M., Martínez, M., Mazin, D., Meucci, M., Miranda, J. M., Mirzoyan, R., Moldón, J., Moralejo, A., Munar-Adrover, P., Niedzwiecki, A., Nieto, D., Nilsson, K., Nowak, N., Orito, R., Paiano, S., Paneque, D., Paoletti, R., Pardo, S., Paredes, J. M., Partini, S., Perez-Torres, M. A., Persic, M., Pilia, M., Pochon, J., Prada, F., Moroni, P. G. Prada, Prandini, E., Gimenez, I. Puerto, Puljak, I., Reichardt, I., Reinthal, R., Rhode, W., Ribó, M., Rico, J., Rügamer, S., Saggion, A., Saito, K., Saito, T. Y., Salvati, M., Satalecka, K., Scalzotto, V., Scapin, V., Schultz, C., Schweizer, T., Shore, S. N., Sillanpää, A., Sitarek, J., Snidaric, I., Sobczynska, D., Spanier, F., Spiro, S., Stamatescu, V., Stamerra, A., Steinke, B., Storz, J., Strah, N., Sun, S., Surić, T., Takalo, L., Takami, H., Tavecchio, F., Temnikov, P., Terzić, T., Tescaro, D., Teshima, M., Tibolla, O., Torres, D. F., Treves, A., Uellenbeck, M., Vogler, P., Wagner, R. M., Weitzel, Q., Zabalza, V., Zandanel, F., and Zanin, R.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: The very high energy (VHE) \gamma-ray source HESS J0632+057 has recently been confirmed to be a \gamma-ray binary. The optical counterpart is the Be star MWC 148, and a compact object of unknown nature orbits it every ~321 d with a high eccentricity of ~0.8. We monitored HESS J0632+057 with the stereoscopic MAGIC telescopes from 2010 October to 2011 March and detected significant VHE \gamma-ray emission during 2011 February, when the system exhibited an X-ray outburst. We find no \gamma-ray signal in the other observation periods when the system did not show increased X-ray flux. Thus HESS J0632+057 exhibits \gamma-ray variability on timescales of the order of one to two months possibly linked to the X-ray outburst that takes place about 100 days after the periastron passage. Furthermore our measurements provide for the first time the \gamma-ray spectrum down to about 140 GeV and indicate no turnover of the spectrum at low energies. We compare the properties of HESS J0632+057 with the similar \gamma-ray binary LS I +61 303, and discuss on the possible origin of the multi-wavelength emission of the source, Comment: 6 pages and 3 figures, submitted, corresponding authors T. Jogler and P. Munar-Adrover
Published: 2012
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104. Discovery of VHE gamma-rays from the blazar 1ES 1215+303 with the MAGIC Telescopes and simultaneous multi-wavelength observations

Author: MAGIC Collaboration, Aleksić, J., Alvarez, E. A., Antonelli, L. A., Antoranz, P., Ansoldi, S., Asensio, M., Backes, M., de Almeida, U. Barres, Barrio, J. A., Bastieri, D., González, J. Becerra, Bednarek, W., Berger, K., Bernardini, E., Biland, A., Blanch, O., Bock, R. K., Boller, A., Bonnoli, G., Tridon, D. Borla, Bretz, T., Cañellas, A., Carmona, E., Carosi, A., Colin, P., Colombo, E., Contreras, J. L., Cortina, J., Cossio, L., Covino, S., Da Vela, P., Dazzi, F., De Angelis, A., De Caneva, G., del Pozo, E. De Cea, De Lotto, B., Mendez, C. Delgado, Ortega, A. Diago, Doert, M., Domínguez, A., Prester, D. Dominis, Dorner, D., Doro, M., Eisenacher, D., Elsaesser, D., Ferenc, D., Fonseca, M. V., Font, L., Fruck, C., López, R. J. García, Garczarczyk, M., Terrats, D. Garrido, Giavitto, G., Godinović, N., Muñoz, A. González, Gozzini, S. R., Hadasch, D., Häfner, D., Herrero, A., Hildebrand, D., Hose, J., Hrupec, D., Huber, B., Jankowski, F., Jogler, T., Kadenius, V., Kellermann, H., Klepser, S., Krähenbühl, T., Krause, J., La Barbera, A., Lelas, D., Leonardo, E., Lewandowska, N., Lindfors, E., Lombardi, S., López, M., López-Coto, R., López-Oramas, A., Lorenz, E., Makariev, M., Maneva, G., Mankuzhiyil, N., Mannheim, K., Maraschi, L., Mariotti, M., Martínez, M., Mazin, D., Meucci, M., Miranda, J. M., Mirzoyan, R., Moldón, J., Moralejo, A., Munar-Adrover, P., Niedzwiecki, A., Nieto, D., Nilsson, K., Nowak, N., Orito, R., Paiano, S., Paneque, D., Paoletti, R., Pardo, S., Paredes, J. M., Partini, S., Perez-Torres, M. A., Persic, M., Pilia, M., Pochon, J., Prada, F., Moroni, P. G. Prada, Prandini, E., Gimenez, I. Puerto, Puljak, I., Reichardt, I., Reinthal, R., Rhode, W., Ribó, M., Rico, J., Rügamer, S., Saggion, A., Saito, K., Saito, T. Y., Salvati, M., Satalecka, K., Scalzotto, V., Scapin, V., Schultz, C., Schweizer, T., Shore, S. N., Sillanpää, A., Sitarek, J., Snidaric, I., Sobczynska, D., Spanier, F., Spiro, S., Stamatescu, V., Stamerra, A., Steinke, B., Storz, J., Strah, N., Sun, S., Surić, T., Takalo, L., Takami, H., Tavecchio, F., Temnikov, P., Terzić, T., Tescaro, D., Teshima, M., Tibolla, O., Torres, D. F., Treves, A., Uellenbeck, M., Vogler, P., Wagner, R. M., Weitzel, Q., Zabalza, V., Zandanel, F., Zanin, R., Berdyugin, A., Buson, S., Järvelä, E., Larsson, S., Lähteenmäki, A., and Tammi, J.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: Context. We present the discovery of very high energy (VHE, E > 100GeV) gamma-ray emission from the BL Lac object 1ES 1215+303 by the MAGIC telescopes and simultaneous multi-wavelength data in a broad energy range from radio to gamma-rays. Aims. We study the VHE gamma-ray emission from 1ES 1215+303 and its relation to the emissions in other wavelengths. Methods. Triggered by an optical outburst, MAGIC observed the source in January-February 2011 for 20.3 hrs. The target was monitored in the optical R-band by the KVA telescope that also performed optical polarization measurements. We triggered target of opportunity observations with the Swift satellite and obtained simultaneous and quasi-simultaneous data from the Fermi Large Area Telescope and from the Mets\"ahovi radio telescope. We also present the analysis of older MAGIC data taken in 2010. Results. The MAGIC observations of 1ES 1215+303 carried out in January-February 2011 resulted in the first detection of the source at VHE with a statistical significance of 9.4 sigma. Simultaneously, the source was observed in a high optical and X-ray state. In 2010 the source was observed in a lower state in optical, X-ray, and VHE, while the GeV gamma-ray flux and the radio flux were comparable in 2010 and 2011. The spectral energy distribution obtained with the 2011 data can be modeled with a simple one zone SSC model, but it requires extreme values for the Doppler factor or the electron energy distribution., Comment: 10 pages, 8 figures, accepted to A&A
Published: 2012
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105. Morphological and spectral properties of the W51 region measured with the MAGIC telescopes

Author: MAGIC Collaboration, Aleksić, J., Alvarez, E. A., Antonelli, L. A., Antoranz, P., Asensio, M., Backes, M., de Almeida, U. Barres, Barrio, J. A., Bastieri, D., González, J. Becerra, Bednarek, W., Berger, K., Bernardini, E., Biland, A., Blanch, O., Bock, R. K., Boller, A., Bonnoli, G., Tridon, D. Borla, Bretz, T., Cañellas, A., Carmona, E., Carosi, A., Colin, P., Colombo, E., Contreras, J. L., Cortina, J., Cossio, L., Covino, S., Da Vela, P., Dazzi, F., De Angelis, A., De Caneva, G., del Pozo, E. De Cea, De Lotto, B., Mendez, C. Delgado, Ortega, A. Diago, Doert, M., Domínguez, A., Prester, D. Dominis, Dorner, D., Doro, M., Eisenacher, D., Elsaesser, D., Ferenc, D., Fonseca, M. V., Font, L., Fruck, C., López, R. J. García, Garczarczyk, M., Garrido, D., Giavitto, G., Godinović, N., Muñoz, A. González, Gozzini, S. R., Hadasch, D., Häfner, D., Herrero, A., Hildebrand, D., Hose, J., Hrupec, D., Huber, B., Jankowski, F., Jogler, T., Kadenius, V., Kellermann, H., Klepser, S., Krähenbühl, T., Krause, J., La Barbera, A., Lelas, D., Leonardo, E., Lewandowska, N., Lindfors, E., Lombardi, S., López, M., López-Coto, R., López-Oramas, A., Lorenz, E., Makariev, M., Maneva, G., Mankuzhiyil, N., Mannheim, K., Maraschi, L., Mariotti, M., Martínez, M., Mazin, D., Meucci, M., Miranda, J. M., Mirzoyan, R., Moldón, J., Moralejo, A., Munar-Adrover, P., Niedzwiecki, A., Nieto, D., Nilsson, K., Nowak, N., Orito, R., Paiano, S., Paneque, D., Paoletti, R., Pardo, S., Paredes, J. M., Partini, S., Perez-Torres, M. A., Persic, M., Pilia, M., Pochon, J., Prada, F., Moroni, P. G. Prada, Prandini, E., Gimenez, I. Puerto, Puljak, I., Reichardt, I., Reinthal, R., Rhode, W., Ribó, M., Rico, J., Rügamer, S., Saggion, A., Saito, K., Saito, T. Y., Salvati, M., Satalecka, K., Scalzotto, V., Scapin, V., Schultz, C., Schweizer, T., Shore, S. N., Sillanpää, A., Sitarek, J., Snidaric, I., Sobczynska, D., Spanier, F., Spiro, S., Stamatescu, V., Stamerra, A., Steinke, B., Storz, J., Strah, N., Sun, S., Surić, T., Takalo, L., Takami, H., Tavecchio, F., Temnikov, P., Terzić, T., Tescaro, D., Teshima, M., Tibolla, O., Torres, D. F., Treves, A., Uellenbeck, M., Vogler, P., Wagner, R. M., Weitzel, Q., Zabalza, V., Zandanel, F., and Zanin, R.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: The W51 complex hosts the supernova remnant W51C which is known to interact with the molecular clouds in the star forming region W51B. In addition, a possible pulsar wind nebula CXO J192318.5+140305 was found likely associated with the supernova remnant. Gamma-ray emission from this region was discovered by Fermi/LAT (between 0.2 and 50 GeV) and H.E.S.S. (>1 TeV). The spatial distribution of the events could not be used to pinpoint the location of the emission among the pulsar wind nebula, the supernova remnant shell and/or the molecular cloud. However, the modeling of the spectral energy distribution presented by the Fermi/LAT collaboration suggests a hadronic emission mechanism. We performed observations of the W51 complex with the MAGIC telescopes for more than 50 hours. The good angular resolution in the medium (few hundred GeV) to high (above 1 TeV) energies allow us to perform morphological studies. We detect an extended emission of very-high-energy gamma rays, with a significance of 11 standard deviations. We extend the spectrum from the highest Fermi/LAT energies to \sim 5 TeV and find that it follows a single power law with an index of 2.58 \pm 0.07stat \pm 0.22syst . The main part of the emission coincides with the shocked cloud region, while we find a feature extending towards the pulsar wind nebula. The possible contribution of the pulsar wind nebula, assuming a point-like source, shows no dependence on energy and it is about 20% of the overall emission. The broad band spectral energy distribution can be explained with a hadronic model that implies proton acceleration above 100 TeV. This result, together with the morphology of the source, tentatively suggests that we observe ongoing acceleration of ions in the interaction zone between supernova remnant and cloud. These results shed light on the long-standing problem of the origin of galactic cosmic rays., Comment: 11 pages, 7 figures, accepted by A&A, corresponding authors: J. Krause, I Reichardt, E. Carmona
Published: 2012
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106. Discovery of VHE gamma-ray emission from the BL Lac object B3 2247+381 with the MAGIC telescopes

Author: The MAGIC Collaboration, Aleksić, J., Alvarez, E. A., Antonelli, L. A., Antoranz, P., Asensio, M., Backes, M., Barrio, J. A., Bastieri, D., González, J. Becerra, Bednarek, W., Berdyugin, A., Berger, K., Bernardini, E., Biland, A., Blanch, O., Bock, R. K., Boller, A., Bonnoli, G., Tridon, D. Borla, Braun, I., Bretz, T., Cañellas, A., Carmona, E., Carosi, A., Colin, P., Colombo, E., Contreras, J. L., Cortina, J., Cossio, L., Covino, S., Dazzi, F., De Angelis, A., De Caneva, G., del Pozo, E. De Cea, De Lotto, B., Mendez, C. Delgado, Ortega, A. Diago, Doert, M., Domínguez, A., Prester, D. Dominis, Dorner, D., Doro, M., Elsaesser, D., Ferenc, D., Fonseca, M. V., Font, L., Fruck, C., López, R. J. García, Garczarczyk, M., Garrido, D., Giavitto, G., Godinović, N., Hadasch, D., Häfner, D., Herrero, A., Hildebrand, D., Höhne-Mönch, D., Hose, J., Hrupec, D., Huber, B., Jogler, T., Kellermann, H., Klepser, S., Krähenbühl, T., Krause, J., La Barbera, A., Lelas, D., Leonardo, E., Lindfors, E., Lombardi, S., López, M., López-Oramas, A., Lorenz, E., Makariev, M., Maneva, G., Mankuzhiyil, N., Mannheim, K., Maraschi, L., Mariotti, M., Martínez, M., Mazin, D., Meucci, M., Miranda, J. M., Mirzoyan, R., Miyamoto, H., Moldón, J., Moralejo, A., Munar-Adrover, P., Nieto, D., Nilsson, K., Orito, R., Oya, I., Paneque, D., Paoletti, R., Pardo, S., Paredes, J. M., Partini, S., Pasanen, M., Pauss, F., Perez-Torres, M. A., Persic, M., Peruzzo, L., Pilia, M., Pochon, J., Prada, F., Moroni, P. G. Prada, Prandini, E., Puljak, I., Reichardt, I., Reinthal, R., Rhode, W., Ribó, M., Rico, J., Rügamer, S., Saggion, A., Saito, K., Saito, T. Y., Salvati, M., Satalecka, K., Scalzotto, V., Scapin, V., Schultz, C., Schweizer, T., Shayduk, M., Shore, S. N., Sillanpää, A., Sitarek, J., Snidaric, I., Sobczynska, D., Spanier, F., Spiro, S., Stamatescu, V., Stamerra, A., Steinke, B., Storz, J., Strah, N., Surić, T., Takalo, L., Takami, H., Tavecchio, F., Temnikov, P., Terzić, T., Tescaro, D., Teshima, M., Tibolla, O., Torres, D. F., Treves, A., Uellenbeck, M., Vankov, H., Vogler, P., Wagner, R. M., Weitzel, Q., Zabalza, V., Zandanel, F., Zanin, R., Kadenius, V., Weidinger, M., and Buson, S.
Subjects: Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract: We study the non-thermal jet emission of the BL Lac object B3 2247+381 during a high optical state. The MAGIC telescopes observed the source during 13 nights between September 30th and October 30th 2010, collecting a total of 14.2 hours of good quality very high energy (VHE) $\gamma$-ray data. Simultaneous multiwavelength data was obtained with X-ray observations by the Swift satellite and optical R-band observations at the KVA-telescope. We also use high energy $\gamma$-ray (HE, 0.1 GeV-100 GeV) data from the Fermi satellite. The BL Lac object B3 2247+381 (z=0.119) was detected, for the first time, at VHE $\gamma$-rays at a statistical significance of 5.6 $\sigma$. A soft VHE spectrum with a photon index of -3.2 $\pm$ 0.6 was determined. No significant short term flux variations were found. We model the spectral energy distribution using a one-zone SSC-model, which can successfully describe our data., Comment: 7 pages, 6 figures, 1 table, accepted for publication in Astronomy and Astrophysics
Published: 2012
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107. Detection of very-high energy \gamma-ray emission from NGC 1275 by the MAGIC telescopes

Author: MAGIC Collaboration, Aleksić, J., Alvarez, E. A., Antonelli, L. A., Antoranz, P., Asensio, M., Backes, M., de Almeida, U. Barres, Barrio, J. A., Bastieri, D., González, J. Becerra, Bednarek, W., Berdyugin, A., Berger, K., Bernardini, E., Biland, A., Blanch, O., Bock, R. K., Boller, A., Bonnoli, G., Tridon, D. Borla, Braun, I., Bretz, T., Cañellas, A., Carmona, E., Carosi, A., Colin, P., Colombo, E., Contreras, J. L., Cortina, J., Cossio, L., Covino, S., Dazzi, F., De Angelis, A., De Caneva, G., del Pozo, E. De Cea, De Lotto, B., Mendez, C. Delgado, Ortega, A. Diago, Doert, M., Domínguez, A., Prester, D. Dominis, Dorner, D., Doro, M., Eisenacher, D., Elsaesser, D., Ferenc, D., Fonseca, M. V., Font, L., Fruck, C., López, R. J. García, Garczarczyk, M., Garrido, D., Giavitto, G., Godinović, N., Gozzini, S. R., Hadasch, D., Häfner, D., Herrero, A., Hildebrand, D., Höhne-Mönch, D., Hose, J., Hrupec, D., Jogler, T., Kellermann, H., Klepser, S., Krähenbühl, T., Krause, J., Kushida, J., La Barbera, A., Lelas, D., Leonardo, E., Lewandowska, N., Lindfors, E., Lombardi, S., López, M., López-Coto, R., López-Oramas, A., Lorenz, E., Makariev, M., Maneva, G., Mankuzhiyil, N., Mannheim, K., Maraschi, L., Mariotti, M., Martínez, M., Mazin, D., Meucci, M., Miranda, J. M., Mirzoyan, R., Moldón, J., Moralejo, A., Munar-Adrover, P., Niedzwiecki, A., Nieto, D., Nilsson, K., Nowak, N., Orito, R., Paiano, S., Paneque, D., Paoletti, R., Pardo, S., Paredes, J. M., Partini, S., Perez-Torres, M. A., Persic, M., Peruzzo, L., Pilia, M., Pochon, J., Prada, F., Moroni, P. G. Prada, Prandini, E., Gimenez, I. Puerto, Puljak, I., Reichardt, I., Reinthal, R., Rhode, W., Ribó, M., Rico, J., Rügamer, S., Saggion, A., Saito, K., Saito, T. Y., Salvati, M., Satalecka, K., Scalzotto, V., Scapin, V., Schultz, C., Schweizer, T., Shayduk, M., Shore, S. N., Sillanpää, A., Sitarek, J., Snidaric, I., Sobczynska, D., Spanier, F., Spiro, S., Stamatescu, V., Stamerra, A., Steinke, B., Storz, J., Strah, N., Sun, S., Surić, T., Takalo, L., Takami, H., Tavecchio, F., Temnikov, P., Terzić, T., Tescaro, D., Teshima, M., Tibolla, O., Torres, D. F., Treves, A., Uellenbeck, M., Vankov, H., Vogler, P., Wagner, R. M., Weitzel, Q., Zabalza, V., Zandanel, F., Zanin, R., Pfrommer, C., and Pinzke, A.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: We report on the detection of very-high energy (VHE, E>100 GeV) gamma-ray emission from NGC 1275, the central radio galaxy of the Perseus cluster of galaxies. The source has been detected by the MAGIC telescopes with a statistical significance of 6.6 sigma above 100 GeV in 46 hr of stereo observations carried out between August 2010 and February 2011. The measured differential energy spectrum between 70 GeV and 500 GeV can be described by a power law with a steep spectral index of \Gamma=-4.1+/-0.7stat+/-0.3syst, and the average flux above 100 GeV is F_{gamma}=(1.3+/-0.2stat+/-0.3syst) x 10^-11 cm^-2 s^-1. These results, combined with the power-law spectrum measured in the first two years of observations by the Fermi-LAT above 100 MeV, with a spectral index of Gamma ~ -2.1, strongly suggest the presence of a break or cut-off around tens of GeV in the NGC 1275 spectrum. The light curve of the source above 100 GeV does not show hints of variability on a month time scale. Finally, we report on the nondetection in the present data of the radio galaxy IC 310, previously discovered by the Fermi-LAT and MAGIC. The derived flux upper limit F^{U.L.}_{gamma} (>300 GeV)=1.2 x 10^-12 cm^-2 s^-1 is a factor ~ 3 lower than the mean flux measured by MAGIC between October 2009 and February 2010, thus confirming the year time-scale variability of the source at VHE., Comment: Corresponding authors are S. Lombardi, P. Colin, D. Hildebrand, and F. Zandanel. Published in A&A; 4 pages, 4 figures
Published: 2011
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108. Detection of the gamma-ray binary LS I +61 303 in a low flux state at Very High Energy gamma-rays with the MAGIC Telescopes in 2009

Author: MAGIC Collaboration, Aleksić, J., Alvarez, E. A., Antonelli, L. A., Antoranz, P., Asensio, M., Backes, M., Barrio, J. A., Bastieri, D., González, J. Becerra, Bednarek, W., Berdyugin, A., Berger, K., Bernardini, E., Biland, A., Blanch, O., Bock, R. K., Boller, A., Bonnoli, G., Tridon, D. Borla, Bosch-Ramon, V., Braun, I., Bretz, T., Cañellas, A., Carmona, E., Carosi, A., Colin, P., Colombo, E., Contreras, J. L., Cortina, J., Cossio, L., Covino, S., Dazzi, F., De Angelis, A., De Caneva, G., del Pozo, E. De Cea, De Lotto, B., Mendez, C. Delgado, Ortega, A. Diago, Doert, M., Domínguez, A., Prester, D. Dominis, Dorner, D., Doro, M., Elsaesser, D., Ferenc, D., Fonseca, M. V., Font, L., Fruck, C., López, R. J. García, Garczarczyk, M., Garrido, D., Giavitto, G., Godinović, N., Hadasch, D., Häfner, D., Herrero, A., Hildebrand, D., Höhne-Mönch, D., Hose, J., Hrupec, D., Huber, B., Jogler, T., Kellermann, H., Klepser, S., Krähenbühl, T., Krause, J., La Barbera, A., Lelas, D., Leonardo, E., Lindfors, E., Lombardi, S., López, M., López-Oramas, A., Lorenz, E., Makariev, M., Maneva, G., Mankuzhiyil, N., Mannheim, K., Maraschi, L., Mariotti, M., Martínez, M., Mazin, D., Meucci, M., Miranda, J. M., Mirzoyan, R., Miyamoto, H., Moldón, J., Moralejo, A., Munar-Adrover, P., Nieto, D., Nilsson, K., Orito, R., Oya, I., Paneque, D., Paoletti, R., Pardo, S., Paredes, J. M., Partini, S., Pasanen, M., Pauss, F., Perez-Torres, M. A., Persic, M., Peruzzo, L., Pilia, M., Pochon, J., Prada, F., Moroni, P. G. Prada, Prandini, E., Puljak, I., Reichardt, I., Reinthal, R., Rhode, W., Ribó, M., Rico, J., Rügamer, S., Saggion, A., Saito, K., Saito, T. Y., Salvati, M., Satalecka, K., Scalzotto, V., Scapin, V., Schultz, C., Schweizer, T., Shayduk, M., Shore, S. N., Sillanpää, A., Sitarek, J., Sobczynska, D., Spanier, F., Spiro, S., Stamatescu, V., Stamerra, A., Steinke, B., Storz, J., Strah, N., Surić, T., Takalo, L., Takami, H., Tavecchio, F., Temnikov, P., Terzić, T., Tescaro, D., Teshima, M., Tibolla, O., Torres, D. F., Treves, A., Uellenbeck, M., Vankov, H., Vogler, P., Wagner, R. M., Weitzel, Q., Zabalza, V., Zandanel, F., and Zanin, R.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: We present very high energy (VHE, E > 100 GeV) {\gamma}-ray observations of the {\gamma}-ray binary system LS I+61 303 obtained with the MAGIC stereo system between 2009 October and 2010 January. We detect a 6.3{\sigma} {\gamma}-ray signal above 400 GeV in the combined data set. The integral flux above an energy of 300 GeV is F(E>300 GeV)=(1.4 +- 0.3stat +- 0.4syst) * 10^{-12} cm^{-2} s^{-1}, which corresponds to about 1.3% of the Crab Nebula flux in the same energy range. The orbit-averaged flux of LS I +61 303 in the orbital phase interval 0.6--0.7, where a maximum of the TeV flux is expected, is lower by almost an order of magnitude compared to our previous measurements between 2005 September and 2008 January. This provides evidence for a new low emission state in LS I +61 303. We find that the change to the low flux state cannot be solely explained by an increase of photon-photon absorption around the compact star., Comment: Corresponding authors: T. Jogler and O. Blanch; accepted for publication in ApJ, 6 pages and 3 figures
Published: 2011
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109. Constraining Cosmic Rays and Magnetic Fields in the Perseus Galaxy Cluster with TeV observations by the MAGIC telescopes

Author: MAGIC Collaboration, Aleksić, J., Alvarez, E. A., Antonelli, L. A., Antoranz, P., Asensio, M., Backes, M., de Almeida, U. Barres, Barrio, J. A., Bastieri, D., González, J. Becerra, Bednarek, W., Berdyugin, A., Berger, K., Bernardini, E., Biland, A., Blanch, O., Bock, R. K., Boller, A., Bonnoli, G., Tridon, D. Borla, Braun, I., Bretz, T., Cañellas, A., Carmona, E., Carosi, A., Colin, P., Colombo, E., Contreras, J. L., Cortina, J., Cossio, L., Covino, S., Dazzi, F., De Angelis, A., De Caneva, G., del Pozo, E. De Cea, De Lotto, B., Mendez, C. Delgado, Ortega, A. Diago, Doert, M., Domínguez, A., Prester, D. Dominis, Dorner, D., Doro, M., Eisenacher, D., Elsaesser, D., Ferenc, D., Fonseca, M. V., Font, L., Fruck, C., López, R. J. García, Garczarczyk, M., Garrido, D., Giavitto, G., Godinović, N., Gozzini, S. R., Hadasch, D., Häfner, D., Herrero, A., Hildebrand, D., Höhne-Mönch, D., Hose, J., Hrupec, D., Jogler, T., Kellermann, H., Klepser, S., Krähenbühl, T., Krause, J., Kushida, J., La Barbera, A., Lelas, D., Leonardo, E., Lewandowska, N., Lindfors, E., Lombardi, S., López, M., López-Coto, R., López-Oramas, A., Lorenz, E., Makariev, M., Maneva, G., Mankuzhiyil, N., Mannheim, K., Maraschi, L., Mariotti, M., Martínez, M., Mazin, D., Meucci, M., Miranda, J. M., Mirzoyan, R., Moldón, J., Moralejo, A., Munar-Adrover, P., Niedzwiecki, A., Nieto, D., Nilsson, K., Nowak, N., Orito, R., Paiano, S., Paneque, D., Paoletti, R., Pardo, S., Paredes, J. M., Partini, S., Perez-Torres, M. A., Persic, M., Peruzzo, L., Pilia, M., Pochon, J., Prada, F., Moroni, P. G. Prada, Prandini, E., Gimenez, I. Puerto, Puljak, I., Reichardt, I., Reinthal, R., Rhode, W., Ribó, M., Rico, J., Rügamer, S., Saggion, A., Saito, K., Saito, T. Y., Salvati, M., Satalecka, K., Scalzotto, V., Scapin, V., Schultz, C., Schweizer, T., Shayduk, M., Shore, S. N., Sillanpää, A., Sitarek, J., Snidaric, I., Sobczynska, D., Spanier, F., Spiro, S., Stamatescu, V., Stamerra, A., Steinke, B., Storz, J., Strah, N., Sun, S., Surić, T., Takalo, L., Takami, H., Tavecchio, F., Temnikov, P., Terzić, T., Tescaro, D., Teshima, M., Tibolla, O., Torres, D. F., Treves, A., Uellenbeck, M., Vankov, H., Vogler, P., Wagner, R. M., Weitzel, Q., Zabalza, V., Zandanel, F., Zanin, R., Pfrommer, C., and Pinzke, A.
Subjects: Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Cosmology and Extragalactic Astrophysics
Abstract: Galaxy clusters are being assembled today in the most energetic phase of hierarchical structure formation which manifests itself in powerful shocks that contribute to a substantial energy density of cosmic rays (CRs). Hence, clusters are expected to be luminous gamma-ray emitters since they also act as energy reservoirs for additional CR sources, such as active galactic nuclei and supernova-driven galactic winds. To detect the gamma-ray emission from CR interactions with the ambient cluster gas, we conducted the deepest to date observational campaign targeting a galaxy cluster at very high-energy gamma-rays and observed the Perseus cluster with the MAGIC Cherenkov telescopes for a total of ~85 hr of effective observing time. This campaign resulted in the detection of the central radio galaxy NGC 1275 at energies E > 100 GeV with a very steep energy spectrum. Here, we restrict our analysis to energies E > 630 GeV and detect no significant gamma-ray excess. This constrains the average CR-to-thermal pressure ratio to be <= 1-2%, depending on assumptions and the model for CR emission. Comparing these gamma-ray upper limits to predictions from cosmological cluster simulations that include CRs constrains the maximum CR acceleration efficiency at structure formation shocks to be < 50%. Alternatively, this may argue for non-negligible CR transport processes such as CR streaming and diffusion into the outer cluster regions. Finally, we derive lower limits on the magnetic field distribution assuming that the Perseus radio mini-halo is generated by secondary electrons/positrons that are created in hadronic CR interactions: assuming a spectrum of E^-2.2 around TeV energies as implied by cluster simulations, we limit the central magnetic field to be > 4-9 microG, depending on the rate of decline of the magnetic field strength toward larger radii., Comment: Corresponding authors are F. Zandanel, C. Pfrommer, P. Colin, A. Pinzke and S. Lombardi. Accepted for publication in A&A on 06/03/2012
Published: 2011
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110. The 2010 very high energy gamma-ray flare & 10 years of multi-wavelength observations of M 87

Author: Collaboration, The H. E. S. S., Abramowski, A., Acero, F., Aharonian, F., Akhperjanian, A. G., Anton, G., Balzer, A., Barnacka, A., de Almeida, U. Barres, Becherini, Y., Becker, J., Behera, B., 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., Clapson, A. C., Coignet, G., Cologna, G., Conrad, J., 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., Gallant, Y. A., Gast, H., Gérard, L., Gerbig, D., Giebels, B., Glicenstein, J. F., Glück, B., Goret, P., Göring, D., Häffner, S., Hague, J. D., Hampf, D., Hauser, M., Heinz, S., Heinzelmann, G., Henri, G., Hermann, G., Hinton, J. A., Hoffmann, 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., Keogh, D., Khangulyan, D., Khélifi, B., Klochkov, D., Kluźniak, W., Kneiske, T., Komin, Nu., Kosack, K., Kossakowski, R., Laffon, H., Lamanna, G., Lennarz, D., Lohse, T., Lopatin, A., Lu, C. -C., Marandon, V., Marcowith, A., Masbou, J., Maurin, D., Maxted, N., Mayer, M., McComb, T. J. L., Medina, M. C., Méhault, J., Moderski, R., 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, Pedaletti, G., Pelletier, G., Petrucci, P. -O., Pita, S., Pühlhofer, G., Punch, M., Quirrenbach, A., Raue, M., Rayner, S. 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., Ruppel, J., Sahakian, V., Sanchez, D. A., Santangelo, A., Schlickeiser, R., Schöck, F. M., 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., Vialle, J. P., 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., Zechlin, H. -S., Collaboration, The MAGIC, Aleksić, J., Antonelli, L. A., Antoranz, P., Backes, M., Barrio, J. A., Bastieri, D., González, J. Becerra, Bednarek, W., Berdyugin, A., Berger, K., Bernardini, E., Biland, A., Blanch, O., Bock, R. K., Boller, A., Bonnoli, G., Tridon, D. Borla, Braun, I., Bretz, T., Cañellas, A., Carmona, E., Carosi, A., Colin, P., Colombo, E., Contreras, J. L., Cortina, J., Cossio, L., Covino, S., Dazzi, F., De Angelis, A., del Pozo, E. De Cea, De Lotto, B., Mendez, C. Delgado, Ortega, A. Diago, Doert, M., Domínguez, A., Prester, D. Dominis, Dorner, D., Doro, M., Elsaesser, D., Ferenc, D., Fonseca, M. V., Font, L., Fruck, C., López, R. J. García, Garczarczyk, M., Garrido, D., Giavitto, G., Godinović, N., Hadasch, D., Häfner, D., Herrero, A., Hildebrand, D., Höhne-Mönch, D., Hose, J., Hrupec, D., Huber, B., Jogler, T., Klepser, S., Krähenbühl, T., Krause, J., La Barbera, A., Lelas, D., Leonardo, E., Lindfors, E., Lombardi, S., López, M., Lorenz, E., Makariev, M., Maneva, G., Mankuzhiyil, N., Mannheim, K., Maraschi, L., Mariotti, M., Martínez, M., Mazin, D., Meucci, M., Miranda, J. M., Mirzoyan, R., Miyamoto, H., Moldón, J., Moralejo, A., Munar, P., Nieto, D., Nilsson, K., Orito, R., Paneque, D., Paoletti, R., Pardo, S., Paredes, J. M., Partini, S., Pasanen, M., Pauss, F., Perez-Torres, M. A., Persic, M., Peruzzo, L., Pilia, M., Pochon, J., Prada, F., Moroni, P. G. Prada, Prandini, E., Puljak, I., Reichardt, I., Reinthal, R., Rhode, W., Ribó, M., Rico, J., Rügamer, S., Saggion, A., Saito, K., Saito, T. Y., Salvati, M., Satalecka, K., Scalzotto, V., Scapin, V., Schultz, C., Schweizer, T., Shayduk, M., Shore, S. N., Sillanpää, A., Sitarek, J., Sobczynska, D., Spanier, F., Spiro, S., Stamerra, A., Steinke, B., Storz, J., Strah, N., Surić, T., Takalo, L., Takami, H., Tavecchio, F., Temnikov, P., Terzić, T., Tescaro, D., Teshima, M., Thom, M., Tibolla, O., Torres, D. F., Treves, A., Vankov, H., Vogler, P., Wagner, R. M., Weitzel, Q., Zabalza, V., Zandanel, F., Zanin, R., Collaboration, The VERITAS, Arlen, T., Aune, T., Beilicke, M., Benbow, W., Bouvier, A., Bradbury, S. M., Buckley, J. H., Bugaev, V., Byrum, K., Cannon, A., Cesarini, A., Ciupik, L., Connolly, M. P., Cui, W., Dickherber, R., Duke, C., Errando, M., Falcone, A., Finley, J. P., Finnegan, G., Fortson, L., Furniss, A., Galante, N., Gall, D., Godambe, S., Griffin, S., Grube, J., Gyuk, G., Hanna, D., Holder, J., Huan, H., Hui, C. M., Kaaret, P., Karlsson, N., Kertzman, M., Khassen, Y., Kieda, D., Krawczynski, H., Krennrich, F., Lang, M. J., LeBohec, S., Maier, G., McArthur, S., McCann, A., Moriarty, P., Mukherjee, R., Nuñez, P. D., Ong, R. A., Orr, M., Otte, A. N., Park, N., Perkins, J. S., Pichel, A., Pohl, M., Prokoph, H., Ragan, K., Reyes, L. C., Reynolds, P. T., Roache, E., Rose, H. J., Schroedter, M., Sembroski, G. H., Şentürk, G. D., Telezhinsky, I., Tešić, G., Theiling, M., Thibadeau, S., Varlotta, A., Vassiliev, V. V., Vivier, M., Wakely, S. P., Weekes, T. C., Williams, D. A., Zitzer, B., Cara, M., Casadio, C., Cheung, C. C., McConville, W., Davies, F., Doi, A., Giovannini, G., Giroletti, M., Hada, K., Hardee, P., Harris, D. E., Junor, W., Kino, M., Lee, N. P., Ly, C., Madrid, J., Massaro, F., Mundell, C. G., Nagai, H., Perlman, E. S., Steele, I. A., Walker, R. C., and Wood, D. L.
Subjects: Astrophysics - Cosmology and Extragalactic Astrophysics
Abstract: Abridged: The giant radio galaxy M 87 with its proximity, famous jet, and very massive black hole provides a unique opportunity to investigate the origin of very high energy (VHE; E>100 GeV) gamma-ray emission generated in relativistic outflows and the surroundings of super-massive black holes. M 87 has been established as a VHE gamma-ray emitter since 2006. The VHE gamma-ray emission displays strong variability on timescales as short as a day. In this paper, results from a joint VHE monitoring campaign on M 87 by the MAGIC and VERITAS instruments in 2010 are reported. During the campaign, a flare at VHE was detected triggering further observations at VHE (H.E.S.S.), X-rays (Chandra), and radio (43 GHz VLBA). The excellent sampling of the VHE gamma-ray light curve enables one to derive a precise temporal characterization of the flare: the single, isolated flare is well described by a two-sided exponential function with significantly different flux rise and decay times. While the overall variability pattern of the 2010 flare appears somewhat different from that of previous VHE flares in 2005 and 2008, they share very similar timescales (~day), peak fluxes (Phi(>0.35 TeV) ~= (1-3) x 10^-11 ph cm^-2 s^-1), and VHE spectra. 43 GHz VLBA radio observations of the inner jet regions indicate no enhanced flux in 2010 in contrast to observations in 2008, where an increase of the radio flux of the innermost core regions coincided with a VHE flare. On the other hand, Chandra X-ray observations taken ~3 days after the peak of the VHE gamma-ray emission reveal an enhanced flux from the core. The long-term (2001-2010) multi-wavelength light curve of M 87, spanning from radio to VHE and including data from HST, LT, VLA and EVN, is used to further investigate the origin of the VHE gamma-ray emission. No unique, common MWL signature of the three VHE flares has been identified., Comment: 19 pages, 5 figures; Corresponding authors: M. Raue, L. Stawarz, D. Mazin, P. Colin, C. M. Hui, M. Beilicke; Fig. 1 lightcurve data available online: http://www.desy.de/~mraue/m87/
Published: 2011
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111. MAGIC contributions to the 32nd International Cosmic Ray Conference

Author: MAGIC Collaboration, Aleksić, J., Alvarez, E. A., Antonelli, L. A., Antoranz, P., Asensio, M., Backes, M., de Almeida, U. Barres, Barrio, J. A., Bastieri, D., González, J. Becerra, Bednarek, W., Berdyugin, A., Berger, K., Bernardini, E., Biland, A., Blanch, O., Bock, R. K., Boller, A., Bonnoli, G., Tridon, D. Borla, Braun, I., Bretz, T., Cañellas, A., Carmona, E., Carosi, A., Colin, P., Colombo, E., Contreras, J. L., Cortina, J., Cossio, L., Covino, S., Dazzi, F., De Angelis, A., De Caneva, G., del Pozo, E. De Cea, De Lotto, B., Mendez, C. Delgado, Ortega, A. Diago, Doert, M., Domínguez, A., Prester, D. Dominis, Dorner, D., Doro, M., Eisenacher, D., Elsaesser, D., Ferenc, D., Fonseca, M. V., Font, L., Fruck, C., López, R. J. García, Garczarczyk, M., Garrido, D., Giavitto, G., Godinović, N., Gozzini, S. R., Hadasch, D., Häfner, D., Herrero, A., Hildebrand, D., Höhne-Mönch, D., Hose, J., Hrupec, D., Jogler, T., Kellermann, H., Klepser, S., Krähenbühl, T., Krause, J., Kushida, J., La Barbera, A., Lelas, D., Leonardo, E., Lewandowska, N., Lindfors, E., Lombardi, S., López, M., López, R., López-Oramas, A., Lorenz, E., Makariev, M., Maneva, G., Mankuzhiyil, N., Mannheim, K., Maraschi, L., Marcote, B., Mariotti, M., Martínez, M., Mazin, D., Meucci, M., Miranda, J. M., Mirzoyan, R., Moldón, J., Moralejo, A., Munar-Adrover, P., Niedzwiecki, A., Nieto, D., Nilsson, K., Nowak, N., Orito, R., Paiano, S., Paneque, D., Paoletti, R., Pardo, S., Paredes, J. M., Partini, S., Perez-Torres, M. A., Persic, M., Peruzzo, L., Pilia, M., Pochon, J., Prada, F., Moroni, P. G. Prada, Prandini, E., Gimenez, I. Puerto, Puljak, I., Reichardt, I., Reinthal, R., Rhode, W., Ribó, M., Rico, J., Rügamer, S., Saggion, A., Saito, K., Saito, T. Y., Salvati, M., Satalecka, K., Scalzotto, V., Scapin, V., Schultz, C., Schweizer, T., Shayduk, M., Shore, S. N., Sillanpää, A., Sitarek, J., Snidaric, I., Sobczynska, D., Spanier, F., Spiro, S., Stamatescu, V., Stamerra, A., Steinke, B., Storz, J., Strah, N., Sun, S., Surić, T., Takalo, L., Takami, H., Tavecchio, F., Temnikov, P., Terzić, T., Tescaro, D., Teshima, M., Tibolla, O., Torres, D. F., Treves, A., Uellenbeck, M., Vankov, H., Vogler, P., Wagner, R. M., Weitzel, Q., Zabalza, V., Zandanel, F., and Zanin, R.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: Compilation of the papers contributed by the MAGIC collaboration to the 32nd International Cosmic Ray Conference (ICRC 2011), which took place between August 11 and 18, 2011 in Beijing, China. The papers are sorted in 6 categories: Overview and Highlight papers; Instrument, software and techniques; Galactic sources; Extragalactic sources; Multi-wavelength and joint campaigns; Fundamental physics, dark matter and cosmic rays., Comment: Index of the MAGIC conference proceedings at the ICRC 2011 v2: added one missing paper; corrected author list; added affiliations; added ICRC acronym in the abstract
Published: 2011

112. Searches for Dark Matter signatures in the Segue 1 dwarf spheroidal galaxy with the MAGIC-I telescope

Author: Paiano, S., Lombardi, S., Doro, M., Nieto, D., and Fornasa, M.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: Despite the interest in Dark Matter (DM) searches is currently more focused on underground experiments, a signature of DM annihilation/decay in gamma-rays from the space would constitute a smoking gun for its identification. Here, we present the results of the survey of Segue1 by the MAGIC-I telescope performed in 2008 and 2009. This source is considered by many as the most DM dominated Milky Way satellite galaxy known so far. The nearly 43 hours of data taken constitute the deepest observation ever made on a single dwarf galaxy by Cherenkov telescopes. No significant gamma-ray emission was found above an energy threshold of 100 GeV. Integral upper limits on the gamma-ray flux were calculated assuming various power-law spectra for the possible emission spectrum and for different energy thresholds. We also discuss a novel analysis that fully takes into account the spectral features of the gamma-ray spectrum of specific DM models in a SuperSymmetric scenario., Comment: 2011 Fermi Symposium proceedings - eConf C110509
Published: 2011

113. A search for possible dark matter subhalos as IACT targets in the First Fermi-LAT Source Catalog

Author: Nieto, D., Martínez, V., Mirabal, N., Barrio, J. A., Satalecka, K., Pardo, S., and Lozano, I.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: We present a systematic search for potential dark matter subhalos in our Galaxy among the 630 unassociated sources included in the First Fermi-LAT Source Catalog. Assuming a hypothetical dark matter particle that could generate observable gamma-ray photons beyond the Fermi energy range through self-annihilation, we look for reasonable targets for ground-based Imaging Atmospheric Cherenkov Telescopes at energies E > 100 GeV. In order to narrow the origin of these enigmatic sources, we look for their possible counterparts in other wavelengths including X-ray, radio, and optical spectroscopy. We find that the synergy between Fermi and Cherenkov telescopes, along with multiwavelength observations, could play a key role in indirect searches for dark matter., Comment: 4 pages, 3 figures, 1 table, 2011 Fermi Symposium proceedings - eConf C110509
Published: 2011

114. Segue 1: the best dark matter candidate dwarf galaxy surveyed by MAGIC

Author: Aleksić, J., Doro, M., Lombardi, S., Nieto, D., and Fornasa, M.
Subjects: Astrophysics - Cosmology and Nongalactic Astrophysics, Astrophysics - High Energy Astrophysical Phenomena, High Energy Physics - Experiment, High Energy Physics - Phenomenology
Abstract: Despite the interest in Dark Matter (DM) searches is currently more focused on underground experiments, a signature of DM annihilation/decay in gamma-rays from space would constitute a smoking gun for its identification. In this contribution, we start with a brief review of the efforts of the ground-based MAGIC Cherenkov telescopes system to detect DM signatures from dwarf satellite galaxies orbiting the Milky Way halo. We then present the recent survey of Segue 1, considered by many as possibly the most DM dominated satellite galaxy known in our galaxy. No significant gamma-ray emission was found above the background in around 30 hours of observation. This is the largest survey ever made on a single dwarf by Cherenkov telescopes. We present a novel analysis that fully takes into account the spectral features of the gamma-ray spectrum of specific DM models in a Supersymmetric scenario. We also discuss the prospects of detection after the Fermi observation of similar objects at lower energies., Comment: 4 pages, 3 figures, contribution to the 32nd International Cosmic Ray Conference, Beijing, China, August 2011
Published: 2011
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115. Phase-resolved energy spectra of the Crab Pulsar in the range of 50-400 GeV measured with the MAGIC Telescopes

Author: MAGIC Collaboration, Aleksić, J., Alvarez, E. A., Antonelli, L. A., Antoranz, P., Asensio, M., Backes, M., Barrio, J. A., Bastieri, D., González, J. Becerra, Bednarek, W., Berdyugin, A., Berger, K., Bernardini, E., Biland, A., Blanch, O., Bock, R. K., Boller, A., Bonnoli, G., Tridon, D. Borla, Braun, I., Bretz, T., Cañellas, A., Carmona, E., Carosi, A., Colin, P., Colombo, E., Contreras, J. L., Cortina, J., Cossio, L., Covino, S., Dazzi, F., De Angelis, A., De Caneva, G., del Pozo, E. De Cea, De Lotto, B., Mendez, C. Delgado, Ortega, A. Diago, Doert, M., Domínguez, A., Prester, D. Dominis, Dorner, D., Doro, M., Eisenacher, D., Elsaesser, D., Ferenc, D., Fonseca, M. V., Font, L., Fruck, C., López, R. J. García, Garczarczyk, M., Garrido, D., Giavitto, G., Godinović, N., Hadasch, D., Häfner, D., Herrero, A., Hildebrand, D., Höhne-Mönch, D., Hose, J., Hrupec, D., Jogler, T., Kellermann, H., Klepser, S., Krähenbühl, T., Krause, J., Kushida, J., La Barbera, A., Lelas, D., Leonardo, E., Lewandowska, N., Lindfors, E., Lombardi, S., López, M., López-Oramas, A., Lorenz, E., Makariev, M., Maneva, G., Mankuzhiyil, N., Mannheim, K., Maraschi, L., Mariotti, M., Martínez, M., Mazin, D., Meucci, M., Miranda, J. M., Mirzoyan, R., Moldón, J., Moralejo, A., Munar-Adrover, P., Niedzwiecki, A., Nieto, D., Nilsson, K., Nowak, N., Orito, R., Paneque, D., Paoletti, R., Pardo, S., Paredes, J. M., Partini, S., Perez-Torres, M. A., Persic, M., Peruzzo, L., Pilia, M., Pochon, J., Prada, F., Moroni, P. G. Prada, Prandini, E., Gimenez, I. Puerto, Puljak, I., Reichardt, I., Reinthal, R., Rhode, W., Ribó, M., Rico, J., Rügamer, S., Saggion, A., Saito, K., Saito, T. Y., Salvati, M., Satalecka, K., Scalzotto, V., Scapin, V., Schultz, C., Schweizer, T., Shayduk, M., Shore, S. N., Sillanpää, A., Sitarek, J., Snidaric, I., Sobczynska, D., Spanier, F., Spiro, S., Stamatescu, V., Stamerra, A., Steinke, B., Storz, J., Strah, N., Surić, T., Takalo, L., Takami, H., Tavecchio, F., Temnikov, P., Terzić, T., Tescaro, D., Teshima, M., Tibolla, O., Torres, D. F., Treves, A., Uellenbeck, M., Vankov, H., Vogler, P., Wagner, R. M., Weitzel, Q., Zabalza, V., Zandanel, F., Zanin, R., and Hirotani, K.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: We use 73 h of stereoscopic data taken with the MAGIC telescopes to investigate the very high-energy (VHE) gamma-ray emission of the Crab pulsar. Our data show a highly significant pulsed signal in the energy range from 50 to 400 GeV in both the main pulse (P1) and the interpulse (P2) phase regions. We provide the widest spectra to date of the VHE components of both peaks, and these spectra extend to the energy range of satellite-borne observatories. The good resolution and background rejection of the stereoscopic MAGIC system allows us to cross-check the correctness of each spectral point of the pulsar by comparison with the corresponding (strong and well-known) Crab nebula flux. The spectra of both P1 and P2 are compatible with power laws with photon indices of 4.0 \pm 0.8 (P1) and 3.42 \pm 0.26 (P2), respectively, and the ratio P1/P2 between the photon counts of the two pulses is 0.54 \pm 0.12. The VHE emission can be understood as an additional component produced by the inverse Compton scattering of secondary and tertiary e\pm pairs on IR-UV photons., Comment: 6 pages, 4 figures. Accepted for publication in A&A on 16 February 2012
Published: 2011
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116. The search for galactic dark matter clump candidates with Fermi and MAGIC

Author: Nieto, D., Aleksić, J., Barrio, J. A., Contreras, J. L., Doro, M., Lombardi, S., Mirabal, N., Moralejo, A., Pardo, S., Rico, J., and Zandanel, F.
Subjects: Astrophysics - High Energy Astrophysical Phenomena, High Energy Physics - Phenomenology
Abstract: We present a systematic search for potential dark matter clumps in our Galaxy among the 630 unassociated sources included in the LAT 1-year Point Source Catalog. Assuming a dark matter particle that generates observable gamma-ray photons beyond the Fermi energy range through self-annihilation, we compile a list of reasonable targets for the MAGIC Imaging Atmospheric Cherenkov Telescopes. In order to narrow down the origin of these enigmatic sources, we summarize ongoing multiwavelength studies including X-ray, radio, and optical spectroscopy. We report on observations of two of these candidates using the MAGIC Telescopes. We find that the synergy between Fermi and Cherenkov telescopes, along with multiwavelength observations, could play a key role in indirect searches for dark matter., Comment: 4 pages, 2 figures, contribution to the 32nd International Cosmic Ray Conference, Beijing, China, August 2011
Published: 2011

117. Observations of the Crab pulsar between 25 GeV and 100 GeV with the MAGIC I telescope

Author: MAGIC Collaboration, Aleksić, J., Alvarez, E. A., Antonelli, L. A., Antoranz, P., Asensio, M., Backes, M., Barrio, J. A., Bastieri, D., González, J. Becerra, Bednarek, W., Berdyugin, A., Berger, K., Bernardini, E., Biland, A., Blanch, O., Bock, R. K., Boller, A., Bonnoli, G., Tridon, D. Borla, Braun, I., Bretz, T., Cañellas, A., Carmona, E., Carosi, A., Colin, P., Colombo, E., Contreras, J. L., Cortina, J., Cossio, L., Covino, S., Dazzi, F., De Angelis, A., De Caneva, G., del Pozo, E. De Cea, De Lotto, B., Mendez, C. Delgado, Ortega, A. Diago, Doert, M., Domínguez, A., Prester, D. Dominis, Dorner, D., Doro, M., Eisenacher, D., Elsaesser, D., Ferenc, D., Fonseca, M. V., Font, L., Fruck, C., López, R. J. García, Garczarczyk, M., Garrido, D., Giavitto, G., Godinović, N., Hadasch, D., Häfner, D., Herrero, A., Hildebrand, D., Höhne-Mönch, D., Hose, J., Hrupec, D., Jogler, T., Kellermann, H., Klepser, S., Krähenbühl, T., Krause, J., Kushida, J., La Barbera, A., Lelas, D., Leonardo, E., Lindfors, E., Lombardi, S., López, M., López-Oramas, A., Lorenz, E., Makariev, M., Maneva, G., Mankuzhiyil, N., Mannheim, K., Maraschi, L., Marcote, B., Mariotti, M., Martínez, M., Mazin, D., Meucci, M., Miranda, J. M., Mirzoyan, R., Moldón, J., Moralejo, A., Munar-Adrover, P., Nieto, D., Nilsson, K., Orito, R., Otte, N., Oya, I., Paneque, D., Paoletti, R., Pardo, S., Paredes, J. M., Partini, S., Perez-Torres, M. A., Persic, M., Peruzzo, L., Pilia, M., Pochon, J., Prada, F., Moroni, P. G. Prada, Prandini, E., Gimenez, I. Puerto, Puljak, I., Reichardt, I., Reinthal, R., Rhode, W., Ribó, M., Rico, J., Rissi, M., Rügamer, S., Saggion, A., Saito, K., Saito, T. Y., Salvati, M., Satalecka, K., Scalzotto, V., Scapin, V., Schultz, C., Schweizer, T., Shayduk, M., Shore, S. N., Sillanpää, A., Sitarek, J., Snidaric, I., Sobczynska, D., Spanier, F., Spiro, S., Stamatescu, V., Stamerra, A., Steinke, B., Storz, J., Strah, N., Surić, T., Takalo, L., Takami, H., Tavecchio, F., Temnikov, P., Terzić, T., Tescaro, D., Teshima, M., Tibolla, O., Torres, D. F., Treves, A., Uellenbeck, M., Vankov, H., Vogler, P., Wagner, R. M., Weitzel, Q., Zabalza, V., Zandanel, F., Zanin, R., and Hirotani, K.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: We report on the observation of $\gamma$-rays above 25\,GeV from the Crab pulsar (PSR B0532+21) using the MAGIC I telescope. Two data sets from observations during the winter period 2007/2008 and 2008/2009 are used. In order to discuss the spectral shape from 100\,MeV to 100\,GeV, one year of public {\it Fermi} Large Area Telescope ({\it Fermi}-LAT) data are also analyzed to complement the MAGIC data. The extrapolation of the exponential cutoff spectrum determined with the Fermi-LAT data is inconsistent with MAGIC measurements, which requires a modification of the standard pulsar emission models. In the energy region between 25 and 100\,GeV, the emission in the P1 phase (from -0.06 to 0.04, location of the main pulse) and the P2 phase (from 0.32 to 0.43, location of the interpulse) can be described by power laws with spectral indices of $-3.1 \pm 1.0_{stat} \pm 0.3_{syst}$ and $-3.5 \pm 0.5_{stat} \pm 0.3_{syst}$, respectively. Assuming an asymmetric Lorentzian for the pulse shape, the peak positions of the main pulse and the interpulse are estimated to be at phases $-0.009 \pm 0.007$ and $0.393 \pm 0.009$, while the full widths at half maximum are $0.025 \pm 0.008$ and $0.053 \pm 0.015$, respectively., Comment: 14 pages, 15 figures, published in Astrophysical Journal
Published: 2011
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118. Performance of the MAGIC stereo system obtained with Crab Nebula data

Author: MAGIC Collaboration, Aleksić, J., Alvarez, E. A., Antonelli, L. A., Antoranz, P., Asensio, M., Backes, M., Barrio, J. A., Bastieri, D., González, J. Becerra, Bednarek, W., Berdyugin, A., Berger, K., Bernardini, E., Biland, A., Blanch, O., Bock, R. K., Boller, A., Bonnoli, G., Tridon, D. Borla, Braun, I., Bretz, T., Cañellas, A., Carmona, E., Carosi, A., Colin, P., Colombo, E., Contreras, J. L., Cortina, J., Cossio, L., Covino, S., Dazzi, F., De Angelis, A., De Caneva, G., del Pozo, E. De Cea, De Lotto, B., Mendez, C. Delgado, Ortega, A. Diago, Doert, M., Domínguez, A., Prester, D. Dominis, Dorner, D., Doro, M., Eisenacher, D., Elsaesser, D., Ferenc, D., Fonseca, M. V., Font, L., Fruck, C., López, R. J. García, Garczarczyk, M., Garrido, D., Giavitto, G., Godinović, N., Hadasch, D., Häfner, D., Herrero, A., Hildebrand, D., Höhne-Mönch, D., Hose, J., Hrupec, D., Jogler, T., Kellermann, H., Klepser, S., Krähenbühl, T., Krause, J., Kushida, J., La Barbera, A., Lelas, D., Leonardo, E., Lindfors, E., Lombardi, S., López, M., López-Oramas, A., Lorenz, E., Makariev, M., Maneva, G., Mankuzhiyil, N., Mannheim, K., Maraschi, L., Marcote, B., Mariotti, M., Martínez, M., Mazin, D., Meucci, M., Miranda, J. M., Mirzoyan, R., Moldón, J., Moralejo, A., Munar-Adrover, P., Nieto, D., Nilsson, K., Orito, R., Oya, I., Paneque, D., Paoletti, R., Pardo, S., Paredes, J. M., Partini, S., Perez-Torres, M. A., Persic, M., Peruzzo, L., Pilia, M., Pochon, J., Prada, F., Moroni, P. G. Prada, Prandini, E., Gimenez, I. Puerto, Puljak, I., Reichardt, I., Reinthal, R., Rhode, W., Ribó, M., Rico, J., Rügamer, S., Saggion, A., Saito, K., Saito, T. Y., Salvati, M., Satalecka, K., Scalzotto, V., Scapin, V., Schultz, C., Schweizer, T., Shayduk, M., Shore, S. N., Sillanpää, A., Sitarek, J., Snidaric, I., Sobczynska, D., Spanier, F., Spiro, S., Stamatescu, V., Stamerra, A., Steinke, B., Storz, J., Strah, N., Surić, T., Takalo, L., Takami, H., Tavecchio, F., Temnikov, P., Terzić, T., Tescaro, D., Teshima, M., Tibolla, O., Torres, D. F., Treves, A., Uellenbeck, M., Vankov, H., Vogler, P., Wagner, R. M., Weitzel, Q., Zabalza, V., Zandanel, F., and Zanin, R.
Subjects: Astrophysics - Instrumentation and Methods for Astrophysics
Abstract: MAGIC is a system of two Imaging Atmospheric Cherenkov Telescopes located in the Canary island of La Palma. Since autumn 2009 both telescopes have been working together in stereoscopic mode, providing a significant improvement with respect to the previous single-telescope observations. We use observations of the Crab Nebula taken at low zenith angles to assess the performance of the MAGIC stereo system. The trigger threshold of the MAGIC telescopes is 50-60 GeV. Advanced stereo analysis techniques allow MAGIC to achieve a sensitivity as good as (0.76 +/- 0.03)% of the Crab Nebula flux in 50 h of observations above 290 GeV. The angular resolution at those energies is better than ~0.07 degree. We also perform a detailed study of possible systematic effects which may influence the analysis of the data taken with the MAGIC telescopes., Comment: 15 pages, 19 figures, 4 tables, added run-by-run systematics study, and the study of angular resolution as the function of the distance to the camera centre, accepted for publication in Astroparticle Physics
Published: 2011
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119. Mrk 421 active state in 2008: the MAGIC view, simultaneous multi-wavelength observations and SSC model constrained

Author: Aleksic, J., Alvarez, E. A., Antonelli, L. A., Antoranz, P., Asensio, M., Backes, M., Barrio, J. A., Bastieri, D., Gonzalez, J. Becerra, Bednarek, W., Berdyugin, A., Berger, K., Bernardini, E., Biland, A., Blanch, O., Bock, R. K., Boller, A., Bonnoli, G., Tridon, D. Borla, Braun, I., Bretz, T., Canellas, A., Carmona, E., Carosi, A., Colin, P., Colombo, E., Contreras, J. L., Cortina, J., Cossio, L., Covino, S., Dazzi, F., De Angelis, A., De Caneva, G., del Pozo, E. De Cea, De Lotto, B., Mendez, C. Delgado, Ortega, A. Diago, Doert, M., Dominguez, A., Prester, D. Dominis, Dorner, D., Doro, M., Elsaesser, D., Ferenc, D., Fonseca, M. V., Font, L., Fruck, C., Lopez, R. J. Garcia, Garczarczyk, M., Garrido, D., Giavitto, G., Godinovic, N., Hadasch, D., Häfner, D., Herrero, A., Hildebrand, D., Höhne-Mönch, D., Hose, J., Hrupec, D., Huber, B., Jogler, T., Kellermann, H., Klepser, S., Krahenbuh, T., Krause, J., La Barbera, A., Lelas, D., Leonardo, E., Lindfors, E., Lombardi, S., Lopez, A., Lopez, M., Lorenz, E., Makariev, M., Maneva, G., Mankuzhiyil, N., Mannheim, K., Maraschi, L., Mariotti, M., Martinez, M., Mazin, D., Meucci, M., Miranda, J. M., Mirzoyan, R., Miyamoto, H., Moldon, J., Moralejo, A., Munar-Adrover, P., Nieto, D., Nilsson, K., Orito, R., Oya, I., Paneque, D., Paoletti, R., Pardo, S., Paredes, J. M., Partini, S., Pasanen, M., Pauss, F., Perez-Torres, M. A., Persic, M., Peruzzo, L., Pilia, M., Pochon, J., Prada, F., Moroni, P. G. Prada, Prandini, E., Puljak, I., Reichardt, I., Reinthal, R., Rhode, W., Ribo, M., Rico, J., Rügamer, S., Saggion, A., Saito, K., Saito, T. Y., Salvati, M., Satalecka, K., Scalzotto, V., Scapin, V., Schultz, C., Schweizer, T., Shayduk, M., Shore, S. N., Sillanpaa, A., Sitarek, J., Sobczynska, D., Spanier, F., Spiro, S., Stamerra, A., Steinke, B., Storz, J., Strah, N., Suric, T., Takalo, L., Takami, H., Tavecchio, F., Temnikov, P., Terzic, T., Tescaro, D., Teshima, M., Tibolla, O., Torres, D. F., Treves, A., Uellenbeck, M., Vankov, H., Vogler, P., Wagner, R. M., Weitzel, Q., Zabalza, V., Zandanel, F., and Zanin, R.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: Context: The blazar Markarian 421 is one of the brightest TeV gamma-ray sources of the northern sky. From December 2007 until June 2008 it was intensively observed in the very high energy (VHE, E > 100 GeV) band by the single-dish Major Atmospheric Gamma-ray Imaging Cherenkov telescope (MAGIC-I). Aims: We aimed to measure the physical parameters of the emitting region of the blazar jet during active states. Methods: We performed a dense monitoring of the source in VHE with MAGIC-I, and also collected complementary data in soft X-rays and optical-UV bands; then, we modeled the spectral energy distributions (SED) derived from simultaneous multi-wavelength data within the synchrotron self--compton (SSC) framework. Results: The source showed intense and prolonged gamma-ray activity during the whole period, with integral fluxes (E > 200 GeV) seldom below the level of the Crab Nebula, and up to 3.6 times this value. Eight datasets of simultaneous optical-UV (KVA, Swift/UVOT), soft X-ray (Swift/XRT) and MAGIC-I VHE data were obtained during different outburst phases. The data constrain the physical parameters of the jet, once the spectral energy distributions obtained are interpreted within the framework of a single-zone SSC leptonic model. Conclusions: The main outcome of the study is that within the homogeneous model high Doppler factors (40 <= delta <= 80) are needed to reproduce the observed SED; but this model cannot explain the observed short time-scale variability, while it can be argued that inhomogeneous models could allow for less extreme Doppler factors, more intense magnetic fields and shorter electron cooling times compatible with hour or sub-hour scale variability., Comment: 12 pages, 7 figures. Accepted for publication in A&A 7 January 2012
Published: 2011
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120. A search for Very High Energy gamma-ray emission from Scorpius X-1 with the MAGIC telescopes

Author: MAGIC Collaboration, Aleksić, J., Alvarez, E. A., Antonelli, L. A., Antoranz, P., Asensio, M., Backes, M., Barrio, J. A., Bastieri, D., González, J. Becerra, Bednarek, W., Berdyugin, A., Berger, K., Bernardini, E., Biland, A., Blanch, O., Bock, R. K., Boller, A., Bonnoli, G., Bordas, P., Tridon, D. Borla, Bosch-Ramon, V., Braun, I., Bretz, T., Cañellas, A., Carmona, E., Carosi, A., Colin, P., Colombo, E., Contreras, J. L., Cortina, J., Cossio, L., Covino, S., Dazzi, F., De Angelis, A., del Pozo, E. De Cea, De Lotto, B., Mendez, C. Delgado, Ortega, A. Diago, Doert, M., Domínguez, A., Prester, D. Dominis, Dorner, D., Doro, M., Elsaesser, D., Ferenc, D., Fonseca, M. V., Font, L., Fruck, C., López, R. J. García, Garczarczyk, M., Garrido, D., Giavitto, G., Godinović, N., Hadasch, D., Häfner, D., Herrero, A., Hildebrand, D., Höhne-Mönch, D., Hose, J., Hrupec, D., Huber, B., Jogler, T., Klepser, S., Krähenbühl, T., Krause, J., La Barbera, A., Lelas, D., Leonardo, E., Lindfors, E., Lombardi, S., López, M., Lorenz, E., Makariev, M., Maneva, G., Mankuzhiyil, N., Mannheim, K., Maraschi, L., Mariotti, M., Martínez, M., Mazin, D., Meucci, M., Miranda, J. M., Mirzoyan, R., Miyamoto, H., Moldón, J., Moralejo, A., Munar-Adrover, P., Nieto, D., Nilsson, K., Orito, R., Oya, I., Paneque, D., Paoletti, R., Pardo, S., Paredes, J. M., Partini, S., Pasanen, M., Pauss, F., Perez-Torres, M. A., Persic, M., Peruzzo, L., Pilia, M., Pochon, J., Prada, F., Moroni, P. G. Prada, Prandini, E., Puljak, I., Reichardt, I., Reinthal, R., Rhode, W., Ribó, M., Rico, J., Rügamer, S., Saggion, A., Saito, K., Saito, T. Y., Salvati, M., Satalecka, K., Scalzotto, V., Scapin, V., Schultz, C., Schweizer, T., Shayduk, M., Shore, S. N., Sillanpää, A., Sitarek, J., Sobczynska, D., Spanier, F., Spiro, S., Stamerra, A., Steinke, B., Storz, J., Strah, N., Surić, T., Takalo, L., Takami, H., Tavecchio, F., Temnikov, P., Terzić, T., Tescaro, D., Teshima, M., Thom, M., Tibolla, O., Torres, D. F., Treves, A., Vankov, H., Vogler, P., Wagner, R. M., Weitzel, Q., Zabalza, V., Zandanel, F., and Zanin, R.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: The acceleration of particles up to GeV or higher energies in microquasars has been the subject of considerable theoretical and observational efforts in the past few years. Sco X-1 is a microquasar from which evidence of highly energetic particles in the jet has been found when it is in the so-called Horizontal Branch (HB), a state when the radio and hard X-ray fluxes are higher and a powerful relativistic jet is present. Here we present the first very high energy gamma-ray observations of Sco X-1 obtained with the MAGIC telescopes. An analysis of the whole dataset does not yield a significant signal, with 95% CL flux upper limits above 300 GeV at the level of 2.4x10^{-12} ph/cm^2/s. Simultaneous RXTE observations were conducted to search for TeV emission during particular X-ray states of the source. A selection of the gamma-ray data obtained during the HB based on the X-ray colors did not yield a signal either, with an upper limit of 3.4x10^{-12} ph/cm^2/s. These upper limits place a constraint on the maximum TeV luminosity to non-thermal X-ray luminosity of L_{VHE}/L_{ntX}<0.02, that can be related to a maximum TeV luminosity to jet power ratio of L_{VHE}/L_{j}<10^{-3}. Our upper limits indicate that the underlying high-energy emission physics in Sco X-1 must be inherently different from that of the hitherto detected gamma-ray binaries., Comment: 5 pages, 2 figures, 2 tables. Version as published in ApJL
Published: 2011
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121. Searches for Dark Matter annihilation signatures in the Segue 1 satellite galaxy with the MAGIC-I telescope

Author: The MAGIC Collaboration, Aleksić, J., Alvarez, E. A., Antonelli, L. A., Antoranz, P., Asensio, M., Backes, M., Barrio, J. A., Bastieri, D., González, J. Becerra, Bednarek, W., Berdyugin, A., Berger, K., Bernardini, E., Biland, A., Blanch, O., Bock, R. K., Boller, A., Bonnoli, G., Tridon, D. Borla, Braun, I., Bretz, T., Cañellas, A., Carmona, E., Carosi, A., Colin, P., Colombo, E., Contreras, J. L., Cortina, J., Cossio, L., Covino, S., Dazzi, F., De Angelis, A., del Pozo, E. De Cea, De Lotto, B., Mendez, C. Delgado, Ortega, A. Diago, Doert, M., Domínguez, A., Prester, D. Dominis, Dorner, D., Doro, M., Elsaesser, D., Ferenc, D., Fonseca, M. V., Font, L., Fruck, C., López, R. J. García, Garczarczyk, M., Garrido, D., Giavitto, G., Godinović, N., Hadasch, D., Häfner, D., Herrero, A., Hildebrand, D., Höhne-Mönch, D., Hose, J., Hrupec, D., Huber, B., Jogler, T., Klepser, S., Krähenbühl, T., Krause, J., La Barbera, A., Lelas, D., Leonardo, E., Lindfors, E., Lombardi, S., López, M., Lorenz, E., Makariev, M., Maneva, G., Mankuzhiyil, N., Mannheim, K., Maraschi, L., Mariotti, M., Martínez, M., Mazin, D., Meucci, M., Miranda, J. M., Mirzoyan, R., Miyamoto, H., Moldón, J., Moralejo, A., Munar-Adrover, P., Nieto, D., Nilsson, K., Orito, R., Oya, I., Paiano, S., Paneque, D., Paoletti, R., Pardo, S., Paredes, J. M., Partini, S., Pasanen, M., Pauss, F., Perez-Torres, M. A., Persic, M., Peruzzo, L., Pilia, M., Pochon, J., Prada, F., Moroni, P. G. Prada, Prandini, E., Puljak, I., Reichardt, I., Reinthal, R., Rhode, W., Ribó, M., Rico, J., Rügamer, S., Saggion, A., Saito, K., Saito, T. Y., Salvati, M., Satalecka, K., Scalzotto, V., Scapin, V., Schultz, C., Schweizer, T., Shayduk, M., Shore, S. N., Sillanpää, A., Sitarek, J., Sobczynska, D., Spanier, F., Spiro, S., Stamerra, A., Steinke, B., Storz, J., Strah, N., Surić, T., Takalo, L., Takami, H., Tavecchio, F., Temnikov, P., Terzić, T., Tescaro, D., Teshima, M., Thom, M., Tibolla, O., Torres, D. F., Treves, A., Vankov, H., Vogler, P., Wagner, R. M., Weitzel, Q., Zabalza, V., Zandanel, F., Zanin, R., Fornasa, M., Essig, R., Sehgal, N., and Strigari, L. E.
Subjects: Astrophysics - High Energy Astrophysical Phenomena, High Energy Physics - Experiment
Abstract: We report the results of the observation of the nearby satellite galaxy Segue 1 performed by the MAGIC-I ground-based gamma-ray telescope between November 2008 and March 2009 for a total of 43.2 hours. No significant gamma-ray emission was found above the background. Differential upper limits on the gamma-ray flux are derived assuming various power-law slopes for the possible emission spectrum. Integral upper limits are also calculated for several power-law spectra and for different energy thresholds. The values are of the order of 10^{-11} ph cm^{-2}$ s^{-1} above 100 GeV and 10^{-12} ph cm^{-2} s^{-1} above 200 GeV. Segue 1 is currently considered one of the most interesting targets for indirect dark matter searches. In these terms, the upper limits have been also interpreted in the context of annihilating dark matter particles. For such purpose, we performed a grid scan over a reasonable portion of the parameter space for the minimal SuperGravity model and computed the flux upper limit for each point separately, taking fully into account the peculiar spectral features of each model. We found that in order to match the experimental upper limits with the model predictions, a minimum flux boost of 10^{3} is required, and that the upper limits are quite dependent on the shape of the gamma-ray energy spectrum predicted by each specific model. Finally we compared the upper limits with the predictions of some dark matter models able to explain the PAMELA rise in the positron ratio, finding that Segue 1 data are in tension with the dark matter explanation of the PAMELA spectrum in the case of a dark matter candidate annihilating into tau+tau-. A complete exclusion however is not possible due to the uncertainties in the Segue 1 astrophysical factor., Comment: 26 pages, 10 figures. Matched to published version
Published: 2011
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122. MAGIC discovery of VHE Emission from the FSRQ PKS 1222+21

Author: Aleksić, J., Antonelli, L., Antoranz, P., Backes, M., Barrio, J., Bastieri, D., González, J. Becerra, Bednarek, W., Berdyugin, A., Berger, K., Bernardini, E., Biland, A., Blanch, O., Bock, R., Boller, A., Bonnoli, G., Tridon, D. Borla, Braun, I., Bretz, Dr. Thomas, Cañellas, A., Carmona, E., Carosi, A., Colin, P., Colombo, E., Contreras, J., Cortina, J., Cossio, L., Covino, S., Dazzi, F., De Angelis, A., del Pozo, E. De Cea, De Lotto, Dr. Barbara, Mendez, Dr. Carlos Delgado, Ortega, A. Diago, Doert, M., Domìnguez, A., Prester, D. Dominis, Dorner, D., Doro, M., Elsaesser, D., Ferenc, D., Fonseca, M., Font, L., Fruck, C., Lòpez, R. Garcìa, Garczarczyk, M., Garrido, D., Giavitto, G., Godinović, N., Hadasch, D., Häfner, D., Herrero, A., Hildebrand, D., Höhne-Mönch, D., Hose, J., Hrupec, D., Huber, B., Jogler, T., Klepser, S., Krahenbuhl, T., Krause, J., La Barbera, A., Lelas, D., Leonardo, E., Lindfors, E., Lombardi, S., López, M., Lorenz, E., Makariev, M., Maneva, G., Mankuzhiyil, N., Mannheim, K., Maraschi, L., Mariotti, M., Martínez, M., Mazin, Dr. Daniel, Meucci, M., Miranda, J., Mirzoyan, R., Miyamoto, H., Moldón, Mr. Javier, Moralejo, A., Nieto, D., Nilsson, Dr. Kari, Orito, R., Oya, I., Paneque, D., Paoletti, R., Pardo, S., Paredes, J., Partini, S., Pasanen, M., Pauss, F., Perez-Torres, M., Persic, Dr. Massimo, Peruzzo, L., Pilia, M., Pochon, J., Prada, F., Moroni, Dr. P. G. Prada, Prandini, E., Puljak, I., Reichardt, I., Reinthal, R., Rhode, W., Ribó, Marc, Rico, Dr. Javier, Rügamer, S., Saggion, A., Saito, Mr. Koji, Saito, T., Salvati, M., Satalecka, K., Scalzotto, V., Scapin, V., Schultz, C., Schweizer, T., Shayduk, M., Shore, S., Sillanpää, A., Sitarek, J., Sobczynska, D., Spanier, F., Spiro, S., Stamerra, A., Steinke, B., Storz, J., Strah, N., Surić, T., Takalo, L., Tavecchio, F., Temnikov, P., Terzić, T., Tescaro, D., Teshima, M., Thom, M., Tibolla, O., Perez-Torres, Dr. Miguel-Angel, Treves, A., Vankov, H., Vogler, P., Wagner, R., Weitzel, Q., Zabalza, V., Zandanel, F., Zanin, R., Tanaka, Y., Wood, D., and Buson, S.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: Very High Energy (VHE) gamma-ray emission from the flat spectrum radio quasar (FSRQ) PKS 1222+21 (4C 21.35, z=0.432) was detected with the MAGIC Cherenkov telescopes during a short observation (~0.5 hr) performed on 2010 June 17. The MAGIC detection coincides with high energy MeV/GeV gamma-ray activity measured by the Large Area Telescope (LAT) on board the Fermi satellite. The VHE spectrum measured by MAGIC extends from about 70 GeV up to at least 400 GeV and can be well described by a power law dN/dE \propto E^-Gamma with a photon index Gamma= 3.75+/-0.27stat +/-0.2syst. The averaged integral flux above 100 GeV is (4.56+/-0.46)x10^(-10) cm^-2 s^-1 (~1 Crab Nebula flux). The VHE flux measured by MAGIC varies significantly within the 30 min exposure implying a flux doubling time of about 10 min. The VHE and MeV/GeV spectra, corrected for the absorption by the extragalactic background light (EBL), can be described by a single power law with photon index 2.72+/-0.34 between 3 GeV and 400 GeV, and is consistent with emission belonging to a single component in the jet. The absence of a spectral cutoff constrains the gamma-ray emission region outside the Broad Line Region, which would otherwise absorb the VHE gamma-rays. Together with the detected fast variability, this challenges present emission models from jets in FSRQ. Moreover, the combined Fermi/LAT and MAGIC spectral data yield constraints on the density of the Extragalactic Background Light in the UV-optical to near-infrared range that are compatible with recent models., Comment: 6 pages, 5 figure
Published: 2011
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123. PG 1553+113: five years of observations with MAGIC

Author: MAGIC Collaboration, Aleksić, J., Alvarez, E. A., Antonelli, L. A., Antoranz, P., Asensio, M., Backes, M., Barrio, J. A., Bastieri, D., González, J. Becerra, Bednarek, W., Berdyugin, A., Berger, K., Bernardini, E., Biland, A., Blanch, O., Bock, R. K., Boller, A., Bonnoli, G., Tridon, D. Borla, Braun, I., Bretz, T., Cañellas, A., Carmona, E., Carosi, A., Colin, P., Colombo, E., Contreras, J. L., Cortina, J., Cossio, L., Covino, S., Dazzi, F., De Angelis, A., De Caneva, G., del Pozo, E. De Cea, De Lotto, B., Mendez, C. Delgado, Ortega, A. Diago, Doert, M., Domínguez, A., Prester, D. Dominis, Dorner, D., Doro, M., Elsaesser, D., Ferenc, D., Fonseca, M. V., Font, L., Fruck, C., López, R. J. García, Garczarczyk, M., Garrido, D., Giavitto, G., Godinović, N., Hadasch, D., Häfner, D., Herrero, A., Hildebrand, D., Höhne-Mönch, D., Hose, J., Hrupec, D., Huber, B., Jogler, T., Kellermann, H., Klepser, S., Krähenbühl, T., Krause, J., La Barbera, A., Lelas, D., Leonardo, E., Lindfors, E., Lombardi, S., López, M., López-Oramas, A., Lorenz, E., Makariev, M., Maneva, G., Mankuzhiyil, N., Mannheim, K., Maraschi, L., Mariotti, M., Martínez, M., Mazin, D., Meucci, M., Miranda, J. M., Mirzoyan, R., Miyamoto, H., Moldón, J., Moralejo, A., Munar-Adrover, P., Nieto, D., Nilsson, K., Orito, R., Oya, I., Paneque, D., Paoletti, R., Pardo, S., Paredes, J. M., Partini, S., Pasanen, M., Pauss, F., Perez-Torres, M. A., Persic, M., Peruzzo, L., Pilia, M., Pochon, J., Prada, F., Moroni, P. G. Prada, Prandini, E., Puljak, I., Reichardt, I., Reinthal, R., Rhode, W., Ribó, M., Rico, J., Rügamer, S., Saggion, A., Saito, K., Saito, T. Y., Salvati, M., Satalecka, K., Scalzotto, V., Scapin, V., Schultz, C., Schweizer, T., Shayduk, M., Shore, S. N., Sillanpää, A., Sitarek, J., Sobczynska, D., Spanier, F., Spiro, S., Stamatescu, V., Stamerra, A., Steinke, B., Storz, J., Strah, N., Surić, T., Takalo, L., Takami, H., Tavecchio, F., Temnikov, P., Terzić, T., Tescaro, D., Teshima, M., Tibolla, O., Torres, D. F., Treves, A., Uellenbeck, M., Vankov, H., Vogler, P., Wagner, R. M., Weitzel, Q., Zabalza, V., Zandanel, F., Zanin, R., Buson, S., Horan, D., Larsson, S., and D'Ammando, F.
Subjects: Astrophysics - Cosmology and Nongalactic Astrophysics, Astrophysics - High Energy Astrophysical Phenomena
Abstract: We present the results of five years (2005-2009) of MAGIC observations of the BL Lac object PG 1553+113 at very high energies (VHEs, E > 100 GeV). Power law fits of the individual years are compatible with a steady mean photon index \Gamma = 4.27 $\pm$ 0.14. In the last three years of data, the flux level above 150 GeV shows a clear variability (probability of constant flux < 0.001%). The flux variations are modest, lying in the range from 4% to 11% of the Crab Nebula flux. Simultaneous optical data also show only modest variability that seems to be correlated with VHE gamma ray variability. We also performed a temporal analysis of (all available) simultaneous Fermi/LAT data of PG 1553+113 above 1 GeV, which reveals hints of variability in the 2008-2009 sample. Finally, we present a combination of the mean spectrum measured at very high energies with archival data available for other wavelengths. The mean spectral energy distribution can be modeled with a one-zone Synchrotron Self Compton (SSC) model, which gives the main physical parameters governing the VHE emission in the blazar jet., Comment: 11 pages, 6 figures, accepted for publication in ApJ
Published: 2011
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124. MAGIC observations and multiwavelength properties of the quasar 3C279 in 2007 and 2009

Author: The MAGIC Collaboration, Aleksić, J., Antonelli, L. A., Antoranz, P., Backes, M., Barrio, J. A., Bastieri, D., González, J. Becerra, Bednarek, W., Berdyugin, A., Berger, K., Bernardini, E., Biland, A., Blanch, O., Bock, R. K., Boller, A., Bonnoli, G., Tridon, D. Borla, Braun, I., Bretz, T., Canellas, A., Carmona, E., Carosi, A., Colin, P., Colombo, E., Contreras, J. L., Cortina, J., Cossio, L., Covino, S., Dazzi, F., De Angelis, A., del Pozo, E. De Cea, De Lotto, B., Mendez, C. Delgado, Ortega, A. Diago, Doert, M., Dominguez, A., Prester, D. Dominis, Dorner, D., Doro, M., Elsaesser, D., Ferenc, D., Fonseca, M. V., Font, L., Fruck, C., López, R. J. Garcia, Garczarczyk, M., Garrido, D., Giavitto, G., Godinović, N., Hadasch, D., Häfner, D., Herrero, A., Hildebrand, D., Hose, J., Hrupec, D., Huber, B., Jogler, T., Klepser, S., Krähenbühl, T., Krause, J., La Barbera, A., Lelas, D., Leonardo, E., Lindfors, E., Lombardi, S., López, M., Lorenz, E., Majumdar, P., Makariev, M., Maneva, G., Mankuzhiyil, N., Mannheim, K., Maraschi, L., Mariotti, M., Martinez, M., Mazin, D., Meucci, M., Miranda, J. M., Mirzoyan, R., Miyamoto, H., Moldón, J., Moralejo, A., Nieto, D., Nilsson, K., Orito, R., Oya, I., Paoletti, R., Pardo, S., Paredes, J. M., Partini, S., Pasanen, M., Pauss, F., Perez-Torres, M. A., Persic, M., Peruzzo, L., Pilia, M., Pochon, J., Prada, F., Moroni, P. G. Prada, Prandini, E., Puljak, I., Reichardt, I., Reinthal, R., Rhode, W., Ribó, M., Rico, J., Rügamer, S., Rüger, M., Saggion, A., Saito, K., Saito, T. Y., Salvati, M., Satalecka, K., Scalzotto, V., Scapin, V., Schultz, C., Schweizer, T., Shayduk, M., Shore, S. N., Sillapää, A., Sitarek, J., Sobczynska, D., Spanier, F., Spiro, S., Stamerra, A., Steinke, B., Storz, J., Strah, N., Surić, T., Takalo, L., Tavecchio, F., Temnikov, P., Terzić, T., Tescaro, D., Teshima, M., Thom, M., Tibolla, O., Torres, D. F., Treves, A., Vankov, H., Vogler, P., Wagner, R. M., Weitzel, Q., Zabalza, V., Zandanel, F., and Zanin, R.
Subjects: Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract: Context. 3C 279, the first quasar discovered to emit VHE gamma-rays by the MAGIC telescope in 2006, was reobserved by MAGIC in January 2007 during a major optical flare and from December 2008 to April 2009 following an alert from the Fermi space telescope on an exceptionally high gamma -ray state. Aims. The January 2007 observations resulted in a detection on January 16 with significance 5.2 sigma, corresponding to a F(> 150 GeV) (3.8 \pm 0.8) \cdot 10^-11 ph cm^-2 s^-1 while the overall data sample does not show significant signal. The December 2008 - April 2009 observations did not detect the source. We study the multiwavelength behavior of the source at the epochs of MAGIC observations, collecting quasi-simultaneous data at optical and X-ray frequencies and for 2009 also gamma-ray data from Fermi. Methods. We study the light curves and spectral energy distribution of the source. The spectral energy distributions of three observing epochs (including the February 2006, which has been previously published in Albert et al. 2008a) are modeled with one-zone inverse Compton models and the emission on January 16, 2007 also with two zone model and with a lepto-hadronic model. Results. We find that the VHE gamma-ray emission detected in 2006 and 2007 challenges standard one-zone model, based on relativistic electrons in a jet scattering broad line region photons, while the other studied models fit the observed spectral energy distribution more satisfactorily., Comment: accepted to A&A, 12 pages, 11 figures
Published: 2011
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125. Spectral Energy Distribution of Markarian 501: Quiescent State vs. Extreme Outburst

Author: The VERITAS Collaboration, Acciari, V. A., Arlen, T., Aune, T., Beilicke, M., Benbow, W., Böttcher, M., Boltuch, D., Bradbury, S. M., Buckley, J. H., Bugaev, V., Cannon, A., Cesarini, A., Ciupik, L., Cui, W., Dickherber, R., Duke, C., Errando, M., Falcone, A., Finley, J. P., Finnegan, G., Fortson, L., Furniss, A., Galante, N., Gall, D., Godambe, S., Grube, J., Guenette, R., Gyuk, G., Hanna, D., Holder, J., Huang, D., Hui, C. M., Humensky, T. B., Imran, A., Kaaret, P., Karlsson, N., Kertzman, M., Kieda, D., Konopelko, A., Krawczynski, H., Krennrich, F., Madhavan, A. S, Maier, G., McArthur, S., McCann, A., Moriarty, P., Ong, R. A., Otte, A. N., Pandel, D., Perkins, J. S., Pichel, A., Pohl, M., Quinn, J., Ragan, K., Reyes, L. C., Reynolds, P. T., Roache, E., Rose, H. J., Schroedter, M., Sembroski, G. H., Steele, D., Swordy, S. P., Theiling, M., Thibadeau, S., Varlotta, A., Vassiliev, V. V., Vincent, S., Wakely, S. P., Ward, J. E., Weekes, T. C., Weinstein, A., Weisgarber, T., Williams, D. A., Wood, M., Zitzer, B., Collaboration, The MAGIC, Aleksić, J., Antonelli, L. A., Antoranz, P., Backes, M., Barrio, J. A., Bastieri, D., González, J. Becerra, Bednarek, W., Berdyugin, A., Berger, K., Bernardini, E., Biland, A., Blanch, O., Bock, R. K., Boller, A., Bonnoli, G., Bordas, P., Tridon, D. Borla, Bosch-Ramon, V., Bose, D., Braun, I., Bretz, T., Camara, M., Carmona, E., Carosi, A., Colin, P., Colombo, E., Contreras, J. L., Cortina, J., Covino, S., Dazzi, F., De Angelis, A., del Pozo, E. De Cea, De Lotto, B., De Maria, M., De Sabata, F., Mendez, C. Delgado, Ortega, A. Diago, Doert, M., Domínguez, A., Prester, D. Dominis, Dorner, D., Doro, M., Elsaesser, D., Ferenc, D., Fonseca, M. V., Font, L., López, R. J. García, Garczarczyk, M., Gaug, M., Giavitto, G., Godinović, N., Hadasch, D., Herrero, A., Hildebrand, D., Höhne-Mönch, D., Hose, J., Hrupec, D., Jogler, T., Klepser, S., Krähenbühl, T., Kranich, D., Krause, J., La Barbera, A., Leonardo, E., Lindfors, E., Lombardi, S., Longo, F., López, M., Lorenz, E., Majumdar, P., Makariev, M., Maneva, G., Mankuzhiyil, N., Mannheim, K., Maraschi, L., Mariotti, M., Martínez, M., Mazin, D., Meucci, M., Miranda, J. M., Mirzoyan, R., Miyamoto, H., Moldón, J., Moralejo, A., Nieto, D., Nilsson, K., Orito, R., Oya, I., Paoletti, R., Paredes, J. M., Partini, S., Pasanen, M., Pauss, F., Pegna, R. G., Perez-Torres, M. A., Persic, M., Peruzzo, L., Pochon, J., Prada, F., Moroni, P. G. Prada, Prandini, E., Puchades, N., Puljak, I., Reichardt, I., Reinthal, R., Rhode, W., Ribó, M., Rico, J., Rissi, M., Rügamer, S., Saggion, A., Saito, K., Saito, T. Y., Salvati, M., Sánchez-Conde, M., Satalecka, K., Scalzotto, V., Scapin, V., Schultz, C., Schweizer, T., Shayduk, M., Shore, S. N., Sierpowska-Bartosik, A., Sillanpää, A., Sitarek, J., Sobczynska, D., Spanier, F., Spiro, S., Stamerra, A., Steinke, B., Storz, J., Strah, N., Struebig, J. C., Suric, T., Takalo, L., Tavecchio, F., Temnikov, P., Terzić, T., Tescaro, D., Teshima, M., Torres, D. F., Vankov, H., Wagner, R. M., Weitzel, Q., Zabalza, V., Zandanel, F., Zanin, R., Paneque, D., and Hayashida, M.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: The very high energy (VHE; E > 100 GeV) blazar Markarian 501 has a well-studied history of extreme spectral variability and is an excellent laboratory for studying the physical processes within the jets of active galactic nuclei. However, there are few detailed multiwavelength studies of Markarian 501 during its quiescent state, due to its low luminosity. A short-term multiwavelength study of Markarian 501 was coordinated in March 2009, focusing around a multi-day observation with the Suzaku X-ray satellite and including {\gamma}-ray data from VERITAS, MAGIC, and the Fermi Gamma-ray Space Telescope with the goal of providing a well-sampled multiwavelength baseline measurement of Markarian 501 in the quiescent state. The results of these quiescent-state observations are compared to the historically extreme outburst of April 16, 1997, with the goal of examining variability of the spectral energy distribution between the two states. The derived broadband spectral energy distribution shows the characteristic double-peaked profile. We find that the X-ray peak shifts by over two orders of magnitude in photon energy between the two flux states while the VHE peak varies little. The limited shift in the VHE peak can be explained by the transition to the Klein-Nishina regime. Synchrotron self-Compton models are matched to the data and the implied Klein-Nishina effects are explored., Comment: Accepted for publication in ApJ, 25 pages, 6 figures, corresponding authors: Daniel Gall daniel-d-gall@uiowa.edu and Wei Cui cui@purdue.edu
Published: 2010
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126. Observations of the Blazar 3C 66A with the MAGIC Telescopes in Stereoscopic Mode

Author: The MAGIC Collaboration, Aleksić, J., Antonelli, L. A., Antoranz, P., Backes, M., Barrio, J. A., Bastieri, D., González, J. Becerra, Bednarek, W., Berdyugin, A., Berger, K., Bernardini, E., Biland, A., Blanch, O., Bock, R. K., Boller, A., Bonnoli, G., Bordas, P., Tridon, D. Borla, Bosch-Ramon, V., Bose, D., Braun, I., Bretz, T., Camara, M., Cañellas, A., Carmona, E., Carosi, A., Colin, P., Colombo, E., Contreras, J. L., Cortina, J., Cossio, L., Covino, S., Dazzi, F., De Angelis, A., del Pozo, E. De Cea, De Lotto, B., De Maria, M., De Sabata, F., Mendez, C. Delgado, Ortega, A. Diago, Doert, M., Domínguez, A., Prester, D. Dominis, Dorner, D., Doro, M., Elsaesser, D., Errando, M., Ferenc, D., Fonseca, M. V., Font, L., López, R. J. García, Garczarczyk, M., Garrido, D., Giavitto, G., Godinović, N., Hadasch, D., Herrero, A., Hildebrand, D., Höhne-Mönch, D., Hose, J., Hrupec, D., Huber, B., Jogler, T., Klepser, S., Krähenbühl, T., Kranich, D., Krause, J., La Barbera, A., Lelas, D., Leonardo, E., Lindfors, E., Lombardi, S., Longo, F., López, M., Lorenz, E., Majumdar, P., Makariev, M., Maneva, G., Mankuzhiyil, N., Mannheim, K., Maraschi, L., Mariotti, M., Martínez, M., Mazin, D., Meucci, M., Miranda, J. M., Mirzoyan, R., Miyamoto, H., Moldón, J., Moralejo, A., Nieto, D., Nilsson, K., Orito, R., Oya, I., Paoletti, R., Pardo, S., Paredes, J. M., Partini, S., Pasanen, M., Pauss, F., Pegna, R. G., Perez-Torres, M. A., Persic, M., Peruzzo, L., Pochon, J., Prada, F., Moroni, P. G. Prada, Prandini, E., Puchades, N., Puljak, I., Reichardt, I., Reinthal, R., Rhode, W., Ribó, M., Rico, J., Rügamer, S., Saggion, A., Saito, K., Saito, T. Y., Salvati, M., Sánchez-Conde, M., Satalecka, K., Scalzotto, V., Scapin, V., Schultz, C., Schweizer, T., Shayduk, M., Shore, S. N., Sierpowska-Bartosik, A., Sillanpää, A., Sitarek, J., Sobczynska, D., Spanier, F., Spiro, S., Stamerra, A., Steinke, B., Storz, J., Strah, N., Struebig, J. C., Surić, T., Takalo, L., Tavecchio, F., Temnikov, P., Terzić, T., Tescaro, D., Teshima, M., Thom, M., Torres, D. F., Vankov, H., Vogler, P., Wagner, R. M., Weitzel, Q., Zabalza, V., Zandanel, F., and Zanin, R.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: We report new observations of the intermediate-frequency peaked BL Lacertae object 3C 66A with the MAGIC telescopes. The data sample we use were taken in 2009 December and 2010 January, and comprises 2.3 hr of good quality data in stereoscopic mode. In this period, we find a significant signal from the direction of the blazar 3C 66A. The new MAGIC stereoscopic system is shown to play an essential role for the separation between 3C 66A and the nearby radio galaxy 3C 66B, which is at a distance of only $6^\prime$. The derived integral flux above $100\eh{GeV}$ is 8.3% of Crab Nebula flux and the energy spectrum is reproduced by a power law of photon index $3.64 \pm 0.39_{\rm stat} \pm 0.25_{\rm sys}$. Within errors, this is compatible with the one derived by VERITAS in 2009. From the spectra corrected for absorption by the extragalactic background light, we only find small differences between the four models that we applied, and constrain the redshift of the blazar to $z < 0.68$., Comment: Accepted for publication in ApJ
Published: 2010
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127. Detection of very high energy gamma-ray emission from the Perseus cluster head-tail galaxy IC 310 by the MAGIC telescopes

Author: MAGIC Collaboration, Aleksić, J., Antonelli, L. A., Antoranz, P., Backes, M., Barrio, J. A., Bastieri, D., González, J. Becerra, Bednarek, W., Berdyugin, A., Berger, K., Bernardini, E., Biland, A., Blanch, O., Bock, R. K., Boller, A., Bonnoli, G., Bordas, P., Tridon, D. Borla, Bosch-Ramon, V., Bose, D., Braun, I., Bretz, T., Camara, M., Cañellas, A., Carmona, E., Carosi, A., Colin, P., Colombo, E., Contreras, J. L., Cossio, L., Cortina, J., Covino, S., Dazzi, F., De Angelis, A., del Pozo, E. De Cea, De Lotto, B., De Maria, M., De Sabata, F., Mendez, C. Delgado, Ortega, A. Diago, Doert, M., Domínguez, A., Prester, D. Dominis, Dorner, D., Doro, M., Elsaesser, D., Errando, M., Ferenc, D., Fonseca, M. V., Font, L., López, R. J. García, Garczarczyk, M., Giavitto, G., Godinović, N., Hadasch, D., Herrero, A., Hildebrand, D., Höhne-Mönch, D., Hose, J., Hrupec, D., Jogler, T., Klepser, S., Krähenbühl, T., Kranich, D., Krause, J., La Barbera, A., Leonardo, E., Lindfors, E., Lombardi, S., Longo, F., López, M., Lorenz, E., Majumdar, P., Makariev, M., Maneva, G., Mankuzhiyil, N., Mannheim, K., Maraschi, L., Mariotti, M., Martínez, M., Mazin, D., Meucci, M., Miranda, J. M., Mirzoyan, R., Miyamoto, H., Moldón, J., Moralejo, A., Nieto, D., Nilsson, K., Orito, R., Oya, I., Paoletti, R., Paredes, J. M., Partini, S., Pasanen, M., Pauss, F., Pegna, R. G., Perez-Torres, M. A., Persic, M., Peruzzo, L., Pochon, J., Prada, F., Moroni, P. G. Prada, Prandini, E., Puchades, N., Puljak, I., Reichardt, I., Reinthal, R., Rhode, W., Ribó, M., Rico, J., Rügamer, S., Saggion, A., Saito, K., Saito, T. Y., Salvati, M., Sánchez-Conde, M., Satalecka, K., Scalzotto, V., Scapin, V., Schultz, C., Schweizer, T., Shayduk, M., Shore, S. N., Sierpowska-Bartosik, A., Sillanpää, A., Sitarek, J., Sobczynska, D., Spanier, F., Spiro, S., Stamerra, A., Steinke, B., Storz, J., Strah, N., Struebig, J. C., Suric, T., Takalo, L., Tavecchio, F., Temnikov, P., Terzić, T., Tescaro, D., Teshima, M., Torres, D. F., Vankov, H., Wagner, R. M., Weitzel, Q., Zabalza, V., Zandanel, F., Zanin, R., Neronov, A., Pfrommer, C., Pinzke, A., and Semikoz, D. V.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: We report on the detection with the MAGIC telescopes of very high energy gamma-rays from IC 310, a head-tail radio galaxy in the Perseus galaxy cluster, observed during the interval November 2008 to February 2010. The Fermi satellite has also detected this galaxy. The source is detected by MAGIC at a high statistical significance of 7.6sigma in 20.6 hr of stereo data. The observed spectral energy distribution is flat with a differential spectral index of -2.00 \pm 0.14. The mean flux above 300 GeV, between October 2009 and February 2010, (3.1 \pm 0.5)x10^{-12} cm^{-2} s^{-1}, corresponds to (2.5 \pm 0.4)% of Crab Nebula units. Only an upper limit, of 1.9% of Crab Nebula units above 300 GeV, was obtained with the 2008 data. This, together with strong hints (>3sigma) of flares in the middle of October and November 2009, implies that the emission is variable. The MAGIC results favour a scenario with the very high energy emission originating from the inner jet close to the central engine. More complicated models than a simple one-zone SSC scenario, e.g. multi-zone SSC, external Compton or hadronic, may be required to explain the very flat spectrum and its extension over more than three orders of magnitude in energy., Comment: 6 pages, 5 figures, submitted to ApJL
Published: 2010
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128. MAGIC Upper Limits for two Milagro-detected, Bright Fermi Sources in the Region of SNR G65.1+0.6

Author: Aleksić, J., Antonelli, L. A., Antoranz, P., Backes, M., Barrio, J. A., Bastieri, D., González, J. Becerra, Bednarek, W., Berdyugin, A., Berger, K., Bernardini, E., Biland, A., Blanch, O., Bock, R. K., Boller, A., Bonnoli, G., Bordas, P., Tridon, D. Borla, Bosch-Ramon, V., Bose, D., Braun, I., Bretz, T., Camara, M., Carmona, E., Carosi, A., Colin, P., Contreras, J. L., Cortina, J., Covino, S., Dazzi, F., De Angelis, A., del Pozo, E. De Cea, De Lotto, B., De Maria, M., De Sabata, F., DelgadoMendez, C., Ortega, A. Diago, Doert, M., Domínguez, A., Prester, D. Dominis, Dorner, D., Doro, M., Elsaesser, D., Errando, M., Ferenc, D., Fonseca, M. V., Font, L., López, R. J. García, Garczarczyk, M., Gaug, M., Giavitto, G., Godinović, N., Hadasch, D., Herrero, A., Hildebrand, D., Höhne-Mönch, D., Hose, J., Hrupec, D., Jogler, T., Klepser, S., Krähenbühl, T., Kranich, D., Krause, J., La Barbera, A., Leonardo, E., Lindfors, E., Lombardi, S., Longo, F., López, M., Lorenz, E., Majumdar, P., Maneva, G., Mankuzhiyil, N., Mannheim, K., Maraschi, L., Mariotti, M., Martínez, M., Mazin, D., Meucci, M., Miranda, J. M., Mirzoyan, R., Miyamoto, H., Moldón, J., Moralejo, A., Nieto, D., Nilsson, K., Orito, R., Oya, I., Paoletti, R., Paredes, J. M., Partini, S., Pasanen, M., Pauss, F., Pegna, R. G., Perez-Torres, M. A., Persic, M., Peruzzo, L., Pochon, J., Prada, F., Moroni, P. G. Prada, Prandini, E., Puchades, N., Puljak, I., Reichardt, I., Reinthal, R., Rhode, W., Ribó, M., Rico, J., Rissi, M., Rügamer, S., Saggion, A., Saito, K., Saito, T. Y., Salvati, M., Sánchez-Conde, M., Satalecka, K., Scalzotto, V., Scapin, V., Schultz, C., Schweizer, T., Shayduk, M., Shore, S. N., Sierpowska-Bartosik, A., Sillanpää, A., Sitarek, J., Sobczynska, D., Spanier, F., Spiro, S., Stamerra, A., Steinke, B., Storz, J., Strah, N., Struebig, J. C., Suric, T., Takalo, L., Tavecchio, F., Temnikov, P., Terzić, T., Tescaro, D., Teshima, M., Torres, D. F., Vankov, H., Wagner, R. M., Weitzel, Q., Zabalza, V., Zandanel, F., and Zanin, R.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: We report on the observation of the region around supernova remnant G65.1+0.6 with the stand-alone MAGIC-I telescope. This region hosts the two bright GeV gamma-ray sources 1FGL J1954.3+2836 and 1FGL J1958.6+2845. They are identified as GeV pulsars and both have a possible counterpart detected at about 35 TeV by the Milagro observatory. MAGIC collected 25.5 hours of good quality data, and found no significant emission in the range around 1 TeV. We therefore report differential flux upper limits, assuming the emission to be point-like (<0.1 deg) or within a radius of 0.3 deg. In the point-like scenario, the flux limits around 1 TeV are at the level of 3 % and 2 % of the Crab Nebula flux, for the two sources respectively. This implies that the Milagro emission is either extended over a much larger area than our point spread function, or it must be peaked at energies beyond 1 TeV, resulting in a photon index harder than 2.2 in the TeV band., Comment: 8 pages, 3 figures, 1 table
Published: 2010
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129. The exotic fraction among unassociated Fermi sources

Author: Mirabal, N., Nieto, D., and Pardo, S.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: Revealing the nature of unassociated high-energy (> 100 MeV) gamma-ray sources remains a challenge 35 years after their discovery. Of the 934 gamma-ray sources at high Galactic latitude (|b| > 15 degrees) in the First Fermi-LAT catalogue (1FGL), 316 have no obvious associations at other wavelengths. In this paper, we apply the K-means unsupervised classification algorithm to isolate potential counterparts for 18 unassociated Fermi sources contained within a 3000 square degree `overlap region' of the sky intensively covered in radio and optical wavelengths. Combining our results with previous works, we reach potential associations for 119 out of the 128 Fermi sources within said region. If these associations are correct, we estimate that less than 20% of all remaining unassociated 1FGL sources at high Galactic latitude (|b| > 15 degrees) might host `exotic' counterparts distinct from known classes of gamma-ray emitters. Potentially even these outliers could be explained by high-redshift/dust-obscured analogues of the associated sample or by intrinsically faint radio objects. Although such estimate leaves some room for novel discoveries, it severely restricts the possibility of detecting dark matter subhaloes and other unconventional types of gamma-ray emitters in the 1FGL. In closing, we argue that the identification of Fermi sources at the low end of the flux density distribution will be a complex process that might only be achieved through a clever combination of refined classification algorithms, multi-wavelength efforts, and dedicated optical spectroscopy., Comment: 7 pages, 5 figures, 2 tables
Published: 2010

130. Magic constraints on Gamma-ray emission from Cygnus X-3

Author: Aleksić, J., Antonelli, L. A., Antoranz, P., Backes, M., Baixeras, C., Barrio, J. A., Bastieri, D., González, J. Becerra, Bednarek, W., Berdyugin, A., Berger, K., Bernardini, E., Biland, A., Blanch, O., Bock, R. K., Boller, A., Bonnoli, G., Bordas, P., Tridon, D. Borla, Bosch-Ramon, V., Bose, D., Braun, I., Bretz, T., Britzger, D., Camara, M., Carmona, E., Carosi, A., Colin, P., Contreras, J. L., Cortina, J., Costado, M. T., Covino, S., Dazzi, F., De Angelis, A., del Pozo, E. De Cea, De Lotto, B., De Maria, M., De Sabata, F., Mendez, C. Delgado, Doert, M., Domínguez, A., Prester, D. Dominis, Dorner, D., Doro, M., Elsaesser, D., Errando, M., Ferenc, D., Fonseca, M. V., Font, L., López, R. J. García, Garczarczyk, M., Gaug, M., Godinovic, N., Göebel, F., Hadasch, D., Herrero, A., Hildebrand, D., Höhne-Mönch, D., Hose, J., Hrupec, D., Hsu, C. C., Jogler, T., Klepser, S., Krähenbühl, T., Kranich, D., La Barbera, A., Laille, A., Leonardo, E., Lindfors, E., Lombardi, S., Longo, F., López, M., Lorenz, E., Majumdar, P., Maneva, G., Mankuzhiyil, N., Mannheim, K., Maraschi, L., Mariotti, M., Martínez, M., Mazin, D., Meucci, M., Miranda, J. M., Mirzoyan, R., Miyamoto, H., Moldón, J., Moles, M., Moralejo, A., Nieto, D., Nilsson, K., Ninkovic, J., Orito, R., Oya, I., Paiano, S., Paoletti, R., Paredes, J. M., Partini, S., Pasanen, M, Pascoli, D., Pauss, F., Pegna, R. G., Perez-Torres, M. A., Persic, M., Peruzzo, L., Prada, F., Prandini, E., Puchades, N., Puljak, I., Reichardt, I., Rhode, W., Ribó, M., Rico, J., Rissi, M, Rügamer, S., Saggion, A., Saito, K., Saito, T. Y., Salvati, M., Sánchez-Conde, M., Satalecka, K., Scalzotto, V., Scapin, V., Schultz, C., Schweizer, T., Shayduk, M., Shore, S. N., Sierpowska-Bartosik, A., Sillanpää, A., Sitarek, J., Sobczynska, D., Spanier, F., Spiro, S., Stamerra, A., Steinke, B., Struebig, J. C., Suric, T., Takalo, L., Tavecchio, F., Temnikov, P., Terzic, T., Tescaro, D., Teshima, M., Torres, D. F., Vankov, H., Wagner, R. M., Weitzel, Q., Zabalza, V., Zandanel, F., Zanin, R., Bulgarelli, A., Max-Moerbeck, W., Piano, G., Pooley, G., Readhead, A. C. S., Richards, J. L., Sabatini, S., Striani, E., Tavani, M., and Trushkin, S.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: Cygnus X-3 is a microquasar consisting of an accreting compact object orbiting around a Wolf-Rayet star. It has been detected at radio frequencies and up to high-energy gamma rays (above 100 MeV). However, many models also predict a very high energy (VHE) emission (above hundreds of GeV) when the source displays relativistic persistent jets or transient ejections. Therefore, detecting such emission would improve the understanding of the jet physics. The imaging atmospheric Cherenkov telescope MAGIC observed Cygnus X-3 for about 70 hours between 2006 March and 2009 August in different X-ray/radio spectral states and also during a period of enhanced gamma-ray emission. MAGIC found no evidence for a VHE signal from the direction of the microquasar. An upper limit to the integral flux for energies higher than 250 GeV has been set to 2.2 x 10-12 photons cm-2 s-1 (95% confidence level). This is the best limit so far to the VHE emission from this source. The non-detection of a VHE signal during the period of activity in the high-energy band sheds light on the location of the possible VHE radiation favoring the emission from the innermost region of the jets, where absorption is significant. The current and future generations of Cherenkov telescopes may detect a signal under precise spectral conditions., Comment: 14 pages, 11 figures, This manuscript has been accepted by ApJ (2010)
Published: 2010
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131. MAGIC observation of the GRB080430 afterglow

Author: MAGIC Collaboration, Aleksić, J., Anderhub, H., Antonelli, L. A., Antoranz, P., Backes, M., Baixeras, C., Balestra, S., Barrio, J. A., Bastieri, D., González, J. Becerra, Becker, J. K., Bednarek, W., Berdyugin, A., Berger, K., Bernardini, E., Biland, A., Bock, R. K., Bonnoli, G., Bordas, P., Tridon, D. Borla, Bosch-Ramon, V., Bose, D., Braun, I., Bretz, T., Britzger, D., Camara, M., Carmona, E., Carosi, A., Colin, P., Commichau, S., Contreras, J. L., Cortina, J., Costado, M. T., Covino, S., Dazzi, F., De Angelis, A., del Pozo, E. de Cea, Reyes, R. De los, De Lotto, B., De Maria, M., De Sabata, F., Mendez, C. Delgado, Doert, M., Domínguez, A., Prester, D. Dominis, Dorner, D., Doro, M., Elsaesser, D., Errando, M., Ferenc, D., Fernández, E., Firpo, R., Fonseca, M. V., Font, L., Galante, N., López, R. J. García, Garczarczyk, M., Gaug, M., Godinovic, N., Goebel, F., Hadasch, D., Herrero, A., Hildebrand, D., Höhne-Mönch, D., Hose, J., Hrupec, D., Hsu, C. C., Jogler, T., Klepser, S., Krähenbühl, T., Kranich, D., La Barbera, A., Laille, A., Leonardo, E., Lindfors, E., Lombardi, S., Longo, F., López, M., Lorenz, E., Majumdar, P., Maneva, G., Mankuzhiyil, N., Mannheim, K., Maraschi, L., Mariotti, M., Martínez, M., Mazin, D., Meucci, M., Miranda, J. M., Mirzoyan, R., Miyamoto, H., Moldón, J., Moles, M., Moralejo, A., Nieto, D., Nilsson, K., Ninkovic, J., Orito, R., Oya, I., Paoletti, R., Paredes, J. M., Pasanen, M., Pascoli, D., Pauss, F., Pegna, R. G., Perez-Torres, M. A., Persic, M., Peruzzo, L., Prada, F., Prandini, E., Puchades, N., Puljak, I., Reichardt, I., Rhode, W., Ribó, M., Rico, J., Rissi, M., Rügamer, S., Saggion, A., Saito, T. Y., Salvati, M., Sánchez-Conde, M., Satalecka, K., Scalzotto, V., Scapin, V., Schweizer, T., Shayduk, M., Shore, S. N., Sierpowska-Bartosik, A., Sillanpää, A., Sitarek, J., Sobczynska, D., Spanier, F., Spiro, S., Stamerra, A., Steinke, B., Strah, N., Struebig, J. C., Suric, T., Takalo, L., Tavecchio, F., Temnikov, P., Tescaro, D., Teshima, M., Torres, D. F., Turini, N., Vankov, H., Wagner, R. M., Zabalza, V., Zandanel, F., Zanin, R., Zapatero, J., and de Ugarte-Postigo, A.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: Context: Gamma-ray bursts are cosmological sources emitting radiation from the gamma-rays to the radio band. Substantial observational efforts have been devoted to the study of gamma-ray bursts during the prompt phase, i.e. the initial burst of high-energy radiation, and during the long-lasting afterglows. In spite of many successes in interpreting these phenomena, there are still several open key questions about the fundamental emission processes, their energetics and the environment. Aim: Independently of specific gamma-ray burst theoretical recipes, spectra in the GeV/TeV range are predicted to be remarkably simple, being satisfactorily modeled with power-laws, and therefore offer a very valuable tool to probe the extragalactic background light distribution. Furthermore, the simple detection of a component at very-high energies, i.e. at $\sim 100$\,GeV, would solve the ambiguity about the importance of various possible emission processes, which provide barely distinguishable scenarios at lower energies. Methods: We used the results of the MAGIC telescope observation of the moderate resdhift ($z\sim0.76$) \object{GRB\,080430} at energies above about 80\,GeV, to evaluate the perspective for late-afterglow observations with ground based GeV/TeV telescopes. Results: We obtained an upper limit of $F_{\rm 95%\,CL} = 5.5 \times 10^{-11}$\,erg\,cm$^{-2}$\,s$^{-1}$ for the very-high energy emission of \object{GRB\,080430}, which cannot set further constraints on the theoretical scenarios proposed for this object also due to the difficulties in modeling the low-energy afterglow. Nonetheless, our observations show that Cherenkov telescopes have already reached the required sensitivity to detect the GeV/TeV emission of GRBs at moderate redshift ($z \lesssim 0.8$), provided the observations are carried out at early times, close to the onset of their afterglow phase., Comment: 6 pages, 1 figure. Astronomy & Astrophysics, in press. Revision affects only the author list.
Published: 2010
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132. Search for an extended VHE gamma-ray emission from Mrk 421 and Mrk 501 with the MAGIC Telescope

Author: MAGIC Collaboration, Aleksić, J., Antonelli, L. A., Antoranz, P., Backes, M., Baixeras, C., Barrio, J. A., Bastieri, D., González, J. Becerra, Bednarek, W., Berdyugin, A., Berger, K., Bernardini, E., Biland, A., Blanch, O., Bock, R. K., Bonnoli, G., Bordas, P., Tridon, D. Borla, Bosch-Ramon, V., Bose, D., Braun, I., Bretz, T., Britzger, D., Camara, M., Carmona, E., Carosi, A., Colin, P., Commichau, S., Contreras, J. L., Cortina, J., Costado, M. T., Covino, S., Dazzi, F., De Angelis, A., del Pozo, E. De Cea, Reyes, R. De los, De Lotto, B., De Maria, M., De Sabata, F., Mendez, C. Delgado, Doert, M., Domínguez, A., Prester, D. Dominis, Dorner, D., Doro, M., Elsaesser, D., Errando, M., Ferenc, D., Fonseca, M. V., Font, L., López, R. J. García, Garczarczyk, M., Gaug, M., Godinovic, N., Hadasch, D., Herrero, A., Hildebrand, D., Höhne-Mönch, D., Hose, J., Hrupec, D., Hsu, C. C., Jogler, T., Klepser, S., Krähenbühl, T., Kranich, D., La Barbera, A., Laille, A., Leonardo, E., Lindfors, E., Lombardi, S., Longo, F., López, M., Lorenz, E., Majumdar, P., Maneva, G., Mankuzhiyil, N., Mannheim, K., Maraschi, L., Mariotti, M., Martínez, M., Mazin, D., Meucci, M., Miranda, J. M., Mirzoyan, R., Miyamoto, H., Moldón, J., Moles, M., Moralejo, A., Nieto, D., Nilsson, K., Ninkovic, J., Orito, R., Oya, I., Paiano, S., Paoletti, R., Paredes, J. M., Partini, S., Pasanen, M., Pascoli, D., Pauss, F., Pegna, R. G., Perez-Torres, M. A., Persic, M., Peruzzo, L., Prada, F., Prandini, E., Puchades, N., Puljak, I., Reichardt, I., Rhode, W., Ribó, M., Rico, J., Rissi, M., Rügamer, S., Saggion, A., Saito, T. Y., Salvati, M., Sánchez-Conde, M., Satalecka, K., Scalzotto, V., Scapin, V., Schultz, C., Schweizer, T., Shayduk, M., Shore, S. N., Sierpowska-Bartosik, A., Sillanpää, A., Sitarek, J., Sobczynska, D., Spanier, F., Spiro, S., Stamerra, A., Steinke, B., Struebig, J. C., Suric, T., Takalo, L., Tavecchio, F., Temnikov, P., Terzic, T., Tescaro, D., Teshima, M., Torres, D. F., Vankov, H., Wagner, R. M., Weitzel, Q., Zabalza, V., Zandanel, F., Zanin, R., Neronov, A., and Semikoz, D. V.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: Context: Part of the very high energy $\gamma$-ray radiation coming from extragalactic sources is absorbed through the pair production process on the extragalactic background light photons. Extragalactic magnetic fields alter the trajectories of these cascade pairs and, in turn, convert cosmic background photons to gamma-ray energies by inverse Compton scattering. These secondary photons can form an extended halo around bright VHE sources. Aims: We searched for an extended emission around the bright blazars Mrk 421 and Mrk 501 using the MAGIC telescope data. Methods: If extended emission is present, the angular distribution of reconstructed gamma-ray arrival directions around the source is broader than for a point-like source. In the analysis of a few tens of hours of observational data taken from Mrk 421 and Mrk 501 we used a newly developed method that provides better angular resolution. This method is based on the usage of multidimensional decision trees. Comparing the measured shapes of angular distributions with those expected from a point-like source one can detect or constrain possible extended emission around the source. We also studied the influence of different types of systematic errors on the shape of the distribution of reconstructed gamma-ray arrival directions for a point source. Results: We present upper limits for an extended emission calculated for both sources for various source extensions and emission profiles. We discuss possible constraints on the extragalactic magnetic fields strength. We obtain upper limits on the extended emission around the Mrk~421 (Mrk~501) on the level of < 5% (< 4%) of the Crab Nebula flux above the energy threshold of 300 GeV. Using these results we discuss possible constraints on the extragalactic magnetic fields strength around a few times $10^{-15}$~G., Comment: 8 pages, 9 figures, accepted for publication in A&A
Published: 2010
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133. Willman 1: An X-ray shot in the dark with Chandra

Author: Nieto, D. and Mirabal, N.
Subjects: Astrophysics - Cosmology and Extragalactic Astrophysics, High Energy Physics - Phenomenology
Abstract: The sterile neutrino is a weakly-interacting particle that emerges in the framework of certain extensions of standard particle physics and that fits naturally with the properties of a warm dark matter particle candidate. We present an analysis of a deep archival Chandra observation of Willman 1, one of the darkest purported ultra-faint dwarf galaxies, that excludes the presence of sterile neutrinos in the 1.6-16 keV mass range within 55 pc of its centre down to the limits of the observation. Spectral analysis of the Chandra data fails to find any non-instrumental spectral feature possibly connected with the radiative decay of a dark matter particle. Accordingly, we establish upper bounds on the sterile neutrino parameter space and discuss it in the context of previous measurements. Regarding the point source population, we identify a total of 26 sources within the central 5 arcminutes to a limiting 0.5-2.0 keV X-ray flux of 6 x 10^{-16} erg cm^{-2} s^{-1}. While some of these sources could be formal members of Willman 1, we find no outstanding evidence for either an unusual population of bright X-ray sources or a densely populated cluster core. In fact, the entire X-ray population could be explained by background active galactic nuclei and/or foreground stars unrelated to Willman 1. Finally, possible associations of the X-ray point like population with optical sources from the SDSS DR7 catalogue are discussed., Comment: 13 pages, 5 figures, 2 tables
Published: 2010

134. Gamma-ray excess from a stacked sample of high- and intermediate-frequency peaked blazars observed with the MAGIC telescope

Author: MAGIC Collaboration, Aleksić, J., Antonelli, L. A., Antoranz, P., Backes, M., Baixeras, C., Barrio, J. A., Bastieri, D., González, J. Becerra, Bednarek, W., Berdyugin, A., Berger, K., Bernardini, E., Biland, A., Blanch, O., Bock, R. K., Bonnoli, G., Bordas, P., Tridon, D. Borla, Bosch-Ramon, V., Bose, D., Braun, I., Bretz, T., Britzger, D., Camara, M., Carmona, E., Carosi, A., Colin, P., Commichau, S., Contreras, J. L., Cortina, J., Costado, M. T., Covino, S., Dazzi, F., De Angelis, A., del Pozo, E. De Cea, Reyes, R. De los, De Lotto, B., De Maria, M., De Sabata, F., Mendez, C. Delgado, Doert, M., Domínguez, A., Prester, D. Dominis, Dorner, D., Doro, M., Elsaesser, D., Errando, M., Ferenc, D., Fonseca, M. V., Font, L., López, R. J. García, Garczarczyk, M., Gaug, M., Godinovic, N., Hadasch, D., Herrero, A., Hildebrand, D., Höhne-Mönch, D., Hose, J., Hrupec, D., Hsu, C. C., Jogler, T., Klepser, S., Krähenbühl, T., Kranich, D., La Barbera, A., Laille, A., Leonardo, E., Lindfors, E., Lombardi, S., Longo, F., López, M., Lorenz, E, Majumdar, P., Maneva, G., Mankuzhiyil, N., Mannheim, K., Maraschi, L., Mariotti, M., Martínez, M., Mazin, D., Meucci, M., Miranda, J. M., Mirzoyan, R., Miyamoto, H., Moldón, J., Moles, M., Moralejo, A., Nieto, D., Nilsson, K., Ninkovic, J., Orito, R., Oya, I., Paiano, S., Paoletti, R., Paredes, J. M., Partini, S., Pasanen, M., Pascoli, D., Pauss, F., Pegna, R. G., Perez-Torres, M. A., Persic, M., Peruzzo, L., Prada, F., Prandini, E., Puchades, N., Puljak, I., Reichardt, I., Rhode, W., Ribó, M., Rico, J., Rissi, M., Rügamer, S., Saggion, A., Saito, T. Y., Salvati, M., Sánchez-Conde, M., Satalecka, K., Scalzotto, V., Scapin, V., Schultz, C., Schweizer, T., Shayduk, M., Shore, S. N., Sierpowska-Bartosik, A., Sillanpää, A., Sitarek, J, Sobczynska, D., Spanier, F., Spiro, S., Stamerra, A., Steinke, B., Struebig, J. C., Suric, T., Takalo, L., Tavecchio, F., Temnikov, P., Terzic, T., Tescaro, D., Teshima, M., Tibolla, O., Torres, D. F., Vankov, H., Wagner, R. M., Weitzel, Q., Zabalza, V, Zandanel, F., and Zanin, R.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: Between 2004 and 2009 a sample of 28 X-ray selected high- and intermediate-frequency peaked blazars with a X-ray flux larger than 2 uJy at 1 keV in the redshift range from 0.018 to 0.361 was observed with the MAGIC telescope at energies above 100 GeV. Seven among them were detected and the results of these observations are discussed elsewhere. Here we concentrate on the remaining 21 blazars which were not detected during this observation campaign and present the 3 sigma (99.7 %) confidence upper limits on their flux. The individual flux upper limits lie between 1.6 % and 13.6 % of the integral flux from the Crab Nebula. Applying a stacking method to the sample of non-detections with a total of 394.1 hours exposure time, we find evidence for an excess with a cumulative significance of 4.9 standard deviations. It is not dominated by individual objects or flares, but increases linearly with the observation time as for a constant source with an integral flux level of ~1.5 % of that observed from the Crab Nebula above 150 GeV., Comment: 14 pages, 6 figures, accepted by ApJ
Published: 2010
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135. MAGIC TeV Gamma-Ray Observations of Markarian 421 during Multiwavelength Campaigns in 2006

Author: MAGIC Collaboration, Aleksić, J., Antonelli, L. A., Antoranz, P., Backes, M., Baixeras, C., Balestra, S., Barrio, J. A., Bastieri, D., González, J. Becerra, Bednarek, W., Berdyugin, A., Berger, K., Bernardini, E., Biland, A., Bock, R. K., Bonnoli, G., Bordas, P., Tridon, D. Borla, Bosch-Ramon, V., Bose, D., Braun, I., Bretz, T., Britzger, D., Camara, M., Carmona, E., Carosi, A., Colin, P., Commichau, S., Contreras, J. L., Cortina, J., Costado, M. T., Covino, S., Dazzi, F., De Angelis, A., del Pozo, E. De Cea, Mendez, C. Delgado, Reyes, R. De los, De Lotto, B., De Maria, M., De Sabata, F., Doert, M., Domínguez, A., Prester, D. Dominis, Dorner, D., Doro, M., Elsaesser, D., Errando, M., Ferenc, D., Fonseca, M. V., Font, L., López, R. J. García, Garczarczyk, M., Gaug, M., Godinovic, N., Hadasch, D., Herrero, A., Hildebrand, D., Höhne-Mönch, D., Hose, J., Hrupec, D., Hsu, C. C., Jogler, T., Klepser, S., Krähenbühl, T., Kranich, D., La Barbera, A., Laille, A., Leonardo, E., Lindfors, E., Lombardi, S., Longo, F., López, M., Lorenz, E., Majumdar, P., Maneva, G., Mankuzhiyil, N., Mannheim, K., Maraschi, L., Mariotti, M., Martínez, M., Mazin, D., Meucci, M., Miranda, J. M., Mirzoyan, R., Miyamoto, H., Moldón, J., Moles, M., Moralejo, A., Nieto, D., Nilsson, K., Ninkovic, J., Orito, R., Oya, I., Paiano, S., Paoletti, R., Paredes, J. M., Partini, S., Pasanen, M., Pascoli, D., Pauss, F., Pegna, R. G., Perez-Torres, M. A., Persic, M., Peruzzo, L., Prada, F., Prandini, E., Puchades, N., Puljak, I., Reichardt, I., Rhode, W., Ribó, M., Rico, J., Rissi, M., Rügamer, S., Saggion, A., Saito, T. Y., Salvati, M., Sánchez-Conde, M., Satalecka, K., Scalzotto, V., Scapin, V., Schultz, C., Schweizer, T., Shayduk, M., Shore, S. N., Sierpowska-Bartosik, A., Sillanpää, A., Sitarek, J., Sobczynska, D., Spanier, F., Spiro, S., Stamerra, A., Steinke, B., Struebig, J. C., Suric, T., Takalo, L., Tavecchio, F., Temnikov, P., Terzic, T., Tescaro, D., Teshima, M., Torres, D. F., Vankov, H., Wagner, R. M., Zabalza, V., Zandanel, F., and Zanin, R.
Subjects: Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract: The Major Atmospheric Gamma Imaging Cerenkov (MAGIC) telescope participated in three multiwavelength (MWL) campaigns, observing the blazar Markarian (Mkn) 421 during the nights of 2006 April 28, 29, and 2006 June 14. We analyzed the corresponding MAGIC very-high energy observations during 9 nights from 2006 April 22 to 30 and on 2006 June 14. We inferred light curves with sub-day resolution and night-by-night energy spectra. A strong gamma-ray signal was detected from Mkn 421 on all observation nights. The flux (E > 250 GeV) varied on night-by-night basis between (0.92+-0.11)10^-10 cm^-2 s^-1 (0.57 Crab units) and (3.21+-0.15)10^-10 cm^-2 s^-1 (2.0 Crab units) in 2006 April. There is a clear indication for intra-night variability with a doubling time of 36+-10(stat) minutes on the night of 2006 April 29, establishing once more rapid flux variability for this object. For all individual nights gamma-ray spectra could be inferred, with power-law indices ranging from 1.66 to 2.47. We did not find statistically significant correlations between the spectral index and the flux state for individual nights. During the June 2006 campaign, a flux substantially lower than the one measured by the Whipple 10-m telescope four days later was found. Using a log-parabolic power law fit we deduced for some data sets the location of the spectral peak in the very-high energy regime. Our results confirm the indications of rising peak energy with increasing flux, as expected in leptonic acceleration models., Comment: 11 pages, 7 figures, accepted for publication by Astron. Astrophys
Published: 2010
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136. Simultaneous multi-frequency observation of the unknown redshift blazar PG 1553+113 in March-April 2008

Author: MAGIC Collaboration, Aleksić, J., Anderhub, H., Antonelli, L. A., Antoranz, P., Backes, M., Baixeras, C., Balestra, S., Barrio, J. A., Bastieri, D., González, J. Becerra, Becker, J. K., Bednarek, W., Berdyugin, A., Berger, K., Bernardini, E., Biland, A., Bock, R. K., Bonnoli, G., Bordas, P., Tridon, D. Borla, Bosch-Ramon, V., Bose, D., Braun, I., Bretz, T., Britzger, D., Camara, M., Carmona, E., Carosi, A., Colin, P., Commichau, S., Contreras, J. L., Cortina, J., Costado, M. T., Covino, S., Dazzi, F., De Angelis, A., del Pozo, E. de Cea, Reyes, R. De los, De Lotto, B., De Maria, M., De Sabata, F., Mendez, C. Delgado, Domínguez, A., Prester, D. Dominis, Dorner, D., Doro, M., Elsaesser, D., Errando, M., Ferenc, D., Fernández, E., Firpo, R., Fonseca, M. V., Font, L., Galante, N., López, R. J. García, Garczarczyk, M., Gaug, M., Godinovic, N., Goebel, F., Hadasch, D., Herrero, A., Hildebrand, D., Höhne-Mönch, D., Hose, J., Hrupec, D., Hsu, C. C., Jogler, T., Klepser, S., Krähenbühl, T., Kranich, D., La Barbera, A., Laille, A., Leonardo, E., Lindfors, E., Lombardi, S., Longo, F., López, M., Lorenz, E., Majumdar, P., Maneva, G., Mankuzhiyil, N., Mannheim, K., Maraschi, L., Mariotti, M., Martínez, M., Mazin, D., Meucci, M., Miranda, J. M., Mirzoyan, R., Miyamoto, H., Moldón, J., Moles, M., Moralejo, A., Nieto, D., Nilsson, K., Ninkovic, J., Orito, R., Oya, I., Paoletti, R., Paredes, J. M., Pasanen, M., Pascoli, D., Pauss, F., Pegna, R. G., Perez-Torres, M. A., Persic, M., Peruzzo, L., Prada, F., Prandini, E., Puchades, N., Puljak, I., Reichardt, I., Rhode, W., Ribó, M., Rico, J., Rissi, M., Rügamer, S., Saggion, A., Saito, T. Y., Salvati, M., Sánchez-Conde, M., Satalecka, K., Scalzotto, V., Scapin, V., Schweizer, T., Shayduk, M., Shore, S. N., Sierpowska-Bartosik, A., Sillanpää, A., Sitarek, J., Sobczynska, D., Spanier, F., Spiro, S., Stamerra, A., Steinke, B., Strah, N., Struebig, J. C., Suric, T., Takalo, L., Tavecchio, F., Temnikov, P., Tescaro, D., Teshima, M., Torres, D. F., Turini, N., Vankov, H., Wagner, R. M., Zabalza, V., Zandanel, F., Zanin, R., Zapatero, J., Pian, E., Bianchin, V., D'Ammando, F., Di Cocco, G., Fugazza, D., Ghisellini, G., Kurtanidze, O. M., Raiteri, C. M., Tosti, G., Treves, A., Vercellone, S., and Villata, M.
Subjects: Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract: The blazar PG 1553+113 is a well known TeV gamma-ray emitter. In this paper, we determine its spectral energy distribution using simultaneous multi-frequency data in order to study its emission processes. An extensive campaign was carried out between March and April 2008, where optical, X-ray, high-energy (HE) gamma-ray, and very-high-energy (VHE) gamma-ray data were obtained with the KVA, Abastumani, REM, RossiXTE/ASM, AGILE and MAGIC telescopes, respectively. This is the first simultaneous broad-band (i.e., HE+VHE) gamma-ray observation, though AGILE did not detect the source. We combine data to derive source's spectral energy distribution and interpret its double peaked shape within the framework of a synchrotron self compton model, Comment: 5 pages, 2 figures, published
Published: 2009
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137. Correlated X-ray and Very High Energy emission in the gamma-ray binary LS I +61 303

Author: The MAGIC Collaboration, Anderhub, H., Antonelli, L. A., Antoranz, P., Backes, M., Baixeras, C., Balestra, S., Barrio, J. A., Bastieri, D., González, J. Becerra, Becker, J. K., Bednarek, W., Berger, K., Bernardini, E., Biland, A., Bigas, O. Blanch, Bock, R. K., Bonnoli, G., Bordas, P., Tridon, D. Borla, Bosch-Ramon, V., Bose, D., Braun, I., Bretz, T., Britzger, D., Camara, M., Carmona, E., Carosi, A., Colin, P., Commichau, S., Contreras, J. L., Cortina, J., Costado, M. T., Covino, S., Dazzi, F., De Angelis, A., del Pozo, E. de Cea, Reyes, R. De los, De Lotto, B., De Maria, M., De Sabata, F., Mendez, C. Delgado, Domínguez, A., Prester, D. Dominis, Dorner, D., Doro, M., Elsaesser, D., Errando, M., Ferenc, D., Fernández, E., Firpo, R., Fonseca, M. V., Font, L., Galante, N., López, R. J. García, Garczarczyk, M., Gaug, M., Godinovic, N., Goebel, F., Hadasch, D., Herrero, A., Hildebrand, D., Höhne-Mönch, D., Hose, J., Hrupec, D., Hsu, C. C., Jogler, T., Klepser, S., Kranich, D., La Barbera, A., Laille, A., Leonardo, E., Lindfors, E., Lombardi, S., Longo, F., López, M., Lorenz, E., Majumdar, P., Maneva, G., Mankuzhiyil, N., Mannheim, K., Maraschi, L., Mariotti, M., Martínez, M., Mazin, D., Meucci, M., Miranda, J. M., Mirzoyan, R., Miyamoto, H., Moldón, J., Moles, M., Moralejo, A., Nieto, D., Nilsson, K., Ninkovic, J., Orito, R., Oya, I., Paoletti, R., Paredes, J. M., Pasanen, M., Pascoli, D., Pauss, F., Pegna, R. G., Perez-Torres, M. A., Persic, M., Peruzzo, L., Prada, F., Prandini, E., Puchades, N., Puljak, I., Reichardt, I., Rhode, W., Ribó, M., Rico, J., Rissi, M., Robert, A., Rügamer, S., Saggion, A., Saito, T. Y., Salvati, M., Sánchez-Conde, M., Satalecka, K., Scalzotto, V., Scapin, V., Schweizer, T., Shayduk, M., Shore, S. N., Sidro, N., Sierpowska-Bartosik, A., Sillanpää, A., Sitarek, J., Sobczynska, D., Spanier, F., Spiro, S., Stamerra, A., Stark, L. S., Suric, T., Takalo, L., Tavecchio, F., Temnikov, P., Tescaro, D., Teshima, M., Torres, D. F., Turini, N., Vankov, H., Wagner, R. M., Zabalza, V., Zandanel, F., Zanin, R., Zapatero, J., Falcone, A., Vetere, L., Gehrels, N., Trushkin, S., Dhawan, V., and Reig, P.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: The discovery of very high energy (VHE) gamma-ray emitting X-ray binaries has triggered an intense effort to better understand the particle acceleration, absorption, and emission mechanisms in compact binary systems, which provide variable conditions along eccentric orbits. Despite this, the nature of some of these systems, and of the accelerated particles producing the VHE emission, is unclear. To answer some of these open questions, we conducted a multiwavelength campaign of the VHE gamma-ray emitting X-ray binary LS I +61 303 including the MAGIC telescope, XMM-Newton, and Swift during 60% of an orbit in 2007 September. We detect a simultaneous outburst at X-ray and VHE bands, with the peak at phase 0.62 and a similar shape at both wavelengths. A linear fit to the simultaneous X-ray/VHE pairs obtained during the outburst yields a correlation coefficient of r=0.97, while a linear fit to all simultaneous pairs provides r=0.81. Since a variable absorption of the VHE emission towards the observer is not expected for the data reported here, the correlation found indicates a simultaneity in the emission processes. Assuming that they are dominated by a single particle population, either hadronic or leptonic, the X-ray/VHE flux ratio favors leptonic models. This fact, together with the detected photon indices, suggests that in LS I +61 303 the X-rays are the result of synchrotron radiation of the same electrons that produce VHE emission as a result of inverse Compton scattering of stellar photons., Comment: To appear in The Astrophysical Journal Letters. 6 pages, 2 figures
Published: 2009
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138. MAGIC Gamma-ray Telescope Observation of the Perseus Cluster of Galaxies: implications for cosmic rays, dark matter, and NGC1275

Author: The MAGIC Collaboration, Aleksić, J., Antonelli, L. A., Antoranz, P., Backes, M., Baixeras, C., Balestra, S., Barrio, J. A., Bastieri, D., González, J. Becerra, Bednarek, W., Berdyugin, A., Berger, K., Bernardini, E., Biland, A., Bock, R. K., Bonnoli, G., Bordas, P., Tridon, D. Borla, Bosch-Ramon, V., Bose, D., Braun, I., Bretz, T., Britzger, D., Camara, M., Carmona, E., Carosi, A., Colin, P., Commichau, S., Contreras, J. L., Cortina, J., Costado, M. T., Covino, S., Dazzi, F., De Angelis, A., del Pozo, E. De Cea, Reyes, R. De los, De Lotto, B., De Maria, M., De Sabata, F., Mendez, C. Delgado, Doert, M., Domínguez, A., Prester, D. Dominis, Dorner, D., Doro, M., Elsaesser, D., Errando, M., Ferenc, D., Fonseca, M. V., Font, L., Galante, N., López, R. J. García, Garczarczyk, M., Gaug, M., Godinovic, N., Hadasch, D., Herrero, A., Hildebrand, D., Höhne-Mönch, D., Hose, J., Hrupec, D., Hsu, C. C., Jogler, T., Klepser, S., Krähenbühl, T., Kranich, D., La Barbera, A., Laille, A., Leonardo, E., Lindfors, E., Lombardi, S., Longo, F., López, M., Lorenz, E., Majumdar, P., Maneva, G., Mankuzhiyil, N., Mannheim, K., Maraschi, L., Mariotti, M., Martínez, M., Mazin, D., Meucci, M., Miranda, J. M., Mirzoyan, R., Miyamoto, H., Moldón, J., Moles, M., Moralejo, A., Nieto, D., Nilsson, K., Ninkovic, J., Orito, R., Oya, I., Paiano, S., Paoletti, R., Paredes, J. M., Partini, S., Pasanen, M., Pascoli, D., Pauss, F., Pegna, R. G., Perez-Torres, M. A., Persic, M., Peruzzo, L., Prada, F., Prandini, E., Puchades, N., Puljak, I., Reichardt, I., Rhode, W., Ribó, M., Rico, J., Rissi, M., Rügamer, S., Saggion, A., Saito, T. Y., Salvati, M., Sánchez-Conde, M., Satalecka, K., Scalzotto, V., Scapin, V., Schultz, C., Schweizer, T., Shayduk, M., Shore, S. N., Sierpowska-Bartosik, A., Sillanpää, A., Sitarek, J., Sobczynska, D., Spanier, F., Spiro, S., Stamerra, A., Steinke, B., Struebig, J. C., Suric, T., Takalo, L., Tavecchio, F., Temnikov, P., Terzic, T., Tescaro, D., Teshima, M., Torres, D. F., Vankov, H., Wagner, R. M., Zabalza, V., Zandanel, F., Zanin, R., Zapatero, J., Pfrommer, C., Pinzke, A., Enßlin, T. A., Inoue, S., and Ghisellini, G.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: The Perseus galaxy cluster was observed by the MAGIC Cherenkov telescope for a total effective time of 24.4 hr during 2008 November and December. The resulting upper limits on the gamma-ray emission above 100 GeV are in the range of 4.6 to 7.5 x 10^{-12} cm^{-2} s^{-1} for spectral indices from -1.5 to -2.5, thereby constraining the emission produced by cosmic rays, dark matter annihilations, and the central radio galaxy NGC1275. Results are compatible with cosmological cluster simulations for the cosmic-ray-induced gamma-ray emission, constraining the average cosmic ray-to-thermal pressure to <4% for the cluster core region (<8% for the entire cluster). Using simplified assumptions adopted in earlier work (a power-law spectrum with an index of -2.1, constant cosmic ray-to-thermal pressure for the peripheral cluster regions while accounting for the adiabatic contraction during the cooling flow formation), we would limit the ratio of cosmic ray-to-thermal energy to E_CR/E_th<3%. The upper limit also translates into a level of gamma-ray emission from possible annihilations of the cluster dark matter (the dominant mass component) that is consistent with boost factors of ~10^4 for the typically expected dark matter annihilation-induced emission. Finally, the upper limits obtained for the gamma-ray emission of the central radio galaxy NGC1275 are consistent with the recent detection by the Fermi-LAT satellite. Due to the extremely large Doppler factors required for the jet, a one-zone synchrotron self-Compton model is implausible in this case. We reproduce the observed spectral energy density by using the structured jet (spine-layer) model which has previously been adopted to explain the high-energy emission of radio galaxies., Comment: 15 pages, 5 figures; accepted for publication in ApJ; updated to match the journal final version
Published: 2009
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139. MAGIC Collaboration: Contributions to the 31st International Cosmic Ray Conference (ICRC 2009)

Author: The MAGIC Collaboration, Anderhub, H., Antonelli, L. A., Antoranz, P., Backes, M., Baixeras, C., Balestra, S., Barrio, J. A., Bastieri, D., González, J. Becerra, Becker, J. K., Bednarek, W., Berger, K., Bernardini, E., Biland, A., Bock, R. K., Bonnoli, G., Bordas, P., Tridon, D. Borla, Bosch-Ramon, V., Bose, D., Braun, I., Bretz, T., Britzger, D., Camara, M., Carmona, E., Carosi, A., Colin, P., Commichau, S., Contreras, J. L., Cortina, J., Costado, M. T., Covino, S., Dazzi, F., De Angelis, A., del Pozo, E. de Cea, Mendez, C. Delgado, Reyes, R. De los, De Lotto, B., De Maria, M., De Sabata, F., Domínguez, A., Prester, D. Dominis, Dorner, D., Doro, M., Elsaesser, D., Errando, M., Ferenc, D., Fernández, E., Firpo, R., Fonseca, M. V., Font, L., Galante, N., López, R. J. García, Garczarczyk, M., Gaug, M., Godinovic, N., Goebel, F., Hadasch, D., Herrero, A., Hildebrand, D., Höhne-Mönch, D., Hose, J., Hrupec, D., Hsu, C. C., Jogler, T., Klepser, S., Kranich, D., La Barbera, A., Laille, A., Leonardo, E., Lindfors, E., Lombardi, S., Longo, F., López, M., Lorenz, E., Majumdar, P., Maneva, G., Mankuzhiyil, N., Mannheim, K., Maraschi, L., Mariotti, M., Martínez, M., Mazin, D., Meucci, M., Miranda, J. M., Mirzoyan, R., Miyamoto, H., Moldón, J., Moles, M., Moralejo, A., Nieto, D., Nilsson, K., Ninkovic, J., Orito, R., Oya, I., Paoletti, R., Paredes, J. M., Pasanen, M., Pascoli, D., Pauss, F., Pegna, R. G., Perez-Torres, M. A., Persic, M., Peruzzo, L., Prada, F., Prandini, E., Puchades, N., Puljak, I., Reichardt, I., Rhode, W., Ribó, M., Rico, J., Rissi, M., Robert, A., Rügamer, S., Saggion, A., Saito, T. Y., Salvati, M., Sánchez-Conde, M., Satalecka, K., Scalzotto, V., Scapin, V., Schweizer, T., Shayduk, M., Shore, S. N., Sierpowska-Bartosik, A., Sillanpää, A., Sitarek, J., Sobczynska, D., Spanier, F., Spiro, S., Stamerra, A., Stark, L. S., Suric, T., Takalo, L., Tavecchio, F., Temnikov, P., Tescaro, D., Teshima, M., Torres, D. F., Turini, N., Vankov, H., Wagner, R. M., Zabalza, V., Zandanel, F., Zanin, R., and Zapatero, J.
Subjects: Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Cosmology and Extragalactic Astrophysics, Astrophysics - Instrumentation and Methods for Astrophysics
Abstract: Index entry listing the contributed papers of the MAGIC collaboration to the 31th International Cosmic Ray Conference (ICRC 2009), July 7-15 2009, \L\'od\'z, Poland. The individual papers are sorted by subject: Overview and Highlight Papers; MAGIC-II Status and Components; Software and Analysis Techniques; Technical Developments; Scientific Results. This HTML document includes clickable links to the papers that exist on the astro-ph arXiv. We hope that this will make it easy to access the MAGIC contributions in a systematic way., Comment: Index of the MAGIC conference proceedings for ICRC 2009. Added 6 papers missing in v1
Published: 2009

140. Search for Dark Matter signatures with MAGIC-I and prospects for MAGIC Phase-II

Author: Lombardi, S., Aleksic, J., Barrio, J. A., Biland, A., Doro, M., Elsaesser, D., Gaug, M., Mannheim, K., Mariotti, M., Martinez, M., Nieto, D., Persic, M., Prada, F., Rico, J., Rissi, M., Sanchez-Conde, M. A., Stark, L. S., and Zandanel, F.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: In many Dark Matter (DM) scenarios, the annihilation of DM particles can produce gamma rays with a continuum spectrum that extends up to very high energies of the order of the electroweak symmetry breaking scale (hundreds of GeV). Astrophysical structures supposed to be dynamically dominated by DM, such as dwarf Spheroidal Galaxies, Galaxy Clusters (the largest ones in the local Universe being mostly observable from the northern hemisphere) and Intermediate Mass Black Holes, can be considered as interesting targets to look for DM annihilation with Imaging Atmospheric Cherenkov Telescopes (IACTs). Instead, the center of our Galaxy seems to be strongly contaminated with astrophysical sources. The 17m Major Atmospheric Gamma-ray Imaging Cherenkov (MAGIC-I) Telescope, situated in the Canary island of La Palma (2200 m a.s.l.), is best suited for DM searches, due to its unique combination of high sensitivity and low energy threshold among current IACTs which can potentially allow to provide clues on the high energy end, and possibly peak, of the gamma-ray DM-induced spectrum constrained at lower energies with the Fermi Space Telescope. The recent results achieved by MAGIC-I for some of the best candidates, as well as the DM detection prospects for the MAGIC Phase II, are reported., Comment: Contribution to the 31st ICRC, Lodz, Poland, July 2009
Published: 2009

141. DEEP BROADBAND OBSERVATIONS OF THE DISTANT GAMMA-RAY BLAZAR PKS 1424+240

Author: Archambault, S, Aune, T, Behera, B, Beilicke, M, Benbow, W, Berger, K, Bird, R, Biteau, J, Bugaev, V, Byrum, K, Cardenzana, JV, Cerruti, M, Chen, X, Ciupik, L, Connolly, MP, Cui, W, Dumm, J, Errando, M, Falcone, A, Federici, S, Feng, Q, Finley, JP, Fleischhack, H, Fortson, L, Furniss, A, Galante, N, Gillanders, GH, Griffin, S, Griffiths, ST, Grube, J, Gyuk, G, Hanna, D, Holder, J, Hughes, G, Humensky, TB, Johnson, CA, Kaaret, P, Kertzman, M, Khassen, Y, Kieda, D, Krawczynski, H, Krennrich, F, Kumar, S, Lang, MJ, Madhavan, AS, Maier, G, McCann, A, Meagher, K, Moriarty, P, Mukherjee, R, Nieto, D, de Bhróithe, A O'Faoláin, Ong, RA, Otte, AN, Park, N, Pohl, M, Popkow, A, Prokoph, H, Quinn, J, Ragan, K, Rajotte, J, Reyes, LC, Reynolds, PT, Richards, GT, Roache, E, Sembroski, GH, Shahinyan, K, Staszak, D, Telezhinsky, I, Tucci, JV, Tyler, J, Varlotta, A, Vassiliev, VV, Vincent, S, Wakely, SP, Weinstein, A, Welsing, R, Wilhelm, A, Williams, DA, Ackermann, M, Ajello, M, Albert, A, Baldini, L, Bastieri, D, Bellazzini, R, Bissaldi, E, Bregeon, J, Buehler, R, Buson, S, Caliandro, GA, Cameron, RA, Caraveo, PA, Cavazzuti, E, Charles, E, Chiang, J, Ciprini, S, Claus, R, Cutini, S, D'Ammando, F, and de Angelis, A
Subjects: BL Lacertae objects: individual (PKS 1424+240)-cosmic background radiation, gamma rays: galaxies, astro-ph.HE, Astronomical and Space Sciences, Astronomy & Astrophysics
Abstract: We present deep VERITAS observations of the blazar PKS 1424+240, along with contemporaneous Fermi Large Area Telescope, Swift X-ray Telescope, and Swift UV Optical Telescope data between 2009 February 19 and 2013 June 8. This blazar resides at a redshift of z ≥ 0.6035, displaying a significantly attenuated gamma-ray flux above 100 GeV due to photon absorption via pair-production with the extragalactic background light. We present more than 100 hr of VERITAS observations over three years, a multiwavelength light curve, and the contemporaneous spectral energy distributions. The source shows a higher flux of (2.1 ± 0.3) × 10-7 photons m-2 s -1 above 120 GeV in 2009 and 2011 as compared to the flux measured in 2013, corresponding to (1.02 ± 0.08) × 10-7 photons m-2 s-1 above 120 GeV. The measured differential very high energy (VHE; E ≥ 100 GeV) spectral indices are Γ = 3.8 ± 0.3, 4.3 ± 0.6 and 4.5 ± 0.2 in 2009, 2011, and 2013, respectively. No significant spectral change across the observation epochs is detected. We find no evidence for variability at gamma-ray opacities of greater than τ = 2, where it is postulated that any variability would be small and occur on timescales longer than a year if hadronic cosmic-ray interactions with extragalactic photon fields provide a secondary VHE photon flux. The data cannot rule out such variability due to low statistics. © 2014. The American Astronomical Society. All rights reserved..
Published: 2014

142. [Artíulo traducido] Seguridad de minoxidil oral a dosis bajas en pacientes con hipertensión o arritmias: estudio multicéntrico de 264 pacientes

Author: Jimenez-Cauhe, J., primary, Pirmez, R., additional, Müller-Ramos, P., additional, Melo, D.F., additional, Ortega-Quijano, D., additional, Moreno-Arrones, O.M., additional, Saceda-Corralo, D., additional, Gil-Redondo, R., additional, Hermosa-Gelbard, A., additional, Dias-Sanabria, B., additional, Restom, D., additional, Porriño-Bustamante, M.L., additional, Pindado-Ortega, C., additional, Berna-Rico, E., additional, Fernandez-Nieto, D., additional, Ramos, M., additional, Jaen-Olasolo, P., additional, and Vaño-Galvan, S., additional
Published: 2023
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143. The performance of the MAGIC telescopes using deep convolutional neural networks with CTLearn

Author: Miener, Tjark, primary, Nieto, D., additional, López-Coto, R., additional, Contreras, J. L., additional, Green, J. G., additional, Green, D., additional, and Mariotti, E., additional
Published: 2023
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144. The MAGIC Project: Contributions to ICRC 2007

Author: Albert, J., Aliu, E., Anderhub, H., Antoranz, P., Armada, A., Baixeras, C., Barrio, J. A., Bartko, H., Bastieri, D., Becker, J. K., Bednarek, W., Berger, K., Bigongiari, C., Biland, A., Bock, R. K., Bordas, P., Bosch-Ramon, V., Bretz, T., Britvitch, I., Cabras, G., Camara, M., Carmona, E., Chilingarian, A., Coarasa, J. A., Commichau, S., Contreras, J. L., Cortina, J., Costado, M. T., Curtef, V., Danielyan, V., Dazzi, F., De Angelis, A., Delgado, C., Reyes, R. de los, De Lotto, B., De Maria, M., De Sabata, F., Dorner, D., Doro, M., Errando, M., Fagiolini, M., Ferenc, D., Fernández, E., Firpo, R., Flix, J., Fonseca, M. V., Font, L., Fuchs, M., Galante, N., García-López, R. J., Garczarczyk, M., Gaug, M., Giller, M., Goebel, F., Hakobyan, D., Hayashida, M., Hengstebeck, T., Herrero, A., Höhne, D., Hose, J., Hsu, C. C., Jacon, P., Jogler, T., Kosyra, R., Kranich, D., Kritzer, R., Laille, A., Lindfors, E., Lombardi, S., Longo, F., López, J., López, M., Lorenz, E., Majumdar, P., Maneva, G., Mannheim, K., Mansutti, O., Mariotti, M., Martínez, M., Mazin, D., Merck, C., Meucci, M., Meyer, M., Miranda, J. M., Mirzoyan, R., Mizobuchi, S., Moralejo, A., Nieto, D., Nilsson, K., Ninkovic, J., na-Wilhelmi, E. O, Otte, N., Oya, I., Paneque, D., Paoletti, R., Paredes, J. M., Pasanen, M., Pascoli, D., Pauss, F., Pegna, R., Persic, M., Peruzzo, L., Piccioli, A., Prandini, E., Puchades, N., Raymers, A., Rhode, W., Ribó, M., Rico, J., Rissi, M., Robert, A., Rügamer, S., Saggion, A., Saito, T. Y., Sánchez, A., Sartori, P., Scalzotto, V., Scapin, V., Schmitt, R., Schweizer, T., Shayduk, M., Shinozaki, K., Shore, S. N., Sidro, N., Sillanpää, A., Sobczynska, D., Spanier, F., Stamerra, A., Stark, L. S., Takalo, L., Temnikov, P., Tescaro, D., Teshima, M., Torres, D. F., Turini, N., Vankov, H., Venturini, A., Vitale, V., Wagner, R. M., Wibig, T., Wittek, W., Zandanel, F., Zanin, R., and Zapatero, J.
Subjects: Astrophysics
Abstract: The MAGIC Project: Contributions to ICRC 2007, Merida, Mexico. Contents pages for the Contribution on behalf of the MAGIC Collaboration to the 30th ICRC that took place in July 2007 in Merida, Mexico. The contents are in html form with clickable links to the papers that exist on the Astrophysics archive. We hope that this will make it easier to access the output of the conference in a systematic way. Comments on how useful this is/ how it could be improved should be sent to michela.demaria@iuav.it., Comment: HTML file with clickable links to papers
Published: 2007

145. IACT event analysis with the MAGIC telescopes using deep convolutional neural networks with CTLearn.

Author: Miener, T., López-Coto, R., Contreras, J. L., Green, J. G., Green, D., Mariotti, E., Nieto, D., Romanato, L., and Yadav, S.
Published: 2024

146. Open-source Analysis Tools for Multi-instrument Dark Matter Searches.

Author: Miener, T., Kerszberg, D., Nigro, C., Rico, J., and Nieto, D.
Published: 2024

147. Science with e-ASTROGAM: A space mission for MeV–GeV gamma-ray astrophysics

Author: De Angelis, A., Tatischeff, V., Grenier, I.A., McEnery, J., Mallamaci, M., Tavani, M., Oberlack, U., Hanlon, L., Walter, R., Argan, A., Von Ballmoos, P., Bulgarelli, A., Bykov, A., Hernanz, M., Kanbach, G., Kuvvetli, I., Pearce, M., Zdziarski, A., Conrad, J., Ghisellini, G., Harding, A., Isern, J., Leising, M., Longo, F., Madejski, G., Martinez, M., Mazziotta, M.N., Paredes, J.M., Pohl, M., Rando, R., Razzano, M., Aboudan, A., Ackermann, M., Addazi, A., Ajello, M., Albertus, C., Álvarez, J.M., Ambrosi, G., Antón, S., Antonelli, L.A., Babic, A., Baibussinov, B., Balbo, M., Baldini, L., Balman, S., Bambi, C., Barres de Almeida, U., Barrio, J.A., Bartels, R., Bastieri, D., Bednarek, W., Bernard, D., Bernardini, E., Bernasconi, T., Bertucci, B., Biland, A., Bissaldi, E., Boettcher, M., Bonvicini, V., Bosch-Ramon, V., Bottacini, E., Bozhilov, V., Bretz, T., Branchesi, M., Brdar, V., Bringmann, T., Brogna, A., Budtz Jørgensen, C., Busetto, G., Buson, S., Busso, M., Caccianiga, A., Camera, S., Campana, R., Caraveo, P., Cardillo, M., Carlson, P., Celestin, S., Cermeño, M., Chen, A., Cheung, C.C., Churazov, E., Ciprini, S., Coc, A., Colafrancesco, S., Coleiro, A., Collmar, W., Coppi, P., Curado da Silva, R., Cutini, S., D'Ammando, F., De Lotto, B., de Martino, D., De Rosa, A., Del Santo, M., Delgado, L., Diehl, R., Dietrich, S., Dolgov, A.D., Domínguez, A., Dominis Prester, D., Donnarumma, I., Dorner, D., Doro, M., Dutra, M., Elsaesser, D., Fabrizio, M., Fernández-Barral, A., Fioretti, V., Foffano, L., Formato, V., Fornengo, N., Foschini, L., Franceschini, A., Franckowiak, A., Funk, S., Fuschino, F., Gaggero, D., Galanti, G., Gargano, F., Gasparrini, D., Gehrz, R., Giammaria, P., Giglietto, N., Giommi, P., Giordano, F., Giroletti, M., Ghirlanda, G., Godinovic, N., Gouiffés, C., Grove, J.E., Hamadache, C., Hartmann, D.H., Hayashida, M., Hryczuk, A., Jean, P., Johnson, T., José, J., Kaufmann, S., Khelifi, B., Kiener, J., Knödlseder, J., Kole, M., Kopp, J., Kozhuharov, V., Labanti, C., Lalkovski, S., Laurent, P., Limousin, O., Linares, M., Lindfors, E., Lindner, M., Liu, J., Lombardi, S., Loparco, F., López-Coto, R., López Moya, M., Lott, B., Lubrano, P., Malyshev, D., Mankuzhiyil, N., Mannheim, K., Marchã, M.J., Marcianò, A., Marcote, B., Mariotti, M., Marisaldi, M., McBreen, S., Mereghetti, S., Merle, A., Mignani, R., Minervini, G., Moiseev, A., Morselli, A., Moura, F., Nakazawa, K., Nava, L., Nieto, D., Orienti, M., Orio, M., Orlando, E., Orleanski, P., Paiano, S., Paoletti, R., Papitto, A., Pasquato, M., Patricelli, B., Pérez-García, M.Á., Persic, M., Piano, G., Pichel, A., Pimenta, M., Pittori, C., Porter, T., Poutanen, J., Prandini, E., Prantzos, N., Produit, N., Profumo, S., Queiroz, F.S., Rainó, S., Raklev, A., Regis, M., Reichardt, I., Rephaeli, Y., Rico, J., Rodejohann, W., Rodriguez Fernandez, G., Roncadelli, M., Roso, L., Rovero, A., Ruffini, R., Sala, G., Sánchez-Conde, M.A., Santangelo, A., Saz Parkinson, P., Sbarrato, T., Shearer, A., Shellard, R., Short, K., Siegert, T., Siqueira, C., Spinelli, P., Stamerra, A., Starrfield, S., Strong, A., Strümke, I., Tavecchio, F., Taverna, R., Terzić, T., Thompson, D.J., Tibolla, O., Torres, D.F., Turolla, R., Ulyanov, A., Ursi, A., Vacchi, A., Van den Abeele, J., Vankova-Kirilovai, G., Venter, C., Verrecchia, F., Vincent, P., Wang, X., Weniger, C., Wu, X., Zaharijaš, G., Zampieri, L., Zane, S., Zimmer, S., and Zoglauer, A.
Published: 2018
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148. Seguridad de minoxidil oral a dosis bajas en pacientes con hipertensión o arritmias: estudio multicéntrico de 264 pacientes

Author: Cauhe, J Jimenez, primary, Pirmez, R, additional, Ramos, P Müller, additional, Melo, D Fernandes, additional, Quijano, D Ortega, additional, Moreno-Arrones, O M, additional, Corralo, D Saceda, additional, Redondo, R Gil, additional, Gelbard, A Hermosa, additional, Sanabria, B Dias, additional, Restom, D, additional, Porriño-Bustamante, M L, additional, Ortega, C Pindado, additional, Rico, E Berna, additional, Nieto, D Fernandez, additional, Ramos, M, additional, Olasolo, P Jaen, additional, and Galvan, S Vaño, additional
Published: 2023
Full Text: View/download PDF

149. U-Pb and Lu-Hf zircon geochronology of the Cañadón Asfalto Basin, Chubut, Argentina: Implications for the magmatic evolution in central Patagonia

Author: Hauser, N., Cabaleri, N.G., Gallego, O.F., Monferran, M.D., Silva Nieto, D., Armella, C., Matteini, M., Aparicio González, P.A., Pimentel, M.M., Volkheimer, W., and Reimold, W.U.
Published: 2017
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150. Extreme events in epileptic EEG of rodents after ischemic stroke

Author: Pisarchik, A. N., Grubov, V. V., Maksimenko, V. A., Lüttjohann, A., Frolov, N. S., Marqués-Pascual, C., Gonzalez-Nieto, D., Khramova, M. V., and Hramov, A. E.
Published: 2018
Full Text: View/download PDF

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