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90 results on '"VHE"'

1. Light scalar explanation for the 18 TeV GRB 221009A

Author

Balaji, Shyam, Maura Elizabeth Ramirez Quezada, Silk, Joseph, Zhang, Yongchao, and HEP, INSPIRE

Subjects
scalar, air, FOS: Physical sciences, Higgs particle, VHE, High Energy Physics - Phenomenology (hep-ph), optical, TeV, attenuation, two-photon, High Energy Astrophysical Phenomena (astro-ph.HE), new physics, radiative decay, background, photon, high, singlet, showers, redshift, [PHYS.HPHE] Physics [physics]/High Energy Physics - Phenomenology [hep-ph], High Energy Physics - Phenomenology, gamma ray, atmosphere, [PHYS.ASTR] Physics [physics]/Astrophysics [astro-ph], Astrophysics - High Energy Astrophysical Phenomena, burst, energy
Abstract

Recent astrophysical transient Swift J1913.1+1946 may be associated with the $\gamma$-ray burst GRB 221009A. The redshift of this event is $z\simeq 0.151$. Very high-energy $\gamma$-rays (up to 18 TeV) followed the transient and were observed by LHAASO, additionally Carpet-2 detected a photon-like air shower of 251 TeV. Photons of such high energy are expected to readily annihilate with the diffuse extragalactic background light (EBL) before reaching Earth. If the $\gamma$-ray identification and redshift measurements are correct, new physics could be necessary to explain these measurements. This letter provides the first CP-even scalar explanation of the most energetic 18 TeV event reported by LHAASO. In this minimal scenario, the light scalar singlet $S$ mixes with the Standard Model (SM) Higgs boson $h$. The highly boosted $S$ particles are produced in the GRB and then undergo the radiative decay di-photon $S\rightarrow \gamma\gamma$ while propagating to Earth. The resulting photons may thus be produced at a remote region without being nullified by the EBL. Hence, the usual exponential reduction of $\gamma$-rays is lifted due to an attenuation that is inverse in the optical depth, which becomes much larger due to the scalar carriers., Comment: 6 pages, 2 figures

Published
2023

2. 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, Laboratoire Leprince-Ringuet (LLR), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), AstroParticule et Cosmologie (APC (UMR_7164)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Laboratoire Univers et Théories (LUTH (UMR_8102)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Laboratoire de Physique Nucléaire et de Hautes Énergies (LPNHE (UMR_7585)), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Annecy de Physique des Particules (LAPP), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Laboratoire Univers et Particules de Montpellier (LUPM), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM), Centre de Physique des Particules de Marseille (CPPM), Aix Marseille Université (AMU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique des Deux Infinis Bordeaux (LP2I - Bordeaux), Université de Bordeaux (UB)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), H.E.S.S., ANR-22-CE31-0012,MOTS,Observations multi-messagers du ciel transitoire(2022), and Astronomy

Subjects
ratio, electron, Non-thermal radiation sources, brightness, FOS: Physical sciences, GeV, VHE, X-ray, 5/3, HESS, synchrotron, High Energy Astrophysical Phenomena (astro-ph.HE), gamma-ray bursts, non-thermal radiation sources, Astronomy and Astrophysics, high, gamma-rays, flux, high-energy cosmic radiation, High-energy cosmic radiation, Space and Planetary Science, gamma ray, atmosphere, correction, Gamma-ray bursts, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Gamma-rays, Astrophysics - High Energy Astrophysical Phenomena, burst, upper limit, energy
Abstract

GRB221009A is the brightest gamma-ray burst ever detected. To probe the very-high-energy (VHE, $>$\!100 GeV) emission, the High Energy Stereoscopic System (H.E.S.S.) began observations 53 hours 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 $\Phi_\mathrm{UL}^{95\%} = 9.7 \times 10^{-12}~\mathrm{erg\,cm^{-2}\,s^{-1}}$ above $E_\mathrm{thr} = 650$ 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 SED occurring above the X-ray band. Compared to the VHE-bright GRB190829A, the upper limits for GRB221009A 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 GRB221009A, effectively ruling out an IC dominated scenario., Comment: 10 pages, 4 figures. Accepted for publication in APJL. Corresponding authors: J. Damascene Mbarubucyeye, H. Ashkar, S. J. Zhu, B. Reville, F. Sch\"ussler

Published
2023

3. HAWC Detection of a TeV Halo Candidate Surrounding a Radio-quiet pulsar

Author

A. Albert, R. Alfaro, J. C. Arteaga-Velázquez, H. A. Ayala Solares, E. Belmont-Moreno, T. Capistrán, A. Carramiñana, S. Casanova, J. Cotzomi, S. Coutiño De León, E. De la Fuente, C. de León, R. Diaz Hernandez, M. A. DuVernois, J. C. Díaz-Vélez, C. Espinoza, K. L. Fan, N. Fraija, K. Fang, J. A. García-González, F. Garfias, A. Jardin-Blicq, M. M. González, J. A. Goodman, J. P. Harding, S. Hernandez, D. Huang, F. Hueyotl-Zahuantitla, P. Hüntemeyer, A. Iriarte, V. Joshi, A. Lara, J. Lee, H. León Vargas, J. T. Linnemann, A. L. Longinotti, G. Luis-Raya, K. Malone, O. Martinez, J. Martínez-Castro, J. A. Matthews, J. A. Morales-Soto, E. Moreno, M. Mostafá, A. Nayerhoda, L. Nellen, M. Newbold, M. U. Nisa, Y. Pérez Araujo, Y. Son, E. G. Pérez-Pérez, C. D. Rho, D. Rosa-González, A. Sandoval, M. Schneider, J. Serna-Franco, A. J. Smith, R. W. Springer, K. Tollefson, I. Torres, R. Torres-Escobedo, X. Wang, K. Whitaker, E. Willox, H. Zhou, and HEP, INSPIRE

Subjects
High Energy Astrophysical Phenomena (astro-ph.HE), formation, water, halo, FOS: Physical sciences, Astronomy and Astrophysics, VHE, observatory, Space and Planetary Science, gamma ray, TeV, spectral, Cherenkov, galaxy, Astrophysics - High Energy Astrophysical Phenomena, [PHYS.ASTR] Physics [physics]/Astrophysics [astro-ph], HAWC, pulsar
Abstract

Extended very-high-energy (VHE; 0.1–100 TeV) γ-ray emission has been observed around several middle-aged pulsars and referred to as “TeV halos.” Their formation mechanism remains under debate. It is also unknown whether they are ubiquitous or related to a certain subgroup of pulsars. With 2321 days of observation, the High Altitude Water Cherenkov (HAWC) Gamma-Ray Observatory detected VHE γ-ray emission at the location of the radio-quiet pulsar PSR J0359+5414 with >6σ significance. By performing likelihood tests with different spectral and spatial models and comparing the TeV spectrum with multiwavelength observations of nearby sources, we show that this excess is consistent with a TeV halo associated with PSR J0359+5414, though future observation of HAWC and multiwavelength follow-ups are needed to confirm this nature. This new halo candidate is located in a noncrowded region in the outer galaxy. It shares similar properties to the other halos but its pulsar is younger and radio-quiet. Our observation implies that TeV halos could commonly exist around pulsars and their formation does not depend on the configuration of the pulsar magnetosphere.

Published
2023

4. Validating Monte Carlo simulations for an analysis chain in H.E.S.S

Author

Leuschner, Fabian, Schäfer, Johannes, Steinmassl, Simon, Holch, Tim Lukas, Bernlöhr, Konrad, Funk, Stefan, Hinton, Jim, Ohm, Stefan, and Pühlhofer, Gerd

Subjects
numerical calculations, Monte Carlo, air, imaging, trigger, VHE, photon, energy, flux, Cherenkov counter, showers, electromagnetic, gamma ray, cosmic radiation, HESS, atmosphere, propagation, site, radiation, Cherenkov, showers, cascade, photon, primary
Abstract

Imaging Air Cherenkov Telescopes (IACTs) detect very high energetic (VHE) gamma rays. They observe the Cherenkov light emitted in electromagnetic shower cascades that gamma rays induce in the atmosphere. A precise reconstruction of the primary photon energy and the source flux depends heavily on accurate Monte Carlo (MC) simulations of the shower propagation and the detector response, and therefore also on adequate assumptions about the atmosphere at the site and time of a measurement. Here, we present the results of an extensive validation of the MC simulations for an analysis chain of the H.E.S.S. experiment with special focus on the recently installed FlashCam camera on the large 28 m telescope. One goal of this work was to create a flexible and easy-to-use framework to facilitate the detailed validation of MC simulations also for past and future phases of the H.E.S.S. experiment. Guided by the underlying physics, the detector simulation and the atmospheric transmission profiles were gradually improved until low level parameters such as cosmic ray (CR) trigger rates matched within a few percent between simulations and observational data. This led to instrument response functions (IRFs) with which the analysis of current H.E.S.S. data can ultimately be carried out within percent accuracy, substantially improving earlier simulations.

Published
2023
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5. Validating Monte Carlo simulations for an analysis chain in H.E.S.S

Author

Leuschner, Fabian, Schäfer, Johannes, Steinmassl, Simon, Holch, Tim Lukas, Bernlöhr, Konrad, Funk, Stefan, Hinton, Jim, Ohm, Stefan, and Pühlhofer, Gerd

Subjects
High Energy Astrophysical Phenomena (astro-ph.HE), numerical calculations, Monte Carlo, air, FOS: Physical sciences, imaging, trigger, VHE, photon, energy, flux, Cherenkov counter, showers, electromagnetic, gamma ray, cosmic radiation, HESS, atmosphere, propagation, site, radiation, Cherenkov, showers, cascade, Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - High Energy Astrophysical Phenomena, photon, primary, Instrumentation and Methods for Astrophysics (astro-ph.IM)
Abstract

Imaging Air Cherenkov Telescopes (IACTs) detect very high energetic (VHE) gamma rays. They observe the Cherenkov light emitted in electromagnetic shower cascades that gamma rays induce in the atmosphere. A precise reconstruction of the primary photon energy and the source flux depends heavily on accurate Monte Carlo (MC) simulations of the shower propagation and the detector response, and therefore also on adequate assumptions about the atmosphere at the site and time of a measurement. Here, we present the results of an extensive validation of the MC simulations for an analysis chain of the H.E.S.S. experiment with special focus on the recently installed FlashCam camera on the large 28 m telescope. One goal of this work was to create a flexible and easy-to-use framework to facilitate the detailed validation of MC simulations also for past and future phases of the H.E.S.S. experiment. Guided by the underlying physics, the detector simulation and the atmospheric transmission profiles were gradually improved until low level parameters such as cosmic ray (CR) trigger rates matched within a few percent between simulations and observational data. This led to instrument response functions (IRFs) with which the analysis of current H.E.S.S. data can ultimately be carried out within percent accuracy, substantially improving earlier simulations., 8 pages, 4 figures, 1 table. Accepted as Proceeding of the 7th Heidelberg International Symposium on High-Energy Gamma-Ray Astronomy (Gamma2022)

Published
2023
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6. Multi-wavelength study of the galactic PeVatron candidate LHAASO J2108+5157

Author

Abe, S., Aguasca-Cabot, A., Agudo, I., Crespo, N. Alvarez, Antonelli, L. A., Aramo, C., Arbet-Engels, A., Artero, M., Asano, K., Aubert, P., Baktash, A., Bamba, A., Larriva, A. Baquero, Baroncelli, L., Almeida, U. Barres, Barrio, J. A., Batkovic, I., Baxter, J., González, J. Becerra, Bernardini, E., Bernardos, M. I., Medrano, J. Bernete, Berti, A., Bhattacharjee, P., Biederbeck, N., Bigongiari, C., Bissaldi, E., Blanch, O., Bordas, P., Buisson, C., Bulgarelli, A., Burelli, I., Buscemi, M., Cardillo, M., Caroff, S., Carosi, A., Cassol, F., Cauz, D., Ceribella, G., Chai, Y., Cheng, K., Chiavassa, A., Chikawa, M., Chytka, L., Cifuentes, A., Contreras, J. L., Cortina, J., Costantini, H., D Amico, G., Dalchenko, M., Angelis, A., Lavergne, M. Bony, Lotto, B., Menezes, R., Deleglise, G., Delgado, C., Mengual, J. Delgado, Della Volpe, D., Dellaiera, M., Di Piano, A., Di Pierro, F., Di Tria, R., Di Venere, L., Díaz, C., Dominik, R. M., Dominis Prester, D., Donini, A., Dorner, D., Doro, M., Elsässer, D., Emery, G., Escudero, J., Fallah Ramazani, V., Ferrara, G., Fiasson, A., Coromina, L. Freixas, Fröse, S., Fukami, S., Fukazawa, Y., Garcia, E., López, R. Garcia, Gasparrini, D., Geyer, D., Paiva, J. Giesbrecht, Giglietto, N., Giordano, F., Giro, E., Gliwny, P., Godinovic, N., Grau, R., Green, D., Green, J., Gunji, S., Hackfeld, J., Hadasch, D., Hahn, A., Hashiyama, K., Hassan, T., Hayashi, K., Heckmann, L., Heller, M., Llorente, J. Herrera, Hirotani, K., Hoffmann, D., Horns, D., Houles, J., Hrabovsky, M., Hrupec, D., Hui, D., Hütten, M., Imazawa, R., Tomohiro Inada, Inome, Y., Ioka, K., Iori, M., Ishio, K., Iwamura, Y., Jacquemont, M., Martinez, I. Jimenez, Jurysek, J., Kagaya, M., Karas, V., Katagiri, H., Kataoka, J., Kerszberg, D., Kobayashi, Y., Kong, A., Kubo, H., Kushida, J., Lainez, M., Lamanna, G., Lamastra, A., Flour, T. Le, Linhoff, M., Longo, F., López-Coto, R., López-Moya, M., López-Oramas, A., Loporchio, S., Lorini, A., Luque-Escamilla, P. L., Majumdar, P., Makariev, M., Mandat, D., Manganaro, M., Manicò, G., Mannheim, K., Mariotti, M., Marquez, P., Marsella, G., Martí, J., Martinez, O., Martínez, G., Martínez, M., Marusevec, P., Mas-Aguilar, A., Maurin, G., Mazin, D., Guillen, E. Mestre, Micanovic, S., Miceli, D., Miener, T., Miranda, J. M., Mirzoyan, R., Mizuno, T., Gonzalez, M. Molero, Molina, E., Montaruli, T., Monteiro, I., Moralejo, A., Morcuende, D., Morselli, A., Mrakovcic, K., Murase, K., Nagai, A., Nakamori, T., Nickel, L., Nievas, M., Nishijima, K., Noda, K., Nosek, D., Nozaki, S., Ohishi, M., Ohtani, Y., Okazaki, N., Okumura, A., Orito, R., Otero-Santos, J., Palatiello, M., Paneque, D., Pantaleo, F. R., Paoletti, R., Paredes, J. M., Pavletić, L., Pech, M., Pecimotika, M., Pietropaolo, E., Pirola, G., Podobnik, F., Poireau, V., Polo, M., Pons, E., Prandini, E., Prast, J., Priyadarshi, C., Prouza, M., Rando, R., Rhode, W., Ribó, M., Rizi, V., Fernandez, G. Rodriguez, Saito, T., Sakurai, S., Sanchez, D. A., Šarić, T., Saturni, F. G., Scherpenberg, J., Schleicher, B., Schmuckermaier, F., Schubert, J. L., Schussler, F., Schweizer, T., Arroyo, M. Seglar, Sitarek, J., Sliusar, V., Spolon, A., Strišković, J., Strzys, M., Suda, Y., Sunada, Y., Tajima, H., Takahashi, M., Takahashi, H., Takata, J., Takeishi, R., Tam, P. H. T., Tanaka, S. J., Tateishi, D., Temnikov, P., Terada, Y., Terauchi, K., Terzic, T., Teshima, M., Tluczykont, M., Tokanai, F., Torres, D. F., Travnicek, P., Truzzi, S., Tutone, A., Uhlrich, G., Vacula, M., Vázquez Acosta, M., Verguilov, V., Viale, I., Vigliano, A., Vigorito, C. F., Vitale, V., Voutsinas, G., Vovk, I., Vuillaume, T., Walter, R., Will, M., Yamamoto, T., Yamazaki, R., Yoshida, T., Yoshikoshi, T., Zywucka, N., Balbo, M., Eckert, D., Tramacere, A., Laboratoire d'Annecy de Physique des Particules (LAPP), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Centre de Physique des Particules de Marseille (CPPM), Aix Marseille Université (AMU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, and CTA-LST

Subjects
halo, FOS: Physical sciences, electron: relativistic, power spectrum, UHE, GLAST, VHE, ISM: individual objects: LHAASO J2108+5157, X-ray, pulsars: general, synchrotron, supernova, TeV, cloud, High Energy Astrophysical Phenomena, pulsar, High Energy Astrophysical Phenomena (astro-ph.HE), magnetic field: low, photon, Astronomy and Astrophysics, gamma rays: general, acceleration, radiation mechanisms: non-thermal, p: interaction, Large-Sized Telescope, LHAASO J2108+5157, Space and Planetary Science, quality, gamma ray, spectral, galaxy, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - High Energy Astrophysical Phenomena
Abstract

LHAASO J2108+5157 is one of the few known unidentified Ultra-High-Energy (UHE) gamma-ray sources with no Very-High-Energy (VHE) counterpart, recently discovered by the LHAASO collaboration. We observed LHAASO J2108+5157 in the X-ray band with XMM-Newton in 2021 for a total of 3.8 hours and at TeV energies with the Large-Sized Telescope prototype (LST-1), yielding 49 hours of good quality data. In addition, we analyzed 12 years of Fermi-LAT data, to better constrain emission of its High-Energy (HE) counterpart 4FGL J2108.0+5155. We found an excess (3.7 sigma) in the LST-1 data at energies E > 3 TeV. Further analysis in the whole LST-1 energy range assuming a point-like source, resulted in a hint (2.2 sigma) of hard emission which can be described with a single power law with photon index Gamma = 1.6 +- 0.2 between 0.3 - 100 TeV. We did not find any significant extended emission which could be related to a Supernova Remnant (SNR) or Pulsar Wind Nebula (PWN) in the XMM-Newton data, which puts strong constraints on possible synchrotron emission of relativistic electrons. The LST-1 and LHAASO observations can be explained as inverse Compton-dominated leptonic emission of relativistic electrons with a cutoff energy of $100^{+70}_{-30}$ TeV. The low magnetic field in the source imposed by the X-ray upper limits on synchrotron emission is compatible with a hypothesis of a PWN or a TeV halo. The lack of a pulsar in the neighborhood of the UHE source is a challenge to the PWN/TeV-halo scenario. The UHE gamma rays can also be explained as $π^0$ decay-dominated hadronic emission due to interaction of relativistic protons with one of the two known molecular clouds in the direction of the source. The hard spectrum in the LST-1 band is compatible with protons escaping a shock around a middle-aged SNR because of their high low-energy cut-off., 26 pages, 9 figures, 5 tables; Astronomy and Astrophysics (accepted on 6 March 2023)

Published
2022

7. The throughput calibration of the VERITAS telescopes

Author

Adams, C. B., Benbow, W., Brill, A., Buckley, J. H., Christiansen, J. L., Falcone, A., Feng, Q., Finley, J. P., Foote, G. M., Fortson, L., Furniss, A., Giuri, C., Hanna, D., Hassan, T., Hervet, O., Holder, J., Hona, B., Humensky, T. B., Jin, W., Kaaret, P., Kleiner, T. K., Kumar, S., Lang, M. J., Lundy, M., Maier, G., Moriarty, P., Mukherjee, R., Rosillo, M. Nievas, O'Brien, S., Park, N., Patel, S., Pfrang, K., Pohl, M., Prado, R. R., Pueschel, E., Quinn, J., Ragan, K., Reynolds, P. T., Ribeiro, D., Roache, E., Ryan, J. L., Santander, M., Weinstein, A., Williams, D. A., and Williamson, T. J.

Subjects
numerical calculations, Monte Carlo, atmosphere [Cherenkov counter], damage, time dependence, techniques: image processing, optical, mirror, High Energy Astrophysical Phenomena (astro-ph.HE), photomultiplier, image processing [techniques], performance [detector], imaging [detector], photon, Astrophysics::Instrumentation and Methods for Astrophysics, Throughput calibration, Monte Carlo [numerical calculations], detector: imaging, efficiency: quantum, time dependence [damage], astroparticle physics, VERITAS, Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - High Energy Astrophysical Phenomena, numerical calculations: Monte Carlo, atmosphere [showers], efficiency, quantum, Cherenkov counter, atmosphere, detector: performance, air, Astrophysics::High Energy Astrophysical Phenomena, tube, FOS: Physical sciences, Cherenkov telescopes, Cherenkov counter: atmosphere, damage: time dependence, VHE, Instrument Response Functions, Instrumentation and Methods for Astrophysics (astro-ph.IM), quantum [efficiency], detector, imaging, showers, atmosphere, detectors [instrumentation], detector, performance, showers: atmosphere, instrumentation: detectors, telescopes, calibration, monitoring, gamma ray, ddc:520
Abstract

Astronomy and astrophysics 658, A83 (2022). doi:10.1051/0004-6361/202142275, Context. The response of imaging air Cherenkov telescopes to incident $γ$-ray-initiated showers in the atmosphere changes as the telescopes age due to exposure to light and weather. These aging processes affect the reconstructed energies of the events and $γ$-ray fluxes.Aims. This work discusses the implementation of signal calibration methods for the Very Energetic Radiation Imaging Telescope Array System (VERITAS) to account for changes in the optical throughput and detector performance over time. Methods. The total throughput of a Cherenkov telescope is the product of camera-dependent factors, such as the photomultiplier tube gains and their quantum efficiencies, and the mirror reflectivity and Winston cone response to incoming radiation. This document summarizes different methods to determine how the camera gains and mirror reflectivity have evolved over time and how we can calibrate this changing throughput in reconstruction pipelines for imaging air cherenkov telescopes. The implementation is validated against seven years of observations with the VERITAS telescopes of the Crab Nebula, which is a reference object in very-high-energy astronomy.Results. Regular optical throughput monitoring and the corresponding signal calibrations are found to be critical for the reconstruction of extensive air shower images. The proposed implementation is applied as a correction to the signals of the photomultiplier tubes in the telescope simulation to produce fine-tuned instrument response functions. This method is shown to be effective for calibrating the acquired $γ$-ray data and for recovering the correct energy of the events and photon fluxes. At the same time, it keeps the computational effort of generating Monte Carlo simulations for instrument response functions affordably low., Published by EDP Sciences, Les Ulis

Published
2022
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8. Search for Dark Matter Annihilation Signals in the H.E.S.S. Inner Galaxy Survey

Author

Abdalla, H., Aharonian, F., Becherini, Y., Rueda Ricarte, H., Ruiz-Velasco, E., Sahakian, V., Salzmann, H., Santangelo, A., Sasaki, M., Schüssler, F., Schutte, H. M., Schwanke, U., Senniappan, M., Berge, D., Shapopi, J. N. S., Sol, H., Specovius, A., Spencer, S., Stawarz, L., Stegmann, C., Steinmassl, S., Steppa, C., Takahashi, T., Tanaka, T., Bernlöhr, K., Terrier, R., Thorpe-Morgan, C., Tluczykont, M., Tsirou, M., Tsuji, N., Uchiyama, Y., van Eldik, C., Veh, J., Vink, J., Wagner, S. J., Bi, B., White, R., Wierzcholska, A., Wong, Yu Wun, Zacharias, M., Zargaryan, D., Zdziarski, A. A., Zech, A., Zhu, S. J., Zouari, S., Zywucka, N., Böttcher, M., H. E. S. S. Collaboration, Bolmont, J., de Bony de Lavergne, M., Brose, R., Brun, F., Cangemi, F., Benkhali, F. Ait, Caroff, S., Cerruti, M., Chand, T., Chen, A., Cotter, G., Damascene Mbarubucyeye, J., Devin, J., Djannati-Ataï, A., Dmytriiev, A., Doroshenko, V., Angüner, E. O., Egberts, K., Fiasson, A., Fichet de Clairfontaine, G., Fontaine, G., Funk, S., Gabici, S., Giavitto, G., Glawion, D., Glicenstein, J. F., Grondin, M.-H., Armand, C., Hinton, J. A., Hofmann, W., Holch, T. L., Holler, M., Horns, D., Huang, Zhiqiu, Jamrozy, M., Jankowsky, F., Kasai, E., Katarzynski, K., Ashkar, H., Katz, U., Khélifi, B., Klúzniak, W., Komin, Nu., Kosack, K., Kostunin, D., Lamanna, G., Lemoine-Goumard, M., Lenain, J.-P., Leuschner, F., Backes, M., Lohse, T., Luashvili, A., Lypova, I., Mackey, J., Malyshev, D., Marandon, V., Marchegiani, P., Martí-Devesa, G., Marx, R., Baghmanyan, V., Maurin, G., Meyer, M., Mitchell, A., Moderski, R., Montanari, A., Moulin, E., Muller, J., de Naurois, M., Niemiec, J., Noel, A. Priyana, Barbosa Martins, V., Ohm, S., Olivera-Nieto, L., de Ona Wilhelmi, Emma Maria, Ostrowski, M., Panny, S., Panter, M., Parsons, R. D., Peron, G., Poireau, V., Prokoph, H., Batzofin, R., Pühlhofer, G., Punch, M., Quirrenbach, A., Reichherzer, P., Reimer, A., Reimer, O., Renaud, M., Rieger, F., Rowell, G., Rudak, B., Centre de Physique des Particules de Marseille (CPPM), Aix Marseille Université (AMU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Annecy de Physique des Particules (LAPP), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Laboratoire de Physique Nucléaire et de Hautes Énergies (LPNHE (UMR_7585)), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), AstroParticule et Cosmologie (APC (UMR_7164)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Centre d'Etudes Nucléaires de Bordeaux Gradignan (CENBG), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Univers et Théories (LUTH (UMR_8102)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Leprince-Ringuet (LLR), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Univers et Particules de Montpellier (LUPM), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM), H.E.S.S., High Energy Astrophys. & Astropart. Phys (API, FNWI), and H.E.S.S. Collaboration

Subjects
General Physics and Astronomy, FOS: Physical sciences, mass [dark matter], dark matter: density, GeV, annihilation [dark matter], VHE, cross section: annihilation, HESS, TeV, ddc:530, High Energy Astrophysical Phenomena (astro-ph.HE), dark matter: mass, density [dark matter], central region, dark matter: annihilation, Navarro-Frenk-White profile, annihilation [cross section], Cherenkov counter, gamma ray, HESS - Abteilung Hinton, galaxy, Astrophysics - High Energy Astrophysical Phenomena, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], signature
Abstract

Physical review letters 129(11), 111101 (2022). doi:10.1103/PhysRevLett.129.111101, 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 by APS, College Park, Md.

Published
2022
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9. Current and Future $γ$-Ray Searches for Dark Matter Annihilation Beyond the Unitarity Limit

Author

Tak, Donggeun, Baumgart, Matthew, Rodd, Nicholas L., and Pueschel, Elisa

Subjects
Astrophysics and Astronomy, Cosmology and Nongalactic Astrophysics (astro-ph.CO), air, atmosphere [Cherenkov counter], FOS: Physical sciences, mass [dark matter], GeV, Cherenkov counter: atmosphere, geometrical [cross section], annihilation [dark matter], VHE, High Energy Physics - Experiment, cross section, geometrical, High Energy Physics - Experiment (hep-ex), High Energy Physics - Phenomenology (hep-ph), unitarity, TeV, Dark Matter, cross section: geometrical, Particle Physics - Phenomenology, High Energy Astrophysical Phenomena (astro-ph.HE), background, dark matter: mass, imaging, dark matter: annihilation, showers, observatory, High Energy Physics - Phenomenology, Cherenkov counter, gamma ray, ddc:520, Ultra-heavy Dark Matter, VERITAS, dark matter, annihilation, Astrophysics - High Energy Astrophysical Phenomena, HAWC, Particle Physics - Experiment, signature, dark matter, mass, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

The astrophysical journal / 2 938(1), L4 (2022). doi:10.3847/2041-8213/ac9387, For decades, searches for electroweak-scale dark matter (DM) have been performed without a definitive detection. This lack of success may hint that DM searches have focused on the wrong mass range. A proposed candidate beyond the canonical parameter space is ultraheavy DM (UHDM). In this work, we consider indirect UHDM annihilation searches for masses between 30 TeV and 30 PeV—extending well beyond the unitarity limit at ∼100 TeV—and discuss the basic requirements for DM models in this regime. We explore the feasibility of detecting the annihilation signature, and the expected reach for UHDM with current and future very-high-energy (VHE; >100 GeV) $γ$-ray observatories. Specifically, we focus on three reference instruments: two Imaging Atmospheric Cherenkov Telescope arrays, modeled on VERITAS and CTA-North, and one extended air shower array, motivated by HAWC. With reasonable assumptions on the instrument response functions and background rate, we find a set of UHDM parameters (mass and cross section) for which a γ-ray signature can be detected by the aforementioned observatories. We further compute the expected upper limits for each experiment. With realistic exposure times, the three instruments can probe DM across a wide mass range. At the lower end, it can still have a point-like cross section, while at higher masses the DM could have a geometric cross section, indicative of compositeness., Published by Institute of Physics Publ., London

Published
2022
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10. Monte Carlo Simulations and Validation of NectarCAM, a Medium Sized Telescope Camera for CTA

Author

Thomas Armstrong, Ullrich Schwanke, Thomas Tavernier, Heide Costantini, Jean-Francois Glicenstein, Jean-Philippe Lenain, Centre de Physique des Particules de Marseille (CPPM), Aix Marseille Université (AMU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Laboratoire de Physique Nucléaire et de Hautes Énergies (LPNHE (UMR_7585)), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), CTA Consortium, and Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)

Subjects
Photomultiplier, Cherenkov Telescope Array, Computer science, Physics::Instrumentation and Detectors, air, Astrophysics::High Energy Astrophysical Phenomena, Monte Carlo method, FOS: Physical sciences, Field of view, magnetic field, GeV, 7. Clean energy, programming, VHE, law.invention, Telescope, law, Observatory, pixel, ultraviolet, TeV, Sensitivity (control systems), structure, [PHYS.PHYS.PHYS-INS-DET]Physics [physics]/Physics [physics]/Instrumentation and Detectors [physics.ins-det], Instrumentation and Methods for Astrophysics (astro-ph.IM), Remote sensing, High Energy Astrophysical Phenomena (astro-ph.HE), photomultiplier, Pixel, showers: atmosphere, background, photon, Astrophysics::Instrumentation and Methods for Astrophysics, parametrization, trigger, sensitivity, readout: performance, observatory, gamma ray, Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - High Energy Astrophysical Phenomena, numerical calculations: Monte Carlo, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

The upcoming Cherenkov Telescope Array (CTA) ground-based gamma-ray observatory will open up our view of the very high energy Universe, offering an improvement in sensitivity of 5-10 times that of previous experiments. NectarCAM is one of the proposed cameras for the Medium-Sized Telescopes (MST) which have been designed to cover the core energy range of CTA, from 100 GeV to 10 TeV. The final camera will be capable of GHz sampling and provide a field of view of 8 degrees with its 265 modules of 7 photomultiplier each (for a total of 1855 pixels). In order to validate the performance of NectarCAM, a partially-equipped prototype has been constructed consisting of only the inner 61-modules. It has so far undergone testing at the integration test-bench facility in CEA Paris-Saclay (France) and on a prototype of the MST structure in Adlershof (Germany). To characterize the performance of the prototype, Monte Carlo simulations were conducted using a detailed model of the 61 module camera in the CORSIKA/sim_telarray framework. This contribution provides an overview of this work including the comparison of trigger and readout performance on test-bench data and trigger and image parameterization performance during on-sky measurements., 8 pages, 5 figures

Published
2021

11. Search for enhanced TeV gamma ray emission from Giant Molecular Clouds using H.E.S.S

Author

Abdalla, H., Aharonian, F., Ait Benkhali, F., Angüner, E. O., Arcaro, C., Armand, C., Armstrong, T., Ashkar, H., Backes, M., Baghmanyan, V., Barbosa Martins, V., Barnacka, A., Barnard, M., Batzofin, R., Becherini, Y., Berge, D., Bernlöhr, K., Bi, B., Böttcher, M., Boisson, C., Bolmont, J., Bony Lavergne, M., Breuhaus, M., Brose, R., Brun, F., Bulik, T., Bylund, T., Cangemi, F., Caroff, S., Casanova, S., Catalano, J., Chambery, P., Chand, T., Chen, A., Cotter, G., Curyło, M., Dalgleish, H., Damascene Mbarubucyeye, J., Davids, I. D., Davies, J., Devin, J., Djannati-Ataï, A., Dmytriiev, A., Donath, A., Doroshenko, V., Dreyer, L., Du Plessis, L., Duffy, C., Egberts, K., Einecke, S., Ernenwein, J. -P, Fegan, S., Feijen, K., Fiasson, A., Fichet Clairfontaine, G., Fontaine, G., Lott, F., Füßling, M., Funk, S., Gabici, S., Gallant, Y. A., Giavitto, G., Giunti, L., Glawion, D., Glicenstein, J. F., Grondin, M. -H, Hattingh, S., Haupt, M., Hermann, G., Hinton, J. A., Hofmann, W., Hoischen, C., Holch, T. L., Holler, M., Horns, D., Huang, Z., Huber, D., Hörbe, M., Jamrozy, M., Jankowsky, F., Joshi, V., Jung-Richardt, I., Kasai, E., Katarzyński, K., Katz, U., Khangulyan, D., Khélifi, B., Klepser, S., Kluźniak, W., Komin, Nu, Konno, R., Kosack, K., Kostunin, D., Kreter, M., Kukec Mezek, G., Kundu, A., Lamanna, G., Le Stum, S., Lemière, A., Lemoine-Goumard, M., Lenain, J. -P, Leuschner, F., Levy, C., Lohse, T., Luashvili, A., Lypova, I., Mackey, J., Majumdar, J., Malyshev, D., Marandon, V., Marchegiani, P., Marcowith, A., Mares, A., Martí-Devesa, G., Marx, R., Maurin, G., Meintjes, P. J., Meyer, M., Mitchell, A., Moderski, R., Mohrmann, L., Montanari, A., Moore, C., Morris, P., Moulin, E., Muller, J., Murach, T., Nakashima, K., Naurois, M., Nayerhoda, A., Ndiyavala, H., Niemiec, J., Priyana Noel, A., O Brien, P., Oberholzer, L., Ohm, S., Olivera-Nieto, L., Ona Wilhelmi, E., Ostrowski, M., Panny, S., Panter, M., Parsons, R. D., Peron, G., Pita, S., Poireau, V., Prokhorov, D. A., Prokoph, H., Pühlhofer, G., Punch, M., Quirrenbach, A., Reichherzer, P., Reimer, A., Reimer, O., Remy, Q., Renaud, M., Reville, B., Rieger, F., Romoli, C., Rowell, G., Rudak, B., Rueda Ricarte, H., Ruiz-Velasco, E., Sahakian, V., Sailer, S., Salzmann, H., Sanchez, D. A., Santangelo, A., Sasaki, M., Johannes Schäfer, Schutte, H. M., Schwanke, U., Schüssler, F., Senniappan, M., Seyffert, A. S., Shapopi, J. N. S., Shiningayamwe, K., Simoni, R., Sinha, A., Sol, H., Spackman, H., Specovius, A., Spencer, S., Spir-Jacob, M., Stawarz, Ł., Steenkamp, R., Stegmann, C., Steinmassl, S., Steppa, C., Sun, L., Takahashi, T., Tanaka, T., Tavernier, T., Taylor, A. M., Terrier, R., Thiersen, J. H. E., Thorpe-Morgan, C., Tluczykont, M., Tomankova, L., Tsirou, M., Tsuji, N., Tuffs, R., Uchiyama, Y., Walt, D. J., Eldik, C., Rensburg, C., Soelen, B., Vasileiadis, G., Veh, J., Venter, C., Vincent, P., Vink, J., Völk, H. J., Wagner, S. J., Watson, J., Werner, F., White, R., Wierzcholska, A., Wong, Y. W., Yassin, H., Yusafzai, A., Zacharias, M., Zanin, R., Zargaryan, D., Zdziarski, A. A., Zech, A., Zhu, S. J., Zmija, A., Zouari, S., Żywucka, N., Laboratoire Univers et Particules de Montpellier (LUPM), Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Montpellier 2 - Sciences et Techniques (UM2), HESS, for the H.E.S.S. collaboration, and H.E.S.S.

Subjects
dimension: 3, accelerator, Astrophysics::High Energy Astrophysical Phenomena, Hadron, FOS: Physical sciences, Neutral pions, Cosmic ray, cosmic radiation: density, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Cherenkov counter: atmosphere, 7. Clean energy, Dense gas, Imaging atmospheric Cherenkov telescopes, Clouds, Cosmology, Gamma rays, Cosmic ray interactions, diffuse emission, Giant molecular clouds, Ray density, TeV gamma-ray emission, VHE, Pion, TRACER, gas, HESS, TeV, cloud, matter: density, Cherenkov radiation, Astrophysics::Galaxy Astrophysics, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), Molecular cloud, Gamma ray, Astrophysics::Instrumentation and Methods for Astrophysics, imaging, model: hadronic, Galaxy, background: hadronic, Cherenkov counter, gamma ray: emission, 13. Climate action, cosmic radiation: galaxy, HESS - Abteilung Hinton, Astrophysics - High Energy Astrophysical Phenomena, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

Cosmic Ray (CR) interactions with the dense gas inside Giant Molecular Clouds (GMCs) produce neutral pions, which in turn decay into gamma rays. Thus, the gamma ray emission from GMCs is a direct tracer of the cosmic ray density and the matter density inside the clouds. Detection of enhanced TeV emission from GMCs, i.e., an emission significantly larger than what is expected from the average Galactic cosmic rays illuminating the cloud, can imply a variation in the local cosmic ray density, due to, for example, the presence of a recent accelerator in proximity to the cloud. Such gamma-ray observations can be crucial in probing the cosmic ray distribution across our Galaxy, but are complicated to perform with present generation Imaging Atmospheric Cherenkov Telescopes (IACTs). These studies require differentiating between the strong cosmic-ray induced background, the large scale diffuse emission, and the emission from the clouds, which is difficult to the small field of view of present generation IACTs. In this contribution, we use H.E.S.S. data collected over 16 years to search for TeV emission from GMCs in the inner molecular galacto-centric ring of our Galaxy. We implement a 3D FoV likelihood technique, and simultaneously model the hadronic background, the galactic diffuse emission and the emission expected from known VHE sources to probe for excess TeV gamma ray emission from GMCs., PoS: Proceedings of Science, 395, ISSN:1824-8039, Proceedings of 37th International Cosmic Ray Conference

Published
2021

12. Performance of a proposed event-type based analysis for CTA

Author

Tarek M. Hassan, Maximilian Nöthe, Gernot Maier, Ievgen Vovk, Michele Peresano, Orel Gueta, Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7), CTA Consortium, Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Cherenkov Telescope Array, Computer science, Astrophysics::High Energy Astrophysical Phenomena, Monte Carlo method, energy resolution, GeV, VHE, GLAST, Set (abstract data type), Observatory, TeV, ddc:530, Sensitivity (control systems), [PHYS.PHYS.PHYS-INS-DET]Physics [physics]/Physics [physics]/Instrumentation and Detectors [physics.ins-det], Event (probability theory), Astroparticle physics, Monte Carlo [numerical calculations], sensitivity, observatory, gamma ray, quality, numerical calculations: Monte Carlo, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Algorithm, Energy (signal processing), performance
Abstract

37th International Cosmic Ray Conference, ICRC 2021, Berlin, online, Germany, 12 Jul 2021 - 23 Jul 2021; Proceedings of Science / International School for Advanced Studies (ICRC2021), 752 (2021). doi:10.22323/1.395.0752, The Cherenkov Telescope Array (CTA) will be the next-generation observatory in the field of very-high-energy (20 GeV to 300 TeV) gamma-ray astroparticle physics. Classically, data analysis in the field maximizes sensitivity by applying quality cuts on the data acquired. These cuts, optimized using Monte Carlo simulations, select higher quality events from the initial dataset. Subsequent steps of the analysis typically use the surviving events to calculate one set of instrument response functions (IRFs). An alternative approach is the use of event types, as implemented in experiments such as the Fermi-LAT. In this approach, events are divided into sub-samples based on their reconstruction quality, and a set of IRFs is calculated for each sub-sample. The sub-samples are then combined in a joint analysis, treating them as independent observations. This leads to an improvement in performance parameters such as sensitivity, angular and energy resolution. Data loss is reduced since lower quality events are included in the analysis as well, rather than discarded. In this study, machine learning methods will be used to classify events according to their expected angular reconstruction quality. We will report the impact on CTA high-level performance when applying such an event-type classification, compared to the classical procedure., Published by SISSA, Trieste

Published
2021

13. Cosmic ray acceleration and gamma-ray emission from protostellar jets

Author

Marco Padovani, Anabella T. Araudo, Alexandre Marcowith, Laboratoire Univers et Particules de Montpellier (LUPM), and Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Montpellier 2 - Sciences et Techniques (UM2)

Subjects
velocity, Cherenkov Telescope Array, Astrophysics::High Energy Astrophysical Phenomena, satellite, electron: relativistic, Cosmic ray, magnetic field, Astrophysics, GeV, 7. Clean energy, GLAST, VHE, Acceleration, synchrotron, TeV, cosmic radiation: acceleration, Astrophysics::Galaxy Astrophysics, Physics, radio wave, energy: high, hybrid, formation, Gamma ray, acceleration: shock waves, stability, star: massive, gamma ray: emission, p: energy, 13. Climate action, Physics::Accelerator Physics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

International audience; The detection of synchrotron radio emission from jetspowered by massive protostars indicates the presence of relativistic electrons and magnetic fields of strength $\sim$0.3$-$5~mG. We study diffusive shock acceleration andmagnetic field amplification in protostellar jets with speed1000 km s$^{-1}$. We show that the magnetic field in the synchrotron emitter can be amplified by the non-resonant hybrid (Bell) instability excited by the cosmic-ray streaming. By combining the synchrotron data with basic theory of Bell instability we estimate the magnetic field in the synchrotron emitter and the maximum energy of protons.Protons can achieve maximum energies $\sim 0.1$ TeV and emit $\gamma$ rays in their interaction with matter fields. We predict detectable levels of $\gamma$ rays in IRAS~16547-5247 and IRAS~16848-4603.The detection of this radiation by the Fermi satellite in the GeV domain and the forthcoming Cherenkov Telescope Array at higher energies may open a new window to study the formation of massive stars, as well as diffusive acceleration and magnetic field amplification in shocks with velocities of about 1000 km s$^{-1}$.

Published
2021

14. The gamma-ray signal from type IIP core-collapse supernovae

Author

Pierre Cristofari, Alexandre Marcowith, Matthieu Renaud, Vikram V. Dwarkadas, V. Tatischeff, Observatoire de Paris - Site de Meudon (OBSPM), Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Univers et Particules de Montpellier (LUPM), Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique des 2 Infinis Irène Joliot-Curie (IJCLab), and Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)

Subjects
Shock wave, Physics, Photosphere, Cherenkov Telescope Array, Photon, two-photon: absorption, supernova: collapse, Astrophysics::High Energy Astrophysical Phenomena, photon, Gamma ray, shock waves, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, VHE, observatory, star: massive, Supernova, Observatory, time dependence, Astrophysics::Solar and Stellar Astrophysics, Red supergiant, gamma ray: flux, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics::Galaxy Astrophysics
Abstract

International audience; The shock wave resulting from the core-collapse of a massive star can accelerate particles up to PeV energies in the first few days to weeks after the explosion. This can lead to the production of a potentially detectable gamma-ray signal. The gamma-ray flux however is strongly affected by the two photon-annihilation process, where gamma-ray photons interact with photons from the SN photosphere. This process hampers the detection of gamma-rays from core-collapse supernovae at very high energies. In order to probe the detectability of the gamma-rays with current and upcoming gamma-ray facilities, we estimate the gamma-ray flux from typical type IIP core collapse supernovae (CCSNe). These are the most common type of supernovae, and are presumed to arise from red supergiant progenitors. We include a detailed time-dependent calculation of two-photon absorption. Our results will be very useful in creating a strategic observing program to detect CCSNe with the next generation gamma-ray observatory, such as the Cherenkov Telescope Array (CTA).

Published
2021

15. H.E.S.S. follow-up observations of binary black hole coalescence events during the second and third gravitational-wave observing runs of advanced LIGO and advanced Virgo

Author

Abdalla, H., Aharonian, F., Berge, D., Prokoph, Heike, Pühlhofer, G., Punch, M., Quirrenbach, A., Reichherzer, P., Renaud, M., Rieger, F., Rowell, G., Rudak, B., Ricarte, H. Rueda, Bernlöhr, K., Velasco, E. Ruiz, Sahakian, V., Sailer, S., Salzmann, H., Sanchez, D. A., Santangelo, A., Sasaki, M., Schüssler, F., Schutte, H. M., Schwanke, U., Bi, B., Senniappan, M., Shapopi, J. N. S., Sinha, A., Sol, H., Specovius, A., Spencer, S., Stawarz, L., Steinmassl, S., Steppa, C., Sun, L., Böttcher, M., Takahashi, T., Tanaka, T., Terrier, R., Thorpe-Morgan, C., Tsirou, M., Tsuji, N., Uchiyama, Y., van Eldik, C., Veh, J., Vink, J., Boisson, C., Wagner, S. J., Werner, F., White, R., Wierzcholska, A., Wong, Yu Wun, Zacharias, M., Zargaryan, D., Zdziarski, A. A., Zech, A., Zhu, Sylvia Jiechen, Bolmont, J., Zouari, S., Zywucka, N., H. E. S. S. Collaboration, de Lavergne, M. de Bony, Brose, R., Brun, F., Bulik, T., Benkhali, F. Ait, Bylund, T., Cangemi, F., Caroff, S., Casanova, S., Chand, T., Chen, A., Cotter, G., Mbarubucyeye, Jean Damascene, Devin, J., Djannati-AtaÏ, A., Angüner, E. O., Egberts, K., Ernenwein, J.-P., Fegan, S., Fiasson, A., de Clairfontaine, G. Fichet, Fontaine, G., Funk, S., Gabici, S., Giavitto, G., Giunti, L., Ashkar, H., Glawion, D., Glicenstein, J. F., Grondin, M.-H., Hinton, J. A., Hörbe, M., Hofmann, W., Holch, Tim Lukas, Holler, M., Huang, Zhiqiu, Huber, D., Backes, M., Jamrozy, M., Jankowsky, F., Jung-Richardt, I., Kasai, E., Katarzyński, K., Katz, U., Khélifi, B., Komin, Nu., Konno, Ruslan, Kosack, K., Baghmanyan, V., Kostunin, D., Kundu, A., Lamanna, G., Stum, S. Le, Lemière, A., Lemoine-Goumard, M., Lenain, J.-P., Leuschner, F., Lohse, T., Luashvili, A., Martins, V. Barbosa, Lypova, I., Mackey, J., Majumdar, Jhilik, Malyshev, D., Marandon, V., Marchegiani, P., Martí-Devesa, G., Marx, R., Maurin, G., Meintjes, P. J., Batzofin, R., Mitchell, A., Mohrmann, L., Montanari, A., Moulin, E., Muller, J., Murach, T., de Naurois, M., Nayerhoda, A., Niemiec, J., Noel, A. Priyana, Becherini, Y., O'Brien, P., Ohm, S., Olivera-Nieto, L., Wilhelmi, E. de Ona, Ostrowski, M., Panter, M., Parsons, R. D., Peron, G., Poireau, V., Prokhorov, D. A., University of Namibia (UNAM), Dublin Institute of Technology (DIT), Max-Planck-Institut für Kernphysik (MPIK), Max-Planck-Gesellschaft, Russian-Armenian University (RAU), Centre de Physique des Particules de Marseille (CPPM), Aix Marseille Université (AMU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Instytut Fizyki Jądrowej PAN (IFJ), Polskiej Akademii Nauk, Deutsches Elektronen-Synchrotron [Hamburg] (DESY), University of the Witwatersrand [Johannesburg] (WITS), Linnaeus University, Max Planck Institut für Infektionsbiologie (MPIIB), Eberhard Karls Universität Tübingen = Eberhard Karls University of Tuebingen, North-West University [Potchefstroom] (NWU), Laboratoire Univers et Théories (LUTH (UMR_8102)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Laboratoire de Physique Nucléaire et de Hautes Énergies (LPNHE (UMR_7585)), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Annecy de Physique des Particules (LAPP), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), University of Warsaw (UW), Instytut Fizyki Jadrowej, PAN (IFJ/PAN), University of Oxford, Centre d'Etudes Nucléaires de Bordeaux Gradignan (CENBG), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), AstroParticule et Cosmologie (APC (UMR_7164)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, University of Potsdam = Universität Potsdam, Laboratoire Leprince-Ringuet (LLR), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Erlangen Centre for Astroparticle Physics (ECAP), Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Leopold Franzens Universität Innsbruck - University of Innsbruck, Uniwersytet Jagielloński w Krakowie = Jagiellonian University (UJ), Universität Heidelberg [Heidelberg] = Heidelberg University, Nicolaus Copernicus University [Toruń], Institut fur Physik, Humboldt Universitat zu Berlin, Humboldt University Of Berlin, Dublin City University [Dublin] (DCU), Laboratoire Univers et Particules de Montpellier (LUPM), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), H.E.S.S., Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Université Sciences et Technologies - Bordeaux 1-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Montpellier 2 - Sciences et Techniques (UM2), and Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)

Subjects
coalescence, black hole: binary: coalescence, gamma ray, burst, binary, FOS: Physical sciences, GeV, gamma ray: burst, 7. Clean energy, 030226 pharmacology & pharmacy, 01 natural sciences, black hole, binary, VHE, localization, 03 medical and health sciences, 0302 clinical medicine, HESS, 0103 physical sciences, black hole, TeV, ddc:530, LIGO, 010303 astronomy & astrophysics, High Energy Astrophysical Phenomena (astro-ph.HE), energy: high, gravitational radiation, Astronomy and Astrophysics, high, VIRGO, energy, high, gamma ray: VHE, black hole: binary, 13. Climate action, Space and Planetary Science, gamma ray, ddc:520, black hole, binary, coalescence, Astrophysics - High Energy Astrophysical Phenomena, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], burst, energy
Abstract

We report on the observations of four well-localized binary black hole (BBH) mergers by the High Energy Stereoscopic System (H.E.S.S.) during the second and third observing runs of Advanced LIGO and Advanced Virgo, O2 and O3. H.E.S.S. can observe 20 deg2 of the sky at a time and follows up gravitational-wave (GW) events by “tiling” localization regions to maximize the covered localization probability. During O2 and O3, H.E.S.S. observed large portions of the localization regions, between 35% and 75%, for four BBH mergers (GW170814, GW190512_180714, GW190728_064510, and S200224ca). For these four GW events, we find no significant signal from a pointlike source in any of the observations, and we set upper limits on the very high energy (>100 GeV) γ-ray emission. The 1–10 TeV isotropic luminosity of these GW events is below 1045 erg s−1 at the times of the H.E.S.S. observations, around the level of the low-luminosity GRB 190829A. Assuming no changes are made to how follow-up observations are conducted, H.E.S.S. can expect to observe over 60 GW events per year in the fourth GW observing run, O4, of which eight would be observable with minimal latency.

Published
2021

16. Probing extreme environments with the Cherenkov Telescope Array

Author

Boisson, C., Brown, A. M., Burtovoi, A., Cerruti, M., Chernyakova, M., Hassan, T., Lenain, J.-P., Manganaro, M., Romano, P., Sol, H., Tavecchio, F., Vercellone, S., Zampieri, L., Zanin, R., Zech, A., Agudo, I., Alves Batista, R., Anguner, E. O., Antonelli, L. A., Backes, M., Balazs, C., Becerra Gonz��lez, J., Bigongiari, C., Bissaldi, E., Bolmont, J., Bordas, P., Bo��njak, ��., B��ttcher, M., Burton, M., Cangemi, F., Caraveo, P., Cardillo, M., Caroff, S., Carosi, A., Casanova, S., Chaty, S., Contreras, J. L., Coelho, J. G., Cotter, G., D'A��, A., D'Ammando, F., de Gouveia Dal Pino, E. M., de Martino, D., Delgado, C., della Volpe, D., Djannati-Ata��, A., Anjos, R. C. Dos, Wilhelmi, E. de O��a, Dwarkadas, V., Emery, G., Fedorova, E., Fegan, S., Filipovic, M. D., Galanti, G., Gasparrini, D., Ghirlanda, G., Goldoni, P., Granot, J., Green, J. G., Heller, M., Hnatyk, B., Hnatyk, R., Horan, D., Hovatta, T., Inoue, S., Jamrozy, M., Kh��lifi, B., Komin, N., Kohri, K., Lamastra, A., La Palombara, N., Lindfors, E., Liodakis, I., Lombardi, S., Longo, F., Lucarelli, F., Luque-Escamilla, P. L., Marti, J., Martinez, M., Mazin, D., Mbarubucyeye, J. D., Menchiari, S., Mohrmann, L., Montaruli, T., Moralejo Olaizola, A., Morcuende, D., Morlino, G., Morselli, A., Mundell, C. G., Murach, T., Nagai, A., Nayerhoda, A., Niemiec, J., Nikolajuk, M., Olmi, B., Orienti, M., Paredes, J. M., Pareschi, G., Pe'er, A., P��hlhofer, G., Punch, M., Reimer, O., Rib��, M., Rieger, F., Rodriguez, G., Rodriguez, J., Romeo, G., Roncadelli, M., Rowell, G., Rudak, B., Sadeh, I., Salesa Greus, F., Sawangwit, U., Sch��ssler, F., Sergijenko, O., Shellard, R. C., Saturni, F. G., Stamerra, A., Stolarczyk, Th., Tagliaferri, G., Testa, V., Tibaldo, L., Ventura, S., Viana, A., Vink, J., Vitale, V., Vorobiov, S., Wierzcholska, A., Zacharias, M., and Zavrtanik, D.

Subjects
Cherenkov Telescope Array, Astrophysics::High Energy Astrophysical Phenomena, Astrophysics::Instrumentation and Methods for Astrophysics, energy resolution, imaging, magnetic field, acceleration, GeV, Cherenkov counter: atmosphere, sensitivity, MAGIC, VHE, jet: relativistic, electromagnetic, angular resolution, gamma ray, HESS, supernova, black hole, site, galaxy: cluster, VERITAS, neutron star
Abstract

The physics of the non-thermal Universe provides information on the acceleration mechanisms in extreme environments, such as black holes and relativistic jets, neutron stars, supernovae or clusters of galaxies. In the presence of magnetic fields, particles can be accelerated towards relativistic energies. As a consequence, radiation along the entire electromagnetic spectrum can be observed, and extreme environments are also the most likely sources of multi-messenger emission. The most energetic part of the electromagnetic spectrum corresponds to the very-high-energy (VHE, E>100 GeV) gamma-ray regime, which can be extensively studied with ground based Imaging Atmospheric Cherenkov Telescopes (IACTs). The results obtained by the current generation of IACTs, such as H.E.S.S., MAGIC, and VERITAS, demonstrate the crucial importance of the VHE band in understanding the non-thermal emission of extreme environments in our Universe. In some objects, the energy output in gamma rays can even outshine the rest of the broadband spectrum. The Cherenkov Telescope Array (CTA) is the next generation of IACTs, which, with cutting edge technology and a strategic configuration of ~100 telescopes distributed in two observing sites, in the northern and southern hemispheres, will reach better sensitivity, angular and energy resolution, and broader energy coverage than currently operational IACTs. With CTA we can probe the most extreme environments and considerably boost our knowledge of the non-thermal Universe.

Published
2021
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17. Performance of the Cherenkov Telescope Array in the presence of clouds

Author

Pecimotika, Mario, Adamczykc, Katarzyna, Szanecki, Michał, Array, Cherenkov Telescope, Prester, Dijana Dominis, Gueta, Orel, Hrupec, Dario, Maier, Gernot, Mićanović, Saša, Pavletić, Lovro, Sitarek, Julian, Sobczyńska, Dorota, API (FNWI), High Energy Astrophys. & Astropart. Phys (API, FNWI), and GRAPPA (ITFA, IoP, FNWI)

Subjects
Cherenkov Telescope Array, energy resolution, law.invention, energy: threshold, Observatory, law, HESS, optical, cloud, MAGIC (telescope), energy: low, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), MODTRAN, photon, Astrophysics::Instrumentation and Methods for Astrophysics, Mars Exploration Program, Monte Carlo [numerical calculations], threshold [energy], observatory, Astrophysics::Earth and Planetary Astrophysics, numerical calculations: Monte Carlo, Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - High Energy Astrophysical Phenomena, performance, atmosphere [showers], data analysis method, sensitivity [detector], air, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, programming, VHE, Atmosphere, Telescope, Cherenkov [radiation], low [energy], ddc:530, Instrumentation and Methods for Astrophysics (astro-ph.IM), Cherenkov radiation, Remote sensing, showers: atmosphere, Cherenkov telescopes, clouds, CTA, MODTRAN, Monte Carlo simulations, background, resolution, trigger, radiation: Cherenkov, MAGIC, detector: sensitivity, Cherenkov counter, angular resolution, gamma ray
Abstract

37th International Cosmic Ray Conference, ICRC 2021, Berlin, online, Germany, 12 Jul 2021 - 23 Jul 2021; Proceedings of Science / International School for Advanced Studies (ICRC2021), 773 (2021). doi:10.22323/1.395.0773, The Cherenkov Telescope Array (CTA) is the future ground-based observatory for gamma-ray astronomy at very high energies. The atmosphere is an integral part of every Cherenkov telescope. Different atmospheric conditions, such as clouds, can reduce the fraction of Cherenkov photons produced in air showers that reach ground-based telescopes, which may affect the performance. Decreased sensitivity of the telescopes may lead to misconstructed energies and spectra. This study presents the impact of various atmospheric conditions on CTA performance. The atmospheric transmission in a cloudy atmosphere in the wavelength range from 203 nm to 1000 nm was simulated for different cloud bases and different optical depths using the MODerate resolution atmospheric TRANsmission (MODTRAN) code. MODTRAN output files were used as inputs for generic Monte Carlo simulations. The analysis was performed using the MAGIC Analysis and Reconstruction Software (MARS) adapted for CTA. As expected, the effects of clouds are most evident at low energies, near the energy threshold. Even in the presence of dense clouds, high-energy gamma rays may still trigger the telescopes if the first interaction occurs lower in the atmosphere, below the cloud base. A method to analyze very high-energy data obtained in the presence of clouds is presented. The systematic uncertainties of the method are evaluated. These studies help to gain more precise knowledge about the CTA response to cloudy conditions and give insights on how to proceed with data obtained in such conditions. This may prove crucial for alert-based observations and time-critical studies of transient phenomena., Published by SISSA, Trieste

Published
2021

18. Constraining the Origin of the Puzzling Source HESS J1640−465 and the PeVatron Candidate HESS J1641−463 Using Fermi-Large Area Telescope Observations

Author

M.-H. Grondin, Fabio Acero, C. J. Clark, M. Lemoine-Goumard, J. D. Gelfand, J. Devin, Arnaud Mares, Dave Green, S. Gabici, Centre d'Etudes Nucléaires de Bordeaux Gradignan (CENBG), Université Sciences et Technologies - Bordeaux 1-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7), Mares, A [0000-0003-3345-7800], Lemoine-Goumard, M [0000-0002-4462-3686], Clark, CJ [0000-0003-4355-3572], Gelfand, JD [0000-0003-4679-1058], Green, DA [0000-0003-3189-9998], Grondin, MH [0000-0002-8383-251X], Apollo - University of Cambridge Repository, Université Sciences et Technologies - Bordeaux 1 (UB)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), and ANR-17-CE31-0014,PECORA,Rayons Cosmiques au PeV(2017)

Subjects
Astrophysics::High Energy Astrophysical Phenomena, Cosmic ray, Astrophysics::Cosmology and Extragalactic Astrophysics, GeV, power spectrum, 01 natural sciences, GLAST, VHE, law.invention, Telescope, particle: acceleration, Pulsar, law, HESS, 0103 physical sciences, supernova, cloud, flux: upper limit, 010303 astronomy & astrophysics, X-ray: flux, Astrophysics::Galaxy Astrophysics, pulsar, Physics, astro-ph.HE, cosmic radiation: spectrum, 010308 nuclear & particles physics, Astronomy, Astronomy and Astrophysics, Gamma-ray astronomy, 13. Climate action, Space and Planetary Science, gamma ray, curvature, spectral, High Energy Physics::Experiment, galaxy, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Fermi Gamma-ray Space Telescope
Abstract

There are only a few very-high-energy sources in our Galaxy that might accelerate particles up to the knee of the cosmic-ray spectrum. To understand the mechanisms of particle acceleration in these PeVatron candidates, Fermi-Large Area Telescope (LAT) and High-Energy Stereoscopic System (H.E.S.S.) observations are essential to characterize their γ-ray emission. HESS J1640–465 and the PeVatron candidate HESS J1641–463 are two neighboring (0.25°) γ-ray sources, spatially coincident with the radio supernova remnants (SNRs) G338.3–0.0 and G338.5+0.1. Detected both by H.E.S.S. and the Fermi-LAT, we present here a morphological and spectral analysis of these two sources using 8 yr of Fermi-LAT data between 200 MeV and 1 TeV with multiwavelength observations to assess their nature. The morphology of HESS J1640–465 is described by a 2D Gaussian (σ = 0.053° ± 0.011°stat ± 0.03°syst) and its spectrum is modeled by a power law with a spectral index Γ = 1.8 ± 0.1stat ± 0.2syst. HESS J1641–463 is detected as a point-like source and its GeV emission is described by a logarithmic-parabola spectrum with α = 2.7 ± 0.1stat ± 0.2syst and significant curvature of β = 0.11 ± 0.03stat ± 0.05syst. Radio and X-ray flux upper limits were derived. We investigated scenarios to explain their emission, namely, the emission from accelerated particles within the SNRs spatially coincident with each source, molecular clouds illuminated by cosmic rays from the close-by SNRs, and a pulsar/pulsar wind nebula origin. Our new Fermi-LAT results and the radio and flux X-ray upper limits pose severe constraints on some of these models.

Published
2021

19. ANTARES search for point sources of neutrinos using astrophysical catalogs: a likelihood analysis

Author

A. Albert, M. André, M. Anghinolfi, G. Anton, M. Ardid, J.-J. Aubert, J. Aublin, B. Baret, S. Basa, B. Belhorma, V. Bertin, S. Biagi, M. Bissinger, J. Boumaaza, M. Bouta, M. C. Bouwhuis, H. Brânzaş, R. Bruijn, J. Brunner, J. Busto, A. Capone, L. Caramete, J. Carr, V. Carretero, S. Celli, M. Chabab, T. N. Chau, R. Cherkaoui El Moursli, T. Chiarusi, M. Circella, A. Coleiro, M. Colomer-Molla, R. Coniglione, P. Coyle, A. Creusot, A. F. Díaz, G. de Wasseige, A. Deschamps, C. Distefano, I. Di Palma, A. Domi, C. Donzaud, D. Dornic, D. Drouhin, T. Eberl, N. El Khayati, A. Enzenhöfer, P. Fermani, G. Ferrara, F. Filippini, L. Fusco, Y. Gatelet, P. Gay, H. Glotin, R. Gozzini, R. Gracía, K. Graf, C. Guidi, S. Hallmann, H. van Haren, A. J. Heijboer, Y. Hello, J. J. Hernández-Rey, J. Hößl, J. Hofestädt, F. Huang, G. Illuminati, C. W. James, B. Jisse-Jung, M. de Jong, P. de Jong, M. Jongen, M. Kadler, O. Kalekin, U. Katz, N. R. Khan-Chowdhury, A. Kouchner, I. Kreykenbohm, V. Kulikovskiy, R. Lahmann, R. Le Breton, D. Lefèvre, E. Leonora, G. Levi, M. Lincetto, D. Lopez-Coto, S. Loucatos, L. Maderer, J. Manczak, M. Marcelin, A. Margiotta, A. Marinelli, J. A. Martínez-Mora, S. Mazzou, K. Melis, P. Migliozzi, M. Moser, A. Moussa, R. Muller, L. Nauta, S. Navas, E. Nezri, A. Nuñez-Castiñeyra, B. O’Fearraigh, M. Organokov, G. E. Păvălaş, C. Pellegrino, M. Perrin-Terrin, P. Piattelli, C. Pieterse, C. Poirè, V. Popa, T. Pradier, N. Randazzo, S. Reck, G. Riccobene, F. Salesa Greus, D. F. E. Samtleben, A. Sánchez-Losa, M. Sanguineti, P. Sapienza, J. Schnabel, F. Schüssler, M. Spurio, Th. Stolarczyk, M. Taiuti, Y. Tayalati, T. Thakore, S. J. Tingay, B. Vallage, V. Van Elewyck, F. Versari, S. Viola, D. Vivolo, J. Wilms, A. Zegarelli, J. D. Zornoza, J. Zúñiga, S. Buson, Centre Tecnològic de Vilanova i la Geltrú, Universitat Politècnica de Catalunya. LAB - Laboratori d'Aplicacions Bioacústiques, Institut Pluridisciplinaire Hubert Curien (IPHC), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA)), Centre de Physique des Particules de Marseille (CPPM), Aix Marseille Université (AMU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), AstroParticule et Cosmologie (APC (UMR_7164)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Géoazur (GEOAZUR 7329), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud]), Université Paris-Sud - Paris 11 (UP11), Laboratoire de Physique de Clermont (LPC), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA), Laboratoire d'Informatique et Systèmes (LIS), Aix Marseille Université (AMU)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, IUT Orsay, ANTARES, Albert A., Andre M., Anghinolfi M., Anton G., Ardid M., Aubert J.-J., Aublin J., Baret B., Basa S., Belhorma B., Bertin V., Biagi S., Bissinger M., Boumaaza J., Bouta M., Bouwhuis M.C., Branza H., Bruijn R., Brunner J., Busto J., Capone A., Caramete L., Carr J., Carretero V., Celli S., Chabab M., Chau T.N., Cherkaoui El Moursli R., Chiarusi T., Circella M., Coleiro A., Colomer-Molla M., Coniglione R., Coyle P., Creusot A., Diaz A.F., De Wasseige G., Deschamps A., Distefano C., Di Palma I., Domi A., Donzaud C., Dornic D., Drouhin D., Eberl T., El Khayati N., Enzenhofer A., Fermani P., Ferrara G., Filippini F., Fusco L., Gatelet Y., Gay P., Glotin H., Gozzini R., Gracia R., Graf K., Guidi C., Hallmann S., Van Haren H., Heijboer A.J., Hello Y., Hernandez-Rey J.J., Hossl J., Hofestadt J., Huang F., Illuminati G., James C.W., Jisse-Jung B., De Jong M., De Jong P., Jongen M., Kadler M., Kalekin O., Katz U., Khan-Chowdhury N.R., Kouchner A., Kreykenbohm I., Kulikovskiy V., Lahmann R., Le Breton R., Lefevre D., Leonora E., Levi G., Lincetto M., Lopez-Coto D., Loucatos S., Maderer L., Manczak J., Marcelin M., Margiotta A., Marinelli A., Martinez-Mora J.A., Mazzou S., Melis K., Migliozzi P., Moser M., Moussa A., Muller R., Nauta L., Navas S., Nezri E., Nunez-Castineyra A., O Fearraigh B., Organokov M., Pvla G.E., Pellegrino C., Perrin-Terrin M., Piattelli P., Pieterse C., Poire C., Popa V., Pradier T., Randazzo N., Reck S., Riccobene G., Salesa Greus F., Samtleben D.F.E., Sanchez-Losa A., Sanguineti M., Sapienza P., Schnabel J., Schossler F., Spurio M., Stolarczyk Th., Taiuti M., Tayalati Y., Thakore T., Tingay S.J., Vallage B., Van Elewyck V., Versari F., Viola S., Vivolo D., Wilms J., Zegarelli A., Zornoza J.D., Zuniga J., Buson S., KM3NeT (IHEF, IoP, FNWI), ATLAS (IHEF, IoP, FNWI), IHEF (IoP, FNWI), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), and Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)

Subjects
Astrofísica, 010504 meteorology & atmospheric sciences, Radio galaxy, Astrophysics, astrophysical catalogs, 01 natural sciences, IceCube, Astronomy data analysis (1858), Investigació quantitativa, 010303 astronomy & astrophysics, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), education.field_of_study, neutrinos, astrophysical catalogs, likelihood analysis, Astrophysics::Instrumentation and Methods for Astrophysics, neutrinos, space-time, Neutrino astronomy, stacking, Neutrino, Astrophysics - High Energy Astrophysical Phenomena, Particle astrophysics, Catalogs (205), Active galactic nucleus, Astrophysics::High Energy Astrophysical Phenomena, Population, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, GLAST, VHE, Partícules (Física nuclear), blazar, muon, 0103 physical sciences, Particle astrophysics (96), AGN, education, Blazar, 0105 earth and related environmental sciences, Neutrino astronomy (1100), Particles (Nuclear physics), ANTARES, galaxy: radio wave, likelihood analysis, Astronomy and Astrophysics, neutrino: particle source, tracks, Galaxy, Space and Planetary Science, gamma ray, correlation, Física::Astronomia i astrofísica [Àrees temàtiques de la UPC], Astronomy data analysis, Catalogs, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Quantitative research, Fermi Gamma-ray Space Telescope
Abstract

A search for astrophysical pointlike neutrino sources using the data collected by the ANTARES detector between 2007 January 29 and 2017 December 31 is presented. A likelihood method is used to assess the significance of an excess of muon neutrinos inducing track-like events in correlation with the location of a list of possible sources. Different sets of objects are tested in the analysis: (a) a subsample of the Fermi 3LAC catalog of blazars, (b) a jet-obscured population of active galactic nuclei, (c) a sample of hard X-ray selected radio galaxies, (d) a star-forming galaxy catalog, and (e) a public sample of 56 very-high-energy track events from the IceCube experiment. None of the tested sources shows a significant association with the sample of neutrinos detected by ANTARES. The smallest p-value is obtained for the catalog of radio galaxies with an equal-weights hypothesis, with a pre-trial p-value equivalent to a 2.8σ excess, which is equivalent to 1.6σ post-trial. In addition, the results of a dedicated analysis for the blazar MG3 J225517+2409 are also reported: this source is found to be the most significant within the Fermi 3LAC sample, with five ANTARES events located less than one degree from the source. This blazar showed evidence of flaring activity in Fermi data, in spacetime coincidence with a high-energy track detected by IceCube. An a posteriori significance of 2.6σ for the combination of ANTARES and IceCube data is reported.

Published
2021

20. Multiwavelength variability and correlation studies of Mrk 421 during historically low X-ray and γ-ray activity in 2015-2016

Author

Banerjee, B., Terzić, T., Paneque, D., Majumdar, P., Acciari, V. A., Ansoldi, S., Antonelli, L. A., Artero, M., Asano, K., Babić, A., Banrje, B., Baquero, A., Barres Almeida, U., Barrio, J. A., Batković, I., Becerra González, J., Bednarek, W., Bellizzi, L., Bernardini, E., Bernardos, M., Berti, A., Besenrieder, J., Bhattacharyya, W., Bigongiari, C., Blanch, O., Bökenkamp, H., Bonnoli, G., Bošnjak, Ž, Busetto, G., Carosi, R., Ceribella, G., Cerruti, M., Chai, Y., Chilingarian, A., Cikota, S., Colak, S. M., Colombo, E., Contreras, J. L., Cortina, J., Covino, S., Giacomo D'Amico, D’elia, V., Da Vela, P., Dazzi, F., Angelis, A., Lotto, B., Delfino, M., Delgado, J., Delgado Mendez, C., Depaoli, D., Di Pierro, F., Di Venere, L., Do Souto Espiñeira, E., Dominis Prester, D., Donini, A., Doro, M., Fallah Ramazani, V., Fattorini, A., Fonseca, M. V., Font, L., Fruck, C., Fukami, S., Fukazawa, Y., García López, R. J., Garczarczyk, M., Gasparyan, S., Gaug, M., Giglietto, N., Giordano, F., Gliwny, P., Godinović, N., Green, J. G., Green, D., Hadasch, D., Hahn, A., Heckmann, L., Herrera, J., Hoang, J., Hrupec, D., Hütten, M., Inada, T., Ishio, K., Iwamura, Y., Jiménez Martínez, I., Jormanainen, J., Jouvin, L., Karjalainen, M., Kerszberg, D., Kobayashi, Y., Kubo, H., Kushida, J., Lamastra, A., Lelas, D., Leone, F., Lindfors, E., Linhoff, L., Lombardi, S., Longo, F., López-Coto, R., López-Moya, M., López-Oramas, A., Loporchio, S., Machado Oliveira Fraga, B., Maggio, C., Righini, S., Makariev, M., Mallamaci, M., Maneva, G., Manganaro, M., Maraschi, L., Mariotti, M., Martínez, M., Mazin, D., Menchiari, S., Mender, S., Mićanović, S., Miceli, D., Miener, T., Miranda, J. M., Mirzoyan, R., Molina, E., Moralejo, A., Morcuende, D., Moreno, V., Moretti, E., Nakamori, T., Nava, L., Neustroev, V., Nigro, C., Nilsson, K., Nishijima, K., Noda, K., Nozaki, S., Ohtani, Y., Oka, T., Otero-Santos, J., Paiano, S., Palatiello, M., Vera, R. J. C., Paoletti, R., Paredes, J. M., Pavletić, L., Peñil, P., Persic, M., Pihet, M., Prada Moroni, P. G., Prandini, E., Priyadarshi, C., Puljak, I., Ribó, M., Rico, J., Righi, C., Rugliancich, A., Sahakyan, N., Saito, T., Sakurai, S., Satalecka, K., Saturni, F. G., Lien, A. Y., Schmidt, K., Schweizer, T., Sitarek, J., Šnidarić, I., Sobczynska, D., Spolon, A., Stamerra, A., Strišković, J., Strom, D., Strzys, M., Suda, Y., Surić, T., Takahashi, M., Takeishi, R., Tavecchio, F., Temnikov, P., Järvelä, E., Teshima, M., Tosti, L., Truzzi, S., Tutone, A., Ubach, S., Scherpenberg, J., Vanzo, G., Vazquez Acosta, M., Ventura, S., Verguilov, V., Vigorito, C. F., Vitale, V., Vovk, I., Will, M., Wunderlich, C., Yamamoto, T., Zarić, D., Arbet-Engels, A., Baack, D., Balbo, M., Biland, A., Bretz, T., Buss, J., Dorner, D., Eisenberger, L., Elsaesser, D., Hildebrand, D., Iotov, R., Kalenski, A., Mannheim, K., Mitchell, A., Neise, D., Noethe, M., Paravac, A., Rhode, W., Schleicher, B., Sliusar, V., Walter, R., Valverde, J., Horan, D., Giroletti, M., Perri, M., Verrecchia, F., Leto, C., Sadun, A. C., Moody, J. W., Joner, M., Marscher, A. P., Jorstad, S. G., Lähteenmäki, A., Tornikoski, M., Ramakrishnan, V., Laboratoire Leprince-Ringuet (LLR), Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), MAGIC, ITA, USA, GBR, DEU, ARM, BRA, CHL, HRV, FIN, JPN, IND, POL, RUS, CHE, German Research Foundation, Istituto Nazionale di Fisica Nucleare, Istituto Nazionale di Astrofisica, Swiss National Science Foundation, Ministerio de Ciencia, Innovación y Universidades (España), Ministerio de Economía y Competitividad (España), Department of Atomic Energy (India), Japan Society for the Promotion of Science, Ministry of Education, Culture, Sports, Science and Technology (Japan), Ministry of Education, Youth and Science (Bulgaria), Academy of Finland, University of Tokyo, La Caixa, University of Rijeka, Polish National Agency for Academic Exchange, Ministério da Ciência e Tecnologia (Brasil), Croatian Science Foundation, Department of Electronics and Nanoengineering, Metsähovi Radio Observatory, Aalto-yliopisto, Aalto University, Acciari, Va, Ansoldi, S, Antonelli, La, Asano, K, Babic, A, Banerjee, B, Baquero, A, de Almeida, Ub, Barrio, Ja, Gonzalez, Jb, Bednarek, W, Bellizzi, L, Bernardini, E, Bernardos, M, Berti, A, Besenrieder, J, Bhattacharyya, W, Bigongiari, C, Blanch, O, Bonnoli, G, Bosnjak, Z, Busetto, G, Carosi, R, Ceribella, G, Cerruti, M, Chai, Y, Chilingarian, A, Cikota, S, Colak, Sm, Colombo, E, Contreras, Jl, Cortina, J, Covino, S, D'Amico, G, D'Elia, V, Da Vela, P, Dazzi, F, De Angelis, A, De Lotto, B, Delfino, M, Delgado, J, Mendez, Cd, Depaoli, D, Di Girolamo, T, Di Pierro, F, Di Venere, L, Neira, Ede, Prester, Dd, Donini, A, Doro, M, Ramazani, Vf, Fattorini, A, Ferrara, G, Foffano, L, Fonseca, Mv, Font, L, Fruck, C, Fukami, S, Lopez, Rjg, Garczarczyk, M, Gasparyan, S, Gaug, M, Giglietto, N, Giordano, F, Gliwny, P, Green, Jg, Green, D, Hadasch, D, Hahn, A, Heckmann, L, Herrera, J, Hoang, J, Hrupec, D, Hutten, M, Inada, T, Inoue, S, Ishio, K, Iwamura, Y, Jormanainen, J, Jouvin, L, Kajiwara, Y, Karjalainen, M, Kerszberg, D, Kobayashi, Y, Kubo, H, Kushida, J, Lamastra, A, Lelas, D, Leone, F, Lindfors, E, Lombardi, S, Longo, F, Lopez, M, Lopez-Coto, R, Lopez-Oramas, A, Loporchio, S, Fraga, Bmd, Maggio, C, Majumdar, P, Makariev, M, Mallamaci, M, Maneva, G, Manganaro, M, Maraschi, L, Mariotti, M, Martinez, M, Mazin, D, Mender, S, Micanovic, S, Miceli, D, Miener, T, Minev, M, Miranda, Jm, Mirzoyan, R, Molina, E, Moralejo, A, Morcuende, D, Moreno, V, Moretti, E, Munar-Adrover, P, Neustroev, V, Nigro, C, Nilsson, K, Ninci, D, Nishijima, K, Noda, K, Nozaki, S, Ohtani, Y, Oka, T, Otero-Santos, J, Palatiello, M, Paneque, D, Paoletti, R, Paredes, Jm, Pavletic, L, Penil, P, Perennes, C, Persic, M, Moroni, Pgp, Prandini, E, Priyadarshi, C, Puljak, I, Rhode, W, Ribo, M, Rico, J, Righi, C, Rugliancich, A, Saha, L, Sahakyan, N, Saito, T, Sakurai, S, Satalecka, K, Schleicher, B, Schmidt, K, Schweizer, T, Sitarek, J, Snidaric, I, Sobczynska, D, Spolon, A, Stamerra, A, Strom, D, Strzys, M, Suda, Y, Suric, T, Takahashi, M, Tavecchio, F, Temnikov, P, Terzic, T, Teshima, M, Torres-Alba, N, Tosti, L, Truzzi, S, van Scherpenberg, J, Vanzo, G, Acosta, Mv, Ventura, S, Verguilov, V, Vigorito, Cf, Vitale, V, Vovk, I, Will, M, Zaric, D, Arbet-Engels, A, Baack, D, Balbo, M, Beck, M, Biederbeck, N, Biland, A, Bretz, T, Bruegge, K, Buss, J, Dorner, D, Elsaesser, D, Hildebrand, D, Iotov, R, Klinger, M, Mannheim, K, Neise, D, Neronov, A, Noethe, M, Paravac, A, Sliusar, V, Theissen, F, Walter, R, Valverde, J, Horan, D, Giroletti, M, Perri, M, Verrecchia, F, Leto, C, Sadun, Ac, Moody, Jw, Joner, M, Marscher, Ap, Jorstad, Sg, Lahteenmaki, A, Tornikoski, M, Ramakrishnan, V, Jarvela, E, Vera, Rjc, Righini, S, and Lien, Ay

Subjects
BL Lacertae objects: individual: Mrk 421, galaxies: active, methods: data analysis, methods: observational, radiation mechanisms: non-thermal, Non-thermal, Astrophysics, 4/3, GeV, 01 natural sciences, law.invention, Correlation, law, optical, MAGIC (telescope), data analysis [Methods], 010303 astronomy & astrophysics, Physics, individual: Mrk 421 [BL Lacertae objects], radio wave, Gamma ray, Low activity, X-ray, non-thermal [radiation mechanisms], Synchrotron, Log-normal distribution, Electrónica, Electricidad, Astrophysics - High Energy Astrophysical Phenomena, Radio wave, active [Galaxies], Astrophysics::High Energy Astrophysical Phenomena, Astrophysics::Cosmology and Extragalactic Astrophysics, VHE, GLAST, blazar, Flux (metallurgy), 0103 physical sciences, synchrotron, Radiation mechanisms, TeV, observational [Methods], Blazar, 010308 nuclear & particles physics, Astronomy and Astrophysics, Spectral component, MAGIC, flux, Space and Planetary Science, 13. Climate action, gamma ray, correlation, data analysi [methods], ddc:520, spectral, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Energy (signal processing)
Abstract

Acciari, V. A., et al. (MAGIC Collaboration), We report a characterization of the multiband flux variability and correlations of the nearby (z = 0.031) blazar Markarian 421 (Mrk 421) using data from Metsähovi, Swift, Fermi-LAT, MAGIC, FACT, and other collaborations and instruments from 2014 November till 2016 June. Mrk 421 did not show any prominent flaring activity, but exhibited periods of historically low activity above 1 TeV (F>1 TeV < 1.7 × 10-12 ph cm-2 s-1) and in the 2-10 keV (X-ray) band (F 2-10, keV< 3.6× 10-11 erg cm-2 s-1), during which the Swift-BAT data suggest an additional spectral component beyond the regular synchrotron emission. The highest flux variability occurs in X-rays and very high-energy (E > 0.1 TeV) γ-rays, which, despite the low activity, show a significant positive correlation with no time lag. The HRkeV and HRTeV show the harder-when-brighter trend observed in many blazars, but the trend flattens at the highest fluxes, which suggests a change in the processes dominating the blazar variability. Enlarging our data set with data from years 2007 to 2014, we measured a positive correlation between the optical and the GeV emission over a range of about 60 d centred at time lag zero, and a positive correlation between the optical/GeV and the radio emission over a range of about 60 d centred at a time lag of 43+9-6 d. This observation is consistent with the radio-bright zone being located about 0.2 parsec downstream from the optical/GeV emission regions of the jet. The flux distributions are better described with a lognormal function in most of the energy bands probed, indicating that the variability in Mrk 421 is likely produced by a multiplicative process., The financial support of the German BMBF and MPG; the Italian INFN and INAF; the Swiss National Fund SNF; the ERDF under the Spanish MINECO (FPA2017-87859-P, FPA2017-85668-P, FPA2017-82729-C6-2-R, FPA2017-82729-C6-6-R, FPA2017-82729-C6-5-R, AYA2015-71042-P, AYA2016-76012-C3-1-P, ESP2017-87055-C2-2-P, FPA2017-90566-REDC); the Indian Department of Atomic Energy; the Japanese ICRR, the University of Tokyo, JSPS, and MEXT; the Bulgarian Ministry of Education and Science, National RI Roadmap Project DO1-268/16.12.2019 and the Academy of Finland grant nr. 320045 is gratefully acknowledged. This work was also supported by the Spanish Centro de Excelencia ‘Severo Ochoa’ SEV-2016-0588 and SEV-2015-0548, the Unidad de Excelencia ‘María de Maeztu’ MDM-2014-0369 and the ‘la Caixa’ Foundation (fellowship LCF/BQ/PI18/11630012), by the Croatian Science Foundation (HrZZ) Project IP-2016-06-9782 and the University of Rijeka Project 13.12.1.3.02, by the DFG Collaborative Research Centers SFB823/C4 and SFB876/C3, the Polish National Research Centre grant UMO-2016/22/M/ST9/00382 and by the Brazilian MCTIC, CNPq, and FAPERJ.

Published
2021

21. Cosmology with Very-High-Energy Gamma Rays

Author

Pueschel, Elisa, Biteau, Jonathan, Laboratoire de Physique des 2 Infinis Irène Joliot-Curie (IJCLab), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), and HEP, INSPIRE

Subjects
Planck, cosmological model, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, magnetic field, cosmic background radiation, Astrophysics::Cosmology and Extragalactic Astrophysics, VHE, star, ionization, TeV, surface, structure, High Energy Astrophysical Phenomena (astro-ph.HE), background, formation, critical phenomena, electromagnetic, background field, gamma ray: VHE, gamma ray, galaxy, history, [PHYS.ASTR] Physics [physics]/Astrophysics [astro-ph], [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - High Energy Astrophysical Phenomena
Abstract

In this chapter, we discuss the contributions of gamma-ray astronomy at TeV energies to our understanding of the visible content and structure of the universe. We start from the present epoch with the second most intense electromagnetic background field after the CMB: the extragalactic background light (EBL). The EBL is composed of all the light emitted by stars and galaxies since the beginning of reionization, including light absorbed and re-emitted by dust. As such, the EBL traces the history of radiating matter in the universe. We then further dive into the large voids of the universe to study the large-scale magnetic fields that should permeate them. These fields could originate from the onset of structure formation or early phase transitions, bringing us back to the infancy of the universe. We conclude by looking back to the elusive Planck time scale, where the standard models of cosmology and particle physics are no longer applicable. Observations with current-generation gamma-ray astronomy experiments have now started to scratch the surface of cosmology, as we will show in this chapter., Comment: To appear in "Advances in Very High Energy Astrophysics", Mukherjee & Zanin, World Scientific (2022)

Published
2021
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22. Reconstruction of truncated images for PeVatron searches with the Cherenkov Telescope Array

Author

Verna, G., Cassol, F., Costantini, H., Armstrong, T., Angüner, E.O., Centre de Physique des Particules de Marseille (CPPM), Aix Marseille Université (AMU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and CTA

Subjects
particle: acceleration, Cherenkov Telescope Array, gamma ray, Astrophysics::High Energy Astrophysical Phenomena, Astrophysics::Instrumentation and Methods for Astrophysics, imaging, [PHYS.PHYS.PHYS-INS-DET]Physics [physics]/Physics [physics]/Instrumentation and Detectors [physics.ins-det], Cherenkov counter: atmosphere, sensitivity, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], VHE
Abstract

International audience; The Cherenkov Telescope Array (CTA) will be the future groundbasedgamma-ray observatory using the imaging atmospheric Cherenkov technique.One of CTA’s key science projects is the search for galactic PeVatrons, extremesources of accelerating cosmic particles. CTA’s sensitivity in the multi-TeV region iscrucial for this goal. A dedicated reconstruction of the telescopes’ truncated imageshas been implemented in the CTA reconstruction pipeline in order to optimize CTA’ssensitivity at very high energies (E > 10TeV). First results are presented togetherwith perspectives for PeVatron searches with CTA-North array.

Published
2020

24. Broadband characterisation of the very intense TeV flares of the blazar 1ES 1959+650 in 2016

Author

MAGIC Collaboration, Acciari, V. A., Ansoldi, S., Antonelli, L. A., Arbet Engels, A., Baack, D., Babić, A., Banerjee, B., Barres de Almeida, U., Barrio, J. A., Becerra González, J., Bednarek, W., Bellizzi, L., Bernardini, E., Berti, A., Besenrieder, J., Bhattacharyya, W., Bigongiari, C., Biland, A., Blanch, O., Bonnoli, G., Bosnjak, Z., Busetto, G., Carosi, R., Ceribella, G., Chai, Y., Cikota, S., Colak, S. M., Colin, U., Colombo, E., Contreras, J. L., Cortina, J., Covino, S., D’Elia, V., Da Vela, P., Dazzi, F., De Angelis, A., De Lotto, B., Delfino, M., Delgado, J., Di Pierro, F., Do Souto Espiñeira, E., Dominis Prester, D., Donini, A., Dorner, D., Doro, M., Elsaesser, D., Fallah Ramazani, V., Fattorini, A., Fernández-Barral, A., Ferrara, G., Fidalgo, D., Foffano, L., Fonseca, M. V., Font, L., Fruck, C., Fukami, S., Gallozzi, S., García López, R. J., Garczarczyk, M., Gasparyan, S., Gaug, M., Godinović, N., Green, D., Guberman, D., Hadasch, D., Hahn, A., Herrera, J., Hoang, J., Hrupec, D., Inada, T., Inoue, S., Ishio, K., Iwamura, Y., Jouvin, L., Kubo, H., Kushida, J., Lamastra, A., Lelas, D., Leone, F., Lindfors, E., Lombardi, S., Longo, F., López, M., López-Coto, R., López-Oramas, A., Machado de Oliveira Fraga, B., Maggio, C., Majumdar, P., Makariev, M., Mallamaci, M., Maneva, G., Manganaro, M., Mannheim, K., Maraschi, L., Mariotti, M., Martínez, M., Masuda, S., Mazin, D., Mićanović, S., Miceli, D., Minev, M., Miranda, J. M., Mirzoyan, R., Molina, E., Moralejo, A., Morcuende, D., Moreno, V., Moretti, E., Munar-Adrover, P., Neustroev, V., Niedzwiecki, A., Nigro, C., Nilsson, K., Ninci, D., Nishijima, K., Noda, K., Nogués, L., Nöthe, M., Nozaki, S., Paiano, S., Palacio, J., Palatiello, M., Paneque, D., Paoletti, R., Paredes, J. M., Peñil, P., Peresano, M., Persic, M., Prada Moroni, P. G., Prandini, E., Puljak, I., Rhode, W., Ribó, M., Rico, J., Righi, C., Rugliancich, A., Saha, L., Sahakyan, N., Saito, T., Sakurai, S., Satalecka, K., Schweizer, T., Sitarek, J., Šnidarić, I., Sobczynska, D., Somero, A., Stamerra, A., Strom, D., Strzys, M., Surić, T., Takahashi, M., Tavecchio, F., Temnikov, P., Terzić, T., Teshima, M., Torres-Albà, N., Tsujimoto, S., van Scherpenberg, J., Vanzo, G., Vazquez Acosta, M., Vovk, I., Will, M., Zarić, D., Hayashida, M., Fermi-LAT Collaboration, Acciari, V. A., Ansoldi, S., Antonelli, L. A., Arbet Engels, A., Baack, D., Babic, A., Banerjee, B., Barres De Almeida, U., Barrio, J. A., Becerra Gonzalez, J., Bednarek, W., Bellizzi, L., Bernardini, E., Berti, A., Besenrieder, J., Bhattacharyya, W., Bigongiari, C., Biland, A., Blanch, O., Bonnoli, G., Bosnjak, Z., Busetto, G., Carosi, R., Ceribella, G., Chai, Y., Cikota, S., Colak, S. M., Colin, U., Colombo, E., Contreras, J. L., Cortina, J., Covino, S., D'Elia, V., Da Vela, P., Dazzi, F., De Angelis, A., De Lotto, B., Delfino, M., Delgado, J., Di Pierro, F., Do Souto Espineira, E., Dominis Prester, D., Donini, A., Dorner, D., Doro, M., Elsaesser, D., Fallah Ramazani, V., Fattorini, A., Fernandez-Barral, A., Ferrara, G., Fidalgo, D., Foffano, L., Fonseca, M. V., Font, L., Fruck, C., Fukami, S., Gallozzi, S., Garcia Lopez, R. J., Garczarczyk, M., Gasparyan, S., Gaug, M., Godinovic, N., Green, D., Guberman, D., Hadasch, D., Hahn, A., Herrera, J., Hoang, J., Hrupec, D., Inada, T., Inoue, S., Ishio, K., Iwamura, Y., Jouvin, L., Kubo, H., Kushida, J., Lamastra, A., Lelas, D., Leone, F., Lindfors, E., Lombardi, S., Longo, F., Lopez, M., Lopez-Coto, R., Lopez-Oramas, A., MacHado De Oliveira Fraga, B., Maggio, C., Majumdar, P., Makariev, M., Mallamaci, M., Maneva, G., Manganaro, M., Mannheim, K., Maraschi, L., Mariotti, M., Martinez, M., Masuda, S., Mazin, D., Micanovic, S., Miceli, D., Minev, M., Miranda, J. M., Mirzoyan, R., Molina, E., Moralejo, A., Morcuende, D., Moreno, V., Moretti, E., Munar-Adrover, P., Neustroev, V., Niedzwiecki, A., Nigro, C., Nilsson, K., Ninci, D., Nishijima, K., Noda, K., Nogues, L., Nothe, M., Nozaki, S., Paiano, S., Palacio, J., Palatiello, M., Paneque, D., Paoletti, R., Paredes, J. M., Penil, P., Peresano, M., Persic, M., Prada Moroni, P. G., Prandini, E., Puljak, I., Rhode, W., Ribo, M., Rico, J., Righi, C., Rugliancich, A., Saha, L., Sahakyan, N., Saito, T., Sakurai, S., Satalecka, K., Schweizer, T., Sitarek, J., Snidaric, I., Sobczynska, D., Somero, A., Stamerra, A., Strom, D., Strzys, M., Suric, T., Takahashi, M., Tavecchio, F., Temnikov, P., Terzic, T., Teshima, M., Torres-Alba, N., Tsujimoto, S., Van Scherpenberg, J., Vanzo, G., Vazquez Acosta, M., Vovk, I., Will, M., Zaric, D., Hayashida, M., Federal Ministry of Education and Research (Germany), Istituto Nazionale di Fisica Nucleare, Istituto Nazionale di Astrofisica, Swiss National Science Foundation, Ministerio de Economía y Competitividad (España), Department of Atomic Energy (India), Japan Society for the Promotion of Science, Ministry of Education and Culture (Hungary), Fundación Severo Ochoa, Universidad de Barcelona, Croatian Science Foundation, German Research Foundation, National Centre for Research and Development (Poland), Ministério da Ciência, Tecnologia e Inovação (Brasil), National Aeronautics and Space Administration (US), Institut National de Physique Nucléaire et de Physique des Particules (France), Agenzia Spaziale Italiana, Ministry of Education, Culture, Sports, Science and Technology (Japan), High Energy Accelerator Research Organization (Japan), Japan Aerospace Exploration Agency, Knut and Alice Wallenberg Foundation, Swedish Research Council, Swedish National Space Board, and European Commission

Subjects
jets [galaxies], observational [methods], Flux, magnetic field, Astrophysics, jet [Galaxies], 01 natural sciences, 7. Clean energy, BL Lacertae objects: individual: 1ES 1959+650, Cherenkov, Astroparticle physics, Galaxies: jets, Methods: observational, Neutrinos, Radiation mechanisms: non-thermal, MAGIC (telescope), 010303 astronomy & astrophysics, High Energy Astrophysical Phenomena (astro-ph.HE), Physics, imaging, neutrinos, non-thermal [radiation mechanisms], astroparticle physics, galaxies: jets, methods: observational, radiation mechanisms: non-thermal, Spectral energy distribution, Física nuclear, Astrophysics - High Energy Astrophysical Phenomena, BL Lac object, exceptional, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astroparticle physic, VHE, GLAST, energy [p], blazar, X-ray, synchrotron, Neutrino, 0103 physical sciences, Blazar, Cherenkov radiation, 010308 nuclear & particles physics, Computer Science::Information Retrieval, Astronomy and Astrophysics, MAGIC, proton synchrotron, flux, Crab Nebula, field strength, gamma ray, 13. Climate action, Space and Planetary Science, ddc:520, spectral, hadronic [model], individual: 1ES 1959+650 [BL Lacertae objects], Fermi Gamma-ray Space Telescope
Abstract

1ES 1959+650 is a bright TeV high-frequency-peaked BL Lac object exhibiting interesting features like orphan TeV flares and broad emission in the high-energy regime that are difficult to interpret using conventional one-zone Synchrotron Self-Compton (SSC) scenarios. We report the results from the Major Atmospheric Gamma Imaging Cherenkov (MAGIC) observations in 2016 along with the multi-wavelength data from the Fermi Large Area Telescope (LAT) and Swift instruments. MAGIC observed 1ES 1959+650 with different emission levels in the very-high-energy (VHE, E > 100 GeV) -ray band during 2016. In the long-term data, the X-ray spectrum becomes harder with increasing flux and a hint of a similar trend is also visible in the VHE band. An exceptionally high VHE flux reaching ∼3 times the Crab Nebula flux was measured by MAGIC on the 13 and 14 of June, and 1 July 2016 (the highest flux observed since 2002). During these flares, the high-energy peak of the spectral energy distribution (SED) lies in the VHE domain and extends up to several TeV. The spectrum in the -ray (both Fermi-LAT and VHE bands) and the X-ray bands are quite hard. On 13 June and 1 July 2016, the source showed rapid variations in the VHE flux within timescales of less than an hour. A simple one-zone SSC model can describe the data during the flares requiring moderate to large values of the Doppler factors (δ ≥ 30..60). Alternatively, the high-energy peak of the SED can be explained by a purely hadronic model attributed to proton-synchrotron radiation with jet power L∼ 10erg sand under high values of the magnetic field strength (∼100 G) and maximum proton energy (∼few EeV). Mixed leptohadronic models require super-Eddington values of the jet power. We conclude that it is difficult to get detectable neutrino emission from the source during the extreme VHE flaring period of 2016., The financial support of the German BMBF and MPG, the Italian INFN and INAF, the Swiss National Fund SNF, the ERDF under the Spanish MINECO (FPA2015-69818-P, FPA2012-36668, FPA2015-68378-P, FPA2015-69210-C6-2-R, FPA2015-69210-C6-4-R, FPA2015-69210-C6-6-R, AYA2015-71042-P, AYA2016-76012-C3-1-P, ESP2015-71662-C2-2-P, FPA2017-90566-REDC), the Indian Department of Atomic Energy, the Japanese JSPS and MEXT and the Bulgarian Ministry of Education and Science, National RI Roadmap Project DO1-153/28.08.2018 is gratefully acknowledged. This work was also supported by the Spanish Centro de Excelencia “Severo Ochoa” SEV-2016-0588 and SEV-2015-0548, and Unidad de Excelencia “María de Maeztu” MDM-2014-0369, by the Croatian Science Foundation (HrZZ) Project IP-2016-06-9782 and the University of Rijeka Project 13.12.1.3.02, by the DFG Collaborative Research Centers SFB823/C4 and SFB876/C3, the Polish National Research Centre grant UMO-2016/22/M/ST9/00382 and by the Brazilian MCTIC, CNPq and FAPERJ. The Fermi-LAT Collaboration acknowledges generous ongoing support from a number of agencies and institutes that have supported both the development and the operation of the LAT as well as scientific data analysis. These include the National Aeronautics and Space Administration and the Department of Energy in the United States, the Commissariat à l’Energie Atomique and the Centre National de la Recherche Scientifique / Insti-tut National de Physique Nucléaire et de Physique des Particules in France, the Agenzia Spaziale Italiana and the Istituto Nazionale di Fisica Nucleare in Italy, the Ministry of Education, Culture, Sports, Science and Technology (MEXT), High Energy Accelerator Research Organization (KEK) and Japan Aerospace Exploration Agency (JAXA) in Japan, and the K. A. Wallenberg Foundation, the Swedish Research Council and the Swedish National Space Board in Sweden. Additional support for science analysis during the operations phase is gratefully acknowledged from the Istituto Nazionale di Astrofisica in Italy and the Centre National d’Études Spatiales in France. This work performed in part under DOE Contract DE-AC02-76SF00515. We also appreciate a helpful framework which we used for the Fermi-LAT data analysis, Fermipy (Wood et al. 2017).

Published
2020

25. VERITAS Discovery of VHE Emission from the Radio Galaxy 3C 264: A Multi-Wavelength Study

Author

A. Brill, Alasdair E. Gent, James Ryan, Manel Errando, E. T. Meyer, Gordon T. Richards, Olivier Hervet, M. Kertzman, E. Roache, A. Archer, T. T.Y. Lin, K. Ragan, R. A. Ong, S. O'Brien, B. Stevenson, D. S. Hanna, G. Hughes, Wystan Benbow, P. Moriarty, Matthew L. Lister, C. B. Rulten, M. Lundy, K. Ramirez, Karlen Shahinyan, T. J. Williamson, Tarek M. Hassan, A. Wilhelm, David Kieda, Daniel Nieto, M. Nievas-Rosillo, A. C. Sadun, Jodi Christiansen, Jamie Holder, Marcos Santander, P. T. Reynolds, K. Pfrang, John L. Quinn, D. Ribeiro, R. Shang, M. J. Lang, Gernot Maier, A. D. Falcone, A. Weinstein, M. Pohl, S. P. Wakely, R. R. Prado, M. K. Daniel, P. Fortin, Ralph Bird, David A. Williams, Orel Gueta, P. Wilcox, J. H. Buckley, S. S. Scott, A. J. Chromey, Michael T. Carini, F. Krennrich, M. Georganopoulos, Reshmi Mukherjee, C. Giuri, Q. Feng, G. H. Gillanders, T. B. Humensky, P. Kaaret, Lucy Fortson, M. Buchovecky, G. H. Sembroski, E. Pueschel, Vladimir Vassiliev, and Amy Furniss

Subjects
010504 meteorology & atmospheric sciences, Radio galaxy, atmosphere [Cherenkov counter], Astrophysics, cosmic background radiation, power spectrum, 01 natural sciences, law.invention, Astrophysical jet, law, pixel, ultraviolet, black hole, optical, dimension: 2, 010303 astronomy & astrophysics, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), photon, 2 [dimension], Elliptical galaxy, Spectral energy distribution, VERITAS, Astrophysics - High Energy Astrophysical Phenomena, Lorentz, Active galactic nucleus, Astrophysics::High Energy Astrophysical Phenomena, radio wave [galaxy], energy spectrum, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, Cherenkov counter: atmosphere, VHE, GLAST, Telescope, X-ray, 0103 physical sciences, structure, Very Long Baseline Array, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, polarization, synchrotron radiation, background, galaxy: radio wave, Astronomy and Astrophysics, Doppler effect, flux, Crab Nebula, Space and Planetary Science, gamma ray, ddc:520, spectral, statistical
Abstract

The astrophysical journal 896(1), 41 - (2020). doi:10.3847/1538-4357/ab910e, The radio source 3C 264, hosted by the giant elliptical galaxy NGC 3862, was observed with VERITAS between February 2017 and May 2019. These deep observations resulted in the discovery of very-high-energy (VHE; E $>100$ GeV) $\gamma$-ray emission from this active galaxy. An analysis of $\sim$57 hours of quality-selected live time yields a detection at the position of the source, corresponding to a statistical significance of 7.8 standard deviations above background. The observed VHE flux is variable on monthly time scales, with an elevated flux seen in 2018 observations. The VHE emission during this elevated state is well-characterized by a power-law spectrum with a photon index $\Gamma = 2.20 \pm 0.27$ and flux F($>315$ GeV) = ($7.6\pm 1.2_{\mathrm stat} \pm 2.3_{\mathrm syst})\times 10^{-13}$ cm$^{-2}$ s$^{-1}$, or approximately 0.7% of the Crab Nebula flux above the same threshold. 3C 264 ($z = 0.0217$) is the most distant radio galaxy detected at VHE, and the elevated state is thought to be similar to that of the famously outbursting jet in M 87. Consequently, extensive contemporaneous multi-wavelength data were acquired in 2018 at the time of the VHE high state. An analysis of these data, including VLBA, VLA, HST, Chandra and Swift observations in addition to the VERITAS data, is presented, along with a discussion of the resulting spectral energy distribution., Published by Univ.8743, Chicago, Ill. [u.a.]

Published
2020
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26. Searches for counterparts of gravitational waves at very high energies with H.E.S.S

Author

Seglar-Arroyo, Monica, Ashkar, Halim, Rowell, Gavin, Schüssler, Fabian, Taylor, Andrew, H. E. S. S. Collaboration, Bonnefoy, Simon, Brun, Francois, Egberts, Kathrin, Füßling, Matthias, Hoischen, Clemens, Murach, Thomas, Ohm, Stefan, Pühlhofer, Gerd, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, and H.E.S.S.

Subjects
neutron star: binary, Astrophysics::High Energy Astrophysical Phenomena, Binary number, FOS: Physical sciences, production [electromagnetic field], binary [neutron star], VHE, electromagnetic field: production, emission [gravitational radiation], Binary black hole, binary: coalescence, emission [gamma ray], HESS, binary [black hole], Cherenkov radiation, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), energy: high, Gravitational wave, Gamma ray, gravitational radiation, Astronomy, imaging, binary: compact, Neutron star, Cherenkov counter, gamma ray: emission, black hole: binary, gravitational radiation: emission, compact [binary], high [energy], Astrophysical Phenomena, coalescence [binary], Focus (optics), Astrophysics - High Energy Astrophysical Phenomena, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

36th International Cosmic Ray Conference, Madison, USA, 24 Jul 2019 - 1 Aug 2019; PoS(ICRC2019)789 (2019)., The recent milestones in multi-messenger astronomy have opened new ways to study the Unverse. The unprecedented gravitational wave (GW) follow-up campaigns established the power that the combination of different messengers has to identify and study the nature and evolution of astrophysical phenomena. Here we focus on the search for high-energy gamma ray emission as electromagnetic counterpart of compact binary coalescences with the H.E.S.S. Imaging Air Cherenkov Telescopes (IACTs). In this contribution, the optimized strategies developed specifically for the prompt follow-up of gravitational wave events with H.E.S.S are presented. As illustration, the successful observation campaigns up to this time will be described, including the ones during Observation Run O2 on the binary black hole (BH-BH) merger GW170814 and the binary neutron star (NS-NS) merger GW170817, and an update on recent events occurring during O3. Results of these searches are presented and the constraints that prompt observations can put on very-high-energy, non-thermal emission, are briefly discussed. Finally, an outlook on further improvements for the gravitational waves follow-up program with H.E.S.S. will be provided.

Published
2019

27. Investigating the Nature of MGRO J1908+06 with Multiwavelength Observations

Author

Diego F. Torres, Jian Li, Ruo-Yu Liu, Emma de Ona Wilhelmi, Hao-Ning He, Y. Su, Meng-Yuan Xiao, Qian-Cheng Liu, Rolf Bühler, Matthew Kerr, National Aeronautics and Space Administration (US), Ministry of Education, Culture, Sports, Science and Technology (Japan), Centre National de la Recherche Scientifique (France), Istituto Nazionale di Fisica Nucleare, Alexander von Humboldt Foundation, Foundation for Introducing Talent of Nanjing University of Information Science and Technology, Swedish National Space Agency, Japan Aerospace Exploration Agency, Centre National D'Etudes Spatiales (France), and National Natural Science Foundation of China

Subjects
Supernova remnants, Astrophysics::High Energy Astrophysical Phenomena, Rotation powered pulsars, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, GeV, neutrino: flux, VHE, IceCube, supernova, Molecular clouds, TeV, cloud, Astrophysics::Galaxy Astrophysics, pulsar, High Energy Astrophysical Phenomena (astro-ph.HE), Physics, Gamma-ray astronomy, Gamma-ray sources, Molecular cloud, Astronomy, Astronomy and Astrophysics, flux [neutrino], gamma ray, Space and Planetary Science, ddc:520, spectral, High Energy Physics::Experiment, galaxy, Astrophysics - High Energy Astrophysical Phenomena
Abstract

The astrophysical journal 913(2), L33 (2021). doi:10.3847/2041-8213/abf925, The unidentified TeV source MGRO J1908+06, with emission extending from hundreds of GeV to beyond 100 TeV, is one of the most intriguing sources in the Galactic plane. MGRO J1908+06 spatially associates with an IceCube hotspot of neutrino emission. Although the hotspot is not significant yet, this suggests a possible hadronic origin of the observed gamma-ray radiation. Here we describe a multiwavelength analysis on MGRO J1908+06 to determine its nature. We identify, for the first time, an extended GeV source as the counterpart of MGRO J1908 + 06, discovering possibly associated molecular clouds (MCs). The GeV spectrum shows two well-differentiated components: a soft spectral component below ∼10 GeV, and a hard one (Γ ∼ 1.6) above these energies. The lower-energy part is likely associated with the dense MCs surrounding the supernova remnant (SNR) G40.5−0.5, whereas the higher-energy component, which connects smoothly with the spectrum observed in TeV range, resembles the inverse Compton emission observed in relic pulsar wind nebulae. This simple scenario seems to describe the data satisfactorily, but raises questions about the interpretation of the emission at hundreds of TeV. In this scenario, no detectable neutrino flux would be expected., Published by Univ., Chicago, Ill. [u.a.]

Published
2021

28. Searching for Variability of the Crab Nebula Flux at TeV Energies using MAGIC Very Large Zenith Angle Observations

Author

Nikola Godinovic, Ievgen Vovk, Michele Peresano, Juliane van Scherpenberg, Razmik Mirzoyan, D. Zarić, Petar Temnikov, Jürgen Besenrieder, Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), MAGIC, Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7), and Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112))

Subjects
electron, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Synchrotron radiation, Astrophysics, VHE, GLAST, law.invention, law, synchrotron, synchrotron radiation: emission, MAGIC (telescope), Zenith, High Energy Astrophysical Phenomena (astro-ph.HE), Physics, Nebula, energy: high, scattering, stability, Light curve, MAGIC, Synchrotron, observatory, flux, Crab Nebula, Compton scattering: inverse, gamma ray, efficiency, Physics::Accelerator Physics, Astrophysics - High Energy Astrophysical Phenomena, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Fermi Gamma-ray Space Telescope
Abstract

The Crab nebula was once considered to be a stable source until strong flares, up to 30 times increase in flux, were observed in the MeV and GeV energy range by the AGILE and Fermi Gamma-ray Observatories. Existing nebula models often assume that the electron population emitting synchrotron radiation at lower energies is responsible for the VHE emission via Inverse Compton (IC) scattering. This suggests that the variability of the synchrotron $\gamma$-ray emission may also become observable in the multi-TeV energy range. Until now, no variability in the Crab Nebula flux has been found in the VHE regime. In 2015, MAGIC started an observational campaign which improved the collection efficiency of $\gamma$-rays above several tens of TeV. These observations are performed under Very Large Zenith Angles (VLZA) and lead to a large increase in the collection area. This allows us to observe the low fluxes at TeV energies in a shorter time compared to standard observations, and to significantly increase the observable energy towards higher energies. We have studied the Crab Nebula light curve obtained from the VLZA data since 2015 in search for the flux variability at the highest TeV energies. The results of this study will be presented., Comment: Proceedings of the ICRC 2019

Published
2019

29. Resolving the kpc jet of Centaurus A in TeV gamma-rays

Author

De Naurois, M., Holler, M., Rieger, Frank, Sanchez, D., Taylor, Andrew, Laboratoire Leprince-Ringuet (LLR), Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Laboratoire d'Annecy de Physique des Particules (LAPP), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), and H.E.S.S.

Subjects
Physics, High energy, Jet (fluid), Radio galaxy, Astrophysics::High Energy Astrophysical Phenomena, Centaurus A, Gamma ray, Astrophysics::Instrumentation and Methods for Astrophysics, imaging, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Galaxy, VHE, Black hole, Cherenkov counter, gamma ray, statistics, HESS, black hole, photon: jet, galaxy, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Cherenkov radiation, Astrophysics::Galaxy Astrophysics
Abstract

International audience; The point-spread function (PSF) of existing Imaging Atmospheric Cherenkov Telescopes is limited to scales of a few arcminutes. Measuring source sizes at or below the PSF level is generally restricted by statistics as well as the systematic uncertainties of the PSF characterisation. Employing new simulation and analysis techniques, the understanding of the PSF of the H.E.S.S. array has considerably increased, allowing to measure extensions of very high energy (VHE; E > 100 GeV) gamma-ray sources down to below one arcminute. Here we present the first detection of extended VHE emission from an extragalactic source, the kpc jet of the nearby radio galaxy Centaurus A. The physical extension of the VHE jet of Centaurus A exceeds 1.8 kpc, meaning that a large part of the emission originates far away from the central black hole. Our results as well as physical implications are going to be discussed.

Published
2019

30. MAGIC observations of the nearby short GRB 160821B: implications for afterglow physics and gravitational wave follow-up

Author

Susumu Inoue, Koji Noda, Alessandro Carosi, Satoshi Fukami, Francesco Longo, Alessio Berti, Pierre Colin, Lara Nava, Michele Palatiello, Laboratoire d'Annecy de Physique des Particules (LAPP), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), and MAGIC

Subjects
Physics, radiation: electromagnetic, Gravitational wave, electron: acceleration, Astrophysics::High Energy Astrophysical Phenomena, Gamma ray, gravitational radiation, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Kilonova, gamma ray: burst, Cherenkov counter: atmosphere, Electromagnetic radiation, MAGIC, VHE, Afterglow, Neutron star, 13. Climate action, gravitational radiation: emission, synchrotron, Gamma-ray burst, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Cherenkov radiation, neutron star: coalescence
Abstract

International audience; Gamma-ray bursts (GRBs) are the most luminous sources of electromagnetic radiation in the Universe, many of whose fundamental aspects are still mysterious. Aiming to clarify their physical origin by detecting them in very-high-energy (VHE; >0.1 TeV) gamma rays, the MAGIC telescopes have been conducting fast, automatic follow-up of GRBs as a key observation program. GRB 160821B, one of the nearest short GRBs known at z~0.16 with evidence of a coincident kilonova, was followed up, starting from 24 sec after the burst trigger. Despite non-optimal observing conditions, hints of a gamma-ray signal are found above ~500 GeV a few hours after the burst. Assuming that the signal was real, we interpret the multi-wavelength observations of this GRB in terms of standard afterglow models. The potential VHE signal can be consistently explained as synchrotron-self-Compton emission from electrons accelerated in the external forward shock with a plausible set of parameters. We also discuss the expectations when such afterglow emission is observed at large angles from the GRB jet axis, corresponding to VHE follow-up of gravitational wave alerts for neutron star (NS) mergers. Interesting prospects are found for sufficiently nearby events with current imaging atmospheric Cherenkov telescopes. Future VHE observations of short GRBs as well as GW sources may provide important new insight into the physics of NS mergers and related phenomena.

Published
2019

31. Constraints on gamma-ray and neutrino emission from NGC 1068 with the MAGIC telescopes

Author

MAGIC Collaboration, Acciari, V. A., Ansoldi, S., Antonelli, L. A., Engels, A. Arbet, Baack, D., Babić, A., Banerjee, B., de Almeida, U. Barres, Barrio, J. A., González, J. Becerra, Bednarek, W., Bellizzi, L., Bernardini, E., Berti, A., Besenrieder, J., Bhattacharyya, W., Bigongiari, C., Biland, A., Blanch, O., Bonnoli, G., Bošnjak, Ž., Busetto, G., Carosi, R., Ceribella, G., Chai, Y., Chilingaryan, A., Cikota, S., Colak, S. M., Colin, U., Colombo, E., Contreras, J. L., Cortina, J., Covino, S., D'Elia, V., Da Vela, P., Dazzi, F., De Angelis, A., De Lotto, B., Delfino, M., Delgado, J., Depaoli, D., Di Pierro, F., Di Venere, L., Espiñeira, E. Do Souto, Prester, D. Dominis, Donini, A., Dorner, D., Doro, M., Elsaesser, D., Ramazani, V. Fallah, Fattorini, A., Ferrara, G., Fidalgo, D., Foffano, L., Fonseca, M. V., Font, L., Fruck, C., Fukami, S., López, R. J. García, Garczarczyk, M., Gasparyan, S., Gaug, M., Giglietto, N., Giordano, F., Godinović, N., Green, D., Guberman, D., Hadasch, D., Hahn, A., Herrera, J., Hoang, J., Hrupec, D., Hütten, M., Inada, T., Inoue, S., Ishio, K., Iwamura, Y., Jouvin, L., Kerszberg, D., Kubo, H., Kushida, J., Lamastra, A., Lelas, D., Leone, F., Lindfors, E., Lombardi, S., Longo, F., López, M., López-Coto, R., López-Oramas, A., Loporchio, S., Fraga, B. Machado de Oliveira, Maggio, C., Majumdar, P., Makariev, M., Mallamaci, M., Maneva, G., Manganaro, M., Mannheim, K., Maraschi, L., Mariotti, M., Martínez, M., Mazin, D., Mićanović, S., Miceli, D., Minev, M., Miranda, J. M., Mirzoyan, R., Molina, E., Moralejo, A., Morcuende, D., Moreno, V., Moretti, E., Munar-Adrover, P., Neustroev, V., Nigro, C., Nilsson, K., Ninci, D., Nishijima, K., Noda, K., Nogués, L., Nozaki, S., Paiano, S., Palacio, J., Palatiello, M., Paneque, D., Paoletti, R., Paredes, J. M., Peñil, P., Peresano, M., Persic, M., Moroni, P. G. Prada, Prandini, E., Puljak, I., Rhode, W., Ribó, M., Rico, J., Righi, C., Rugliancich, A., Saha, L., Sahakyan, N., Saito, T., Sakurai, S., Satalecka, K., Schmidt, K., Schweizer, T., Sitarek, J., Šnidarić, I., Sobczynska, D., Somero, A., Stamerra, A., Strom, D., Strzys, M., Suda, Y., Surić, T., Takahashi, M., Tavecchio, F., Temnikov, P., Terzić, T., Teshima, M., Torres-Albà, N., Tosti, L., Vagelli, V., van Scherpenberg, J., Vanzo, G., Acosta, M. Vazquez, Vigorito, C. F., Vitale, V., Vovk, I., Will, M., Zarić, D., Fiore, F., Feruglio, C., Rephaeli, Y., Acciari, V. A., Ansoldi, S., Antonelli, L. A., Engels, A. A., Baack, D., Babic, A., Banerjee, B., Barres De Almeida, U., Barrio, J. A., Becerra Gonzalez, J., Bednarek, W., Bellizzi, L., Bernardini, E., Berti, A., Besenrieder, J., Bhattacharyya, W., Bigongiari, C., Biland, A., Blanch, O., Bonnoli, G., Bosnjak, Z., Busetto, G., Carosi, R., Ceribella, G., Chai, Y., Chilingaryan, A., Cikota, S., Colak, S. M., Colin, U., Colombo, E., Contreras, J. L., Cortina, J., Covino, S., D'Elia, V., Da Vela, P., Dazzi, F., De Angelis, A., De Lotto, B., Delfino, M., Delgado, J., Depaoli, D., Di Pierro, F., Di Venere, L., Souto Espineira, E. D., Dominis Prester, D., Donini, A., Dorner, D., Doro, M., Elsaesser, D., Fallah Ramazani, V., Fattorini, A., Ferrara, G., Fidalgo, D., Foffano, L., Fonseca, M. V., Font, L., Fruck, C., Fukami, S., Garcia Lopez, R. J., Garczarczyk, M., Gasparyan, S., Gaug, M., Giglietto, N., Giordano, F., Godinovic, N., Green, D., Guberman, D., Hadasch, D., Hahn, A., Herrera, J., Hoang, J., Hrupec, D., Hutten, M., Inada, T., Inoue, S., Ishio, K., Iwamura, Y., Jouvin, L., Kerszberg, D., Kubo, H., Kushida, J., Lamastra, A., Lelas, D., Leone, F., Lindfors, E., Lombardi, S., Longo, F., Lopez, M., Lopez-Coto, R., Lopez-Oramas, A., Loporchio, S., Machado De Oliveira Fraga, B., Maggio, C., Majumdar, P., Makariev, M., Mallamaci, M., Maneva, G., Manganaro, M., Mannheim, K., Maraschi, L., Mariotti, M., Martinez, M., Mazin, D., Micanovic, S., Miceli, D., Minev, M., Miranda, J. M., Mirzoyan, R., Molina, E., Moralejo, A., Morcuende, D., Moreno, V., Moretti, E., Munar-Adrover, P., Neustroev, V., Nigro, C., Nilsson, K., Ninci, D., Nishijima, K., Noda, K., Nogues, L., Nozaki, S., Paiano, S., Palacio, J., Palatiello, M., Paneque, D., Paoletti, R., Paredes, J. M., Penil, P., Peresano, M., Persic, M., Prada Moroni, P. G., Prandini, E., Puljak, I., Rhode, W., Ribo, M., Rico, J., Righi, C., Rugliancich, A., Saha, L., Sahakyan, N., Saito, T., Sakurai, S., Satalecka, K., Schmidt, K., Schweizer, T., Sitarek, J., Snidaric, I., Sobczynska, D., Somero, A., Stamerra, A., Strom, D., Strzys, M., Suda, Y., Suric, T., Takahashi, M., Tavecchio, F., Temnikov, P., Terzic, T., Teshima, M., Torres-Alba, N., Tosti, L., Vagelli, V., Van Scherpenberg, J., Vanzo, G., Vazquez Acosta, M., Vigorito, C. F., Vitale, V., Vovk, I., Will, M., Zaric, D., Fiore, F., Feruglio, C., and Rephaeli, Y.

Subjects
Active galactic nucleus, accelerator, Astrophysics::High Energy Astrophysical Phenomena, gamma-ray astrophysic, Hadron, FOS: Physical sciences, Starburst galaxies, Cosmic ray, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Active galaxies, Gamma-ray sources, 01 natural sciences, GLAST, VHE, IceCube, neutrino, cosmic radiation [p], emission [gamma ray], formation [star], 0103 physical sciences, flux [gamma ray], MAGIC (telescope), AGN, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, High Energy Astrophysical Phenomena (astro-ph.HE), Physics, 010308 nuclear & particles physics, Gamma ray, background [neutrino], Astronomy and Astrophysics, MAGIC, Galaxy, gamma-ray astrophysics, Space and Planetary Science, active galactic nuclei, slope, ddc:520, spectral, galaxy, Neutrino, Astrophysics - High Energy Astrophysical Phenomena, Event (particle physics)
Abstract

Starburst galaxies and star-forming active galactic nuclei (AGN) are among the candidate sources thought to contribute appreciably to the extragalactic gamma-ray and neutrino backgrounds. NGC 1068 is the brightest of the star-forming galaxies found to emit gamma rays from 0.1 to 50 GeV. Precise measurements of the high-energy spectrum are crucial to study the particle accelerators and probe the dominant emission mechanisms. We have carried out 125 hours of observations of NGC 1068 with the MAGIC telescopes in order to search for gamma-ray emission in the very high energy band. We did not detect significant gamma-ray emission, and set upper limits at 95\% confidence level to the gamma-ray flux above 200 GeV f, 11 pages, 4 figures, accepted for publication in The Astrophysical Journal

Published
2019

32. Pulsar gamma-ray emission in the radiation reaction regime

Author

Jérôme Pétri, Observatoire astronomique de Strasbourg (ObAS), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), and Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)

Subjects
Electromagnetic field, Photon, geometry, gamma-rays: stars, lepton, Electromagnetic spectrum, Astrophysics::High Energy Astrophysical Phenomena, Magnetosphere, magnetic field, Astrophysics, Cherenkov counter: atmosphere, 01 natural sciences, VHE, particle: acceleration, particle: velocity, stars: neutron, Pulsar, electromagnetic field: high, pulsars: general, 0103 physical sciences, rotator, stars: magnetic fields, site, multiplicity, 010306 general physics, 010303 astronomy & astrophysics, relativistic processes, Physics, photon, Gamma ray, Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy and Astrophysics, radiation mechanisms: non-thermal, Particle acceleration, gamma ray: emission, field strength, Space and Planetary Science, curvature, trajectory, radiation: spectrum, pulsar: emission, Astrophysics - High Energy Astrophysical Phenomena, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], dipole, Fermi Gamma-ray Space Telescope
Abstract

Since the era of the Fermi/LAT and atmospheric Cerenkov telescopes, pulsars are known to emit high and very high-energy photons, in the MeV-GeV range and sometimes up to TeV. To date, it is still unclear where and how these photons are produced. Nevertheless gamma-ray photons require particle acceleration to ultra-relativistic speeds. In this paper, we compute single particle trajectories for leptons in an arbitrary strong electromagnetic field in the so-called radiation reaction limit. In this picture, particle velocity only depends on the local electromagnetic field which we assume to follow the vacuum dipole rotator. From this velocity field, we compute the curvature radiation spectrum and light-curves. Sky maps and phase-resolved spectra are then deduced accounting for realistic pulsar periods and magnetic field strengths. Emission sites within the pulsar magnetosphere where most of radiation emanates are then localized. For standard parameters of millisecond and normal pulsars, we show that a break in the spectrum occurs at several GeV in agreement with the Fermi/LAT second pulsar catalogue. A sample of representative phase-resolved spectra and sky-maps are shown. A pair multiplicity of several tenths to several thousands is required to account for the total gamma-ray luminosity. Moreover depending on the geometry, single or double-peaked light-curves are found. Our model shows that minimalist assumptions are already able to reproduce salient features of pulsar emission., Comment: Accepted for publication in MNRAS

Published
2019

33. MAGIC and Fermi-LAT gamma-ray results on unassociated HAWC sources

Author

Ahnen, M L, Ansoldi, S, Antonelli, L A, Arcaro, C, Baack, D, Babić, A, Banerjee, B, Bangale, P, Barres&nbsp, de&nbsp, Almeida, U, Barrio, J A, Becerra&nbsp, González, J, Bednarek, W, Bernardini, E, Berse, R Ch, Berti, A, Bhattacharyya, W, Biland, A, Blanch, O, Bonnoli, G, Carosi, R, Carosi, A, Ceribella, G, Chatterjee, A, Colak, S M, Colin, P, Colombo, E, Contreras, J L, Cortina, J, Covino, S, Cumani, P, Da&nbsp, Vela, P, Dazzi, F, De&nbsp, Angelis, A, Lotto, B, Delfino, M, Delgado, J, Di&nbsp, Pierro, F, Domínguez, A, Dominis&nbsp, Prester, D, Dorner, D, Doro, M, Einecke, S, Elsaesser, D, Fallah&nbsp, Ramazani, V, Fernández-Barral, A, Fidalgo, D, Fonseca, M V, Font, L, Fruck, C, Galindo, D, García&nbsp, López, R J, Garczarczyk, M, Gaug, M, Giammaria, P, Godinović, N, Gora, D, Guberman, D, Hadasch, D, Hahn, A, Hassan, T, Hayashida, M, Herrera, J, Hose, J, Hrupec, D, Ishio, K, Konno, Y, Kubo, H, Kushida, J, Kuveždić, D, Lelas, D, Lindfors, E, Lombardi, S, Longo, F, López, M, Maggio, C, Majumdar, P, Makariev, M, Maneva, G, Manganaro, M, Mannheim, K, Maraschi, L, Mariotti, M, Martínez, M, Masuda, S, Mazin, D, Mielke, K, Minev, M, Miranda, J M, Mirzoyan, R, Moralejo, A, Moreno, V, Moretti, E, Nagayoshi, T, Neustroev, V, Niedzwiecki, A, Nievas&nbsp, Rosillo, M, Nigro, C, Nilsson, K, Ninci, D, Nishijima, K, Noda, K, Nogués, L, Paiano, S, Palacio, J, Paneque, D, Paoletti, R, Paredes, J M, Pedaletti, G, Peresano, M, Persic, M, Prada&nbsp, Moroni, P G, Prandini, E, Puljak, I, Garcia, J R, Reichardt, I, Rhode, W, Ribó, M, Rico, J, Righi, C, Rugliancich, A, Saito, T, Satalecka, K, Schweizer, T, Sitarek, J, Šnidarić, I, Sobczynska, D, Stamerra, A, Strzys, M, Surić, T, Takahashi, M, Takalo, L, Tavecchio, F, Temnikov, P, Terzić, T, Teshima, M, Torres-Albà, N, Treves, A, Tsujimoto, S, Vanzo, G, Vazquez&nbsp, Acosta, M, Vovk, I, Ward, J E, Will, M, Zarić, D, Albert, A, Alfaro, R, Alvarez, C, Arceo, R, Arteaga-Velázquez, J C, Avila&nbsp, Rojas, D, Ayala&nbsp, Solares, H A, Becerril, A, Belmont-Moreno, E, Benzvi, S Y, Bernal, A, Braun, J, Caballero-Mora, K S, Capistrán, T, Carramiñana, A, Casanova, S, Castillo, M, Cotti, U, Cotzomi, J, Coutiño&nbsp, León, S, León, C, la&nbsp, Fuente, E, Diaz&nbsp, Hernandez, R, Dichiara, S, Dingus, B L, Duvernois, M A, Díaz-Vélez, J C, Ellsworth, R W, Engel, K, Enriquez-Rivera, O, Fiorino, D W, Fleischhack, H, Fraija, N, García-González, J A, Garfias, F, González-Muñoz, A, González, M M, Goodman, J A, Hampel-Arias, Z, Harding, J P, Hernandez, S, Hueyotl-Zahuantitla, F, Hui, C M, Hüntemeyer, P, Iriarte, A, Jardin-Blicq, A, Joshi, V, Kaufmann, S, Lara, A, Lauer, R J, Lee, W H, Lennarz, D, León&nbsp, Vargas, H, Linnemann, J T, Longinotti, A L, Luis-Raya, G, Luna-García, R, López-Coto, R, Malone, K, Marinelli, S S, Martinez, O, Martinez-Castellanos, I, Martínez-Castro, J, Martínez-Huerta, H, Matthews, J A, Miranda-Romagnoli, P, Moreno, E, Mostafá, M, Nayerhoda, A, Nellen, L, Newbold, M, Nisa, M U, Noriega-Papaqui, R, Pelayo, R, Pretz, J, Pérez-Pérez, E G, Ren, Z, Rho, C D, Rivière, C, Rosa-González, D, Rosenberg, M, Ruiz-Velasco, E, Salesa&nbsp, Greus, F, Sandoval, A, Schneider, M, Seglar&nbsp, Arroyo, M, Sinnis, G, Smith, A J, Springer, R W, Surajbali, P, Taboada, I, Tibolla, O, Tollefson, K, Torres, I, Ukwatta, T N, Vianello, G, Villaseñor, L, Werner, F, Westerhoff, S, Wood, J, Yapici, T, Yodh, G, Zepeda, A, Zhou, H, Álvarez, J D, Ajello, M, Baldini, L, Barbiellini, G, Berenji, B, Bissaldi, E, Blandford, R D, Bonino, R, Bottacini, E, Brandt, T J, Bregeon, J, Bruel, P, Cameron, R A, Caputo, R, Caraveo, P A, Castro, D, Cavazzuti, E, Chiaro, G, Ciprini, S, Costantin, D, D’Ammando, F, Palma, F, Desai, A, Lalla, N, Mauro, M, Venere, L, Favuzzi, C, Fukazawa, Y, Funk, S, Fusco, P, Gargano, F, Gasparrini, D, Giglietto, N, Giordano, F, Giroletti, M, Glanzman, T, Green, D, Grenier, I A, Guiriec, S, Harding, A K, Hays, E, Hewitt, J W, Horan, D, Jóhannesson, G, Kuss, M, Larsson, S, Liodakis, I, Loparco, F, Lubrano, P, Magill, J D, Maldera, S, Manfreda, A, Mazziotta, M N, Mereu, I, Michelson, P F, Mizuno, T, Monzani, M E, Morselli, A, Moskalenko, I V, Negro, M, Nuss, E, Omodei, N, Orienti, M, Orlando, E, Ormes, J F, Palatiello, M, Paliya, V S, Pesce-Rollins, M, Petrosian, V, Piron, F, Porter, T A, Principe, G, Rainò, S, Rani, B, Razzano, M, Razzaque, S, Reimer, A, Reimer, O, Sgrò, C, Siskind, E J, Spandre, G, Spinelli, P, Tajima, H, Thayer, J B, Thompson, D J, Torres, D F, Torresi, E, Troja, E, Valverde, J, Wood, K, Yassine, M, Fermi-LAT&nbsp, Collaboration, Null, Laboratoire Univers et Particules de Montpellier (LUPM), Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Montpellier 2 - Sciences et Techniques (UM2), Laboratoire Leprince-Ringuet (LLR), Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7), MAGIC, HAWC, Fermi-LAT, ITA, Ahnen, M. L., Ansoldi, S., Antonelli, L. A., Arcaro, C., Baack, D., Babic, A., Banerjee, B., Bangale, P., Barres De Almeida, U., Barrio, J. A., Becerra Gonzalez, J., Bednarek, W., Bernardini, E., Berse, R. C., Berti, A., Bhattacharyya, W., Biland, A., Blanch, O., Bonnoli, G., Carosi, R., Carosi, A., Ceribella, G., Chatterjee, A., Colak, S. M., Colin, P., Colombo, E., Contreras, J. L., Cortina, J., Covino, S., Cumani, P., Da Vela, P., Dazzi, F., De Angelis, A., De Lotto, B., Delfino, Delgado, J., Di Pierro, F., Dominguez, A., Dominis Prester, D., Dorner, D., Doro, M., Einecke, S., Elsaesser, D., Fallah Ramazani, V., Fernandez-Barral, A., Fidalgo, D., Fonseca, M. V., Font, L., Fruck, C., Galindo, D., Garcia Lopez, R. J., Garczarczyk, M., Gaug, M., Giammaria, P., Godinovic, N., Gora, D., Guberman, D., Hadasch, D., Hahn, A., Hassan, T., Hayashida, M., Herrera, J., Hose, J., Hrupec, D., Ishio, K., Konno, Y., Kubo, H., Kushida, J., Kuvedic, D., Lelas, D., Lindfors, E., Lombardi, S., Longo, Francesco, Lopez, M., Maggio, C., Majumdar, P., Makariev, M., Maneva, G., Manganaro, M., Mannheim, K., Maraschi, L., Mariotti, M., Martinez, M., Masuda, S., Mazin, Mielke, K., Minev, M., Miranda, J. M., Mirzoyan, R., Moralejo, A., Moreno, V., Moretti, E., Nagayoshi, T., Neustroev, V., Niedzwiecki, A., Nievas Rosillo, M., Nigro, C., Nilsson, K., Ninci, D., Nishijima, K., Noda, K., Nogues, L., Paiano, S., Palacio, J., Paneque, D., Paoletti, R., Paredes, J. M., Pedaletti, G., Peresano, M., Persic, M., Prada Moroni, P. G., Prandini, E., Puljak, I., Garcia, J. R., Reichardt, I., Rhode, W., Ribo, M., Rico, J., Righi, C., Rugliancich, A., Saito, T., Satalecka, K., Schweizer, T., Sitarek, J., Snidaric, I., Sobczynska, D., Stamerra, A., Strzys, M., Suric, T., Takahashi, M., Takalo, L., Tavecchio, F., Temnikov, P., Terzic, T., Teshima, Torres-Alba, N., Treves, A., Tsujimoto, S., Vanzo, G., Vazquez Acosta, M., Vovk, I., Ward, J. E., Will, M., Zaric, D., Albert, A., Alfaro, R., Alvarez, C., Arceo, R., Arteaga-Velazquez, J. C., Avila Rojas, D., Ayala Solares, H. A., Becerril, A., Belmont-Moreno, E., Benzvi, S. Y., Bernal, A., Braun, J., Caballero-Mora, K. S., Capistran, T., Carraminana, A., Casanova, S., Castillo, M., Cotti, U., Cotzomi, J., Coutino De Leon, S., De Leon, C., De La Fuente, E., Diaz Hernandez, R., Dichiara, S., Dingus, B. L., Duvernois, M. A., Diaz-Velez, J. C., Ellsworth, R. W., Engel, K., Enriquez-Rivera, O., Fiorino, D., Fleischhack, H., Fraija, N., Garcia-Gonzalez, J. A., Garfias, F., Gonzalez-Munoz, A., Gonzalez, M. M., Goodman, J. A., Hampel-Arias, Z., Harding, J. P., Hernandez, S., Hueyotl-Zahuantitla, F., Hui, C. M., Huntemeyer, P., Iriarte, A., Jardin-Blicq, A., Joshi, V., Kaufmann, S., Lara, A., Lauer, R. J., Lee, W. H., Lennarz, D., Leon Vargas, H., Linnemann, J. T., Longinotti, A. L., Luis-Raya, G., Luna-Garcia, R., Lopez-Coto, Malone, K., Marinelli, S. S., Martinez, O., Martinez-Castellanos, I., Martinez-Castro, J., Martinez-Huerta, H., Matthews, J. A., Miranda-Romagnoli, P., Moreno, E., Mostafa, M., Nayerhoda, A., Nellen, L., Newbold, M., Nisa, M. U., Noriega-Papaqui, R., Pelayo, R., Pretz, J., Perez-Perez, E. G., Ren, Z., Rho, C. D., Riviere, C., Rosa-Gonzalez, D., Rosenberg, M., Ruiz-Velasco, E., Salesa Greus, F., Sandoval, A., Schneider, M., Seglar Arroyo, M., Sinnis, G., Smith, A. J., Springer, R. W., Surajbali, P., Taboada, I., Tibolla, O., Tollefson, K., Torres, I., Ukwatta, T. N., Vianello, G., Villasenor, L., Werner, F., Westerhoff, S., Wood, J., Yapici, T., Yodh, G., Zepeda, A., Zhou, H., Alvarez, J. D., Ajello, M., Baldini, L., Barbiellini, G., Berenji, B., Bissaldi, E., Blandford, R. D., Bonino, R., Bottacini, Brandt, T. J., Bregeon, J., Bruel, P., Cameron, R. A., Caputo, R., Caraveo, P. A., Castro, D., Cavazzuti, E., Chiaro, G., Ciprini, Costantin, D., D'Ammando, De Palma, F., Desai, A., Di Lalla, N., Di Mauro, M., Di Venere, L., Favuzzi, C., Fukazawa, Y., Funk, S., Fusco, Gargano, F., Gasparrini, Giglietto, N., Giordano, Giroletti, M., Glanzman, T., Green, D., Grenier, I. A., Guiriec, S., Harding, A. K., Hays, E., Hewitt, J. W., Horan, D., Johannesson, Kuss, M., Larsson, Liodakis, I., Loparco, F., Lubrano, P., Magill, J. D., Maldera, S., Manfreda, A., Mazziotta, M. N., Mereu, I., Michelson, P. F., Mizuno, T., Monzani, M. E., Morselli, A., Moskalenko, I. V., Negro, M., Nuss, E., Omodei, N., Orienti, M., Orlando, E., Ormes, J. F., Palatiello, M., Paliya, V. S., Pesce-Rollins, M., Petrosian, V., Piron, F., Porter, T. A., Principe, G., Raino, S., Rani, B., Razzano, M., Razzaque, S., Reimer, A., Reimer, Sgro, C., Siskind, E. J., Spandre, G., Spinelli, Tajima, H., Thayer, J. B., Thompson, D. J., Torres, D. F., Torresi, E., Troja, E., Valverde, J., Wood, K., Yassine, Manal, Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Longo, Yassine, Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), and Université de Montpellier (UM)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Astrophysics::High Energy Astrophysical Phenomena, pulsars: general – gamma rays: general – astroparticle physics, FOS: Physical sciences, Astrophysics, general [pulsars], 01 natural sciences, VHE, GLAST, Pulsar, Observatory, pulsars: general, 0103 physical sciences, MAGIC (telescope), 010303 astronomy & astrophysics, pulsar, Astroparticle physics, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), gamma rays: general, astroparticle physics, 010308 nuclear & particles physics, Gamma ray, astroparticle physic, Astronomy and Astrophysics, MAGIC, observatory, gamma ray: emission, Space and Planetary Science, Pulsars: general, Física nuclear, Astrophysics - High Energy Astrophysical Phenomena, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], general [gamma rays], HAWC, Fermi Gamma-ray Space Telescope
Abstract

The HAWC Collaboration released the 2HWC catalog of TeV sources, in which 19 show no association with any known high-energy (HE; E > 10 GeV) or very-high-energy (VHE; E > 300 GeV) sources. This catalog motivated follow-up studies by both the MAGIC and Fermi-LAT observatories with the aim of investigating gamma-ray emission over a broad energy band. In this paper, we report the results from the first joint work between HAWC, MAGIC and Fermi-LAT on three unassociated HAWC sources: 2HWC J2006+341, 2HWC J1907+084* and 2HWC J1852+013*. Although no significant detection was found in the HE and VHE regimes, this investigation shows that a minimum 1 degree extension (at 95% confidence level) and harder spectrum in the GeV than the one extrapolated from HAWC results are required in the case of 2HWC J1852+013*, while a simply minimum extension of 0.16 degrees (at 95% confidence level) can already explain the scenario proposed by HAWC for the remaining sources. Moreover, the hypothesis that these sources are pulsar wind nebulae is also investigated in detail., 12 pages, 3 figures. Accepted for publication in MNRAS

Published
2019
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34. Detection of sub-TeV gamma-ray emission from the flaring blazar TXS 1515-273 with the MAGIC telescopes

Author

Mirzoyan, Razmik, Babić, Ana, Bošnjak, Željka, Cikota, Stefan, Dominis Prester, Dijana, Godinović, Nikola, Hrupec, Dario, Lelas, Damir, Manganaro, Marina, Mićanović, Saša, Puljak, Ivica, Surić, Tihomir, Šnidarić, Iva, Terzić, Tomislav, and Zarić, Darko

Subjects
Gamma Ray, GeV%22">>GeV, TeV, VHE, AGN, Blazar
Abstract

The MAGIC collaboration reports the first detection of very-high-energy (VHE ; E>100 GeV) gamma-ray emission from the flaring blazar TXS1515-273 (RA=15 18 03.610, Dec= -27 31 31.40, J2000.0). The object was observed with the MAGIC telescopes for 1.9 hours on 2019/02/28 under moderate moonlight in the zenith distance range 55 - 60 deg. The preliminary real-time analysis of this data shows a detection of TXS1515-273 with a statistical significance more than 5 standard deviations. The MAGIC observations were triggered by the flaring activity reported by Fermi-LAT from 2019/02/24 to 2019/02/25 (ATel#12532). Few hours before that ATel, a communication from Dave Thompson from the Fermi team alerted the MAGIC collaboration about this source. The redshift of this source is uncertain, with an upper limit z

Published
2019

35. First time detection of a GRB at sub-TeV energies ; MAGIC detects the GRB 190114C

Author

Mirzoyan, Razmik, Babić, Ana, Bošnjak, Željka, Cikota, Stefan, Dominis Prester, Dijana, Godinović, Nikola, Hrupec, Dario, Lelas, Damir, Manganaro, Marina, Mićanović, Saša, Puljak, Ivica, Surić, Tihomir, Šnidarić, Iva, Terzić, Tomislav, Zarić, Darko, and (the MAGIC Collaboration)

Subjects
Gamma Ray, GeV%22">>GeV, TeV, VHE, Request for Observations, Gamma-Ray Burst
Abstract

The MAGIC telescopes performed a rapid follow-up observation of GRB 190114C (Gropp et al., GCN 23688 ; Tyurina et al., GCN 23690, de Ugarte Postigo et al., GCN 23692, Lipunov et al. GCN 23693, Selsing et al. GCN 23695). This observation was triggered by the Swift-BAT alert ; we started observing at about 50s after Swift T0: 20:57:03.19. The MAGIC real-time analysis shows a significance >20 sigma in the first 20 min of observations (starting at T0+50s) for energies >300GeV. The relatively high detection threshold is due to the large zenith angle of observations (>60 degrees) and the presence of partial Moon. Given the brightness of the event, MAGIC will continue the observation of GRB 190114C until it is observable tonight and also in the next days. We strongly encourage follow-up observations by other instruments. The MAGIC contact persons for these observations are R. Mirzoyan (Razmik.Mirzoyan@mpp.mpg.de) and K. Noda (nodak@icrr.u-tokyo.ac.jp). MAGIC is a system of two 17m-diameter Imaging Atmospheric Cherenkov Telescopes located at the Observatory Roque de los Muchachos on the Canary island La Palma, Spain, and designed to perform gamma-ray astronomy in the energy range from 50 GeV to greater than 50 TeV.

Published
2019

36. A very-high-energy component deep in the $\gamma$-ray burst afterglow

Author

H. Abdalla, R. Adam, F. Aharonian, F. Ait Benkhali, E. O. Angüner, M. Arakawa, C. Arcaro, C. Armand, H. Ashkar, M. Backes, V. Barbosa Martins, M. Barnard, Y. Becherini, D. Berge, K. Bernlöhr, E. Bissaldi, R. Blackwell, M. Böttcher, C. Boisson, J. Bolmont, S. Bonnefoy, J. Bregeon, M. Breuhaus, F. Brun, P. Brun, M. Bryan, M. Büchele, T. Bulik, T. Bylund, M. Capasso, S. Caroff, A. Carosi, S. Casanova, M. Cerruti, T. Chand, S. Chandra, A. Chen, S. Colafrancesco, M. Curyło, I. D. Davids, C. Deil, J. Devin, P. deWilt, L. Dirson, A. Djannati-Ataï, A. Dmytriiev, A. Donath, V. Doroshenko, J. Dyks, K. Egberts, G. Emery, J.-P. Ernenwein, S. Eschbach, K. Feijen, S. Fegan, A. Fiasson, G. Fontaine, S. Funk, M. Füßling, S. Gabici, Y. A. Gallant, F. Gaté, G. Giavitto, L. Giunti, D. Glawion, J. F. Glicenstein, D. Gottschall, M.-H. Grondin, J. Hahn, M. Haupt, G. Heinzelmann, G. Henri, G. Hermann, J. A. Hinton, W. Hofmann, C. Hoischen, T. L. Holch, M. Holler, D. Horns, D. Huber, H. Iwasaki, M. Jamrozy, D. Jankowsky, F. Jankowsky, A. Jardin-Blicq, I. Jung-Richardt, M. A. Kastendieck, K. Katarzyński, M. Katsuragawa, U. Katz, D. Khangulyan, B. Khélifi, J. King, S. Klepser, W. Kluźniak, Nu. Komin, K. Kosack, D. Kostunin, M. Kreter, G. Lamanna, A. Lemière, M. Lemoine-Goumard, J.-P. Lenain, E. Leser, C. Levy, T. Lohse, I. Lypova, J. Mackey, J. Majumdar, D. Malyshev, V. Marandon, A. Marcowith, A. Mares, C. Mariaud, G. Martí-Devesa, R. Marx, G. Maurin, P. J. Meintjes, A. M. W. Mitchell, R. Moderski, M. Mohamed, L. Mohrmann, C. Moore, E. Moulin, J. Muller, T. Murach, S. Nakashima, M. de Naurois, H. Ndiyavala, F. Niederwanger, J. Niemiec, L. Oakes, P. O’Brien, H. Odaka, S. Ohm, E. de Ona Wilhelmi, M. Ostrowski, I. Oya, M. Panter, R. D. Parsons, C. Perennes, P.-O. Petrucci, B. Peyaud, Q. Piel, S. Pita, V. Poireau, A. Priyana Noel, D. A. Prokhorov, H. Prokoph, G. Pühlhofer, M. Punch, A. Quirrenbach, S. Raab, R. Rauth, A. Reimer, O. Reimer, Q. Remy, M. Renaud, F. Rieger, L. Rinchiuso, C. Romoli, G. Rowell, B. Rudak, E. Ruiz-Velasco, V. Sahakian, S. Sailer, S. Saito, D. A. Sanchez, A. Santangelo, M. Sasaki, R. Schlickeiser, F. Schüssler, A. Schulz, H. M. Schutte, U. Schwanke, S. Schwemmer, M. Seglar-Arroyo, M. Senniappan, A. S. Seyffert, N. Shafi, K. Shiningayamwe, R. Simoni, A. Sinha, H. Sol, A. Specovius, M. Spir-Jacob, Ł. Stawarz, R. Steenkamp, C. Stegmann, C. Steppa, T. Takahashi, T. Tavernier, A. M. Taylor, R. Terrier, D. Tiziani, M. Tluczykont, C. Trichard, M. Tsirou, N. Tsuji, R. Tuffs, Y. Uchiyama, D. J. van der Walt, C. van Eldik, C. van Rensburg, B. van Soelen, G. Vasileiadis, J. Veh, C. Venter, P. Vincent, J. Vink, H. J. Völk, T. Vuillaume, Z. Wadiasingh, S. J. Wagner, R. White, A. Wierzcholska, R. Yang, H. Yoneda, M. Zacharias, R. Zanin, A. A. Zdziarski, A. Zech, A. Ziegler, J. Zorn, N. Żywucka, F. de Palma, M. Axelsson, O. J. Roberts, Laboratoire Leprince-Ringuet (LLR), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Centre de Physique des Particules de Marseille (CPPM), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Aix Marseille Université (AMU), Laboratoire d'Annecy de Physique des Particules (LAPP/Laboratoire d'Annecy-le-Vieux de Physique des Particules), Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Laboratoire Univers et Théories (LUTH (UMR_8102)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Univers et Particules de Montpellier (LUPM), Université de Montpellier (UM)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique Nucléaire et de Hautes Énergies (LPNHE (UMR_7585)), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Centre d'Etudes Nucléaires de Bordeaux Gradignan (CENBG), Université Sciences et Technologies - Bordeaux 1-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), AstroParticule et Cosmologie (APC (UMR_7164)), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Aix Marseille Université (AMU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Annecy de Physique des Particules (LAPP), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7), Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Montpellier 2 - Sciences et Techniques (UM2), Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA), Abdalla, H., Adam, R., Aharonian, F., Ait Benkhali, F., Anguner, E. O., Arakawa, M., Arcaro, C., Armand, C., Ashkar, H., Backes, M., Barbosa Martins, V., Barnard, M., Becherini, Y., Berge, D., Bernlohr, K., Bissaldi, E., Blackwell, R., Bottcher, M., Boisson, C., Bolmont, J., Bonnefoy, S., Bregeon, J., Breuhaus, M., Brun, F., Brun, P., Bryan, M., Buchele, M., Bulik, T., Bylund, T., Capasso, M., Caroff, S., Carosi, A., Casanova, S., Cerruti, M., Chand, T., Chandra, S., Chen, A., Colafrancesco, S., Curylo, M., Davids, I. D., Deil, C., Devin, J., Dewilt, P., Dirson, L., Djannati-Atai, A., Dmytriiev, A., Donath, A., Doroshenko, V., Dyks, J., Egberts, K., Emery, G., Ernenwein, J. -P., Eschbach, S., Feijen, K., Fegan, S., Fiasson, A., Fontaine, G., Funk, S., Fussling, M., Gabici, S., Gallant, Y. A., Gate, F., Giavitto, G., Giunti, L., Glawion, D., Glicenstein, J. F., Gottschall, D., Grondin, M. -H., Hahn, J., Haupt, M., Heinzelmann, G., Henri, G., Hermann, G., Hinton, J. A., Hofmann, W., Hoischen, C., Holch, T. L., Holler, M., Horns, D., Huber, D., Iwasaki, H., Jamrozy, M., Jankowsky, D., Jankowsky, F., Jardin-Blicq, A., Jung-Richardt, I., Kastendieck, M. A., Katarzynski, K., Katsuragawa, M., Katz, U., Khangulyan, D., Khelifi, B., King, J., Klepser, S., Kluzniak, W., Komin, N., Kosack, K., Kostunin, D., Kreter, M., Lamanna, G., Lemiere, A., Lemoine-Goumard, M., Lenain, J. -P., Leser, E., Levy, C., Lohse, T., Lypova, I., Mackey, J., Majumdar, J., Malyshev, D., Marandon, V., Marcowith, A., Mares, A., Mariaud, C., Marti-Devesa, G., Marx, R., Maurin, G., Meintjes, P. J., Mitchell, A. M. W., 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, R. D., Perennes, C., Petrucci, P. -O., Peyaud, B., Piel, Q., Pita, S., Poireau, V., Priyana Noel, A., Prokhorov, D. A., Prokoph, H., Puhlhofer, 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, D. A., Santangelo, A., Sasaki, M., Schlickeiser, R., Schussler, F., Schulz, A., Schutte, H. M., Schwanke, U., Schwemmer, S., Seglar-Arroyo, M., Senniappan, M., Seyffert, A. S., Shafi, N., Shiningayamwe, K., Simoni, R., Sinha, A., Sol, H., Specovius, A., Spir-Jacob, M., Stawarz, L., Steenkamp, R., Stegmann, C., Steppa, C., Takahashi, T., Tavernier, T., Taylor, A. M., Terrier, R., Tiziani, D., Tluczykont, M., Trichard, C., Tsirou, M., Tsuji, N., Tuffs, R., Uchiyama, Y., van der Walt, D. J., van Eldik, C., van Rensburg, C., van Soelen, B., Vasileiadis, G., Veh, J., Venter, C., Vincent, P., Vink, J., Volk, H. J., Vuillaume, T., Wadiasingh, Z., Wagner, S. J., White, R., Wierzcholska, A., Yang, R., Yoneda, H., Zacharias, M., Zanin, R., Zdziarski, A. A., Zech, A., Ziegler, A., Zorn, J., Zywucka, N., de Palma, F., Axelsson, M., Roberts, O. J., Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Institut national des sciences de l'Univers (INSU - CNRS), Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), 26598973 - Abdalla, Hassan, 30588766 - Arcaro, Cornelia, 28644743 - Backes, Michael, 20574266 - Barnard, Monica, 24420530 - Böttcher, Markus, 30366755 - Chand, Tej B., 31125417 - Chandra, Sunil, 26403366 - Ndiyavala, Hambeleleni, 22799133 - Schutte, Hester M., 20126999 - Seyffert, Albertus Stefanus, 10060499 - Van der Walt, Diederick Johannes, 21106266 - Van Rensburg, Carlo, 12006653 - Venter, Christo, 26594080 - Wadiasingh, Zorawar, 29092086 - Zacharias, Michael, 34208968 - Zywucka-Hejzner, Natalia, 33379009 - Kreter, Michael, Faculty of Science, and High Energy Astrophys. & Astropart. Phys (API, FNWI)

Subjects
electron, Brightness, Photon, Astrophysics::High Energy Astrophysical Phenomena, brightness, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Radiation, gamma ray: burst, 7. Clean energy, 01 natural sciences, VHE, Transient astrophysical phenomena, 0103 physical sciences, synchrotron, ddc:530, 010303 astronomy & astrophysics, X-ray: flux, Astrophysics::Galaxy Astrophysics, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), Range (particle radiation), Multidisciplinary, 010308 nuclear & particles physics, particle: energy, photon, Gamma ray, Time-domain astronomy, Institut für Physik und Astronomie, Afterglow, High-energy astrophysics, Automatic Keywords, gamma ray: UHE, Orders of magnitude (time), 13. Climate action, Gamma-ray burst, Particle astrophysics, Astrophysics - High Energy Astrophysical Phenomena, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

Gamma-ray bursts (GRBs) are brief flashes of gamma rays, considered to be the most energetic explosive phenomena in the Universe. 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. GRBs typically emit most of their energy via gamma-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. 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 elussive. 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 gamma-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., Comment: Preprint version of Nature paper. Contacts: E.Ruiz-Velasco, F. Aharonian, E.Bissaldi, C.Hoischen, R.D Parsons, Q.Piel, A.Taylor, D.Khangulyan

Published
2019

37. MAGIC detection of an increased activity from BL Lacertae at very-high-energy gamma rays

Author

Mirzoyan, Razmik, Babić, Ana, Bošnjak, Željka, Cikota, Stefan, Dominis Prester, Dijana, Godinović, Nikola, Hrupec, Dario, Lelas, Damir, Manganaro, Marina, Mićanović, Saša, Puljak, Ivica, Surić, Tihomir, Šnidarić, Iva, Terzić, Tomislav, and Zarić, Darko.

Subjects
Gamma Ray, GeV%22">>GeV, TeV, VHE, Request for Observations, AGN, Blazar, Quasar
Abstract

The MAGIC telescopes have observed an increase in the very-high-energy (VHE ; >100 GeV) gamma-ray flux from a position compatible with the blazar BL Lacertae (RA=22h02m43.3s Dec=+42d16m40s, J2000.0, z=0.07). The preliminary analysis of 0.76 hours of MAGIC data taken on 2019/05/03 (MJD 58606.18 to 58606.20) under zenith angle range from 46 to 53 deg and dark time conditions with the atmospheric transmission of 0.85, indicates a flux larger than 0.1 of the flux from the Crab nebula above 200 GeV, and detection significance over 6 sigma. The MAGIC observations were triggered by the flaring activity at HE gamma-rays reported by Fermi-LAT (ATel #12718), and optical observations by Astronomical Observatory of the University of Siena (ATel #12722). MAGIC observations on BL Lacertae will continue during the next days and multiwavelength observations are encouraged. The MAGIC contact persons for these observations are R. Mirzoyan (Razmik.Mirzoyan@mpp.mpg.de) and D. Dominis Prester (dijana@phy.uniri.hr) MAGIC is a system of two 17m-diameter Imaging Atmospheric Cherenkov Telescopes located at the Canary island of La Palma, Spain, and designed to perform gamma-ray astronomy in the energy range from 50 GeV to greater than 50 TeV.

Published
2019

38. MAGIC detects an unprecedented activity from the blazar 1ES 1218+304 at very high energy gamma rays

Author

Mirzoyan, Razmik, Babić, Ana, Bošnjak, Željka, Cikota, Stefan, Dominis Prester, Dijana, Godinović, Nikola, Hrupec, Dario, Lelas, Damir, Manganaro, Marina, Mićanović, Saša, Puljak, Ivica, Surić, Tihomir, Šnidarić, Iva, Terzić, Tomislav, Zarić, Darko, and (the MAGIC Collaboration)

Subjects
Gamma Ray, GeV%22">>GeV, TeV, VHE, AGN, Blazar
Abstract

The MAGIC telescopes have observed an unprecedented level of very-high-energy (VHE ; >100 GeV) gamma-ray flux from 1ES 1218+304 (12h21m21.941s, +30d10m37.11s, J2000.0). The preliminary analysis of the data from 2018/12/31 to 2019/01/02 indicates a VHE gamma-ray flux reaching the level of ~25 % of the flux from the Crab nebula above 100 GeV. Compared to the quiescent state reported by VERITAS, this implies an increase by a factor of ~4. The previous record of VHE gamma-ray flux of this source was ~20% of the flux from the Crab nebula above 100 GeV. It was measured by VERITAS on the night of 30 January 2009 (2010ApJ, 709L, 163A). 1ES 1218+304 is a high-synchrotron-peaked BL Lac object located at redshift z=0.182. It was first recognized as a VHE gamma-ray emitter by the MAGIC Collaboration in 2005 (Albert, J., 2006, ApJ, 642L, 119A). The MAGIC observations were triggered by the flaring activity in the optical R-band, measured by the KVA telescope from 2018/12/24 to 2019/01/02. The KVA data showed a flux of 2.35+/-0.05 mJy on 2019/01/02, which is the highest optical flux measurement from this source in a time span of 15 years (http://users.utu.fi/kani/1m/1ES_1218+304_jy.html). MAGIC observations on 1ES 1218+304 will continue during the next weeks and multiwavelength observations are encouraged. The MAGIC contact persons for these observations are R. Mirzoyan (Razmik.Mirzoyan@mpp.mpg.de), V. Fallah Ramazani (vafara@utu.fi) and M. Cerruti (matteo.cerruti@icc.ub.edu). MAGIC is a system of two 17m-diameter Imaging Atmospheric Cherenkov Telescopes located at the Canary island of La Palma, Spain, and designed to perform gamma-ray astronomy in the energy range from 50 GeV to greater than 50 TeV.

Published
2019

39. Acceleration of particles up to PeV energies at the galactic centre

Author

A. Viana, Emmanuel Moulin, Stefano Gabici, Felix Aharonian, AstroParticule et Cosmologie (APC (UMR_7164)), Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Département de Physique des Particules (ex SPP) (DPP), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Département de Physique des Particules (ex SPP) (DPhP), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Observatoire de Paris, and PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)

Subjects
Physics, Acceleration of particles, 010308 nuclear & particles physics, Astrophysics::High Energy Astrophysical Phenomena, Gamma ray, Gamma rays: theory, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Gamma rays: observations, 01 natural sciences, VHE, particle: acceleration, Black hole, Particle acceleration, Acceleration, gamma ray, Space and Planetary Science, HESS, cosmic radiation: galaxy, 0103 physical sciences, black hole, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics
Abstract

Recent very high energy observations of the galactic centre region performed by H.E.S.S. revealed the presence of a powerful PeVatron. This is the first of such objects detected, and its most plausible counterpart seems to be associated to Sgr A*, the supermassive black hole in the centre of our galaxy. The implications of this discovery will be discussed, in particular in the context of the problem of the origin of galactic cosmic rays.

Published
2016

40. Detection of very-high-energy gamma-ray emission from the FSRQ Ton 0599 with the MAGIC telescopes

Author

Mirzoyan, Razmik, Babić, Ana, Dominis Prester, Dijana, Godinović, Nikola, Hrupec, Dario, Lelas, Damir, Puljak, Ivica, Surić, Tihomir, Šnidarić, Iva, Terzić, Tomislav, and (the MAGIC Collaboration)

Subjects
Gamma Ray, TeV, VHE, Blazar
Abstract

The MAGIC collaboration reports on the first time detection of very-high-energy (VHE ; E>100 GeV) gamma-ray emission from Ton 0599 (RA:+11:59:31.83 DEC:+29:14:43.83, J2000). The object was observed with the MAGIC telescopes for ~1 hour on 2017/12/15 (MJD 58102.2). The preliminary analysis of these data resulted in the detection of Ton 0599 with a statistical significance of about 10 standard deviations. The VHE flux of this detection was estimated to be around 0.15x10^-9 [ph/cm2/s] (corresponding to about 0.3 CU) above 100 GeV, with a soft spectrum. TON599 is a gamma-ray FSRQ at z=0.72 which is in a remarkably high state from optical to gamma-ray since October 2017 (ATel #10931, #10932, #10937, #10938, #10948, #10949). MAGIC observations on TON 0599 will continue during the next days and multi-wavelength observations are strongly encouraged.

Published
2018

41. The Blazar TXS 0506+056 associated with a high-energy neutrino: insights into extragalactic jets and cosmic-ray acceleration

Author

M. Makariev, John Hoang, J. Besenrieder, J. Rico, W. Rhode, M. Vazquez Acosta, L. Nogués, J. Kushida, Simona Paiano, D. Hadasch, R. Ch. Berse, Jose Luis Contreras, Abelardo Moralejo, E. Moretti, K. Mielke, P. Da Vela, Ievgen Vovk, Francesco Dazzi, A. Fernández-Barral, M. I. Martínez, Juan Cortina, P. Bangale, A. Hahn, W. Bhattacharyya, K. Pfrang, F. Di Pierro, D. Fidalgo, M. Mariotti, K. Nishijima, G. Pedaletti, V. Moreno, G. Vanzo, S. Gallozzi, Sabrina Einecke, K. Mannheim, T. Saito, D. Dorner, C. Maggio, D. Dominis Prester, Stefano Covino, Matteo Cerruti, Marina Manganaro, Juan Abel Barrio, P. G. Prada Moroni, M. Strzys, S. Lombardi, P. Cumani, Konstancja Satalecka, Michele Doro, J. R. Garcia, P. Peñil, M. Minev, D. Lelas, F. Leone, B. De Lotto, Elisa Prandini, Rodolfo Carosi, Dario Hrupec, R. Paoletti, S. M. Colak, C. Arcaro, M. A. Lopez, M. Peresano, G. Ceribella, A. Niedzwiecki, M. V. Fonseca, Tarek M. Hassan, W. Bednarek, Ana Babić, David Paneque, Ciro Bigongiari, Petar Temnikov, Koji Noda, Elisa Bernardini, Stefano Ansoldi, Fabrizio Tavecchio, I. Šnidarić, Eduardo Colombo, Razmik Mirzoyan, Elina Lindfors, Ll. Font, Markus Gaug, D. Guberman, Daniel Mazin, A. Berti, J. Palacio, Christian Fruck, A. Fattorini, Tomislav Terzić, B. Banerjee, Dorota Sobczyńska, J. M. Paredes, Antonio Stamerra, Y. Iwamura, M. Hayashida, P. Giammaria, R. J. García López, Markus Garczarczyk, Francesco Longo, N. Godinović, Lab Saha, Pierre Colin, Kari Nilsson, G. Maneva, V. Fallah Ramazani, Marc Ribó, Massimo Persic, M. Will, Hidetoshi Kubo, Pratik Majumdar, D. Elsaesser, Jose Carlos Herrera, G. Ferrara, G. Bonnoli, Oscar Blanch, Jordi Delgado, M. Delfino, Julian Sitarek, Masahiro Teshima, T. Schweizer, D. Ninci, Chiara Righi, Satoshi Masuda, Arka Chatterjee, Yusuke Konno, I. Puljak, Laura Maraschi, C. Nigro, Darko Zarić, Luca Foffano, Aaron Dominguez, A. Lamastra, J. E. Ward, Shimpei Tsujimoto, A. Rugliancich, Vitaly Neustroev, Susumu Inoue, N. Torres-Albà, Valerio D'Elia, Dominik Baack, Adrian Biland, Jose Miguel Miranda, Tihomir Surić, Louis Antonelli, A. De Angelis, U. Barres de Almeida, M. Nievas Rosillo, K. Ishio, J. Becerra González, Ansoldi, S., Antonelli, L. A., Arcaro, C., Baack, D., Babić, A., Banerjee, B., Bangale, P., Barres De Almeida, U., Barrio, J. A., González, J. Becerra, Bednarek, W., Bernardini, E., Berse, R. Ch., Berti, A., Besenrieder, J., Bhattacharyya, W., Bigongiari, C., Biland, A., Blanch, O., Bonnoli, G., Carosi, R., Ceribella, G., Chatterjee, A., Colak, S. M., Colin, P., Colombo, E., Contreras, J. L., Cortina, J., Covino, S., Cumani, P., D'Elia, V., Vela, P. Da, Dazzi, F., Angelis, A. De, Lotto, B. De, Delfino, M., Delgado, J., Pierro, F. Di, Domínguez, A., Prester, D. Domini, Dorner, D., Doro, M., Einecke, S., Elsaesser, D., Ramazani, V. Fallah, Fattorini, A., Fernández-Barral, A., Ferrara, G., Fidalgo, D., Foffano, L., Fonseca, M. V., Font, L., Fruck, C., Gallozzi, S., López, R. J. García, Garczarczyk, M., Gaug, M., Giammaria, P., Godinović, N., Guberman, D., Hadasch, D., Hahn, A., Hassan, T., Hayashida, M., Herrera, J., Hoang, J., Hrupec, D., Inoue, S., Ishio, K., Iwamura, Y., Konno, Y., Kubo, H., Kushida, J., Lamastra, A., Lelas, D., Leone, F., Lindfors, E., Lombardi, S., Longo, F., López, M., Maggio, C., Majumdar, P., Makariev, M., Maneva, G., Manganaro, M., Mannheim, K., Maraschi, L., Mariotti, M., Martínez, M., Masuda, S., Mazin, D., Mielke, K., Minev, M., Miranda, J. M., Mirzoyan, R., Moralejo, A., Moreno, V., Moretti, E., Neustroev, V., Niedzwiecki, A., Rosillo, M. Nieva, Nigro, C., Nilsson, K., Ninci, D., Nishijima, K., Noda, K., Nogués, L., Paiano, S., Palacio, J., Paneque, D., Paoletti, R., Paredes, J. M., Pedaletti, G., Peñil, P., Peresano, M., Persic, M., Pfrang, K., Moroni, P. G. Prada, Prandini, E., Puljak, I., Garcia, J. R., Rhode, W., Ribó, M., Rico, J., Righi, C., Rugliancich, A., Saha, L., Saito, T., Satalecka, K., Schweizer, T., Sitarek, J., Šnidarić, I., Sobczynska, D., Stamerra, A., Strzys, M., Surić, T., Tavecchio, F., Temnikov, P., Terzić, T., Teshima, M., Torres-Albá, N., Tsujimoto, S., Vanzo, G., Acosta, M. Vazquez, Vovk, I., Ward, J. E., Will, M., Zarić, D., Cerruti, Matteo, Laboratoire de Physique Nucléaire et de Hautes Énergies (LPNHE (UMR_7585)), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), MAGIC, and Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)

Subjects
neutrino: energy: high, jets [galaxies], Electron, Astrophysics, individual (TXS 0506+056) [BL Lacertae objects], 01 natural sciences, neutrino, Absorption (logic), MAGIC (telescope), 010303 astronomy & astrophysics, interaction [electron], cosmic ray, High Energy Astrophysical Phenomena (astro-ph.HE), Physics, photon, neutrinos, 520 Astronomie und zugeordnete Wissenschaften, non-thermal [radiation mechanisms], Neutrino detector, inverse [Compton scattering], electron: interaction, galaxies [gamma rays], acceleration [cosmic radiation], Física nuclear, Neutrino, Astrophysics - High Energy Astrophysical Phenomena, BL Lac object, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Cosmic ray, VHE, energy [p], blazar, X-ray, cosmic rays, 0103 physical sciences, gamma rays: galaxies, ddc:530, galaxie [gamma rays], energy: high [neutrino], cosmic radiation: acceleration, Blazar, plasma, BL Lacertae objects: individual, 010308 nuclear & particles physics, Astronomy and Astrophysics, Astronomy and Astrophysic, galaxies: jets, radiation mechanisms: non-thermal, 530 Physik, MAGIC, BL Lacertae objects: individual (TXS 0506+056), cosmic rays, galaxies: jets, gamma rays: galaxies, neutrinos, radiation mechanisms: non-thermal, Astronomy and Astrophysics, Space and Planetary Science, BL Lacertae objects: individual (TXS 0506+056), messenger, electromagnetic, Compton scattering: inverse, p: energy, jet [galaxies], gamma ray, Space and Planetary Science, ddc:520, High Energy Physics::Experiment, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], absorption
Abstract

A neutrino with energy of $\sim$290 TeV, IceCube-170922A, was detected in coincidence with the BL Lac object TXS~0506+056 during enhanced gamma-ray activity, with chance coincidence being rejected at $\sim 3\sigma$ level. We monitored the object in the very-high-energy (VHE) band with the MAGIC telescopes for $\sim$41 hours from 1.3 to 40.4 days after the neutrino detection. Day-timescale variability is clearly resolved. We interpret the quasi-simultaneous neutrino and broadband electromagnetic observations with a novel one-zone lepto-hadronic model, based on interactions of electrons and protons co-accelerated in the jet with external photons originating from a slow-moving plasma sheath surrounding the faster jet spine. We can reproduce the multiwavelength spectra of TXS 0506+056 with neutrino rate and energy compatible with IceCube-170922A, and with plausible values for the jet power of $\sim 10^{45} - 4 \times 10^{46} {\rm erg \ s^{-1}}$. The steep spectrum observed by MAGIC is concordant with internal $\gamma\gamma$ absorption above a few tens of GeV entailed by photohadronic production of a $\sim$290 TeV neutrino, corroborating a genuine connection between the multi-messenger signals. In contrast to previous predictions of predominantly hadronic emission from neutrino sources, the gamma-rays can be mostly ascribed to inverse Compton up-scattering of external photons by accelerated electrons. The X-ray and VHE bands provide crucial constraints on the emission from both accelerated electrons and protons. We infer that the maximum energy of protons in the jet co-moving frame can be in the range $\sim 10^{14}$ to $10^{18}$ eV., Comment: 11 pages, 3 figues, 3 tables, Accepted for publication in ApJL. Major changes in the revised Version: corrected author list

Published
2018

42. MAGIC detects enhanced flux of VHE gamma rays from TXS 0506+056

Author

Mirzoyan, Razmik, Babić, Ana, Cikota, Stefan, Dominis Prester, Dijana, Godinović, Nikola, Hrupec, Dario, Lelas, Damir, Manganaro, Marina, Mićanović, Saša, Puljak, Ivica, Surić, Tihomir, Šnidarić, Iva, Terzić, Tomislav, Zarić, Darko, and (the MAGIC Collaboration)

Subjects
Gamma Ray, GeV%22">>GeV, TeV, VHE, AGN, Blazar
Abstract

We report an enhanced emission of VHE gamma-rays from the direction of the blazar TXS 0506+056 (05 09 25.96370, +05 41 35.3279 (J2000), [Lani et al., Astron. J., 139, 1695-1712 (2010)]), located 6 arcmin from the estimated direction of the high energy IceCube neutrino event IceCube-170922A (ATel #10791). On Dec 3rd 2018 the MAGIC telescopes observed this source for about 2 hours under good weather conditions. The source was detected at VHE gamma-rays above 90 GeV with a significance larger than 5 sigma. The preliminary analysis yields an estimate of the VHE gamma-ray flux above 90 GeV of ~10-15% of the flux from the Crab Nebula above the same energy threshold, and a spectral index of ~4. This flux is consistent with the emission level integrated between September 28th 2017 to October 3rd 2017, when the source was discovered at VHE gamma-rays (ATel #10817). The MAGIC telescopes will continue monitoring the VHE gamma-ray emission of TXS 0506+056. Soft-X-rays and ultraviolet ToO observations with the Neil Gehrels Swift Observatory have been approved for the next three nights (PI: Cerruti, on behalf of MAGIC), to occur within the time-window 00:00 to 04:00 UTC. NuSTAR ToO observations have also been approved (PI: Satalecka). Multi-wavelength observations (quasi)-simultaneous with MAGIC in this time-window are strongly encouraged.

Published
2018

43. The blazar TXS 0506+056 associated with a high-energy neutrino: insights into extragalactic jets and cosmic ray acceleration

Author

Ansoldi, S., Antonelli, L. A., Antonelli, Lucio Angelo, Arcaro, Cornelia, Baack, Dominik, Babić, Ana, Banerjee, Biswajit, Bangale, Priyadarshini, Barres De Almeida, Ulisses, Barrio, Juan Abel, Becerra González, Josefa, Bednarek, Wlodek, Bernardini, Elisa, Berti, Alessio, Bhattacharyya, Wrijupan, Biland, Adrian, Blanch, Oscar, Bonnoli, Giacomo, Carosi, Roberto, Carosi, Alessandro, Ceribella, Giovanni, Chatterjee, Anshu, Colak, Sidika Merve, Colin, Pierre, Colombo, Eduardo, Contreras, Jose Luis, Cortina, Juan, Covino, Stefano, Cumani, Paolo, Da Vela, Paolo, Dazzi, Francesco, De Angelis, Alessandro, De Lotto, Barbara, Delfino, Manuel, Delgado, Jordi, Di Pierro, Federico, Domínguez, Alberto, Dominis Prester, Dijana, Dorner, Daniela, Doro, Michele, Einecke, Sabrina, Elsaesser, Dominik, Fallah Ramazani, Vandad, Fernández-Barral, Alba, Fidalgo, David, Foffano, Luca, Pfrang, Konstantin, Fonseca, Maria Victoria, Font, Lluis, Fruck, Christian, Galindo, Daniel, Gallozzi, Stefano, López, Ramon J. García, Garczarczyk, Markus, Gaug, Markus, Giammaria, Paola, Godinović, Nikola, Gora, Dariusz, Guberman, Daniel, Hadasch, Daniela, Hahn, Alexander, Hassan, Tarek, Hayashida, Masaaki, Herrera, Javier, Hose, Juergen, Hrupec, Dario, Inoue, Susumu, Ishio, Kazuma, Iwamura, Yuki, Konno, Yusuke, Kubo, Hidetoshi, Kushida, Junko, Lelas, Damir, Lindfors, Elina, Lombardi, Saverio, Longo, Francesco, López, Marcos, Maggio, Camilla, Majumdar, Pratik, Makariev, Martin, Maneva, Galina, Manganaro, Marina, Mannheim, Karl, Maraschi, Laura, Mariotti, Mosé, Martínez, Manel, Masuda, Shu, Mazin, Daniel, Minev, Milen, Miranda, Jose Miguel, Mirzoyan, Razmik, Moralejo, Abelardo, Moreno, Victoria, Moretti, Elena, Nagayoshi, Tsutomu, Neustroev, Vitaly, Niedzwiecki, Andrzej, Nievas Rosillo, Mireia, Nigro, Cosimo, Nilsson, Kari, Ninci, Daniele, Nishijima, Kyoshi, Noda, Koji, Nogués, Leyre, Paiano, Simona, Palacio, Joaquim, Paneque, David, Paoletti, Riccardo, Paredes, Josep M., Pedaletti, Giovanna, Peresano, Michele, Persic, Massimo, Prada Moroni, Pier Giorgio, Prandini, Elisa, Puljak, Ivica, Rodriguez Garcia, Jezabel, Reichardt, Ignasi, Rhode, Wolfgang, Ribó, Marc, Rico, Javier, Righi, Chiara, Rugliancich, Andrea, Saito, Takayuki, Satalecka, Konstancja, Schweizer, Thomas, Sitarek, Julian, Snidarić, Iva, Sobczynska, Dorota, Stamerra, Antonio, Strzys, Marcel, Surić, Tihomir, Takahashi, Mitsunari, Tavecchio, Fabrizio, Temnikov, Petar, Terzić, Tomislav, Teshima, Masahiro, Torres-Albà, Nuria, Treves, Aldo, Tsujimoto, Shimpei, Vanzo, Gaia, Vazquez Acosta, Monica, Vovk, Ievgen, Ward, John E., Will, Martin, Zarić, Darko, and Cerruti, Matteo

Subjects
neutrino: energy: high, photon, MAGIC, VHE, blazar, X-ray, messenger, electromagnetic, p: energy, Compton scattering: inverse, gamma ray, electron: interaction, cosmic radiation: acceleration, absorption, plasma
Abstract

The astrophysical journal 863(1), L10 (2018). doi:10.3847/2041-8213/aad083, A neutrino with energy ∼290 TeV, IceCube-170922A, was detected in coincidence with the BL Lac object TXS 0506+056 during enhanced gamma-ray activity, with chance coincidence being rejected at ∼3σ level. We monitored the object in the very-high-energy (VHE) band with the Major Atmospheric Gamma-ray Imaging Cherenkov (MAGIC) telescopes for ∼41 hr from 1.3 to 40.4 days after the neutrino detection. Day-timescale variability is clearly resolved. We interpret the quasi-simultaneous neutrino and broadband electromagnetic observations with a novel one-zone lepto-hadronic model, based on interactions of electrons and protons co-accelerated in the jet with external photons originating from a slow-moving plasma sheath surrounding the faster jet spine. We can reproduce the multiwavelength spectra of TXS 0506+056 with neutrino rate and energy compatible with IceCube-170922A, and with plausible values for the jet power of $\sim 10^{45} - 4 \times 10^{46} erg s^{-1}$. The steep spectrum observed by MAGIC is concordant with internal γγ absorption above ∼100 GeV entailed by photohadronic production of a ∼290 TeV neutrino, corroborating a genuine connection between the multi-messenger signals. In contrast to previous predictions of predominantly hadronic emission from neutrino sources, the gamma-rays can be mostly ascribed to inverse Compton upscattering of external photons by accelerated electrons. The X-ray and VHE bands provide crucial constraints on the emission from both accelerated electrons and protons. We infer that the maximum energy of protons in the jet comoving frame can be in the range $∼10^{14} – 10^{18}$ eV., Published by IOP, Chicago, Ill. [u.a.]

Published
2018
Full Text
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44. TeV gamma-ray emission from PSR J2032+4127/ MT91 213

Author

Holder, Jamie, Babić, Ana, Dominis Prester, Dijana, Godinović, Nikola, Hrupec, Dario, Lelas, Damir, Puljak, Ivica, Surić, Tihomir, Šnidarić, Iva, Terzić, Tomislav, and (the VERITAS Collaboration and the MAGIC Collaboration)

Subjects
Gamma Ray, TeV, VHE, Request for Observations, Binary, Neutron Star, Transient, Pulsar
Abstract

The VERITAS and MAGIC collaborations report the detection of an enhanced TeV gamma-ray flux from the pulsar/ Be-star binary system PSR J2032+4127/ MT91 213 (RA 20h32m13.13s, Dec +41d27m24.4s, J2000.0). The binary nature of this system was identified in 2015 through radio and gamma-ray timing observations (Lyne et al., MNRAS, 451, 581, 2015). The orbital period is estimated at 45-50 years, with periastron expected to occur around November 2017. The X-ray flux has been steadily increasing as the system approaches periastron (Bird et al., arXiv:1708.04718). PSR J2032+4127 is co-located with the extended TeV gamma-ray source, TeV J2032+4130, and may be physically associated with it. Both VERITAS and MAGIC observations were conducted as part of a coordinated long-term monitoring campaign. The source was observed most recently by VERITAS between 16 September and 27 September 2017 for a total exposure of 15.3 hours. In a preliminary analysis, the integral flux measured by VERITAS above 200 GeV is 4.2e-12 ± 0.7e-12 photons cm^-2 s^-1 (~2% of the Crab Nebula flux), corresponding to approximately twice the flux measured at the same location in archival VERITAS observations from spring 2017. The emission is consistent with a point source at the location of PSR J2032+4127, offset from the center of the previously known extended TeV source. The VERITAS source name is VER J2032+414. The statistical significance of the gamma-ray excess at the pulsar position is 6.8 standard deviations. MAGIC observations comprise 5.6 hours taken between 10 September and 25 September. A preliminary analysis of the MAGIC data indicates a flux of 5.6e-12 ± 1.2e-12 photons cm^-2 s^-1 above 200 GeV, which implies an increase by about a factor of 2 with respect to the mean flux observed by MAGIC in June-August 2017. The MAGIC source name is MAGIC J2032+4127. The gamma-ray flux is predicted to continue to increase over the coming months (e.g. Takata et al., ApJ, 836, 241), and VERITAS and MAGIC observations will continue with highest priority. We strongly encourage coordinated multiwavelength observations.

Published
2018

45. Temporal analysis of an unprecedented data set for the $\gamma$-ray blazar 1ES 1215+303: Fermi-LAT and VERITAS light curves spanning ten years

Author

Reshmi Mukherjee, Giuliana Noto, J. Valverde, Deirdre Horan, D. Bernard, Laboratoire Leprince-Ringuet (LLR), Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Fermi-LAT, VERITAS, Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Leprince-Ringuet ( LLR ), and Institut National de Physique Nucléaire et de Physique des Particules du CNRS ( IN2P3 ) -École polytechnique ( X ) -Centre National de la Recherche Scientifique ( CNRS )

Subjects
jet: blazar, 0209 industrial biotechnology, [ PHYS.ASTR ] Physics [physics]/Astrophysics [astro-ph], Astrophysics::High Energy Astrophysical Phenomena, energy spectrum, Flux, 02 engineering and technology, Astrophysics, Spectral line, GLAST, VHE, 020901 industrial engineering & automation, [ PHYS.HEXP ] Physics [physics]/High Energy Physics - Experiment [hep-ex], 0202 electrical engineering, electronic engineering, information engineering, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], Blazar, Physics, energy: high, Gamma ray, Light curve, Data set, flux, Automatic Keywords, gamma ray, 020201 artificial intelligence & image processing, VERITAS, Astrophysics - High Energy Astrophysical Phenomena, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Fermi Gamma-ray Space Telescope, BL Lac object
Abstract

We present here the results of the analysis of the $\gamma$-ray blazar, 1ES 1215+303, over a 10-year period, from 2008 to 2017, measured at high energies (HE; 200 MeV $< E $ 100 GeV) by Fermi-LAT and VERITAS. This is the longest temporal study of this high-frequency-peaked BL Lac object (HBL) at $\gamma$-ray energies to date. The spectrum follows a log parabola over this time period, and its HE and VHE spectra are well-connected. Its flux is sufficiently strong at HE to allow us to bin the Fermi-LAT data in 3-day intervals, enabling us to investigate the temporal evolution of the flux in unprecedented detail. Several flaring episodes were detected and evidence for an overall trend of increasing flux over the span of the 10 years was observed. These light curves, in addition to the spectra, are presented. This unique data set will help us to advance our understanding of the underlying physical processes in blazar jets., Comment: Presented at the 7th Fermi Symposium 2017, 15-20 October 2017, Garmisch-Partenkirchen, Germany. Submitted to Proceedings of Science (PoS(IFS2017)116)

Published
2017

46. H.E.S.S. discovery of very-high-energy emission from the blazar PKS 0736+017: on the location of the $\gamma$-ray emitting region in FSRQs

Author

Matteo Cerruti, Jean-Philippe Lenain, H. Prokoph, Laboratoire de Physique Nucléaire et de Hautes Énergies (LPNHE (UMR_7585)), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), and H.E.S.S.

Subjects
High energy, Opacity, Astrophysics::High Energy Astrophysical Phenomena, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Cherenkov counter: atmosphere, 01 natural sciences, 7. Clean energy, VHE, GLAST, law.invention, jet: relativistic, blazar, Telescope, energy: threshold, law, HESS, 0103 physical sciences, Blazar, 010303 astronomy & astrophysics, Cherenkov radiation, Physics, radio wave, 010308 nuclear & particles physics, Gamma ray, Astrophysics::Instrumentation and Methods for Astrophysics, opacity, imaging, trigger, Threshold energy, frequency: low, 13. Climate action, gamma ray, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - High Energy Astrophysical Phenomena, Radio wave
Abstract

With the installation of a new 28-m diameter imaging atmospheric Cherenkov telescope in the middle of the array, the H.E.S.S. instrument has entered since 2012 into its Phase II. The fifth large-size telescope is particularly important to lower the threshold energy of the array, and is thus a unique instrument to observe low-frequency-peaked blazars, such as flat-spectrum radio-quasars (FSRQs), which remain rare in the very-high- energy (VHE; E $>$ 100 GeV) $\gamma$-ray domain. In this contribution, we report on the discovery with the H.E.S.S. telescopes of VHE $\gamma$-ray emission from the FSRQ PKS 0736+017 (z=0.189). H.E.S.S. observations were triggered as a target-of-opportunity in February 2015 following the detection of $\gamma$-ray flaring activity in the MeV-GeV energy-band with Fermi-LAT. Significant VHE emission is detected with H.E.S.S. only during one of the nights of the observing campaign, showing at least night-by-night variability in the VHE regime. We discuss the location of the $\gamma$-ray emitting region within the relativistic jet, using opacity and variability constraints., Comment: 8 pages; to appear in the proceedings of the 35th International Cosmic Ray Conference (ICRC2017)

Published
2017

47. Monitoring of the FSRQ PKS 1510-089 with H.E.S.S

Author

Alicja Wierzcholska, Michael Zacharias, Stefan Wagner, Heike Prokoph, Mahmoud Mohamed, Felix Jankowsky, David Sanchez, Laboratoire d'Annecy de Physique des Particules (LAPP/Laboratoire d'Annecy-le-Vieux de Physique des Particules), Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), H.E.S.S., Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), and Laboratoire d'Annecy de Physique des Particules (LAPP)

Subjects
electron, Astrophysics::High Energy Astrophysical Phenomena, Flux, FOS: Physical sciences, Astrophysics, 01 natural sciences, 7. Clean energy, Radio spectrum, GLAST, VHE, blazar, X-ray, HESS, 0103 physical sciences, Radiative transfer, optical, Blazar, 010303 astronomy & astrophysics, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), radio wave, energy: high, 010308 nuclear & particles physics, quasar: spectrum, Gamma ray, Quasar, acceleration, flux, monitoring, gamma ray, frequency, correlation, Astrophysics - High Energy Astrophysical Phenomena, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], absorption, Fermi Gamma-ray Space Telescope, Radio wave
Abstract

The flat spectrum radio quasar (FSRQ) PKS 1510-089 (z=0.361) is known for its complex multiwavelength behavior. It has been monitored regularly at very high energy (VHE, $E>100\,$GeV) gamma-rays with H.E.S.S. since its discovery in 2009 in order to study the unknown behavior of FSRQs in quiescence at VHE, as well as the flux evolution around flaring events. Given the expected strong cooling of electrons and the absorption of VHE emission within the broad-line region, a detection of PKS 1510-089 at VHE in a quiescent state would be an important result, implying an acceleration and emission region on scales beyond the broad-line region. The H.E.S.S. monitoring has been intensified since 2015 and is complemented by monitoring at high energy ($E>100\,$MeV) gamma-rays with Fermi, at X-rays with Swift-XRT, and at optical frequencies with ATOM. The dense lightcurves allow for the first time detailed comparison studies between these energy bands. The source has been active in several frequency bands for a large fraction of the observation time frames. Yet, we do not find obvious correlations between the VHE and the other bands over the observed time frame indicating a non-trivial interplay of the acceleration, cooling and radiative processes. It also implies a rich variety in flaring behavior, which makes this source difficult to interpret within a unique theoretical framework., To appear in Proceedings of 35th ICRC, Busan (Korea) 2017

Published
2017

48. Supernova remnants in the very–high–energy sky: prospects for the Cherenkov Telescope Array

Author

Cristofari, P., Zanin, R., Gabici, S., Humensky, B. T., Santander, M., Terrier, R., consortium, CTA, AstroParticule et Cosmologie (APC (UMR_7164)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), CTA consortium, Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7), Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)

Subjects
Cherenkov Telescope Array, media_common.quotation_subject, Astrophysics::High Energy Astrophysical Phenomena, Population, FOS: Physical sciences, Cosmic ray, VHE, particle: acceleration, supernova, education, Astrophysics::Galaxy Astrophysics, media_common, High Energy Astrophysical Phenomena (astro-ph.HE), Physics, education.field_of_study, Gamma ray, Astronomy, Galaxy, Particle acceleration, Supernova, 13. Climate action, Sky, cosmic radiation, gamma ray, galaxy, Astrophysics - High Energy Astrophysical Phenomena, numerical calculations: Monte Carlo, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

The Cherenkov Telescope Array is expected to lead to the detection of many new supernova remnants in the TeV and multi-TeV range. In addition to the individual study of each SNR, the study of these objects as a population can help constraining the parameters describing the acceleration of particles and increasing our understanding of the mechanisms involved. We present Monte Carlo simulations of the population of Galactic SNRs emitting TeV gamma rays. We also discuss how the simulated population can be confronted with future observations to provide a novel test for the SNR hypothesis of cosmic ray origins., All CTA contributions at arXiv:1709.03483

Published
2017

49. MAGIC detects activity from PKS 1424+240 at very- high-energy gamma rays

Author

Mirzoyan, Razmik, Babić, Ana, Dominis Prester, Dijana, Godinović, Nikola, Hrupec, Dario, Lelas, Damir, Puljak, Ivica, Surić, Tihomir, Šnidarić, Iva, Terzić, Tomislav, and (the MAGIC Collaboration)

Subjects
Gamma Ray, TeV, VHE, Blazar
Abstract

The MAGIC telescopes have observed an increase in the very-high-energy (VHE ; >50 GeV) gamma- ray flux from PKS 1424+240, RA: 14:27:00.4 and DEC: +23:48:00, J2000.0 (Wenger, M. et al., 2000, A&AS, v.143, 9). The preliminary analysis of the MAGIC data taken on 2017/03/09, indicates an integral photon flux of (7.6 +/- 2.3) x 10^-11 [cm^-2/s] above 70 GeV. The estimated flux corresponds to 10+/-3 % of the Crab Nebula integral flux above the same energy threshold (70 GeV), and shows a hint of elevated flux in comparison with the previous detections (Archambault, S. et al., 2014, ApJL, 785, 1, L16 and the references therein). PKS 1424+240 is a BL Lac object located at redshift z=0.604 (Paiano et al. 2017, arXiv:1701.04305) and was previously reported as a VHE gamma-ray emitter by VERITAS (Acciari, V.A. et al., 2010, ApJ 708 L100) and MAGIC (Aleksi?, J. et al., 2014, A&A 567, 135). It is the most distant VHE emitter whose source type is confirmed as a BL Lac object. The MAGIC observations were triggered by the hard spectrum in HE gamma-ray band (0.1-300 GeV), estimated from daily analysis of Fermi data, and showing a photon spectral index = -1.47 +/- 0.28 (TS = 25.9) during 2017/03/06 and 2017/03/07. MAGIC will observe PKS 1424+240 tonight and multi- wavelength observations are encouraged. The MAGIC contact persons for these observations are R. Mirzoyan (Razmik.Mirzoyan@mpp.mpg.de), V. Fallah Ramazani (vafara@utu.fi) and Gaia Vanzo (gvanzo@iac.es). MAGIC is a system of two 17m-diameter Imaging Atmospheric Cherenkov Telescopes located at the Canary island of La Palma, Spain, and designed to perform gamma-ray astronomy in the energy range from 50 GeV to greater than 50 TeV.

Published
2017

50. MAGIC detection of a giant flaring activity from NGC 1275 at very-high-energy gamma rays

Author

Mirzoyan, Razmik, Babić, Ana, Dominis Prester, Dijana, Godinović, Nikola, Hrupec, Dario, Lelas, Damir, Puljak, Ivica, Surić, Tihomir, Šnidarić, Iva, Terzić, Tomislav, and (the MAGIC Collaboration)

Subjects
Gamma Ray, TeV, VHE, AGN
Abstract

Using the MAGIC telescopes, we have observed an increase in the very-high-energy (VHE ; >100 GeV) gamma-ray flux from NGC 1275 (3C 84, 03:19:48.16, +41:30:42.10, J2000.0). The preliminary analysis of the MAGIC data taken during the night between 31 December 2016 and 1 January 2017 indicates a flux of about 1.5 times the flux from the Crab nebula (C.U.) above 100 GeV. The flux was nearly 10 times larger than the flare reported in October 2016 (ATel #9689) and about 60 times larger than the low state of the source (Aleksic et al. 2014, A&A, 564, A5). Further observations by MAGIC performed on the night of 2nd to 3rd of January still reveal a flaring state of about 0.7 C.U. above 100 GeV. MAGIC observed the source for 2.4 hours in each of the two nights, 4.8 hours in total. NGC 1275 is a Fanaroff-Riley I radio galaxy located at redshift 0.018 in the Perseus Cluster of galaxies, and was first reported as a VHE gamma-ray emitter in Aleksic et al., 2012 (A&A, 539, L2). It is one of only few radio galaxies detected in the VHE gamma-ray range. MAGIC observations of NGC 1275 will continue during the next days and multi-wavelength observations are encouraged. The MAGIC contact person for these observations is R. Mirzoyan (Razmik.Mirzoyan@mpp.mpg.de). MAGIC is a system of two 17m-diameter Imaging Atmospheric Cherenkov Telescopes located at the Canary island of La Palma, Spain, and designed to perform gamma-ray astronomy in the energy range from 50 GeV to greater than 50 TeV.

Published
2017

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