Search

Your search keyword '"D. Glawion"' showing total 10 results
Start Over Author "D. Glawion" Publication Type Academic Journals
10 results on '"D. Glawion"'

1. The Vanishing of the Primary Emission Region in PKS 1510–089

Author

F. Aharonian, F. Ait Benkhali, J. Aschersleben, H. Ashkar, M. Backes, V. Barbosa Martins, J. Barnard, R. Batzofin, Y. Becherini, D. Berge, K. Bernlöhr, B. Bi, M. de Bony de Lavergne, M. Böttcher, C. Boisson, J. Bolmont, J. Borowska, M. Bouyahiaoui, F. Bradascio, M. Breuhaus, R. Brose, A. M. Brown, F. Brun, B. Bruno, T. Bulik, C. Burger-Scheidlin, S. Caroff, S. Casanova, R. Cecil, J. Celic, M. Cerruti, T. Chand, S. Chandra, A. Chen, J. Chibueze, O. Chibueze, G. Cotter, J. Damascene Mbarubucyeye, I. D. Davids, A. Djannati-Ataï, A. Dmytriiev, V. Doroshenko, K. Egberts, S. Einecke, J.-P. Ernenwein, S. Fegan, G. Fontaine, M. Füßling, S. Funk, S. Gabici, S. Ghafourizadeh, G. Giavitto, D. Glawion, J. F. Glicenstein, P. Goswami, G. Grolleron, L. Haerer, W. Hofmann, T. L. Holch, M. Holler, D. Horns, M. Jamrozy, F. Jankowsky, V. Joshi, I. Jung-Richardt, E. Kasai, K. Katarzyński, R. Khatoon, B. Khélifi, W. Kluźniak, Nu. Komin, K. Kosack, D. Kostunin, R. G. Lang, S. Le Stum, F. Leitl, A. Lemière, J.-P. Lenain, F. Leuschner, A. Luashvili, J. Mackey, V. Marandon, P. Marchegiani, G. Martí-Devesa, R. Marx, A. Mehta, M. Meyer, A. Mitchell, R. Moderski, L. Mohrmann, A. Montanari, E. Moulin, M. de Naurois, J. Niemiec, A. Priyana Noel, P. O’Brien, S. Ohm, L. Olivera-Nieto, E. de Ona Wilhelmi, M. Ostrowski, S. Panny, M. Panter, G. Peron, D. A. Prokhorov, G. Pühlhofer, M. Punch, A. Quirrenbach, P. Reichherzer, A. Reimer, O. Reimer, H. Ren, F. Rieger, G. Rowell, B. Rudak, H. Rueda Ricarte, E. Ruiz-Velasco, V. Sahakian, H. Salzmann, D. A. Sanchez, A. Santangelo, M. Sasaki, F. Schüssler, H. M. Schutte, U. Schwanke, J. N. S. Shapopi, H. Sol, A. Specovius, S. Spencer, Ł. Stawarz, R. Steenkamp, S. Steinmassl, C. Steppa, I. Sushch, H. Suzuki, T. Takahashi, T. Tanaka, R. Terrier, N. Tsuji, C. van Eldik, B. van Soelen, M. Vecchi, J. Veh, J. Vink, T. Wach, S. J. Wagner, A. Wierzcholska, M. Zacharias, D. Zargaryan, A. A. Zdziarski, A. Zech, S. Zouari, N. Żywucka, D. A. H. Buckley, J. Cooper, D. Groenewald, and H.E.S.S. Collaboration

Subjects
Blazars, Relativistic jets, Non-thermal radiation sources, Flat-spectrum radio quasars, Gamma-ray sources, Spectropolarimetry, Astrophysics, QB460-466
Abstract

In 2021 July, PKS 1510−089 exhibited a significant flux drop in the high-energy γ -ray (by a factor 10) and optical (by a factor 5) bands and remained in this low state throughout 2022. Similarly, the optical polarization in the source vanished, resulting in the optical spectrum being fully explained through the steady flux of the accretion disk and the broad-line region. Unlike the aforementioned bands, the very-high-energy γ -ray and X-ray fluxes did not exhibit a significant flux drop from year to year. This suggests that the steady-state very-high-energy γ -ray and X-ray fluxes originate from a different emission region than the vanished parts of the high-energy γ -ray and optical jet fluxes. The latter component has disappeared through either a swing of the jet away from the line of sight or a significant drop in the photon production efficiency of the jet close to the black hole. Either change could become visible in high-resolution radio images.

Published
2023
Full Text
View/download PDF

2. Constraints on the Intergalactic Magnetic Field Using Fermi-LAT and H.E.S.S. Blazar Observations

Author

F. Aharonian, J. Aschersleben, M. Backes, V. Barbosa Martins, R. Batzofin, Y. Becherini, D. Berge, B. Bi, M. Bouyahiaoui, M. Breuhaus, R. Brose, F. Brun, B. Bruno, T. Bulik, C. Burger-Scheidlin, T. Bylund, S. Caroff, S. Casanova, J. Celic, M. Cerruti, T. Chand, S. Chandra, A. Chen, J. Chibueze, O. Chibueze, G. Cotter, M. de Bony, K. Egberts, J.-P. Ernenwein, G. Fichet de Clairfontaine, M. Filipovic, G. Fontaine, M. Füssling, S. Funk, S. Gabici, S. Ghafourizadeh, G. Giavitto, D. Glawion, J. F. Glicenstein, P. Goswami, M.-H. Grondin, L. Haerer, T. L. Holch, M. Holler, D. Horns, M. Jamrozy, F. Jankowsky, V. Joshi, I. Jung-Richardt, E. Kasai, K. Katarzyński, R. Khatoon, B. Khélifi, W. Kluźniak, Nu. Komin, K. Kosack, D. Kostunin, R. G. Lang, S. Le Stum, F. Leitl, A. Lemière, J.-P. Lenain, F. Leuschner, T. Lohse, A. Luashvili, I. Lypova, J. Mackey, D. Malyshev, V. Marandon, P. Marchegiani, A. Marcowith, G. Martí-Devesa, R. Marx, M. Meyer, A. Mitchell, R. Moderski, L. Mohrmann, A. Montanari, E. Moulin, J. Muller, T. Murach, K. Nakashima, J. Niemiec, S. Ohm, L. Olivera-Nieto, E. de Ona Wilhelmi, S. Panny, M. Panter, R. D. Parsons, G. Peron, D. A. Prokhorov, H. Prokoph, G. Pühlhofer, M. Punch, A. Quirrenbach, P. Reichherzer, A. Reimer, O. Reimer, B. Reville, F. Rieger, G. Rowell, B. Rudak, E. Ruiz-Velasco, V. Sahakian, D. A. Sanchez, M. Sasaki, F. Schüssler, H. M. Schutte, U. Schwanke, J. N. S. Shapopi, H. Sol, S. Spencer, S. Steinmassl, H. Suzuki, T. Takahashi, T. Tanaka, A. M. Taylor, R. Terrier, C. Thorpe-Morgan, M. Tsirou, N. Tsuji, Y. Uchiyama, C. van Eldik, J. Veh, C. Venter, S. J. Wagner, R. White, A. Wierzcholska, Yu Wun Wong, M. Zacharias, D. Zargaryan, A. A. Zdziarski, S. Zouari, N. Żywucka, H.E.S.S. Collaboration, and Fermi-LAT Collaboration

Subjects
Active galaxies, High energy astrophysics, Extragalactic magnetic fields, Astrophysics, QB460-466
Abstract

Magnetic fields in galaxies and galaxy clusters are believed to be the result of the amplification of intergalactic seed fields during the formation of large-scale structures in the universe. However, the origin, strength, and morphology of this intergalactic magnetic field (IGMF) remain unknown. Lower limits on (or indirect detection of) the IGMF can be obtained from observations of high-energy gamma rays from distant blazars. Gamma rays interact with the extragalactic background light to produce electron−positron pairs, which can subsequently initiate electromagnetic cascades. The gamma-ray signature of the cascade depends on the IGMF since it deflects the pairs. Here we report on a new search for this cascade emission using a combined data set from the Fermi Large Area Telescope and the High Energy Stereoscopic System. Using state-of-the-art Monte Carlo predictions for the cascade signal, our results place a lower limit on the IGMF of B > 7.1 × 10 ^−16 G for a coherence length of 1 Mpc even when blazar duty cycles as short as 10 yr are assumed. This improves on previous lower limits by a factor of 2. For longer duty cycles of 10 ^4 (10 ^7 ) yr, IGMF strengths below 1.8 × 10 ^−14 G (3.9 × 10 ^−14 G) are excluded, which rules out specific models for IGMF generation in the early universe.

Published
2023
Full Text
View/download PDF

3. H.E.S.S. Follow-up Observations of GRB 221009A

Author

F. Aharonian, F. Ait Benkhali, J. Aschersleben, H. Ashkar, M. Backes, A. Baktash, V. Barbosa Martins, R. Batzofin, Y. Becherini, D. Berge, K. Bernlöhr, B. Bi, M. Böttcher, C. Boisson, J. Bolmont, M. de Bony de Lavergne, J. Borowska, M. Bouyahiaoui, F. Bradascio, M. Breuhaus, R. Brose, F. Brun, B. Bruno, T. Bulik, C. Burger-Scheidlin, S. Caroff, S. Casanova, J. Celic, M. Cerruti, T. Chand, S. Chandra, A. Chen, J. Chibueze, O. Chibueze, G. Cotter, S. Dai, J. Damascene Mbarubucyeye, J. Devin, A. Djannati-Ataï, A. Dmytriiev, V. Doroshenko, K. Egberts, S. Einecke, J.-P. Ernenwein, S. Fegan, G. Fichet de Clairfontaine, M. Filipovic, G. Fontaine, M. Füßling, S. Funk, S. Gabici, S. Ghafourizadeh, G. Giavitto, D. Glawion, J. F. Glicenstein, P. Goswami, G. Grolleron, M.-H. Grondin, J. A. Hinton, T. L. Holch, M. Holler, D. Horns, Zhiqiu Huang, M. Jamrozy, F. Jankowsky, V. Joshi, I. Jung-Richardt, E. Kasai, K. Katarzyński, R. Khatoon, B. Khélifi, W. Kluźniak, Nu. Komin, R. Konno, K. Kosack, D. Kostunin, R. G. Lang, S. Le Stum, F. Leitl, A. Lemière, M. Lemoine-Goumard, J.-P. Lenain, F. Leuschner, T. Lohse, I. Lypova, J. Mackey, D. Malyshev, V. Marandon, P. Marchegiani, A. Marcowith, G. Martí-Devesa, R. Marx, M. Meyer, A. Mitchell, L. Mohrmann, A. Montanari, E. Moulin, T. Murach, K. Nakashima, M. de Naurois, J. Niemiec, A. Priyana Noel, P. O’Brien, S. Ohm, L. Olivera-Nieto, E. de Ona Wilhelmi, M. Ostrowski, S. Panny, M. Panter, R. D. Parsons, G. Peron, D. A. Prokhorov, H. Prokoph, G. Pühlhofer, M. Punch, A. Quirrenbach, P. Reichherzer, A. Reimer, O. Reimer, H. Ren, M. Renaud, B. Reville, F. Rieger, G. Rowell, B. Rudak, E. Ruiz-Velasco, V. Sahakian, H. Salzmann, A. Santangelo, M. Sasaki, J. Schäfer, F. Schüssler, H. M. Schutte, U. Schwanke, J. N. S. Shapopi, A. Specovius, S. Spencer, Ł. Stawarz, R. Steenkamp, S. Steinmassl, C. Steppa, I. Sushch, H. Suzuki, T. Takahashi, T. Tanaka, R. Terrier, N. Tsuji, Y. Uchiyama, M. Vecchi, C. Venter, J. Vink, S. J. Wagner, R. White, A. Wierzcholska, Yu Wun Wong, M. Zacharias, D. Zargaryan, A. A. Zdziarski, A. Zech, S. J. Zhu, N. Żywucka, and H.E.S.S. Collaboration

Subjects
Gamma-rays, Gamma-ray bursts, Non-thermal radiation sources, High-energy cosmic radiation, Astrophysics, QB460-466
Abstract

GRB 221009A is the brightest gamma-ray burst (GRB) ever detected. To probe the very-high-energy (VHE; >100 GeV) emission, the High Energy Stereoscopic System (H.E.S.S.) began observations 53 hr after the triggering event, when the brightness of the moonlight no longer precluded observations. We derive differential and integral upper limits using H.E.S.S. data from the third, fourth, and ninth nights after the initial GRB detection, after applying atmospheric corrections. The combined observations yield an integral energy flux upper limit of ${{\rm{\Phi }}}_{\mathrm{UL}}^{95 \% }=9.7\times {10}^{-12}\,\mathrm{erg}\,{\mathrm{cm}}^{-2}\,{{\rm{s}}}^{-1}$ above E _thr = 650 GeV. The constraints derived from the H.E.S.S. observations complement the available multiwavelength data. The radio to X-ray data are consistent with synchrotron emission from a single electron population, with the peak in the spectral energy distribution occurring above the X-ray band. Compared to the VHE-bright GRB 190829A, the upper limits for GRB 221009A imply a smaller gamma-ray to X-ray flux ratio in the afterglow. Even in the absence of a detection, the H.E.S.S. upper limits thus contribute to the multiwavelength picture of GRB 221009A, effectively ruling out an IC-dominated scenario.

Published
2023
Full Text
View/download PDF

4. Multiwavelength Observations of the Blazar PKS 0735+178 in Spatial and Temporal Coincidence with an Astrophysical Neutrino Candidate IceCube-211208A

Author

A. Acharyya, C. B. Adams, A. Archer, P. Bangale, J. T. Bartkoske, P. Batista, W. Benbow, A. Brill, J. H. Buckley, J. L. Christiansen, A. J. Chromey, M. Errando, A. Falcone, Q. Feng, G. M. Foote, L. Fortson, A. Furniss, G. Gallagher, W. Hanlon, D. Hanna, O. Hervet, C. E. Hinrichs, J. Hoang, J. Holder, T. B. Humensky, W. Jin, P. Kaaret, M. Kertzman, M. Kherlakian, D. Kieda, T. K. Kleiner, N. Korzoun, S. Kumar, M. J. Lang, M. Lundy, G. Maier, C. E McGrath, M. J. Millard, J. Millis, C. L. Mooney, P. Moriarty, R. Mukherjee, S. O’Brien, R. A. Ong, M. Pohl, E. Pueschel, J. Quinn, K. Ragan, P. T. Reynolds, D. Ribeiro, E. Roache, I. Sadeh, A. C. Sadun, L. Saha, M. Santander, G. H. Sembroski, R. Shang, M. Splettstoesser, A. Kaushik Talluri, J. V. Tucci, V. V. Vassiliev, A. Weinstein, D. A. Williams, S. L. Wong, J. Woo, The VERITAS Collaboration, F. Aharonian, J. Aschersleben, M. Backes, V. Barbosa Martins, R. Batzofin, Y. Becherini, D. Berge, K. Bernlöhr, B. Bi, M. Böttcher, C. Boisson, J. Bolmont, M. de Bony de Lavergne, J. Borowska, M. Bouyahiaoui, F. Bradascio, M. Breuhaus, R. Brose, F. Brun, B. Bruno, T. Bulik, C. Burger-Scheidlin, S. Caroff, S. Casanova, R. Cecil, J. Celic, M. Cerruti, T. Chand, S. Chandra, A. Chen, J. Chibueze, O. Chibueze, G. Cotter, S. Dai, J. Damascene Mbarubucyeye, A. Djannati-Ataï, A. Dmytriiev, V. Doroshenko, S. Einecke, J.-P. Ernenwein, G. Fichet de Clairfontaine, M. Filipovic, G. Fontaine, M. Füßling, S. Funk, S. Gabici, S. Ghafourizadeh, G. Giavitto, D. Glawion, J. F. Glicenstein, P. Goswami, G. Grolleron, L. Haerer, J. A. Hinton, T. L. Holch, M. Holler, D. Horns, M. Jamrozy, F. Jankowsky, V. Joshi, I. Jung-Richardt, E. Kasai, K. Katarzyński, R. Khatoon, B. Khélifi, S. Klepser, W. Kluźniak, K. Kosack, D. Kostunin, R. G. Lang, S. Le Stum, A. Lemière, J.-P. Lenain, F. Leuschner, T. Lohse, A. Luashvili, I. Lypova, J. Mackey, D. Malyshev, V. Marandon, P. Marchegiani, A. Marcowith, G. Martí-Devesa, R. Marx, A. Mitchell, R. Moderski, L. Mohrmann, A. Montanari, E. Moulin, T. Murach, K. Nakashima, J. Niemiec, A. Priyana Noel, P. O’Brien, L. Olivera-Nieto, E. de Ona Wilhelmi, M. Ostrowski, S. Panny, M. Panter, G. Peron, D. A. Prokhorov, G. Pühlhofer, M. Punch, A. Quirrenbach, P. Reichherzer, A. Reimer, O. Reimer, H. Ren, M. Renaud, F. Rieger, B. Rudak, E. Ruiz-Velasco, V. Sahakian, A. Santangelo, M. Sasaki, J. Schäfer, F. Schüssler, H. M. Schutte, U. Schwanke, J. N. S. Shapopi, A. Specovius, S. Spencer, Ł. Stawarz, R. Steenkamp, S. Steinmassl, I. Sushch, H. Suzuki, T. Takahashi, T. Tanaka, R. Terrier, C. van Eldik, M. Vecchi, J. Veh, C. Venter, J. Vink, R. White, A. Wierzcholska, Yu Wun Wong, M. Zacharias, D. Zargaryan, A. A. Zdziarski, A. Zech, S. Zouari, N. Żywucka, The H.E.S.S. Collaboration, and K. Mori

Subjects
Active galactic nuclei, Blazars, Neutrino astronomy, Gamma-ray astronomy, Astrophysics, QB460-466
Abstract

We report on multiwavelength target-of-opportunity observations of the blazar PKS 0735+178, located 2.°2 away from the best-fit position of the IceCube neutrino event IceCube-211208A detected on 2021 December 8. The source was in a high-flux state in the optical, ultraviolet, X-ray, and GeV γ -ray bands around the time of the neutrino event, exhibiting daily variability in the soft X-ray flux. The X-ray data from Swift-XRT and NuSTAR characterize the transition between the low-energy and high-energy components of the broadband spectral energy distribution (SED), and the γ -ray data from Fermi-LAT, VERITAS, and H.E.S.S. require a spectral cutoff near 100 GeV. Both the X-ray and γ -ray measurements provide strong constraints on the leptonic and hadronic models. We analytically explore a synchrotron self-Compton model, an external Compton model, and a lepto-hadronic model. Models that are entirely based on internal photon fields face serious difficulties in matching the observed SED. The existence of an external photon field in the source would instead explain the observed γ -ray spectral cutoff in both the leptonic and lepto-hadronic models and allow a proton jet power that marginally agrees with the Eddington limit in the lepto-hadronic model. We show a numerical lepto-hadronic model with external target photons that reproduces the observed SED and is reasonably consistent with the neutrino event despite requiring a high jet power.

Published
2023
Full Text
View/download PDF

5. Acceleration and transport of relativistic electrons in the jets of the microquasar SS 433.

Author

Aharonian F, Benkhali FA, Aschersleben J, Ashkar H, Backes M, Martins VB, Batzofin R, Becherini Y, Berge D, Bernlöhr K, Bi B, Böttcher M, Boisson C, Bolmont J, de Lavergne MB, Borowska J, Bouyahiaoui M, Breuhaus M, Brose R, Brown AM, Brun F, Bruno B, Bulik T, Burger-Scheidlin C, Caroff S, Casanova S, Cecil R, Celic J, Cerruti M, Chand T, Chandra S, Chen A, Chibueze J, Chibueze O, Cotter G, Dai S, Mbarubucyeye JD, Djannati-Ataï A, Dmytriiev A, Doroshenko V, Egberts K, Einecke S, Ernenwein JP, Filipovic M, Fontaine G, Füßling M, Funk S, Gabici S, Ghafourizadeh S, Giavitto G, Glawion D, Glicenstein JF, Grolleron G, Haerer L, Hinton JA, Hofmann W, Holch TL, Holler M, Horns D, Jamrozy M, Jankowsky F, Jardin-Blicq A, Joshi V, Jung-Richardt I, Kasai E, Katarzyński K, Khatoon R, Khélifi B, Klepser S, Kluźniak W, Komin N, Kosack K, Kostunin D, Kundu A, Lang RG, Le Stum S, Leitl F, Lemière A, Lenain JP, Leuschner F, Lohse T, Luashvili A, Lypova I, Mackey J, Malyshev D, Malyshev D, Marandon V, Marchegiani P, Marcowith A, Martí-Devesa G, Marx R, Mehta A, Mitchell A, Moderski R, Mohrmann L, Montanari A, Moulin E, Murach T, Nakashima K, de Naurois M, Niemiec J, Noel AP, Ohm S, Olivera-Nieto L, de Ona Wilhelmi E, Ostrowski M, Panny S, Panter M, Parsons RD, Peron G, Prokhorov DA, Pühlhofer G, Punch M, Quirrenbach A, Reichherzer P, Reimer A, Reimer O, Ren H, Renaud M, Reville B, Rieger F, Rowell G, Rudak B, Ricarte HR, Ruiz-Velasco E, Sahakian V, Salzmann H, Santangelo A, Sasaki M, Schäfer J, Schüssler F, Schwanke U, Shapopi JNS, Sol H, Specovius A, Spencer S, Stawarz L, Steenkamp R, Steinmassl S, Steppa C, Streil K, Sushch I, Suzuki H, Takahashi T, Tanaka T, Taylor AM, Terrier R, Tsirou M, Tsuji N, Unbehaun T, van Eldik C, Vecchi M, Veh J, Venter C, Vink J, Wach T, Wagner SJ, Werner F, White R, Wierzcholska A, Wong YW, Zacharias M, Zargaryan D, Zdziarski AA, Zech A, Zouari S, and Żywucka N

Abstract

SS 433 is a microquasar, a stellar binary system that launches collimated relativistic jets. We observed SS 433 in gamma rays using the High Energy Stereoscopic System (H.E.S.S.) and found an energy-dependent shift in the apparent position of the gamma-ray emission from the parsec-scale jets. These observations trace the energetic electron population and indicate that inverse Compton scattering is the emission mechanism of the gamma rays. Our modeling of the energy-dependent gamma-ray morphology constrains the location of particle acceleration and requires an abrupt deceleration of the jet flow. We infer the presence of shocks on either side of the binary system, at distances of 25 to 30 parsecs, and that self-collimation of the precessing jets forms the shocks, which then efficiently accelerate electrons.

Published
2024
Full Text
View/download PDF

6. Search for Dark Matter Annihilation Signals in the H.E.S.S. Inner Galaxy Survey.

Author

Abdalla H, Aharonian F, Benkhali FA, Angüner EO, Armand C, Ashkar H, Backes M, Baghmanyan V, Martins VB, Batzofin R, Becherini Y, Berge D, Bernlöhr K, Bi B, Böttcher M, Bolmont J, de Lavergne MB, Brose R, Brun F, Cangemi F, Caroff S, Cerruti M, Chand T, Chen A, Cotter G, Mbarubucyeye JD, Devin J, Djannati-Ataï A, Dmytriiev A, Doroshenko V, Egberts K, Fiasson A, de Clairfontaine GF, Fontaine G, Funk S, Gabici S, Giavitto G, Glawion D, Glicenstein JF, Grondin MH, Hinton JA, Hofmann W, Holch TL, Holler M, Horns D, Huang Z, Jamrozy M, Jankowsky F, Kasai E, Katarzyński K, Katz U, Khélifi B, Kluźniak W, Komin N, Kosack K, Kostunin D, Lamanna G, Lemoine-Goumard M, Lenain JP, Leuschner F, Lohse T, Luashvili A, Lypova I, Mackey J, Malyshev D, Malyshev D, Marandon V, Marchegiani P, Martí-Devesa G, Marx R, Maurin G, Meyer M, Mitchell A, Moderski R, Montanari A, Moulin E, Muller J, de Naurois M, Niemiec J, Noel AP, Ohm S, Olivera-Nieto L, Wilhelmi EO, Ostrowski M, Panny S, Panter M, Parsons RD, Peron G, Poireau V, Prokoph H, Pühlhofer G, Punch M, Quirrenbach A, Reichherzer P, Reimer A, Reimer O, Renaud M, Rieger F, Rowell G, Rudak B, Ricarte HR, Ruiz-Velasco E, Sahakian V, Salzmann H, Santangelo A, Sasaki M, Schüssler F, Schutte HM, Schwanke U, Senniappan M, Shapopi JNS, Sol H, Specovius A, Spencer S, Stawarz Ł, Stegmann C, Steinmassl S, Steppa C, Takahashi T, Tanaka T, Terrier R, Thorpe-Morgan C, Tluczykont M, Tsirou M, Tsuji N, Uchiyama Y, van Eldik C, Veh J, Vink J, Wagner SJ, White R, Wierzcholska A, Wong YW, Zacharias M, Zargaryan D, Zdziarski AA, Zech A, Zhu SJ, Zouari S, and Żywucka N

Abstract

The central region of the Milky Way is one of the foremost locations to look for dark matter (DM) signatures. We report the first results on a search for DM particle annihilation signals using new observations from an unprecedented γ-ray survey of the Galactic Center (GC) region, i.e., the Inner Galaxy Survey, at very high energies (≳100  GeV) performed with the H.E.S.S. array of five ground-based Cherenkov telescopes. No significant γ-ray excess is found in the search region of the 2014-2020 dataset and a profile likelihood ratio analysis is carried out to set exclusion limits on the annihilation cross section ⟨σv⟩. Assuming Einasto and Navarro-Frenk-White (NFW) DM density profiles at the GC, these constraints are the strongest obtained so far in the TeV DM mass range. For the Einasto profile, the constraints reach ⟨σv⟩ values of 3.7×10^{-26}  cm^{3} s^{-1} for 1.5 TeV DM mass in the W^{+}W^{-} annihilation channel, and 1.2×10^{-26}  cm^{3} s^{-1} for 0.7 TeV DM mass in the τ^{+}τ^{-} annihilation channel. With the H.E.S.S. Inner Galaxy Survey, ground-based γ-ray observations thus probe ⟨σv⟩ values expected from thermal-relic annihilating TeV DM particles.

Published
2022
Full Text
View/download PDF

7. Time-resolved hadronic particle acceleration in the recurrent nova RS Ophiuchi.

Author

Aharonian F, Ait Benkhali F, Angüner EO, Ashkar H, Backes M, Baghmanyan V, Barbosa Martins V, Batzofin R, Becherini Y, Berge D, Bernlöhr K, Bi B, Böttcher M, Boisson C, Bolmont J, de Bony de Lavergne M, Breuhaus M, Brose R, Brun F, Caroff S, Casanova S, Cerruti M, Chand T, Chen A, Cotter G, Damascene Mbarubucyeye J, Djannati-Ataï A, Dmytriiev A, Doroshenko V, Duffy C, Egberts K, Ernenwein JP, Fegan S, Feijen K, Fiasson A, Fichet de Clairfontaine G, Fontaine G, Füßling M, Funk S, Gabici S, Gallant YA, Ghafourizadeh S, Giavitto G, Giunti L, Glawion D, Glicenstein JF, Grondin MH, Hermann G, Hinton JA, Hörbe M, Hofmann W, Hoischen C, Holch TL, Holler M, Horns D, Huang Z, Jamrozy M, Jankowsky F, Jung-Richardt I, Kasai E, Katarzyński K, Katz U, Khangulyan D, Khélifi B, Klepser S, Kluźniak W, Komin N, Konno R, Kosack K, Kostunin D, Le Stum S, Lemière A, Lemoine-Goumard M, Lenain JP, Leuschner F, Lohse T, Luashvili A, Lypova I, Mackey J, Malyshev D, Malyshev D, Marandon V, Marchegiani P, Marcowith A, Martí-Devesa G, Marx R, Maurin G, Meyer M, Mitchell A, Moderski R, Mohrmann L, Montanari A, Moulin E, Muller J, Murach T, Nakashima K, de Naurois M, Nayerhoda A, Niemiec J, Priyana Noel A, O'Brien P, Ohm S, Olivera-Nieto L, de Ona Wilhelmi E, Ostrowski M, Panny S, Panter M, Parsons RD, Peron G, Pita S, Poireau V, Prokhorov DA, Prokoph H, Pühlhofer G, Punch M, Quirrenbach A, Reichherzer P, Reimer A, Reimer O, Renaud M, Reville B, Rieger F, Rowell G, Rudak B, Rueda Ricarte H, Ruiz-Velasco E, Sahakian V, Sailer S, Salzmann H, Sanchez DA, Santangelo A, Sasaki M, Schäfer J, Schüssler F, Schutte HM, Schwanke U, Senniappan M, Shapopi JNS, Simoni R, Sinha A, Sol H, Specovius A, Spencer S, Stawarz Ł, Steinmassl S, Steppa C, Takahashi T, Tanaka T, Taylor AM, Terrier R, Thorpe-Morgan C, Tsirou M, Tsuji N, Tuffs R, Uchiyama Y, Unbehaun T, van Eldik C, van Soelen B, Veh J, Venter C, Vink J, Wagner SJ, Werner F, White R, Wierzcholska A, Wong YW, Yusafzai A, Zacharias M, Zargaryan D, Zdziarski AA, Zech A, Zhu SJ, Zouari S, and Żywucka N

Abstract

Recurrent novae are repeating thermonuclear explosions in the outer layers of white dwarfs, due to the accretion of fresh material from a binary companion. The shock generated when ejected material slams into the companion star's wind can accelerate particles. We report very-high-energy (VHE; [Formula: see text]) gamma rays from the recurrent nova RS Ophiuchi, up to 1 month after its 2021 outburst, observed using the High Energy Stereoscopic System (H.E.S.S.). The temporal profile of VHE emission is similar to that of lower-energy giga-electron volt emission, indicating a common origin, with a 2-day delay in peak flux. These observations constrain models of time-dependent particle energization, favoring a hadronic emission scenario over the leptonic alternative. Shocks in dense winds provide favorable environments for efficient acceleration of cosmic rays to very high energies.

Published
2022
Full Text
View/download PDF

8. Revealing x-ray and gamma ray temporal and spectral similarities in the GRB 190829A afterglow.

Author

Abdalla H, Aharonian F, Ait Benkhali F, Angüner EO, Arcaro C, Armand C, Armstrong T, Ashkar H, Backes M, Baghmanyan V, Barbosa Martins V, Barnacka A, Barnard M, Becherini Y, Berge D, Bernlöhr K, Bi B, Bissaldi E, Böttcher M, Boisson C, Bolmont J, de Bony de Lavergne M, Breuhaus M, Brun F, Brun P, Bryan M, Büchele M, Bulik T, Bylund T, Caroff S, Carosi A, Casanova S, Chand T, Chandra S, Chen A, Cotter G, Curyło M, Damascene Mbarubucyeye J, Davids ID, Davies J, Deil C, Devin J, Dirson L, Djannati-Ataï A, Dmytriiev A, Donath A, Doroshenko V, Dreyer L, Duffy C, Dyks J, Egberts K, Eichhorn F, Einecke S, Emery G, Ernenwein JP, Feijen K, Fegan S, Fiasson A, Fichet de Clairfontaine G, Fontaine G, Funk S, Füßling M, Gabici S, Gallant YA, Giavitto G, Giunti L, Glawion D, Glicenstein JF, Grondin MH, Hahn J, Haupt M, Hermann G, Hinton JA, Hofmann W, Hoischen C, Holch TL, Holler M, Hörbe M, Horns D, Huber D, Jamrozy M, Jankowsky D, Jankowsky F, Jardin-Blicq A, Joshi V, Jung-Richardt I, Kasai E, Kastendieck MA, Katarzyński K, Katz U, Khangulyan D, Khélifi B, Klepser S, Kluźniak W, Komin N, Konno R, Kosack K, Kostunin D, Kreter M, Lamanna G, Lemière A, Lemoine-Goumard M, Lenain JP, Leuschner F, Levy C, Lohse T, Lypova I, Mackey J, Majumdar J, Malyshev D, Malyshev D, Marandon V, Marchegiani P, Marcowith A, Mares A, Martí-Devesa G, Marx R, Maurin G, Meintjes PJ, Meyer M, Mitchell A, Moderski R, Mohrmann L, Montanari A, Moore C, Morris P, Moulin E, Muller J, Murach T, Nakashima K, Nayerhoda A, de Naurois M, Ndiyavala H, Niemiec J, Oakes L, O'Brien P, Odaka H, Ohm S, Olivera-Nieto L, de Ona Wilhelmi E, Ostrowski M, Panny S, Panter M, Parsons RD, Peron G, Peyaud B, Piel Q, Pita S, Poireau V, Priyana Noel A, Prokhorov DA, Prokoph H, Pühlhofer G, Punch M, Quirrenbach A, Raab S, Rauth R, Reichherzer P, Reimer A, Reimer O, Remy Q, Renaud M, Rieger F, Rinchiuso L, Romoli C, Rowell G, Rudak B, Ruiz-Velasco E, Sahakian V, Sailer S, Salzmann H, Sanchez DA, Santangelo A, Sasaki M, Scalici M, Schäfer J, Schüssler F, Schutte HM, Schwanke U, Seglar-Arroyo M, Senniappan M, Seyffert AS, Shafi N, Shapopi JNS, Shiningayamwe K, Simoni R, Sinha A, Sol H, Specovius A, Spencer S, Spir-Jacob M, Stawarz Ł, Sun L, Steenkamp R, Stegmann C, Steinmassl S, Steppa C, Takahashi T, Tam T, Tavernier T, Taylor AM, Terrier R, Thiersen JHE, Tiziani D, Tluczykont M, Tomankova L, Tsirou M, Tuffs R, Uchiyama Y, van der Walt DJ, van Eldik C, van Rensburg C, van Soelen B, Vasileiadis G, Veh J, Venter C, Vincent P, Vink J, Völk HJ, Wadiasingh Z, Wagner SJ, Watson J, Werner F, White R, Wierzcholska A, Wong YW, Yusafzai A, Zacharias M, Zanin R, Zargaryan D, Zdziarski AA, Zech A, Zhu SJ, Zorn J, Zouari S, Żywucka N, Evans P, and Page K

Abstract

Gamma-ray bursts (GRBs), which are bright flashes of gamma rays from extragalactic sources followed by fading afterglow emission, are associated with stellar core collapse events. We report the detection of very-high-energy (VHE) gamma rays from the afterglow of GRB 190829A, between 4 and 56 hours after the trigger, using the High Energy Stereoscopic System (H.E.S.S.). The low luminosity and redshift of GRB 190829A reduce both internal and external absorption, allowing determination of its intrinsic energy spectrum. Between energies of 0.18 and 3.3 tera-electron volts, this spectrum is described by a power law with photon index of 2.07 ± 0.09, similar to the x-ray spectrum. The x-ray and VHE gamma-ray light curves also show similar decay profiles. These similar characteristics in the x-ray and gamma-ray bands challenge GRB afterglow emission scenarios., (Copyright © 2021 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.)

Published
2021
Full Text
View/download PDF

9. A very-high-energy component deep in the γ-ray burst afterglow.

Author

Abdalla H, Adam R, Aharonian F, Ait Benkhali F, Angüner EO, Arakawa M, Arcaro C, Armand C, Ashkar H, Backes M, Barbosa Martins V, Barnard M, Becherini Y, Berge D, Bernlöhr K, Bissaldi E, Blackwell R, Böttcher M, Boisson C, Bolmont J, Bonnefoy S, Bregeon J, Breuhaus M, Brun F, Brun P, Bryan M, Büchele M, Bulik T, Bylund T, Capasso M, Caroff S, Carosi A, Casanova S, Cerruti M, Chand T, Chandra S, Chen A, Colafrancesco S, Curyło M, Davids ID, Deil C, Devin J, deWilt P, Dirson L, Djannati-Ataï A, Dmytriiev A, Donath A, Doroshenko V, Dyks J, Egberts K, Emery G, Ernenwein JP, Eschbach S, Feijen K, Fegan S, Fiasson A, Fontaine G, Funk S, Füßling M, Gabici S, Gallant YA, Gaté F, Giavitto G, Giunti L, Glawion D, Glicenstein JF, Gottschall D, Grondin MH, Hahn J, Haupt M, Heinzelmann G, Henri G, Hermann G, Hinton JA, Hofmann W, Hoischen C, Holch TL, Holler M, Horns D, Huber D, Iwasaki H, Jamrozy M, Jankowsky D, Jankowsky F, Jardin-Blicq A, Jung-Richardt I, Kastendieck MA, Katarzyński K, Katsuragawa M, Katz U, Khangulyan D, Khélifi B, King J, Klepser S, Kluźniak W, Komin N, Kosack K, Kostunin D, Kreter M, Lamanna G, Lemière A, Lemoine-Goumard M, Lenain JP, Leser E, Levy C, Lohse T, Lypova I, Mackey J, Majumdar J, Malyshev D, Marandon V, Marcowith A, Mares A, Mariaud C, Martí-Devesa G, Marx R, Maurin G, Meintjes PJ, Mitchell AMW, Moderski R, Mohamed M, Mohrmann L, Moore C, Moulin E, Muller J, Murach T, Nakashima S, de Naurois M, Ndiyavala H, Niederwanger F, Niemiec J, Oakes L, O'Brien P, Odaka H, Ohm S, de Ona Wilhelmi E, Ostrowski M, Oya I, Panter M, Parsons RD, Perennes C, Petrucci PO, Peyaud B, Piel Q, Pita S, Poireau V, Priyana Noel A, Prokhorov DA, Prokoph H, Pühlhofer G, Punch M, Quirrenbach A, Raab S, Rauth R, Reimer A, Reimer O, Remy Q, Renaud M, Rieger F, Rinchiuso L, Romoli C, Rowell G, Rudak B, Ruiz-Velasco E, Sahakian V, Sailer S, Saito S, Sanchez DA, Santangelo A, Sasaki M, Schlickeiser R, Schüssler F, Schulz A, Schutte HM, Schwanke U, Schwemmer S, Seglar-Arroyo M, Senniappan M, Seyffert AS, Shafi N, Shiningayamwe K, Simoni R, Sinha A, Sol H, Specovius A, Spir-Jacob M, Stawarz Ł, Steenkamp R, Stegmann C, Steppa C, Takahashi T, Tavernier T, Taylor AM, Terrier R, Tiziani D, Tluczykont M, Trichard C, Tsirou M, Tsuji N, Tuffs R, Uchiyama Y, van der Walt DJ, van Eldik C, van Rensburg C, van Soelen B, Vasileiadis G, Veh J, Venter C, Vincent P, Vink J, Völk HJ, Vuillaume T, Wadiasingh Z, Wagner SJ, White R, Wierzcholska A, Yang R, Yoneda H, Zacharias M, Zanin R, Zdziarski AA, Zech A, Ziegler A, Zorn J, Żywucka N, de Palma F, Axelsson M, and Roberts OJ

Abstract

Gamma-ray bursts (GRBs) are brief flashes of γ-rays and are considered to be the most energetic explosive phenomena in the Universe 1 . The emission from GRBs comprises a short (typically tens of seconds) and bright prompt emission, followed by a much longer afterglow phase. During the afterglow phase, the shocked outflow-produced by the interaction between the ejected matter and the circumburst medium-slows down, and a gradual decrease in brightness is observed 2 . GRBs typically emit most of their energy via γ-rays with energies in the kiloelectronvolt-to-megaelectronvolt range, but a few photons with energies of tens of gigaelectronvolts have been detected by space-based instruments 3 . However, the origins of such high-energy (above one gigaelectronvolt) photons and the presence of very-high-energy (more than 100 gigaelectronvolts) emission have remained elusive 4 . Here we report observations of very-high-energy emission in the bright GRB 180720B deep in the GRB afterglow-ten hours after the end of the prompt emission phase, when the X-ray flux had already decayed by four orders of magnitude. Two possible explanations exist for the observed radiation: inverse Compton emission and synchrotron emission of ultrarelativistic electrons. Our observations show that the energy fluxes in the X-ray and γ-ray range and their photon indices remain comparable to each other throughout the afterglow. This discovery places distinct constraints on the GRB environment for both emission mechanisms, with the inverse Compton explanation alleviating the particle energy requirements for the emission observed at late times. The late timing of this detection has consequences for the future observations of GRBs at the highest energies.

Published
2019
Full Text
View/download PDF

10. Search for γ-Ray Line Signals from Dark Matter Annihilations in the Inner Galactic Halo from 10 Years of Observations with H.E.S.S.

Author

Abdallah H, Abramowski A, Aharonian F, Ait Benkhali F, Angüner EO, Arakawa M, Arrieta M, Aubert P, Backes M, Balzer A, Barnard M, Becherini Y, Becker Tjus J, Berge D, Bernhard S, Bernlöhr K, Blackwell R, Böttcher M, Boisson C, Bolmont J, Bonnefoy S, Bordas P, Bregeon J, Brun F, Brun P, Bryan M, Büchele M, Bulik T, Capasso M, Caroff S, Carosi A, Carr J, Casanova S, Cerruti M, Chakraborty N, Chaves RCG, Chen A, Chevalier J, Colafrancesco S, Condon B, Conrad J, Davids ID, Decock J, Deil C, Devin J, deWilt P, Dirson L, Djannati-Ataï A, Domainko W, Donath A, Drury LO, Dutson K, Dyks J, Edwards T, Egberts K, Eger P, Emery G, Ernenwein JP, Eschbach S, Farnier C, Fegan S, Fernandes MV, Fiasson A, Fontaine G, Förster A, Funk S, Füßling M, Gabici S, Gallant YA, Garrigoux T, Gaté F, Giavitto G, Giebels B, Glawion D, Glicenstein JF, Gottschall D, Grondin MH, Hahn J, Haupt M, Hawkes J, Heinzelmann G, Henri G, Hermann G, Hinton JA, Hofmann W, Hoischen C, Holch TL, Holler M, Horns D, Ivascenko A, Iwasaki H, Jacholkowska A, Jamrozy M, Janiak M, Jankowsky D, Jankowsky F, Jingo M, Jouvin L, Jung-Richardt I, Kastendieck MA, Katarzyński K, Katsuragawa M, Katz U, Kerszberg D, Khangulyan D, Khélifi B, King J, Klepser S, Klochkov D, Kluźniak W, Komin N, Kosack K, Krakau S, Kraus M, Krüger PP, Laffon H, Lamanna G, Lau J, Lees JP, Lefaucheur J, Lemière A, Lemoine-Goumard M, Lenain JP, Leser E, Liu R, Lohse T, Lorentz M, López-Coto R, Lypova I, Malyshev D, Marandon V, Marcowith A, Mariaud C, Marx R, Maurin G, Maxted N, Mayer M, Meintjes PJ, Meyer M, Mitchell AMW, Moderski R, Mohamed M, Mohrmann L, Morå K, Moulin E, Murach T, Nakashima S, de Naurois M, Ndiyavala H, Niederwanger F, Niemiec J, Oakes L, O'Brien P, Odaka H, Ohm S, Ostrowski M, Oya I, Padovani M, Panter M, Parsons RD, Pekeur NW, Pelletier G, Perennes C, Petrucci PO, Peyaud B, Piel Q, Pita S, Poireau V, Poon H, Prokhorov D, Prokoph H, Pühlhofer G, Punch M, Quirrenbach A, Raab S, Rauth R, Reimer A, Reimer O, Renaud M, de Los Reyes R, Rieger F, Rinchiuso L, Romoli C, Rowell G, Rudak B, Rulten CB, Sahakian V, Saito S, Sanchez DA, Santangelo A, Sasaki M, Schandri M, Schlickeiser R, Schüssler F, Schulz A, Schwanke U, Schwemmer S, Seglar-Arroyo M, Settimo M, Seyffert AS, Shafi N, Shilon I, Shiningayamwe K, Simoni R, Sol H, Spanier F, Spir-Jacob M, Stawarz Ł, Steenkamp R, Stegmann C, Steppa C, Sushch I, Takahashi T, Tavernet JP, Tavernier T, Taylor AM, Terrier R, Tibaldo L, Tiziani D, Tluczykont M, Trichard C, Tsirou M, Tsuji N, Tuffs R, Uchiyama Y, van der Walt J, van Eldik C, van Rensburg C, van Soelen B, Vasileiadis G, Veh J, Venter C, Viana A, Vincent P, Vink J, Voisin F, Völk HJ, Vuillaume T, Wadiasingh Z, Wagner SJ, Wagner P, Wagner RM, White R, Wierzcholska A, Willmann P, Wörnlein A, Wouters D, Yang R, Zaborov D, Zacharias M, Zanin R, Zdziarski AA, Zech A, Zefi F, Ziegler A, Zorn J, and Żywucka N

Abstract

Spectral lines are among the most powerful signatures for dark matter (DM) annihilation searches in very-high-energy γ rays. The central region of the Milky Way halo is one of the most promising targets given its large amount of DM and proximity to Earth. We report on a search for a monoenergetic spectral line from self-annihilations of DM particles in the energy range from 300 GeV to 70 TeV using a two-dimensional maximum likelihood method taking advantage of both the spectral and spatial features of the signal versus background. The analysis makes use of Galactic center observations accumulated over ten years (2004-2014) with the H.E.S.S. array of ground-based Cherenkov telescopes. No significant γ-ray excess above the background is found. We derive upper limits on the annihilation cross section ⟨σv⟩ for monoenergetic DM lines at the level of 4×10^{-28}  cm^{3} s^{-1} at 1 TeV, assuming an Einasto DM profile for the Milky Way halo. For a DM mass of 1 TeV, they improve over the previous ones by a factor of 6. The present constraints are the strongest obtained so far for DM particles in the mass range 300 GeV-70 TeV. Ground-based γ-ray observations have reached sufficient sensitivity to explore relevant velocity-averaged cross sections for DM annihilation into two γ-ray photons at the level expected from the thermal relic density for TeV DM particles.

Published
2018
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results