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Institute
De Angelis, A. ; Tatischeff, V. ; Tavani, M. ; Oberlack, U. ; Grenier, I. ; Hanloni, L. ; Walter, R. ; Argan, A. ; Von Ballmoos, P. ; Bulgarelli, A. ; Donnarumma, I. ; Hernanz, M. ; Kuvvetli, I. ; Pearce, M. ; Zdziarski, A. ; Aboudan, A. ; Ajello, M. ; Ambrosi, G. ; Bernard, D. ; Bernardini, E. ; Bonvicini, V. ; Brogna, A. ; Branchesi, M. ; Budtz-Jorgensen, C. ; Bykov, A. M. ; Campana, R. ; Cardillo, M. ; Coppi, P. ; De Martino, D. ; Diehl, R. ; Doro, M. ; Fioretti, V. ; Funk, S. ; Ghisellini, G. ; Grove, E. ; Hamadache, C. ; Hartmann, D. H. ; Hayashida, M. ; Isern, J. ; Kanbach, G. ; Kiener, J. ; Knodlseder, J. ; Labanti, C. ; Laurent, P. ; Limousin, O. ; Longo, F. ; Mannheim, K. ; Marisaldi, M. ; Martinez, M. ; Mazziotta, Mario Nicola ; McEnery, J. ; Mereghetti, S. ; Minervini, G. ; Moiseev, A. ; Morselli, A. ; Nakazawa, K. ; Orleanski, P. ; Paredes, J. M. ; Patricelli, B. ; Pevre, J. ; Piano, G. ; Pohl, Martin ; Ramarijaona, H. ; Rando, R. ; Reichardt, I. ; Roncadelli, M. ; Silva, R. ; Tavecchio, F. ; Thompson, D. J. ; Turolla, R. ; Ulyanov, A. ; Vacchi, A. ; Wu, X. ; Zoglauer, A.
e-ASTROGAM (‘enhanced ASTROGAM’) is a breakthrough Observatory space mission, with a detector composed by a Silicon tracker, a calorimeter, and an anticoincidence system, dedicated to the study of the non-thermal Universe in the photon energy range from 0.3 MeV to 3 GeV – the lower energy limit can be pushed to energies as low as 150 keV, albeit with rapidly degrading angular resolution, for the tracker, and to 30 keV for calorimetric detection. The mission is based on an advanced space-proven detector technology, with unprecedented sensitivity, angular and energy resolution, combined with polarimetric capability. Thanks to its performance in the MeV-GeV domain, substantially improving its predecessors, e-ASTROGAM will open a new window on the non-thermal Universe, making pioneering observations of the most powerful Galactic and extragalactic sources, elucidating the nature of their relativistic outflows and their effects on the surroundings. With a line sensitivity in the MeV energy range one to two orders of magnitude better than previous generation instruments, e-ASTROGAM will determine the origin of key isotopes fundamental for the understanding of supernova explosion and the chemical evolution of our Galaxy. The mission will provide unique data of significant interest to a broad astronomical community, complementary to powerful observatories such as LIGO-Virgo-GEO600-KAGRA, SKA, ALMA, E-ELT, TMT, LSST, JWST, Athena, CTA, IceCube, KM3NeT, and the promise of eLISA.
Tatischeff, V. ; De Angelis, A. ; Tavani, M. ; Grenier, I. ; Oberlack, U. ; Hanlon, L. ; Walter, R. ; Argan, A. ; von Ballmoos, P. ; Bulgarelli, A. ; Donnarumma, I. ; Hernanz, Margarita ; Kuvvetli, I. ; Mallamaci, M. ; Pearce, M. ; Zdziarski, A. ; Aboudan, A. ; Ajello, M. ; Ambrosi, G. ; Bernard, D. ; Bernardini, E. ; Bonvicini, V. ; Brogna, A. ; Branchesi, M. ; Budtz-Jorgensen, C. ; Bykov, A. ; Campana, R. ; Cardillo, M. ; Ciprini, S. ; Coppi, P. ; Cumani, P. ; da Silva, R. M. Curado ; De Martino, D. ; Diehl, R. ; Doro, M. ; Fioretti, V. ; Funk, S. ; Ghisellini, G. ; Giordano, F. ; Grove, J. E. ; Hamadache, C. ; Hartmann, D. H. ; Hayashida, M. ; Isern, J. ; Kanbach, G. ; Kiener, J. ; Knodlseder, J. ; Labanti, C. ; Laurent, P. ; Leising, M. ; Limousin, O. ; Longo, F. ; Mannheim, K. ; Marisaldi, M. ; Martinez, M. ; Mazziotta, M. N. ; McEnery, J. E. ; Mereghetti, S. ; Minervini, G. ; Moiseev, A. ; Morselli, A. ; Nakazawa, K. ; Orleanski, P. ; Paredes, J. M. ; Patricelli, B. ; Peyre, J. ; Piano, G. ; Pohl, Martin ; Rando, R. ; Roncadelli, M. ; Tavecchio, F. ; Thompson, D. J. ; Turolla, R. ; Ulyanov, A. ; Vacchi, A. ; Wu, X. ; Zoglauer, A.
e-ASTROGAM is a concept for a breakthrough observatory space mission carrying a gamma-ray telescope dedicated to the study of the non-thermal Universe in the photon energy range from 0.15 MeV to 3 GeV. The lower energy limit can be pushed down to energies as low as 30 keV for gamma-ray burst detection with the calorimeter. The mission is based on an advanced space-proven detector technology, with unprecedented sensitivity, angular and energy resolution, combined with remarkable polarimetric capability. Thanks to its performance in the MeV-GeV domain, substantially improving its predecessors, e-ASTROGAM will open a new window on the non-thermal Universe, making pioneering observations of the most powerful Galactic and extragalactic sources, elucidating the nature of their relativistic outflows and their effects on the surroundings. With a line sensitivity in the MeV energy range one to two orders of magnitude better than previous and current generation instruments, e-ASTROGAM will determine the origin of key isotopes fundamental for the understanding of supernova explosion and the chemical evolution of our Galaxy. The mission will be a major player of the multiwavelength, multimessenger time-domain astronomy of the 2030s, and provide unique data of significant interest to a broad astronomical community, complementary to powerful observatories such as LISA, LIGO, Virgo, KAGRA, the Einstein Telescope and the Cosmic Explorer, IceCube-Gen2 and KM3NeT, SKA, ALMA, JWST, E-ELT, LSST, Athena, and the Cherenkov Telescope Array.
Aleksic, J. ; Ansoldi, S. ; Antonelli, L. A. ; Antoranz, P. ; Babic, A. ; Bangale, P. ; de Almeida, U. Barres ; Barrio, J. A. ; Gonzalez, J. Becerra ; Bednarek, W. ; Berger, K. ; Bernardini, E. ; Bilandli, A. ; Bianch, O. ; Bock, R. K. ; Bonnefoy, S. ; Bonnoli, G. ; Borracci, F. ; Bretz, T. ; Carmona, E. ; Carosi, A. ; Fidalgo, D. Carreto ; Colin, P. ; Colombo, E. ; Contreras, J. L. ; Cortina, J. ; Covino, S. ; Da Vela, P. ; Dazzi, F. ; De Angelis, A. ; De Caneva, G. ; De Lotto, B. ; Delgado Mendez, C. ; Doert, M. ; Dominguez, A. ; Prester, Dijana Dominis ; Dorner, D. ; Doro, M. ; Einecke, S. ; Eisenacher, D. ; Elsaesser, D. ; Farina, E. ; Ferenc, D. ; Fonseca, M. V. ; Font, L. ; Frantzen, K. ; Fruck, C. ; Garcia Lopez, R. J. ; Garczarczyki, M. ; Garrido Terrats, D. ; Gaug, M. ; Giavitto, G. ; Godinovic, N. ; Gonzalez Munoz, A. ; Gozzini, S. R. ; Hadamek, A. ; Hadasch, D. ; Herrero, A. ; Hildebrand, D. ; Hose, J. ; Hrupec, D. ; Idec, W. ; Kadenius, V. ; Kellermann, H. ; Knoetig, M. L. ; Krause, J. ; Kushida, J. ; La Barbera, A. ; Lelas, D. ; Lewandowska, N. ; Lindfors, E. ; Longo, F. ; Lombardi, S. ; Lopez, M. ; Lopez-Coto, R. ; Lopez-Oramas, A. ; Lorenz, E. ; Lozano, I. ; Makariev, M. ; Mallot, K. ; Maneva, G. ; Mankuzhiyil, N. ; Mannheim, K. ; Maraschi, L. ; Marcote, B. ; Mariotti, M. ; Martinez, M. ; Mazin, D. ; Menzel, U. ; Meucci, M. ; Miranda, J. M. ; Mirzoyan, R. ; Moralejo, A. ; Munar-Adrover, P. ; Nakajima, D. ; Niedzwiecki, A. ; Nilsson, K. ; Nowak, N. ; Orito, R. ; Overkemping, A. ; Paiano, S. ; Palatiello, M. ; Paneque, D. ; Paoletti, R. ; Paredes, J. M. ; Paredes-Fortuny, X. ; Partini, S. ; Persic, M. ; Prada, F. ; Moroni, P. G. Prada ; Prandini, E. ; Preziuso, S. ; Puljak, I. ; Reinthal, R. ; Rhode, W. ; Ribo, M. ; Rico, J. ; Garcia, J. Rodriguez ; Ruegamer, S. ; Saggion, A. ; Saito, K. ; Salvati, M. ; Satalecka, K. ; Scalzotto, V. ; Scapin, V. ; Schuliz, C. ; Schweizer, T. ; Shore, S. N. ; Sillanpaa, A. ; Sitarek, J. ; Snidaric, I. ; Sobczynska, D. ; Spanier, F. ; Stamatescu, V. ; Stamerra, A. ; Steinbring, T. ; Storz, J. ; Sun, S. ; Suric, T. ; Takalo, L. ; Tavecchio, F. ; Temnikov, P. ; Terzic, T. ; Tescaro, D. ; Teshima, M. ; Thaele, J. ; Tibolla, O. ; Torres, D. F. ; Toyama, T. ; Treves, A. ; Uellenbeck, M. ; Vogler, P. ; Wagner, R. M. ; Zandanel, F. ; Zanin, R. ; Archambault, S. ; Behera, B. ; Beilicke, M. ; Benbow, W. ; Bird, R. ; Buckley, J. H. ; Bugaev, V. ; Cerruti, M. ; Chen, X. ; Ciupik, L. ; Collins-Hughes, E. ; Cui, W. ; Dumm, J. ; Eisch, J. D. ; Falcone, A. ; Federici, S. ; Feng, Q. ; Finley, J. P. ; Fleischhack, H. ; Fortin, P. ; Fortson, L. ; Furniss, A. ; Griffin, S. ; Griffiths, S. T. ; Grube, J. ; Gyuk, G. ; Hanna, D. ; Holder, J. ; Hughes, G. ; Humensky, T. B. ; Johnson, C. A. ; Kaaret, P. ; Kertzman, M. ; Khassen, Y. ; Kieda, D. ; Krawczynski, H. ; Krennrich, F. ; Kumar, S. ; Lang, M. J. ; Maier, G. ; McArthur, S. ; Meagher, K. ; Moriarty, P. ; Mukherjee, R. ; Ong, R. A. ; Otte, A. N. ; Park, N. ; Pichel, A. ; Pohl, M. ; Popkow, A. ; Prokoph, H. ; Quinn, M. J. ; Ragan, K. ; Rajotte, J. ; Reynolds, P. T. ; Richards, G. T. ; Roache, E. ; Rovero, A. C. ; Sembroski, G. H. ; Shahinyan, K. ; Staszak, D. ; Telezhinsky, Igor O. ; Theiling, M. ; Tucci, J. V. ; Tyler, J. ; Varlotta, A. ; Wakely, S. P. ; Weekes, T. C. ; Weinstein, A. ; Welsing, R. ; Wilhelm, Alina ; Williams, D. A. ; Zitzer, B. ; Villata, M. ; Raiteri, C. ; Aller, H. D. ; Aller, M. F. ; Chen, W. P. ; Jordan, B. ; Koptelova, E. ; Kurtanidze, O. M. ; Lahteenmaki, A. ; McBreen, B. ; Larionov, V. M. ; Lin, C. S. ; Nikolashvili, M. G. ; Angelakis, E. ; Capalbi, M. ; Carraminana, A. ; Carrasco, L. ; Cassaro, P. ; Cesarini, A. ; Fuhrmann, L. ; Giroletti, M. ; Hovatta, T. ; Krichbaum, T. P. ; Krimm, H. A. ; Max-Moerbeck, W. ; Moody, J. W. ; Maccaferri, G. ; Mori, Y. ; Nestoras, I. ; Orlati, A. ; Pace, C. ; Pearson, R. ; Perri, M. ; Readhead, A. C. S. ; Richards, J. L. ; Sadun, A. C. ; Sakamoto, T. ; Tammi, J. ; Tornikoski, M. ; Yatsu, Y. ; Zook, A.
Aims. We perform an extensive characterization of the broadband emission of Mrk 421, as well as its temporal evolution, during the non-flaring (low) state. The high brightness and nearby location (z = 0.031) of Mrk 421 make it an excellent laboratory to study blazar emission. The goal is to learn about the physical processes responsible for the typical emission of Mrk 421, which might also be extended to other blazars that are located farther away and hence are more difficult to study.
Methods. We performed a 4.5-month multi-instrument campaign on Mrk 421 between January 2009 and June 2009, which included VLBA, F-GAMMA, GASP-WEBT, Swift, RXTE, Fermi-LAT, MAGIC, and Whipple, among other instruments and collaborations. This extensive radio to very-high-energy (VHE; E > 100 GeV) gamma-ray dataset provides excellent temporal and energy coverage, which allows detailed studies of the evolution of the broadband spectral energy distribution.
Results. Mrk421 was found in its typical (non-flaring) activity state, with a VHE flux of about half that of the Crab Nebula, yet the light curves show significant variability at all wavelengths, the highest variability being in the X-rays. We determined the power spectral densities (PSD) at most wavelengths and found that all PSDs can be described by power-laws without a break, and with indices consistent with pink/red-noise behavior. We observed a harder-when-brighter behavior in the X-ray spectra and measured a positive correlation between VHE and X-ray fluxes with zero time lag. Such characteristics have been reported many times during flaring activity, but here they are reported for the first time in the non-flaring state. We also observed an overall anti-correlation between optical /UV and X-rays extending over the duration of the campaign.
Conclusions. The harder-when-brighter behavior in the X-ray spectra and the measured positive X-ray/VHE correlation during the 2009 multiwavelength campaign suggests that the physical processes dominating the emission during non-flaring states have similarities with those occurring during flaring activity. In particular, this observation supports leptonic scenarios as being responsible for the emission of Mrk 421 during non-flaring activity. Such a temporally extended X-ray /VHE correlation is not driven by any single flaring event, and hence is difficult to explain within the standard hadronic scenarios. The highest variability is observed in the X-ray band, which, within the one-zone synchrotron self-Compton scenario, indicates that the electron energy distribution is most variable at the highest energies.
De Angelis, A. ; Tatischeff, V. ; Grenier, I. A. ; McEnery, J. ; Mallamaci, Manuela ; Tavani, M. ; Oberlack, U. ; Hanlon, L. ; Walter, R. ; Argan, A. ; Von Ballmoos, P. ; Bulgarelli, A. ; Bykov, A. ; Hernanz, M. ; Kanbach, G. ; Kuvvetli, I. ; Pearce, M. ; Zdziarski, A. ; Conrad, J. ; Ghisellini, G. ; Harding, A. ; Isern, J. ; Leising, M. ; Longo, F. ; Madejski, G. ; Martinez, M. ; Mazziotta, Mario Nicola ; Paredes, J. M. ; Pohl, Martin ; Rando, R. ; Razzano, M. ; Aboudan, A. ; Ackermann, M. ; Addazi, A. ; Ajello, M. ; Albertus, C. ; Alvarez, J. M. ; Ambrosi, G. ; Anton, S. ; Antonelli, L. A. ; Babic, A. ; Baibussinov, B. ; Balbom, M. ; Baldini, L. ; Balman, S. ; Bambi, C. ; Barres de Almeida, U. ; Barrio, J. A. ; Bartels, R. ; Bastieri, D. ; Bednarek, W. ; Bernard, D. ; Bernardini, E. ; Bernasconi, T. ; Bertucci, B. ; Biland, A. ; Bissaldi, E. ; Boettcher, M. ; Bonvicini, V. ; Bosch-Ramon, V. ; Bottacini, E. ; Bozhilov, V. ; Bretz, T. ; Branchesi, M. ; Brdar, V. ; Bringmann, T. ; Brogna, A. ; Jorgensen, C. Budtz ; Busetto, G. ; Buson, S. ; Busso, M. ; Caccianiga, A. ; Camera, S. ; Campana, R. ; Caraveo, P. ; Cardillo, M. ; Carlson, P. ; Celestin, S. ; Cermeno, M. ; Chen, A. ; Cheung, C. C. ; Churazov, E. ; Ciprini, S. ; Coc, A. ; Colafrancesco, S. ; Coleiro, A. ; Collmar, W. ; Coppi, P. ; Curado da Silva, R. ; Cutini, S. ; De Lotto, B. ; de Martino, D. ; De Rosa, A. ; Del Santo, M. ; Delgado, L. ; Diehl, R. ; Dietrich, S. ; Dolgov, A. D. ; Dominguez, A. ; Prester, D. Dominis ; Donnarumma, I. ; Dorner, D. ; Doro, M. ; Dutra, M. ; Elsaesser, D. ; Fabrizio, M. ; Fernandez-Barral, A. ; Fioretti, V. ; Foffano, L. ; Formato, V. ; Fornengo, N. ; Foschini, L. ; Franceschini, A. ; Franckowiak, A. ; Funk, S. ; Fuschino, F. ; Gaggero, D. ; Galanti, G. ; Gargano, F. ; Gasparrini, D. ; Gehrz, R. ; Giammaria, P. ; Giglietto, N. ; Giommi, P. ; Giordano, F. ; Giroletti, M. ; Ghirlanda, G. ; Godinovic, N. ; Gouiffes, C. ; Grove, J. E. ; Hamadache, C. ; Hartmann, D. H. ; Hayashida, M. ; Hryczuk, A. ; Jean, P. ; Johnson, T. ; Jose, J. ; Kaufmann, S. ; Khelifi, B. ; Kiener, J. ; Knodlseder, J. ; Kolem, M. ; Kopp, J. ; Kozhuharov, V. ; Labanti, C. ; Lalkovski, S. ; Laurent, P. ; Limousin, O. ; Linares, M. ; Lindfors, E. ; Lindner, M. ; Liu, J. ; Lombardi, S. ; Loparco, F. ; Lopez-Coto, R. ; Lopez Moya, M. ; Lott, B. ; Lubrano, P. ; Malyshev, D. ; Mankuzhiyil, N. ; Mannheim, K. ; Marcha, M. J. ; Marciano, A. ; Marcote, B. ; Mariotti, M. ; Marisaldi, M. ; McBreen, S. ; Mereghetti, S. ; Merle, A. ; Mignani, R. ; Minervini, G. ; Moiseev, A. ; Morselli, A. ; Moura, F. ; Nakazawa, K. ; Nava, L. ; Nieto, D. ; Orienti, M. ; Orio, M. ; Orlando, E. ; Orleanski, P. ; Paiano, S. ; Paoletti, R. ; Papitto, A. ; Pasquato, M. ; Patricelli, B. ; Perez-Garcia, M. A. ; Persic, M. ; Piano, G. ; Pichel, A. ; Pimenta, M. ; Pittori, C. ; Porter, T. ; Poutanen, J. ; Prandini, E. ; Prantzos, N. ; Produit, N. ; Profumo, S. ; Queiroz, F. S. ; Raino, S. ; Raklev, A. ; Regis, M. ; Reichardt, I. ; Rephaeli, Y. ; Rico, J. ; Rodejohann, W. ; Fernandez, G. Rodriguez ; Roncadelli, M. ; Roso, L. ; Rovero, A. ; Ruffini, R. ; Sala, G. ; Sanchez-Conde, M. A. ; Santangelo, Andrea ; Parkinson, P. Saz ; Sbarrato, T. ; Shearer, A. ; Shellard, R. ; Short, K. ; Siegert, T. ; Siqueira, C. ; Spinelli, P. ; Stamerra, A. ; Starrfield, S. ; Strong, A. ; Strumke, I. ; Tavecchio, F. ; Taverna, R. ; Terzic, T. ; Thompson, D. J. ; Tibolla, O. ; Torres, D. F. ; Turolla, R. ; Ulyanov, A. ; Ursi, A. ; Vacchi, A. ; Van den Abeele, J. ; Vankova-Kirilovai, G. ; Venter, C. ; Verrecchia, F. ; Vincent, P. ; Wang, X. ; Weniger, C. ; Wu, X. ; Zaharijas, G. ; Zampieri, L. ; Zane, S. ; Zimmer, S. ; Zoglauer, A.
Prospects for Cherenkov Telescope Array Observations of the Young Supernova Remnant RX J1713.7-3946
(2017)
Acero, F. ; Aloisio, R. ; Amans, J. ; Amato, Elena ; Antonelli, L. A. ; Aramo, C. ; Armstrong, T. ; Arqueros, F. ; Asano, Katsuaki ; Ashley, M. ; Backes, M. ; Balazs, C. ; Balzer, A. ; Bamba, Aya ; Barkov, Maxim ; Barrio, J. A. ; Benbow, Wystan ; Bernloehr, K. ; Beshley, V. ; Bigongiari, C. ; Biland, A. ; Bilinsky, A. ; Bissaldi, Elisabetta ; Biteau, J. ; Blanch, O. ; Blasi, P. ; Blazek, J. ; Boisson, C. ; Bonanno, G. ; Bonardi, A. ; Bonavolonta, C. ; Bonnoli, G. ; Braiding, C. ; Brau-Nogue, S. ; Bregeon, J. ; Brown, A. M. ; Bugaev, V. ; Bulgarelli, A. ; Bulik, T. ; Burton, Michael ; Burtovoi, A. ; Busetto, G. ; Bottcher, M. ; Cameron, R. ; Capalbi, M. ; Caproni, Anderson ; Caraveo, P. ; Carosi, R. ; Cascone, E. ; Cerruti, M. ; Chaty, Sylvain ; Chen, A. ; Chen, X. ; Chernyakova, M. ; Chikawa, M. ; Chudoba, J. ; Cohen-Tanugi, J. ; Colafrancesco, S. ; Conforti, V. ; Contreras, J. L. ; Costa, A. ; Cotter, G. ; Covino, Stefano ; Covone, G. ; Cumani, P. ; Cusumano, G. ; Daniel, M. ; Dazzi, F. ; De Angelis, A. ; De Cesare, G. ; De Franco, A. ; De Frondat, F. ; Dal Pino, E. M. de Gouveia ; De Lisio, C. ; Lopez, R. de los Reyes ; De Lotto, B. ; de Naurois, M. ; De Palma, F. ; Del Santo, M. ; Delgado, C. ; della Volpe, D. ; Di Girolamo, T. ; Di Giulio, C. ; Di Pierro, F. ; Di Venere, L. ; Doro, M. ; Dournaux, J. ; Dumas, D. ; Dwarkadas, Vikram V. ; Diaz, C. ; Ebr, J. ; Egberts, Kathrin ; Einecke, S. ; Elsaesser, D. ; Eschbach, S. ; Falceta-Goncalves, D. ; Fasola, G. ; Fedorova, E. ; Fernandez-Barral, A. ; Ferrand, Gilles ; Fesquet, M. ; Fiandrini, E. ; Fiasson, A. ; Filipovic, Miroslav D. ; Fioretti, V. ; Font, L. ; Fontaine, Gilles ; Franco, F. J. ; Freixas Coromina, L. ; Fujita, Yutaka ; Fukui, Y. ; Funk, S. ; Forster, A. ; Gadola, A. ; Lopez, R. Garcia ; Garczarczyk, M. ; Giglietto, N. ; Giordano, F. ; Giuliani, A. ; Glicenstein, J. ; Gnatyk, R. ; Goldoni, P. ; Grabarczyk, T. ; Graciani, R. ; Graham, J. ; Grandi, P. ; Granot, Jonathan ; Green, A. J. ; Griffiths, S. ; Gunji, S. ; Hakobyan, H. ; Hara, S. ; Hassan, T. ; Hayashida, M. ; Heller, M. ; Helo, J. C. ; Hinton, J. ; Hnatyk, B. ; Huet, J. ; Huetten, M. ; Humensky, T. B. ; Hussein, M. ; Horandel, J. ; Ikeno, Y. ; Inada, T. ; Inome, Y. ; Inoue, S. ; Inoue, T. ; Inoue, Y. ; Ioka, K. ; Iori, Maurizio ; Jacquemier, J. ; Janecek, P. ; Jankowsky, D. ; Jung, I. ; Kaaret, P. ; Katagiri, H. ; Kimeswenger, S. ; Kimura, Shigeo S. ; Knodlseder, J. ; Koch, B. ; Kocot, J. ; Kohri, K. ; Komin, N. ; Konno, Y. ; Kosack, K. ; Koyama, S. ; Kraus, Michaela ; Kubo, Hidetoshi ; Mezek, G. Kukec ; Kushida, J. ; La Palombara, N. ; Lalik, K. ; Lamanna, G. ; Landt, H. ; Lapington, J. ; Laporte, P. ; Lee, S. ; Lees, J. ; Lefaucheur, J. ; Lenain, J. -P. ; Leto, Giuseppe ; Lindfors, E. ; Lohse, T. ; Lombardi, S. ; Longo, F. ; Lopez, M. ; Lucarelli, F. ; Luque-Escamilla, Pedro Luis ; Lopez-Coto, R. ; Maccarone, M. C. ; Maier, G. ; Malaguti, G. ; Mandat, D. ; Maneva, G. ; Mangano, S. ; Marcowith, Alexandre ; Marti, J. ; Martinez, M. ; Martinez, G. ; Masuda, S. ; Maurin, G. ; Maxted, N. ; Melioli, Claudio ; Mineo, T. ; Mirabal, N. ; Mizuno, T. ; Moderski, R. ; Mohammed, M. ; Montaruli, T. ; Moralejo, A. ; Mori, K. ; Morlino, G. ; Morselli, A. ; Moulin, Emmanuel ; Mukherjee, R. ; Mundell, C. ; Muraishi, H. ; Murase, Kohta ; Nagataki, Shigehiro ; Nagayoshi, T. ; Naito, T. ; Nakajima, D. ; Nakamori, T. ; Nemmen, R. ; Niemiec, Jacek ; Nieto, D. ; Nievas-Rosillo, M. ; Nikolajuk, M. ; Nishijima, K. ; Noda, K. ; Nogues, L. ; Nosek, D. ; Novosyadlyj, B. ; Nozaki, S. ; Ohira, Yutaka ; Ohishi, M. ; Ohm, S. ; Okumura, A. ; Ong, R. A. ; Orito, R. ; Orlati, A. ; Ostrowski, M. ; Oya, I. ; Padovani, Marco ; Palacio, J. ; Palatka, M. ; Paredes, Josep M. ; Pavy, S. ; Persic, M. ; Petrucci, P. ; Petruk, Oleh ; Pisarski, A. ; Pohl, Martin ; Porcelli, A. ; Prandini, E. ; Prast, J. ; Principe, G. ; Prouza, M. ; Pueschel, Elisa ; Puelhofer, G. ; Quirrenbach, A. ; Rameez, M. ; Reimer, O. ; Renaud, M. ; Ribo, M. ; Rico, J. ; Rizi, V. ; Rodriguez, J. ; Fernandez, G. Rodriguez ; Rodriguez Vazquez, J. J. ; Romano, Patrizia ; Romeo, G. ; Rosado, J. ; Rousselle, J. ; Rowell, G. ; Rudak, B. ; Sadeh, I. ; Safi-Harb, S. ; Saito, T. ; Sakaki, N. ; Sanchez, D. ; Sangiorgi, P. ; Sano, H. ; Santander, M. ; Sarkar, S. ; Sawada, M. ; Schioppa, E. J. ; Schoorlemmer, H. ; Schovanek, P. ; Schussler, F. ; Sergijenko, O. ; Servillat, M. ; Shalchi, A. ; Shellard, R. C. ; Siejkowski, H. ; Sillanpaa, A. ; Simone, D. ; Sliusar, V. ; Sol, H. ; Stanic, S. ; Starling, R. ; Stawarz, L. ; Stefanik, S. ; Stephan, M. ; Stolarczyk, T. ; Szanecki, M. ; Szepieniec, T. ; Tagliaferri, G. ; Tajima, H. ; Takahashi, M. ; Takeda, J. ; Tanaka, M. ; Tanaka, S. ; Tejedor, L. A. ; Telezhinsky, Igor O. ; Temnikov, P. ; Terada, Y. ; Tescaro, D. ; Teshima, M. ; Testa, V. ; Thoudam, S. ; Tokanai, F. ; Torres, D. F. ; Torresi, E. ; Tosti, G. ; Townsley, C. ; Travnicek, P. ; Trichard, C. ; Trifoglio, M. ; Tsujimoto, S. ; Vagelli, V. ; Vallania, P. ; Valore, L. ; van Driel, W. ; van Eldik, C. ; Vandenbroucke, Justin ; Vassiliev, V. ; Vecchi, M. ; Vercellone, Stefano ; Vergani, S. ; Vigorito, C. ; Vorobiov, S. ; Vrastil, M. ; Vazquez Acosta, M. L. ; Wagner, S. J. ; Wagner, R. ; Wakely, S. P. ; Walter, R. ; Ward, J. E. ; Watson, J. J. ; Weinstein, A. ; White, M. ; White, R. ; Wierzcholska, A. ; Wilcox, P. ; Williams, D. A. ; Wischnewski, R. ; Wojcik, P. ; Yamamoto, T. ; Yamamoto, H. ; Yamazaki, Ryo ; Yanagita, S. ; Yang, L. ; Yoshida, T. ; Yoshida, M. ; Yoshiike, S. ; Yoshikoshi, T. ; Zacharias, M. ; Zampieri, L. ; Zanin, R. ; Zavrtanik, M. ; Zavrtanik, D. ; Zdziarski, A. ; Zech, Alraune ; Zechlin, Hannes ; Zhdanov, V. ; Ziegler, A. ; Zorn, J.
We perform simulations for future Cherenkov Telescope Array (CTA) observations of RX J1713.7-3946, a young supernova remnant (SNR) and one of the brightest sources ever discovered in very high energy (VHE) gamma rays. Special attention is paid to exploring possible spatial (anti) correlations of gamma rays with emission at other wavelengths, in particular X-rays and CO/H I emission. We present a series of simulated images of RX J1713.7-3946 for CTA based on a set of observationally motivated models for the gamma-ray emission. In these models, VHE gamma rays produced by high-energy electrons are assumed to trace the nonthermal X-ray emission observed by XMM-Newton, whereas those originating from relativistic protons delineate the local gas distributions. The local atomic and molecular gas distributions are deduced by the NANTEN team from CO and H I observations. Our primary goal is to show how one can distinguish the emission mechanism(s) of the gamma rays (i.e., hadronic versus leptonic, or a mixture of the two) through information provided by their spatial distribution, spectra, and time variation. This work is the first attempt to quantitatively evaluate the capabilities of CTA to achieve various proposed scientific goals by observing this important cosmic particle accelerator.
Observations of the young supernova remnant RX J1713.7-3946 with the fermi large area telescope
(2011)
Abdo, A. A. ; Ackermann, Margit ; Ajello, M. ; Allafort, A. J. ; Baldini, L. ; Ballet, J. ; Barbiellini, G. ; Baring, M. G. ; Bastieri, D. ; Bellazzini, R. ; Berenji, B. ; Blandford, R. D. ; Bloom, E. D. ; Bonamente, E. ; Borgland, A. W. ; Bouvier, A. ; Brandt, T. J. ; Bregeon, Johan ; Brigida, M. ; Bruel, P. ; Buehler, R. ; Buson, S. ; Caliandro, G. A. ; Cameron, R. A. ; Caraveo, P. A. ; Casandjian, J. M. ; Cecchi, C. ; Chaty, S. ; Chekhtman, A. ; Cheung, C. C. ; Chiang, J. ; Cillis, A. N. ; Ciprini, S. ; Claus, R. ; Cohen-Tanugi, J. ; Conrad, Jan ; Corbel, S. ; Cutini, S. ; de Angelis, A. ; de Palma, F. ; Dermer, C. D. ; Digel, S. W. ; do Couto e Silva, E. ; Drell, P. S. ; Drlica-Wagner, A. ; Dubois, R. ; Dumora, D. ; Favuzzi, C. ; Ferrara, E. C. ; Fortin, P. ; Frailis, M. ; Fukazawa, Y. ; Fukui, Y. ; Funk, S. ; Fusco, P. ; Gargano, F. ; Gasparrini, D. ; Gehrels, N. ; Germani, S. ; Giglietto, N. ; Giordano, F. ; Giroletti, M. ; Glanzman, T. ; Godfrey, G. ; Grenier, I. A. ; Grondin, M. -H. ; Guiriec, S. ; Hadasch, D. ; Hanabata, Y. ; Harding, A. K. ; Hayashida, M. ; Hayashi, K. ; Hays, E. ; Horan, D. ; Jackson, M. S. ; Johannesson, G. ; Johnson, A. S. ; Kamae, T. ; Katagiri, H. ; Kataoka, J. ; Kerr, M. ; Knoedlseder, J. ; Kuss, M. ; Lande, J. ; Latronico, L. ; Lee, S. -H. ; Lemoine-Goumard, M. ; Longo, F. ; Loparco, F. ; Lovellette, M. N. ; Lubrano, P. ; Madejski, G. M. ; Makeev, A. ; Mazziotta, Mario Nicola ; McEnery, J. E. ; Michelson, P. F. ; Mignani, R. P. ; Mitthumsiri, W. ; Mizuno, T. ; Moiseev, A. A. ; Monte, C. ; Monzani, M. E. ; Morselli, A. ; Moskalenko, I. V. ; Murgia, S. ; Naumann-Godo, M. ; Nolan, P. L. ; Norris, J. P. ; Nuss, E. ; Ohsugi, T. ; Okumura, A. ; Orlando, E. ; Ormes, J. F. ; Paneque, D. ; Parent, D. ; Pelassa, V. ; Pesce-Rollins, M. ; Pierbattista, M. ; Piron, F. ; Pohl, Martin ; Porter, T. A. ; Raino, S. ; Rando, R. ; Razzano, M. ; Reimer, O. ; Reposeur, T. ; Ritz, S. ; Romani, R. W. ; Roth, M. ; Sadrozinski, H. F. -W. ; Parkinson, P. M. Saz ; Sgro, C. ; Smith, D. A. ; Smith, P. D. ; Spandre, G. ; Spinelli, P. ; Strickman, M. S. ; Tajima, H. ; Takahashi, H. ; Takahashi, T. ; Tanaka, T. ; Thayer, J. G. ; Thayer, J. B. ; Thompson, D. J. ; Tibaldo, L. ; Tibolla, O. ; Torres, D. F. ; Tosti, G. ; Tramacere, A. ; Troja, E. ; Uchiyama, Y. ; Vandenbroucke, J. ; Vasileiou, V. ; Vianello, G. ; Vilchez, N. ; Vitale, V. ; Waite, A. P. ; Wang, P. ; Winer, B. L. ; Wood, K. S. ; Yamamoto, H. ; Yamazaki, R. ; Yang, Z. ; Ziegler, M.
We present observations of the young supernova remnant (SNR) RX J1713.7-3946 with the Fermi Large Area Telescope (LAT). We clearly detect a source positionally coincident with the SNR. The source is extended with a best-fit extension of 0 degrees.55 +/- 0 degrees.04 matching the size of the non-thermal X-ray and TeV gamma-ray emission from the remnant. The positional coincidence and the matching extended emission allow us to identify the LAT source with SNR RX J1713.7-3946. The spectrum of the source can be described by a very hard power law with a photon index of Gamma = 1.5 +/- 0.1 that coincides in normalization with the steeper H. E. S. S.-detected gamma-ray spectrum at higher energies. The broadband gamma-ray emission is consistent with a leptonic origin as the dominant mechanism for the gamma-ray emission.
Ahnen, M. L. ; Ansoldi, S. ; Antonelli, L. A. ; Antoranz, P. ; Babic, A. ; Banerjee, B. ; Bangale, P. ; de Almeida, U. Barres ; Barrio, J. A. ; Gonzalez, J. Becerra ; Bednarek, W. ; Bernardini, E. ; Berti, A. ; Biasuzzi, B. ; Biland, A. ; Blanch, O. ; Bonnefoy, S. ; Bonnoli, G. ; Borracci, F. ; Bretz, T. ; Buson, S. ; Carosi, A. ; Chatterjee, A. ; Clavero, R. ; Colin, P. ; Colombo, E. ; Contreras, J. L. ; Cortina, J. ; Covino, S. ; Da Vela, P. ; Dazzi, F. ; De Angelis, A. ; De Lotto, B. ; Wilhelmi, E. de Ona ; Di Pierro, F. ; Doert, M. ; Dominguez, A. ; Prester, D. Dominis ; Dorner, D. ; Doro, M. ; Einecke, S. ; Glawion, D. Eisenacher ; Elsaesser, D. ; Engelkemeier, M. ; Ramazani, V. Fallah ; Fernandez-Barral, A. ; Fidalgo, D. ; Fonseca, M. V. ; Font, L. ; Frantzen, K. ; Fruck, C. ; Galindo, D. ; Lopez, R. J. Garcia ; Garczarczyk, M. ; Terrats, D. Garrido ; Gaug, M. ; Giammaria, P. ; Godinovic, N. ; Gonzalez Munoz, A. ; Gora, D. ; Guberman, D. ; Hadasch, D. ; Hahn, A. ; Hanabata, Y. ; Hayashida, M. ; Herrera, J. ; Hose, J. ; Hrupec, D. ; Hughes, G. ; Idec, W. ; Kodani, K. ; Konno, Y. ; Kubo, H. ; Kushida, J. ; La Barbera, A. ; Lelas, D. ; Lindfors, E. ; Lombardi, S. ; Longo, F. ; Lopez, M. ; Lopez-Coto, R. ; Majumdar, P. ; Makariev, M. ; Mallot, K. ; Maneva, G. ; Manganaro, M. ; Mannheim, K. ; Maraschi, L. ; Marcote, B. ; Mariotti, M. ; Martinez, M. ; Mazin, D. ; Menzel, U. ; Miranda, J. M. ; Mirzoyan, R. ; Moralejo, A. ; Moretti, E. ; Nakajima, D. ; Neustroev, V. ; Niedzwiecki, A. ; Rosillo, M. Nievas ; Nilsson, K. ; Nishijima, K. ; Noda, K. ; Nogues, L. ; Overkemping, A. ; Paiano, S. ; Palacio, J. ; Palatiello, M. ; Paneque, D. ; Paoletti, R. ; Paredes, J. M. ; Paredes-Fortuny, X. ; Pedaletti, G. ; Peresano, M. ; Perri, L. ; Persic, M. ; Poutanen, J. ; Moroni, P. G. Prada ; Prandini, E. ; Puljak, I. ; Reichardt, I. ; Rhode, W. ; Ribo, M. ; Rico, J. ; Rodriguez Garcia, J. ; Saito, T. ; Satalecka, K. ; Schroder, S. ; Schultz, C. ; Schweizer, T. ; Shore, S. N. ; Sillanpaa, A. ; Sitarek, J. ; Snidaric, I. ; Sobczynska, D. ; Stamerra, A. ; Steinbring, T. ; Strzys, M. ; Suric, T. ; Takalo, L. ; Tavecchio, F. ; Temnikov, P. ; Terzic, T. ; Tescaro, D. ; Teshima, M. ; Thaele, J. ; Torres, D. F. ; Toyama, T. ; Treves, A. ; Vanzo, G. ; Verguilov, V. ; Vovk, I. ; Ward, J. E. ; Will, M. ; Wu, M. H. ; Zanin, R. ; Abeysekara, A. U. ; Archambault, S. ; Archer, A. ; Benbow, W. ; Bird, R. ; Buchovecky, M. ; Buckley, J. H. ; Bugaev, V. ; Connolly, M. P. ; Cui, W. ; Dickinson, H. J. ; Falcone, A. ; Feng, Q. ; Finley, J. P. ; Fleischhack, H. ; Flinders, A. ; Fortson, L. ; Gillanders, G. H. ; Griffin, S. ; Grube, J. ; Huetten, M. ; Hanna, D. ; Holder, J. ; Humensky, T. B. ; Kaaret, P. ; Kar, P. ; Kelley-Hoskins, N. ; Kertzman, M. ; Kieda, D. ; Krause, M. ; Krennrich, F. ; Lang, M. J. ; Maier, G. ; McCann, A. ; Moriarty, P. ; Mukherjee, R. ; Nieto, D. ; Ong, R. A. ; Otte, N. ; Park, N. ; Perkins, J. ; Pichel, A. ; Pohl, M. ; Popkow, A. ; Pueschel, Elisa ; Quinn, J. ; Ragan, K. ; Reynolds, P. T. ; Richards, G. T. ; Roache, E. ; Rovero, A. C. ; Rulten, C. ; Sadeh, I. ; Santander, M. ; Sembroski, G. H. ; Shahinyan, K. ; Telezhinsky, Igor O. ; Tucci, J. V. ; Tyler, J. ; Wakely, S. P. ; Weinstein, A. ; Wilcox, P. ; Wilhelm, Alina ; Williams, D. A. ; Zitzer, B. ; Razzaque, S. ; Villata, M. ; Raiteri, C. M. ; Aller, H. D. ; Aller, M. F. ; Larionov, V. M. ; Arkharov, A. A. ; Blinov, D. A. ; Efimova, N. V. ; Grishina, T. S. ; Hagen-Thorn, V. A. ; Kopatskaya, E. N. ; Larionova, L. V. ; Larionova, E. G. ; Morozova, D. A. ; Troitsky, I. S. ; Ligustri, R. ; Calcidese, P. ; Berdyugin, A. ; Kurtanidze, O. M. ; Nikolashvili, M. G. ; Kimeridze, G. N. ; Sigua, L. A. ; Kurtanidze, S. O. ; Chigladze, R. A. ; Chen, W. P. ; Koptelova, E. ; Sakamoto, T. ; Sadun, A. C. ; Moody, J. W. ; Pace, C. ; Pearson, R. ; Yatsu, Y. ; Mori, Y. ; Carraminyana, A. ; Carrasco, L. ; de la Fuente, E. ; Norris, J. P. ; Smith, P. S. ; Wehrle, A. ; Gurwell, M. A. ; Zook, A. ; Pagani, C. ; Perri, M. ; Capalbi, M. ; Cesarini, A. ; Krimm, H. A. ; Kovalev, Y. Y. ; Kovalev, Yu. A. ; Ros, E. ; Pushkarev, A. B. ; Lister, M. L. ; Sokolovsky, K. V. ; Kadler, M. ; Piner, G. ; Lahteenmaki, A. ; Tornikoski, M. ; Angelakis, E. ; Krichbaum, T. P. ; Nestoras, I. ; Fuhrmann, L. ; Zensus, J. A. ; Cassaro, P. ; Orlati, A. ; Maccaferri, G. ; Leto, P. ; Giroletti, M. ; Richards, J. L. ; Max-Moerbeck, W. ; Readhead, A. C. S.
Aims. We present an extensive study of the BL Lac object Mrk 501 based on a data set collected during the multi-instrument campaign spanning from 2009 March 15 to 2009 August 1, which includes, among other instruments, MAGIC, VERITAS, Whipple 10 m, and Fermi-LAT to cover the gamma-ray range from 0.1 GeV to 20 TeV; RXTE and Swift to cover wavelengths from UV to hard X-rays; and GASP-WEBT, which provides coverage of radio and optical wavelengths. Optical polarization measurements were provided for a fraction of the campaign by the Steward and St. Petersburg observatories. We evaluate the variability of the source and interband correlations, the gamma-ray flaring activity occurring in May 2009, and interpret the results within two synchrotron self-Compton (SSC) scenarios. Methods. The multiband variability observed during the full campaign is addressed in terms of the fractional variability, and the possible correlations are studied by calculating the discrete correlation function for each pair of energy bands where the significance was evaluated with dedicated Monte Carlo simulations. The space of SSC model parameters is probed following a dedicated grid-scan strategy, allowing for a wide range of models to be tested and offering a study of the degeneracy of model-to-data agreement in the individual model parameters, hence providing a less biased interpretation than the "single-curve SSC model adjustment" typically reported in the literature. Results. We find an increase in the fractional variability with energy, while no significant interband correlations of flux changes are found on the basis of the acquired data set. The SSC model grid-scan shows that the flaring activity around May 22 cannot be modeled adequately with a one-zone SSC scenario (using an electron energy distribution with two breaks), while it can be suitably described within a two (independent) zone SSC scenario. Here, one zone is responsible for the quiescent emission from the averaged 4.5-month observing period, while the other one, which is spatially separated from the first, dominates the flaring emission occurring at X-rays and very-high-energy (> 100 GeV, VHE) gamma-rays. The flaring activity from May 1, which coincides with a rotation of the electric vector polarization angle (EVPA), cannot be satisfactorily reproduced by either a one-zone or a two-independent-zone SSC model, yet this is partially affected by the lack of strictly simultaneous observations and the presence of large flux changes on sub-hour timescales (detected at VHE gamma rays). Conclusions. The higher variability in the VHE emission and lack of correlation with the X-ray emission indicate that, at least during the 4.5-month observing campaign in 2009, the highest energy (and most variable) electrons that are responsible for the VHE gamma rays do not make a dominant contribution to the similar to 1 keV emission. Alternatively, there could be a very variable component contributing to the VHE gamma-ray emission in addition to that coming from the SSC scenario. The studies with our dedicated SSC grid-scan show that there is some degeneracy in both the one-zone and the two-zone SSC scenarios probed, with several combinations of model parameters yielding a similar model-to-data agreement, and some parameters better constrained than others. The observed gamma-ray flaring activity, with the EVPA rotation coincident with the first gamma-ray flare, resembles those reported previously for low frequency peaked blazars, hence suggesting that there are many similarities in the flaring mechanisms of blazars with different jet properties.
Abdo, A. A. ; Ackermann, Margit ; Ajello, M. ; Allafort, A. J. ; Baldini, L. ; Ballet, J. ; Barbiellini, G. ; Baring, M. G. ; Bastieri, D. ; Bechtol, K. C. ; Bellazzini, R. ; Berenji, B. ; Blandford, R. D. ; Bloom, E. D. ; Bonamente, E. ; Borgland, A. W. ; Bouvier, A. ; Brandt, T. J. ; Bregeon, Johan ; Brez, A. ; Brigida, M. ; Bruel, P. ; Buehler, R. ; Buson, S. ; Caliandro, G. A. ; Cameron, R. A. ; Cannon, A. ; Caraveo, P. A. ; Carrigan, Svenja ; Casandjian, J. M. ; Cavazzuti, E. ; Cecchi, C. ; Celik, O. ; Charles, E. ; Chekhtman, A. ; Cheung, C. C. ; Chiang, J. ; Ciprini, S. ; Claus, R. ; Cohen-Tanugi, J. ; Conrad, Jan ; Cutini, S. ; Dermer, C. D. ; de Palma, F. ; do Couto e Silva, E. ; Drell, P. S. ; Dubois, R. ; Dumora, D. ; Favuzzi, C. ; Fegan, S. J. ; Ferrara, E. C. ; Focke, W. B. ; Fortin, P. ; Frailis, M. ; Fuhrmann, L. ; Fukazawa, Y. ; Funk, S. ; Fusco, P. ; Gargano, F. ; Gasparrini, D. ; Gehrels, N. ; Germani, S. ; Giglietto, N. ; Giordano, F. ; Giroletti, M. ; Glanzman, T. ; Godfrey, G. ; Grenier, I. A. ; Guillemot, L. ; Guiriec, S. ; Hayashida, M. ; Hays, E. ; Horan, D. ; Hughes, R. E. ; Johannesson, G. ; Johnson, A. S. ; Johnson, W. N. ; Kadler, M. ; Kamae, T. ; Katagiri, H. ; Kataoka, J. ; Knoedlseder, J. ; Kuss, M. ; Lande, J. ; Latronico, L. ; Lee, S. -H. ; Lemoine-Goumard, M. ; Longo, F. ; Loparco, F. ; Lott, B. ; Lovellette, M. N. ; Lubrano, P. ; Madejski, G. M. ; Makeev, A. ; Max-Moerbeck, W. ; Mazziotta, Mario Nicola ; McEnery, J. E. ; Mehault, J. ; Michelson, P. F. ; Mitthumsiri, W. ; Mizuno, T. ; Moiseev, A. A. ; Monte, C. ; Monzani, M. E. ; Morselli, A. ; Moskalenko, I. V. ; Murgia, S. ; Naumann-Godo, M. ; Nishino, S. ; Nolan, P. L. ; Norris, J. P. ; Nuss, E. ; Ohsugi, T. ; Okumura, A. ; Omodei, N. ; Orlando, E. ; Ormes, J. F. ; Paneque, D. ; Panetta, J. H. ; Parent, D. ; Pavlidou, V. ; Pearson, T. J. ; Pelassa, V. ; Pepe, M. ; Pesce-Rollins, M. ; Piron, F. ; Porter, T. A. ; Raino, S. ; Rando, R. ; Razzano, M. ; Readhead, A. ; Reimer, A. ; Reimer, O. ; Richards, J. L. ; Ripken, J. ; Ritz, S. ; Roth, M. ; Sadrozinski, H. F. -W. ; Sanchez, D. ; Sander, A. ; Scargle, J. D. ; Sgro, C. ; Siskind, E. J. ; Smith, P. D. ; Spandre, G. ; Spinelli, P. ; Stawarz, L. ; Stevenson, M. ; Strickman, M. S. ; Sokolovsky, K. V. ; Suson, D. J. ; Takahashi, H. ; Takahashi, T. ; Tanaka, T. ; Thayer, J. B. ; Thayer, J. G. ; Thompson, D. J. ; Tibaldo, L. ; Torres, F. ; Tosti, G. ; Tramacere, A. ; Uchiyama, Y. ; Usher, T. L. ; Vandenbroucke, J. ; Vasileiou, V. ; Vilchez, N. ; Vitale, V. ; Waite, A. P. ; Wang, P. ; Wehrle, A. E. ; Winer, B. L. ; Wood, K. S. ; Yang, Z. ; Ylinen, T. ; Zensus, J. A. ; Ziegler, M. ; Aleksic, J. ; Antonelli, L. A. ; Antoranz, P. ; Backes, Michael ; Barrio, J. A. ; Gonzalez, J. Becerra ; Bednarek, W. ; Berdyugin, A. ; Berger, K. ; Bernardini, E. ; Biland, A. ; Blanch Bigas, O. ; Bock, R. K. ; Boller, A. ; Bonnoli, G. ; Bordas, Pol ; Tridon, D. Borla ; Bosch-Ramon, Valentin ; Bose, D. ; Braun, I. ; Bretz, T. ; Camara, M. ; Carmona, E. ; Carosi, A. ; Colin, P. ; Colombo, E. ; Contreras, J. L. ; Cortina, J. ; Covino, S. ; Dazzi, F. ; de Angelis, A. ; del Pozo, E. De Cea ; De Lotto, B. ; De Maria, M. ; De Sabata, F. ; Mendez, C. Delgado ; Ortega, A. Diago ; Doert, M. ; Dominguez, A. ; Prester, Dijana Dominis ; Dorner, D. ; Doro, M. ; Elsaesser, D. ; Ferenc, D. ; Fonseca, M. V. ; Font, L. ; Lopen, R. J. Garcia ; Garczarczyk, M. ; Gaug, M. ; Giavitto, G. ; Godinovi, N. ; Hadasch, D. ; Herrero, A. ; Hildebrand, D. ; Hoehne-Moench, D. ; Hose, J. ; Hrupec, D. ; Jogler, T. ; Klepser, S. ; Kraehenbuehl, T. ; Kranich, D. ; Krause, J. ; La Barbera, A. ; Leonardo, E. ; Lindfors, E. ; Lombardi, S. ; Lopez, M. ; Lorenz, E. ; Majumdar, P. ; Makariev, E. ; Maneva, G. ; Mankuzhiyil, N. ; Mannheim, K. ; Maraschi, L. ; Mariotti, M. ; Martinez, M. ; Mazin, D. ; Meucci, M. ; Miranda, J. M. ; Mirzoyan, R. ; Miyamoto, H. ; Moldon, J. ; Moralejo, A. ; Nieto, D. ; Nilsson, K. ; Orito, R. ; Oya, I. ; Paoletti, R. ; Paredes, J. M. ; Partini, S. ; Pasanen, M. ; Pauss, F. ; Pegna, R. G. ; Perez-Torres, M. A. ; Persic, M. ; Peruzzo, J. ; Pochon, J. ; Moroni, P. G. Prada ; Prada, F. ; Prandini, E. ; Puchades, N. ; Puljak, I. ; Reichardt, T. ; Reinthal, R. ; Rhode, W. ; Ribo, M. ; Rico, J. ; Rissi, M. ; Ruegamer, S. ; Saggion, A. ; Saito, K. ; Saito, T. Y. ; Salvati, M. ; Sanchez-Conde, M. ; Satalecka, K. ; Scalzotto, V. ; Scapin, V. ; Schultz, C. ; Schweizer, T. ; Shayduk, M. ; Shore, S. N. ; Sierpowska-Bartosik, A. ; Sillanpaa, A. ; Sitarek, J. ; Sobczynska, D. ; Spanier, F. ; Spiro, S. ; Stamerra, A. ; Steinke, B. ; Storz, J. ; Strah, N. ; Struebig, J. C. ; Suric, T. ; Takalo, L. O. ; Tavecchio, F. ; Temnikov, P. ; Terzic, T. ; Tescaro, D. ; Teshima, M. ; Vankov, H. ; Wagner, R. M. ; Weitzel, Q. ; Zabalza, V. ; Zandanel, F. ; Zanin, R. ; Acciari, V. A. ; Arlen, T. ; Aune, T. ; Benbow, W. ; Boltuch, D. ; Bradbury, S. M. ; Buckley, J. H. ; Bugaev, V. ; Cannon, A. ; Cesarini, A. ; Ciupik, L. ; Cui, W. ; Dickherber, R. ; Errando, M. ; Falcone, A. ; Finley, J. P. ; Finnegan, G. ; Fortson, L. ; Furniss, A. ; Galante, N. ; Gall, D. ; Gillanders, G. H. ; Godambe, S. ; Grube, J. ; Guenette, R. ; Gyuk, G. ; Hanna, D. ; Holder, J. ; Huang, D. ; Hui, C. M. ; Humensky, T. B. ; Kaaret, P. ; Karlsson, N. ; Kertzman, M. ; Kieda, D. ; Konopelko, A. ; Krawczynski, H. ; Krennrich, F. ; Lang, M. J. ; Maier, G. ; McArthur, S. ; McCann, A. ; McCutcheon, M. ; Moriarty, P. ; Mukherjee, R. ; Ong, R. ; Otte, N. ; Pandel, D. ; Perkins, J. S. ; Pichel, A. ; Pohl, M. ; Quinn, J. ; Ragan, K. ; Reyes, L. C. ; Reynolds, P. T. ; Roache, E. ; Rose, H. J. ; Rovero, A. C. ; Schroedter, M. ; Sembroski, G. H. ; Senturk, G. D. ; Steele, D. ; Swordy, S. P. ; Tesic, G. ; Theiling, M. ; Thibadeau, S. ; Varlotta, A. ; Vincent, S. ; Wakely, S. P. ; Ward, J. E. ; Weekes, T. C. ; Weinstein, A. ; Weisgarber, T. ; Williams, D. A. ; Wood, M. ; Zitzer, B. ; Villata, M. ; Raiteri, C. M. ; Aller, H. D. ; Aller, M. F. ; Arkharov, A. A. ; Blinov, D. A. ; Calcidese, P. ; Chen, W. P. ; Efimova, N. V. ; Kimeridze, G. ; Konstantinova, T. S. ; Kopatskaya, E. N. ; Koptelova, E. ; Kurtanidze, O. M. ; Kurtanidze, S. O. ; Lahteenmaki, A. ; Larionov, V. M. ; Larionova, E. G. ; Larionova, L. V. ; Ligustri, R. ; Morozova, D. A. ; Nikolashvili, M. G. ; Sigua, L. A. ; Troitsky, I. S. ; Angelakis, E. ; Capalbi, M. ; Carraminana, A. ; Carrasco, L. ; Cassaro, P. ; de la Fuente, E. ; Gurwell, M. A. ; Kovalev, Y. Y. ; Kovalev, Yu. A. ; Krichbaum, T. P. ; Krimm, H. A. ; Leto, Paolo ; Lister, M. L. ; Maccaferri, G. ; Moody, J. W. ; Mori, Y. ; Nestoras, I. ; Orlati, A. ; Pagani, C. ; Pace, C. ; Pearson, R. ; Perri, M. ; Piner, B. G. ; Pushkarev, A. B. ; Ros, E. ; Sadun, A. C. ; Sakamoto, T. ; Tornikoski, M. ; Yatsu, Y. ; Zook, A.
We report on the gamma-ray activity of the blazar Mrk 501 during the first 480 days of Fermi operation. We find that the average Large Area Telescope (LAT) gamma-ray spectrum of Mrk 501 can be well described by a single power-law function with a photon index of 1.78 +/- 0.03. While we observe relatively mild flux variations with the Fermi-LAT (within less than a factor of two), we detect remarkable spectral variability where the hardest observed spectral index within the LAT energy range is 1.52 +/- 0.14, and the softest one is 2.51 +/- 0.20. These unexpected spectral changes do not correlate with the measured flux variations above 0.3 GeV. In this paper, we also present the first results from the 4.5 month long multifrequency campaign (2009 March 15-August 1) on Mrk 501, which included the Very Long Baseline Array (VLBA), Swift, RXTE, MAGIC, and VERITAS, the F-GAMMA, GASP-WEBT, and other collaborations and instruments which provided excellent temporal and energy coverage of the source throughout the entire campaign. The extensive radio to TeV data set from this campaign provides us with the most detailed spectral energy distribution yet collected for this source during its relatively low activity. The average spectral energy distribution of Mrk 501 is well described by the standard one-zone synchrotron self-Compton (SSC) model. In the framework of this model, we find that the dominant emission region is characterized by a size less than or similar to 0.1 pc (comparable within a factor of few to the size of the partially resolved VLBA core at 15-43 GHz), and that the total jet power (similar or equal to 10(44) erg s(-1)) constitutes only a small fraction (similar to 10(-3)) of the Eddington luminosity. The energy distribution of the freshly accelerated radiating electrons required to fit the time-averaged data has a broken power-law form in the energy range 0.3 GeV-10 TeV, with spectral indices 2.2 and 2.7 below and above the break energy of 20 GeV. We argue that such a form is consistent with a scenario in which the bulk of the energy dissipation within the dominant emission zone of Mrk 501 is due to relativistic, proton-mediated shocks. We find that the ultrarelativistic electrons and mildly relativistic protons within the blazar zone, if comparable in number, are in approximate energy equipartition, with their energy dominating the jet magnetic field energy by about two orders of magnitude.
Furniss, A. ; Noda, K. ; Boggs, S. ; Chiang, J. ; Christensen, F. ; Craig, W. ; Giommi, P. ; Hailey, C. ; Harisson, F. ; Madejski, G. ; Nalewajko, K. ; Perri, M. ; Stern, D. ; Urry, M. ; Verrecchia, F. ; Zhang, W. ; Ahnen, M. L. ; Ansoldi, S. ; Antonelli, L. A. ; Antoranz, P. ; Babic, A. ; Banerjee, B. ; Bangale, P. ; de Almeida, U. Barres ; Barrio, J. A. ; Becerra Gonzalez, J. ; Bednarek, W. ; Bernardini, E. ; Biasuzzi, B. ; Biland, A. ; Blanch Bigas, O. ; Bonnefoy, S. ; Bonnoli, G. ; Borracci, F. ; Bretz, T. ; Carmona, E. ; Carosi, A. ; Chatterjee, A. ; Clavero, R. ; Colin, P. ; Colombo, E. ; Contreras, J. L. ; Cortina, J. ; Covino, S. ; Da Vela, P. ; Dazzi, F. ; De Angelis, A. ; De Caneva, G. ; De Lotto, B. ; de Ona Wilhelmi, E. ; Delgado Mendez, C. ; Di Pierro, F. ; Prester, Dijana Dominis ; Dorner, D. ; Doro, M. ; Einecke, S. ; Eisenacher Glawion, D. ; Elsaesser, D. ; Fernandez-Barral, A. ; Fidalgo, D. ; Fonseca, M. V. ; Font, L. ; Frantzen, K. ; Fruck, C. ; Galindo, D. ; Garcia Lopez, R. J. ; Garczarczyk, M. ; Garrido Terrats, D. ; Gaug, M. ; Giammaria, P. ; Godinovic, N. ; Gonzalez Munoz, A. ; Guberman, D. ; Hanabata, Y. ; Hayashida, M. ; Herrera, J. ; Hose, J. ; Hrupec, D. ; Hughes, G. ; Idec, W. ; Kellermann, H. ; Kodani, K. ; Konno, Y. ; Kubo, H. ; Kushida, J. ; La Barbera, A. ; Lelas, D. ; Lewandowska, N. ; Lindfors, E. ; Lombardi, S. ; Longo, F. ; Lopez, M. ; Lopez-Coto, R. ; Lopez-Oramas, A. ; Lorenz, E. ; Majumdar, P. ; Makariev, M. ; Mallot, K. ; Maneva, G. ; Manganaro, M. ; Mannheim, K. ; Maraschi, L. ; Marcote, B. ; Mariotti, M. ; Martinez, M. ; Mazin, D. ; Menzel, U. ; Miranda, J. M. ; Mirzoyan, R. ; Moralejo, A. ; Nakajima, D. ; Neustroev, V. ; Niedzwiecki, A. ; Nievas Rosillo, M. ; Nilsson, K. ; Nishijima, K. ; Orito, R. ; Overkemping, A. ; Paiano, S. ; Palacio, J. ; Palatiello, M. ; Paneque, D. ; Paoletti, R. ; Paredes, J. M. ; Paredes-Fortuny, X. ; Persic, M. ; Poutanen, J. ; Moroni, P. G. Prada ; Prandini, E. ; Puljak, I. ; Reinthal, R. ; Rhode, W. ; Ribo, M. ; Rico, J. ; Garcia, J. Rodriguez ; Saito, T. ; Saito, K. ; Satalecka, K. ; Scapin, V. ; Schultz, C. ; Schweizer, T. ; Shore, S. N. ; Sillanpaa, A. ; Sitarek, J. ; Snidaric, I. ; Sobczynska, D. ; Stamerra, A. ; Steinbring, T. ; Strzys, M. ; Takalo, L. ; Takami, H. ; Tavecchio, F. ; Temnikov, P. ; Terzic, T. ; Tescaro, D. ; Teshima, M. ; Thaele, J. ; Torres, D. F. ; Toyama, T. ; Treves, A. ; Verguilov, V. ; Vovk, I. ; Will, M. ; Zanin, R. ; Archer, A. ; Benbow, W. ; Bird, R. ; Biteau, Jonathan ; Bugaev, V. ; Cardenzana, J. V. ; Cerruti, M. ; Chen, Xuhui ; Ciupik, L. ; Connolly, M. P. ; Cui, W. ; Dickinson, H. J. ; Dumm, J. ; Eisch, J. D. ; Falcone, A. ; Feng, Q. ; Finley, J. P. ; Fleischhack, H. ; Fortin, P. ; Fortson, L. ; Gerard, L. ; Gillanders, G. H. ; Griffin, S. ; Griffiths, S. T. ; Grube, J. ; Gyuk, G. ; Hakansson, Nils ; Holder, J. ; Humensky, T. B. ; Johnson, C. A. ; Kaaret, P. ; Kertzman, M. ; Kieda, D. ; Krause, M. ; Krennrich, F. ; Lang, M. J. ; Lin, T. T. Y. ; Maier, G. ; McArthur, S. ; McCann, A. ; Meagher, K. ; Moriarty, P. ; Mukherjee, R. ; Nieto, D. ; Ong, R. A. ; Park, N. ; Petry, D. ; Pohl, Martin ; Popkow, A. ; Ragan, K. ; Ratliff, G. ; Reyes, L. C. ; Reynolds, P. T. ; Richards, G. T. ; Roache, E. ; Santander, M. ; Sembroski, G. H. ; Shahinyan, K. ; Staszak, D. ; Telezhinsky, Igor O. ; Tucci, J. V. ; Tyler, J. ; Vassiliev, V. V. ; Wakely, S. P. ; Weiner, O. M. ; Weinstein, A. ; Wilhelm, Alina ; Williams, D. A. ; Zitzer, B. ; Vince, O. ; Fuhrmann, L. ; Angelakis, E. ; Karamanavis, V. ; Myserlis, I. ; Krichbaum, T. P. ; Zensus, J. A. ; Ungerechts, H. ; Sievers, A. ; Bachev, R. ; Boettcher, Markus ; Chen, W. P. ; Damljanovic, G. ; Eswaraiah, C. ; Guver, T. ; Hovatta, T. ; Hughes, Z. ; Ibryamov, S. I. ; Joner, M. D. ; Jordan, B. ; Jorstad, S. G. ; Joshi, M. ; Kataoka, J. ; Kurtanidze, O. M. ; Kurtanidze, S. O. ; Lahteenmaki, A. ; Latev, G. ; Lin, H. C. ; Larionov, V. M. ; Mokrushina, A. A. ; Morozova, D. A. ; Nikolashvili, M. G. ; Raiteri, C. M. ; Ramakrishnan, V. ; Readhead, A. C. R. ; Sadun, A. C. ; Sigua, L. A. ; Semkov, E. H. ; Strigachev, A. ; Tammi, J. ; Tornikoski, M. ; Troitskaya, Y. V. ; Troitsky, I. S. ; Villata, M.
We report on simultaneous broadband observations of the TeV-emitting blazar Markarian 501 between 2013 April 1 and August 10, including the first detailed characterization of the synchrotron peak with Swift and NuSTAR. During the campaign, the nearby BL Lac object was observed in both a quiescent and an elevated state. The broadband campaign includes observations with NuSTAR, MAGIC, VERITAS, the Fermi Large Area Telescope, Swift X-ray Telescope and UV Optical Telescope, various ground-based optical instruments, including the GASP-WEBT program, as well as radio observations by OVRO, Metsahovi, and the F-Gamma consortium. Some of the MAGIC observations were affected by a sand layer from the Saharan desert, and had to be corrected using event-by-event corrections derived with a Light Detection and Ranging (LIDAR) facility. This is the first time that LIDAR information is used to produce a physics result with Cherenkov Telescope data taken during adverse atmospheric conditions, and hence sets a precedent for the current and future ground-based gamma-ray instruments. The NuSTAR instrument provides unprecedented sensitivity in hard X-rays, showing the source to display a spectral energy distribution (SED) between 3 and 79 keV consistent with a log-parabolic spectrum and hard X-ray variability on hour timescales. None (of the four extended NuSTAR observations) show evidence of the onset of inverse-Compton emission at hard X-ray energies. We apply a single-zone equilibrium synchrotron self-Compton (SSC) model to five simultaneous broadband SEDs. We find that the SSC model can reproduce the observed broadband states through a decrease in the magnetic field strength coinciding with an increase in the luminosity and hardness of the relativistic leptons responsible for the high-energy emission.
Ahnen, M. L. ; Ansoldi, S. ; Antonelli, L. A. ; Arcaro, C. ; Babic, A. ; Banerjee, B. ; Bangale, P. ; Barres de Almeida, U. ; Barrio, J. A. ; Gonzalez, J. Becerra ; Bednarek, W. ; Bernardini, E. ; Berti, A. ; Bhattacharyya, W. ; Blanch, O. ; Bonnoli, G. ; Carosi, R. ; Carosi, A. ; 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, M. ; Delgado, Jose Miguel Martins ; Di Pierro, F. ; Doert, M. ; Dominguez, A. ; Prester, D. Dominis ; Doro, M. ; Glawion, D. Eisenacher ; Engelkemeier, M. ; Ramazani, V. Fallah ; Fernandez-Barral, A. ; Fidalgo, D. ; Fonseca, M. V. ; Font, L. ; Fruck, C. ; Galindo, D. ; Lopez, R. J. Garcia ; 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. ; Kuvezdic, D. ; Lelas, D. ; Lindfors, E. ; Lombardi, S. ; Longo, F. ; Lopez, M. ; Maggio, C. ; Majumdar, P. ; Makariev, M. ; Maneva, G. ; Manganaro, M. ; Maraschi, L. ; Mariotti, M. ; Martinez, M. ; Mazin, D. ; Menzel, U. ; 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. ; Perri, L. ; Persic, M. ; Moroni, P. G. Prada ; Prandini, E. ; Puljak, I. ; Garcia, J. R. ; Reichardt, I. ; Ribo, M. ; Rico, J. ; Righi, C. ; Rugliancich, A. ; Saito, T. ; Satalecka, K. ; Schroeder, S. ; Schweizer, T. ; Shore, S. N. ; Sitarek, J. ; Snidaric, I. ; Sobczynska, D. ; Stamerra, A. ; Strzys, M. ; Suric, T. ; Takalo, L. ; Tavecchio, F. ; Temnikov, P. ; Terzic, T. ; Teshima, M. ; Torres-Alba, N. ; Treves, A. ; Tsujimoto, S. ; Vanzo, G. ; Vazquez Acosta, M. ; Vovk, I. ; Ward, J. E. ; Will, M. ; Zaric, D. ; Arbet-Engels, A. ; Baack, D. ; Balbo, M. ; Biland, A. ; Blank, M. ; Bretz, T. ; Bruegge, K. ; Bulinski, M. ; Buss, J. ; Dmytriiev, A. ; Dorner, D. ; Einecke, S. ; Elsaesser, D. ; Herbst, T. ; Hildebrand, D. ; Kortmann, L. ; Linhoff, L. ; Mahlke, M. ; Mannheim, K. ; Mueller, S. A. ; Neise, D. ; Neronov, A. ; Noethe, M. ; Oberkirch, J. ; Paravac, A. ; Rhode, W. ; Schleicher, B. ; Schulz, F. ; Sedlaczek, K. ; Shukla, A. ; Sliusar, V. ; Walter, R. ; Archer, A. ; Benbow, W. ; Bird, R. ; Brose, Robert ; Buckley, J. H. ; Bugaev, V. ; Christiansen, J. L. ; Cui, W. ; Daniel, M. K. ; Falcone, A. ; Feng, Q. ; Finley, J. P. ; Gillanders, G. H. ; Gueta, O. ; Hanna, D. ; Hervet, O. ; Holder, J. ; Hughes, G. ; Huetten, M. ; Humensky, T. B. ; Johnson, C. A. ; Kaaret, P. ; Kar, P. ; Kelley-Hoskins, N. ; Kertzman, M. ; Kieda, D. ; Krause, M. ; Krennrich, F. ; Kumar, S. ; Lang, M. J. ; Lin, T. T. Y. ; Maier, G. ; McArthur, S. ; Moriarty, P. ; Mukherjee, R. ; Ong, R. A. ; Otte, A. N. ; Park, N. ; Petrashyk, A. ; Pichel, A. ; Pohl, Martin ; Quinn, J. ; Ragan, K. ; Reynolds, P. T. ; Richards, G. T. ; Roache, E. ; Rovero, A. C. ; Rulten, C. ; Sadeh, I. ; Santander, M. ; Sembroski, G. H. ; Shahinyan, K. ; Sushch, Iurii ; Tyler, J. ; Wakely, S. P. ; Weinstein, A. ; Wells, R. M. ; Wilcox, P. ; Wilhel, A. ; Williams, D. A. ; Williamson, T. J. ; Zitzer, B. ; Perri, M. ; Verrecchia, F. ; Leto, C. ; Villata, M. ; Raiteri, C. M. ; Jorstad, S. G. ; Larionov, V. M. ; Blinov, D. A. ; Grishina, T. S. ; Kopatskaya, E. N. ; Larionova, E. G. ; Nikiforova, A. A. ; Morozova, D. A. ; Troitskaya, Yu. V. ; Troitsky, I. S. ; Kurtanidze, O. M. ; Nikolashvili, M. G. ; Kurtanidze, S. O. ; Kimeridze, G. N. ; Chigladze, R. A. ; Strigachev, A. ; Sadun, A. C.
Aims. We aim to characterize the multiwavelength emission from Markarian 501 (Mrk 501), quantify the energy-dependent variability, study the potential multiband correlations, and describe the temporal evolution of the broadband emission within leptonic theoretical scenarios. Methods. We organized a multiwavelength campaign to take place between March and July of 2012. Excellent temporal coverage was obtained with more than 25 instruments, including the MAGIC, FACT and VERITAS Cherenkov telescopes, the instruments on board the Swift and Fermi spacecraft, and the telescopes operated by the GASP-WEBT collaboration. Results. Mrk 501 showed a very high energy (VHE) gamma-ray flux above 0.2 TeV of similar to 0.5 times the Crab Nebula flux (CU) for most of the campaign. The highest activity occurred on 2012 June 9, when the VHE flux was similar to 3 CU, and the peak of the high-energy spectral component was found to be at similar to 2 TeV. Both the X-ray and VHE gamma-ray spectral slopes were measured to be extremely hard, with spectral indices <2 during most of the observing campaign, regardless of the X-ray and VHE flux. This study reports the hardest Mrk 501 VHE spectra measured to date. The fractional variability was found to increase with energy, with the highest variability occurring at VHE. Using the complete data set, we found correlation between the X-ray and VHE bands; however, if the June 9 flare is excluded, the correlation disappears (significance <3 sigma) despite the existence of substantial variability in the X-ray and VHE bands throughout the campaign. Conclusions. The unprecedentedly hard X-ray and VHE spectra measured imply that their low- and high-energy components peaked above 5 keV and 0.5 TeV, respectively, during a large fraction of the observing campaign, and hence that Mrk 501 behaved like an extreme high-frequency-peaked blazar (EHBL) throughout the 2012 observing season. This suggests that being an EHBL may not be a permanent characteristic of a blazar, but rather a state which may change over time. The data set acquired shows that the broadband spectral energy distribution (SED) of Mrk 501, and its transient evolution, is very complex, requiring, within the framework of synchrotron self-Compton (SSC) models, various emission regions for a satisfactory description. Nevertheless the one-zone SSC scenario can successfully describe the segments of the SED where most energy is emitted, with a significant correlation between the electron energy density and the VHE gamma-ray activity, suggesting that most of the variability may be explained by the injection of high-energy electrons. The one-zone SSC scenario used reproduces the behavior seen between the measured X-ray and VHE gamma-ray fluxes, and predicts that the correlation becomes stronger with increasing energy of the X-rays.