@article {2011ApJ...736..131A, title = {{Fermi Large Area Telescope Observations of Markarian 421: The Missing Piece of its Spectral Energy Distribution}}, journal = {The Astrophysical Journal}, volume = {736}, year = {2011}, month = {aug}, pages = {131}, abstract = {We report on the {$\gamma$}-ray activity of the high-synchrotron-peaked BL Lacertae object Markarian 421 (Mrk 421) during the first 1.5 years of Fermi operation, from 2008 August 5 to 2010 March 12. We find that the Large Area Telescope (LAT) {$\gamma$}-ray spectrum above 0.3 GeV can be well described by a power-law function with photon index {$\Gamma$} = 1.78 {\plusmn} 0.02 and average photon flux F({\gt} 0.3 GeV) = (7.23 {\plusmn} 0.16) {\times} 10$^{-8}$ ph cm$^{-2}$ s$^{-1}$. Over this time period, the Fermi-LAT spectrum above 0.3 GeV was evaluated on seven-day-long time intervals, showing significant variations in the photon flux (up to a factor \~{}3 from the minimum to the maximum flux) but mild spectral variations. The variability amplitude at X-ray frequencies measured by RXTE/ASM and Swift/BAT is substantially larger than that in {$\gamma$}-rays measured by Fermi-LAT, and these two energy ranges are not significantly correlated. We also present the first results from the 4.5 month long multifrequency campaign on Mrk 421, which included the VLBA, Swift, RXTE, MAGIC, the F-GAMMA, GASP-WEBT, and other collaborations and instruments that provided excellent temporal and energy coverage of the source throughout the entire campaign (2009 January 19 to 2009 June 1). During this campaign, Mrk 421 showed a low activity at all wavebands. The extensive multi-instrument (radio to TeV) data set provides an unprecedented, complete look at the quiescent spectral energy distribution (SED) for this source. The broadband SED was reproduced with a leptonic (one-zone synchrotron self-Compton) and a hadronic model (synchrotron proton blazar). Both frameworks are able to describe the average SED reasonably well, implying comparable jet powers but very different characteristics for the blazar emission site.}, keywords = {acceleration of particles, BL Lacertae objects: general, BL Lacertae objects: individual: Mrk 421, galaxies: active, gamma rays: general, radiation mechanisms: non-thermal}, doi = {10.1088/0004-637X/736/2/131}, url = {http://adsabs.harvard.edu/abs/2011ApJ...736..131A}, author = {Abdo, A.~A. and Ackermann, M. and Ajello, M. and Baldini, L. and Ballet, J. and Barbiellini, G. and Bastieri, D. and Bechtol, K. and Bellazzini, R. and Berenji, B. and Blandford, R.~D. and Bloom, E.~D. and Bonamente, E. and Borgland, A.~W. and Bouvier, A. and Bregeon, J. and Brez, A. and Brigida, M. and Bruel, P. and Buehler, R. and Buson, S. and Caliandro, G.~A. and Cameron, R.~A. and Cannon, A. and Caraveo, P.~A. and Carrigan, S. and Casandjian, J.~M. and Cavazzuti, E. and Cecchi, C. and {\c C}elik, {\"O}. and Charles, E. and Chekhtman, A. and Chiang, J. and Ciprini, S. and Claus, R. and Cohen-Tanugi, J. and Conrad, J. and Cutini, S. and De Angelis, A. and de Palma, F. and Dermer, C.~D. and Silva, E.~d.~C.~e. and Drell, P.~S. and Dubois, R. and Dumora, D. and Escande, L. and Favuzzi, C. and Fegan, S.~J. and Finke, J. and Focke, W.~B. and Fortin, P. and Frailis, M. and Fuhrmann, L. and Fukazawa, Y. and Fukuyama, T. and Funk, S. and Fusco, P. and Gargano, F. and Gasparrini, D. and Gehrels, N. and Georganopoulos, M. and Germani, S. and Giebels, B. and Giglietto, N. and Giommi, P. and Giordano, F. and Giroletti, M. and Glanzman, T. and Godfrey, G. and Grenier, I.~A. and Guiriec, S. and Hadasch, D. and Hayashida, M. and Hays, E. and Horan, D. and Hughes, R.~E. and J{\'o}hannesson, G. and Johnson, A.~S. and Johnson, W.~N. and Kadler, M. and Kamae, T. and Katagiri, H. and Kataoka, J. and Kn{\"o}dlseder, J. and Kuss, M. and Lande, J. and Latronico, L. and Lee, S.-H. and Longo, F. and Loparco, F. and Lott, B. and Lovellette, M.~N. and Lubrano, P. and Madejski, G.~M. and Makeev, A. and Max-Moerbeck, W. and Mazziotta, M.~N. and McEnery, J.~E. and M{\'e}hault, J. and Michelson, P.~F. and Mitthumsiri, W. and Mizuno, T. and Monte, C. and Monzani, M.~E. and Morselli, A. and Moskalenko, I.~V. and Murgia, S. and Nakamori, T. and Naumann-Godo, M. and Nishino, S. and Nolan, P.~L. and Norris, J.~P. and Nuss, E. and Ohsugi, T. and Okumura, A. and Omodei, N. and Orlando, E. and Ormes, J.~F. and Ozaki, M. and Paneque, D. and Panetta, J.~H. and Parent, D. and Pavlidou, V. and Pearson, T.~J. and Pelassa, V. and Pepe, M. and Pesce-Rollins, M. and Pierbattista, M. and Piron, F. and Porter, T.~A. and Rain{\`o}, S. and Rando, R. and Razzano, M. and Readhead, A. and Reimer, A. and Reimer, O. and Reyes, L.~C. and Richards, J.~L. and Ritz, S. and Roth, M. and Sadrozinski, H.~F.-W. and Sanchez, D. and Sander, A. and Sgr{\`o}, C. and Siskind, E.~J. and Smith, P.~D. and Spandre, G. and Spinelli, P. and Stawarz, {\L}. and Stevenson, M. and Strickman, M.~S. and Suson, D.~J. and Takahashi, H. and Takahashi, T. and Tanaka, T. and Thayer, J.~G. and Thayer, J.~B. and Thompson, D.~J. and Tibaldo, L. and Torres, D.~F. and Tosti, G. and Tramacere, A. and Troja, E. and Usher, T.~L. and Vandenbroucke, J. and Vasileiou, V. and Vianello, G. and Vilchez, N. and Vitale, V. and Waite, A.~P. and Wang, P. and Wehrle, A.~E. and Winer, B.~L. and Wood, K.~S. and Yang, Z. and Yatsu, Y. and Ylinen, T. and Zensus, J.~A. and Ziegler, M. and Fermi LAT Collaboration and Aleksi{\'c}, J. and Antonelli, L.~A. and Antoranz, P. and Backes, M. and Barrio, J.~A. and Becerra Gonz{\'a}lez, J. and Bednarek, W. and Berdyugin, A. and Berger, K. and Bernardini, E. and Biland, A. and Blanch, O. and Bock, R.~K. and Boller, A. and Bonnoli, G. and Bordas, P. and Borla Tridon, D. and Bosch-Ramon, V. and Bose, D. and Braun, I. and Bretz, T. and Camara, M. and Carmona, E. and Carosi, A. and Colin, P. and Colombo, E. and Contreras, J.~L. and Cortina, J. and Covino, S. and Dazzi, F. and De Angelis, A. and De Cea del Pozo, E. and Delgado Mendez, C. and De Lotto, B. and De Maria, M. and De Sabata, F. and Diago Ortega, A. and Doert, M. and Dom{\'\i}nguez, A. and Dominis Prester, D. and Dorner, D. and Doro, M. and Elsaesser, D. and Ferenc, D. and Fonseca, M.~V. and Font, L. and Garc{\'\i}a L{\'o}pez, R.~J. and Garczarczyk, M. and Gaug, M. and Giavitto, G. and Godinovi, N. and Hadasch, D. and Herrero, A. and Hildebrand, D. and H{\"o}hne-M{\"o}nch, D. and Hose, J. and Hrupec, D. and Jogler, T. and Klepser, S. and Kr{\"a}henb{\"u}hl, T. and Kranich, D. and Krause, J. and La Barbera, A. and Leonardo, E. and Lindfors, E. and Lombardi, S. and L{\'o}pez, M. and Lorenz, E. and Majumdar, P. and Makariev, E. and Maneva, G. and Mankuzhiyil, N. and Mannheim, K. and Maraschi, L. and Mariotti, M. and Mart{\'\i}nez, M. and Mazin, D. and Meucci, M. and Miranda, J.~M. and Mirzoyan, R. and Miyamoto, H. and Mold{\'o}n, J. and Moralejo, A. and Nieto, D. and Nilsson, K. and Orito, R. and Oya, I. and Paoletti, R. and Paredes, J.~M. and Partini, S. and Pasanen, M. and Pauss, F. and Pegna, R.~G. and M. A. P{\'e}rez-Torres and Persic, M. and Peruzzo, J. and Pochon, J. and Prada, F. and Prada Moroni, P.~G. and Prandini, E. and Puchades, N. and Puljak, I. and Reichardt, T. and Rhode, W. and Rib{\'o}, M. and Rico, J. and Rissi, M. and R{\"u}gamer, S. and Saggion, A. and Saito, K. and Saito, T.~Y. and Salvati, M. and S{\'a}nchez-Conde, M. and Satalecka, K. and Scalzotto, V. and Scapin, V. and Schultz, C. and Schweizer, T. and Shayduk, M. and Shore, S.~N. and Sierpowska-Bartosik, A. and Sillanp{\"a}{\"a}, A. and Sitarek, J. and Sobczynska, D. and Spanier, F. and Spiro, S. and Stamerra, A. and Steinke, B. and Storz, J. and Strah, N. and Struebig, J.~C. and Suri{\'c}, T. and Takalo, L.~O. and Tavecchio, F. and Temnikov, P. and Terzi{\'c}, T. and Tescaro, D. and Teshima, M. and Vankov, H. and Wagner, R.~M. and Weitzel, Q. and Zabalza, V. and Zandanel, F. and Zanin, R. and MAGIC Collaboration and Villata, M. and Raiteri, C. and Aller, H.~D. and Aller, M.~F. and Chen, W.~P. and Jordan, B. and Koptelova, E. and Kurtanidze, O.~M. and L{\"a}hteenm{\"a}ki, A. and McBreen, B. and Larionov, V.~M. and Lin, C.~S. and Nikolashvili, M.~G. and Reinthal, R. and Angelakis, E. and Capalbi, M. and Carrami{\~n}ana, A. and Carrasco, L. and Cassaro, P. and Cesarini, A. and Falcone, A. and Gurwell, M.~A. and Hovatta, T. and Kovalev, Y.~A. and Kovalev, Y.~Y. and Krichbaum, T.~P. and Krimm, H.~A. and Lister, M.~L. and Moody, J.~W. and Maccaferri, G. and Mori, Y. and Nestoras, I. and Orlati, A. and Pace, C. and Pagani, C. and Pearson, R. and Perri, M. and Piner, B.~G. and Ros, E. and Sadun, A.~C. and Sakamoto, T. and Tammi, J. and Zook, A.} } @article {2011ApJ...729..115A, title = {{Gamma-ray Excess from a Stacked Sample of High- and Intermediate-frequency Peaked Blazars Observed with the MAGIC Telescope}}, journal = {The Astrophysical Journal}, volume = {729}, year = {2011}, month = {mar}, pages = {115}, abstract = {Between 2004 and 2009, a sample of 28 X-ray selected high- and intermediate-frequency peaked blazars with an X-ray flux larger than 2 {$μ$}Jy at 1 keV in the redshift range from 0.018 to 0.361 was observed with the MAGIC telescope at energies above 100 GeV. Seven among them were detected and the results of these observations are discussed elsewhere. Here we concentrate on the remaining 21 blazars which were not detected during this observation campaign and present the 3{$\sigma$} (99.7\%) confidence upper limits on their flux. The individual flux upper limits lie between 1.6\% and 13.6\% of the integral flux from the Crab Nebula. Applying a stacking method to the sample of non-detections with a total of 394.1 hr exposure time, we find evidence for an excess with a cumulative significance of 4.9 standard deviations. It is not dominated by individual objects or flares, but increases linearly with the observation time as for a constant source with an integral flux level of \~{}1.5\% of that observed from the Crab Nebula above 150 GeV.}, keywords = {BL Lacertae objects: general, gamma rays: galaxies}, doi = {10.1088/0004-637X/729/2/115}, url = {http://adsabs.harvard.edu/abs/2011ApJ...729..115A}, author = {Aleksi{\'c}, J. and Antonelli, L.~A. and Antoranz, P. and Backes, M. and Baixeras, C. and Barrio, J.~A. and Bastieri, D. and Becerra Gonz{\'a}lez, J. and Bednarek, W. and Berdyugin, A. and Berger, K. and Bernardini, E. and Biland, A. and Blanch, O. and Bock, R.~K. and Bonnoli, G. and Bordas, P. and Borla Tridon, D. and Bosch-Ramon, V. and Bose, D. and Braun, I. and Bretz, T. and Britzger, D. and Camara, M. and Carmona, E. and Carosi, A. and Colin, P. and Commichau, S. and Contreras, J.~L. and Cortina, J. and Costado, M.~T. and Covino, S. and Dazzi, F. and De Angelis, A. and De Cea del Pozo, E. and de los Reyes, R. and De Lotto, B. and De Maria, M. and De Sabata, F. and Delgado Mendez, C. and Doert, M. and Dom{\'\i}nguez, A. and Dominis Prester, D. and Dorner, D. and Doro, M. and Elsaesser, D. and Errando, M. and Ferenc, D. and Fonseca, M.~V. and Font, L. and Garc{\'\i}a L{\'o}pez, R.~J. and Garczarczyk, M. and Gaug, M. and Godinovi{\'c}, N. and Hadasch, D. and Herrero, A. and Hildebrand, D. and H{\"o}hne-M{\"o}nch, D. and Hose, J. and Hrupec, D. and Hsu, C.~C. and Jogler, T. and Klepser, S. and Kr{\"a}henb{\"u}hl, T. and Kranich, D. and La Barbera, A. and Laille, A. and Leonardo, E. and Lindfors, E. and Lombardi, S. and Longo, F. and L{\'o}pez, M. and Lorenz, E. and Majumdar, P. and Maneva, G. and Mankuzhiyil, N. and Mannheim, K. and Maraschi, L. and Mariotti, M. and Mart{\'\i}nez, M. and Mazin, D. and Meucci, M. and Miranda, J.~M. and Mirzoyan, R. and Miyamoto, H. and Mold{\'o}n, J. and Moles, M. and Moralejo, A. and Nieto, D. and Nilsson, K. and Ninkovic, J. and Orito, R. and Oya, I. and Paiano, S. and Paoletti, R. and Paredes, J.~M. and Partini, S. and Pasanen, M. and Pascoli, D. and Pauss, F. and Pegna, R.~G. and M. A. P{\'e}rez-Torres and Persic, M. and Peruzzo, L. and Prada, F. and Prandini, E. and Puchades, N. and Puljak, I. and Reichardt, I. and Rhode, W. and Rib{\'o}, M. and Rico, J. and Rissi, M. and R{\"u}gamer, S. and Saggion, A. and Saito, T.~Y. and Salvati, M. and S{\'a}nchez-Conde, M. and Satalecka, K. and Scalzotto, V. and Scapin, V. and Schultz, C. and Schweizer, T. and Shayduk, M. and Shore, S.~N. and Sierpowska-Bartosik, A. and Sillanp{\"a}{\"a}, A. and Sitarek, J. and Sobczynska, D. and Spanier, F. and Spiro, S. and Stamerra, A. and Steinke, B. and Struebig, J.~C. and Suri{\'c}, T. and Takalo, L. and Tavecchio, F. and Temnikov, P. and Terzi{\'c}, T. and Tescaro, D. and Teshima, M. and Tibolla, O. and Torres, D.~F. and Vankov, H. and Wagner, R.~M. and Weitzel, Q. and Zabalza, V. and Zandanel, F. and Zanin, R.} } @article {2011ApJ...727..129A, title = {{Insights into the High-energy {$\gamma$}-ray Emission of Markarian 501 from Extensive Multifrequency Observations in the Fermi Era}}, journal = {The Astrophysical Journal}, volume = {727}, year = {2011}, month = {feb}, pages = {129}, abstract = {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 {\plusmn} 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 {\plusmn} 0.14, and the softest one is 2.51 {\plusmn} 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{\mdash}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 lsim0.1 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 (sime10$^{44}$ erg s$^{-1}$) constitutes only a small fraction (\~{}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.}, keywords = {acceleration of particles, BL Lacertae objects: general, BL Lacertae objects: individual: Mrk 501, galaxies: active, gamma rays: general, radiation mechanisms: non-thermal}, doi = {10.1088/0004-637X/727/2/129}, url = {http://adsabs.harvard.edu/abs/2011ApJ...727..129A}, author = {Abdo, A.~A. and Ackermann, M. and Ajello, M. and Allafort, A. and Baldini, L. and Ballet, J. and Barbiellini, G. and Baring, M.~G. and Bastieri, D. and Bechtol, K. and Bellazzini, R. and Berenji, B. and Blandford, R.~D. and Bloom, E.~D. and Bonamente, E. and Borgland, A.~W. and Bouvier, A. and Brandt, T.~J. and Bregeon, J. and Brez, A. and Brigida, M. and Bruel, P. and Buehler, R. and Buson, S. and Caliandro, G.~A. and Cameron, R.~A. and Cannon, A. and Caraveo, P.~A. and Carrigan, S. and Casandjian, J.~M. and Cavazzuti, E. and Cecchi, C. and {\c C}elik, {\"O}. and Charles, E. and Chekhtman, A. and Cheung, C.~C. and Chiang, J. and Ciprini, S. and Claus, R. and Cohen-Tanugi, J. and Conrad, J. and Cutini, S. and Dermer, C.~D. and de Palma, F. and Silva, E.~d.~C.~e. and Drell, P.~S. and Dubois, R. and Dumora, D. and Favuzzi, C. and Fegan, S.~J. and Ferrara, E.~C. and Focke, W.~B. and Fortin, P. and Frailis, M. and Fuhrmann, L. and Fukazawa, Y. and Funk, S. and Fusco, P. and Gargano, F. and Gasparrini, D. and Gehrels, N. and Germani, S. and Giglietto, N. and Giordano, F. and Giroletti, M. and Glanzman, T. and Godfrey, G. and Grenier, I.~A. and Guillemot, L. and Guiriec, S. and Hayashida, M. and Hays, E. and Horan, D. and Hughes, R.~E. and J{\'o}hannesson, G. and Johnson, A.~S. and Johnson, W.~N. and Kadler, M. and Kamae, T. and Katagiri, H. and Kataoka, J. and Kn{\"o}dlseder, J. and Kuss, M. and Lande, J. and Latronico, L. and Lee, S.-H. and Lemoine-Goumard, M. and Longo, F. and Loparco, F. and Lott, B. and Lovellette, M.~N. and Lubrano, P. and Madejski, G.~M. and Makeev, A. and Max-Moerbeck, W. and Mazziotta, M.~N. and McEnery, J.~E. and M{\'e}hault, J. and Michelson, P.~F. and Mitthumsiri, W. and Mizuno, T. and Moiseev, A.~A. and Monte, C. and Monzani, M.~E. and Morselli, A. and Moskalenko, I.~V. and Murgia, S. and Naumann-Godo, M. and Nishino, S. and Nolan, P.~L. and Norris, J.~P. and Nuss, E. and Ohsugi, T. and Okumura, A. and Omodei, N. and Orlando, E. and Ormes, J.~F. and Paneque, D. and Panetta, J.~H. and Parent, D. and Pavlidou, V. and Pearson, T.~J. and Pelassa, V. and Pepe, M. and Pesce-Rollins, M. and Piron, F. and Porter, T.~A. and Rain{\`o}, S. and Rando, R. and Razzano, M. and Readhead, A. and Reimer, A. and Reimer, O. and Richards, J.~L. and Ripken, J. and Ritz, S. and Roth, M. and Sadrozinski, H.~F.-W. and Sanchez, D. and Sander, A. and Scargle, J.~D. and Sgr{\`o}, C. and Siskind, E.~J. and Smith, P.~D. and Spandre, G. and Spinelli, P. and Stawarz, {\L}. and Stevenson, M. and Strickman, M.~S. and Sokolovsky, K.~V. and Suson, D.~J. and Takahashi, H. and Takahashi, T. and Tanaka, T. and Thayer, J.~B. and Thayer, J.~G. and Thompson, D.~J. and Tibaldo, L. and Torres, D.~F. and Tosti, G. and Tramacere, A. and Uchiyama, Y. and Usher, T.~L. and Vandenbroucke, J. and Vasileiou, V. and Vilchez, N. and Vitale, V. and Waite, A.~P. and Wang, P. and Wehrle, A.~E. and Winer, B.~L. and Wood, K.~S. and Yang, Z. and Ylinen, T. and Zensus, J.~A. and Ziegler, M. and Fermi LAT Collaboration and Aleksi{\'c}, J. and Antonelli, L.~A. and Antoranz, P. and Backes, M. and Barrio, J.~A. and Becerra Gonz{\'a}lez, J. and Bednarek, W. and Berdyugin, A. and Berger, K. and Bernardini, E. and Biland, A. and Blanch, O. and Bock, R.~K. and Boller, A. and Bonnoli, G. and Bordas, P. and Borla Tridon, D. and Bosch-Ramon, V. and Bose, D. and Braun, I. and Bretz, T. and Camara, M. and Carmona, E. and Carosi, A. and Colin, P. and Colombo, E. and Contreras, J.~L. and Cortina, J. and Covino, S. and Dazzi, F. and De Angelis, A. and De Cea del Pozo, E. and De Lotto, B. and De Maria, M. and De Sabata, F. and Delgado Mendez, C. and Diago Ortega, A. and Doert, M. and Dom{\'\i}nguez, A. and Dominis Prester, D. and Dorner, D. and Doro, M. and Elsaesser, D. and Ferenc, D. and Fonseca, M.~V. and Font, L. and Garc{\'\i}a L{\'o}pez, R.~J. and Garczarczyk, M. and Gaug, M. and Giavitto, G. and Godinovi, N. and Hadasch, D. and Herrero, A. and Hildebrand, D. and H{\"o}hne-M{\"o}nch, D. and Hose, J. and Hrupec, D. and Jogler, T. and Klepser, S. and Kr{\"a}henb{\"u}hl, T. and Kranich, D. and Krause, J. and La Barbera, A. and Leonardo, E. and Lindfors, E. and Lombardi, S. and L{\'o}pez, M. and Lorenz, E. and Majumdar, P. and Makariev, E. and Maneva, G. and Mankuzhiyil, N. and Mannheim, K. and Maraschi, L. and Mariotti, M. and Mart{\'\i}nez, M. and Mazin, D. and Meucci, M. and Miranda, J.~M. and Mirzoyan, R. and Miyamoto, H. and Mold{\'o}n, J. and Moralejo, A. and Nieto, D. and Nilsson, K. and Orito, R. and Oya, I. and Paoletti, R. and Paredes, J.~M. and Partini, S. and Pasanen, M. and Pauss, F. and Pegna, R.~G. and M. A. P{\'e}rez-Torres and Persic, M. and Peruzzo, J. and Pochon, J. and Prada Moroni, P.~G. and Prada, F. and Prandini, E. and Puchades, N. and Puljak, I. and Reichardt, T. and Reinthal, R. and Rhode, W. and Rib{\'o}, M. and Rico, J. and Rissi, M. and R{\"u}gamer, S. and Saggion, A. and Saito, K. and Saito, T.~Y. and Salvati, M. and S{\'a}nchez-Conde, M. and Satalecka, K. and Scalzotto, V. and Scapin, V. and Schultz, C. and Schweizer, T. and Shayduk, M. and Shore, S.~N. and Sierpowska-Bartosik, A. and Sillanp{\"a}{\"a}, A. and Sitarek, J. and Sobczynska, D. and Spanier, F. and Spiro, S. and Stamerra, A. and Steinke, B. and Storz, J. and Strah, N. and Struebig, J.~C. and Suri{\'c}, T. and Takalo, L.~O. and Tavecchio, F. and Temnikov, P. and Terzi{\'c}, T. and Tescaro, D. and Teshima, M. and Vankov, H. and Wagner, R.~M. and Weitzel, Q. and Zabalza, V. and Zandanel, F. and Zanin, R. and MAGIC Collaboration and Acciari, V.~A. and Arlen, T. and Aune, T. and Benbow, W. and Boltuch, D. and Bradbury, S.~M. and Buckley, J.~H. and Bugaev, V. and Cannon, A. and Cesarini, A. and Ciupik, L. and Cui, W. and Dickherber, R. and Errando, M. and Falcone, A. and Finley, J.~P. and Finnegan, G. and Fortson, L. and Furniss, A. and Galante, N. and Gall, D. and Gillanders, G.~H. and Godambe, S. and Grube, J. and Guenette, R. and Gyuk, G. and Hanna, D. and Holder, J. and Huang, D. and Hui, C.~M. and Humensky, T.~B. and Kaaret, P. and Karlsson, N. and Kertzman, M. and Kieda, D. and Konopelko, A. and Krawczynski, H. and Krennrich, F. and Lang, M.~J. and Maier, G. and McArthur, S. and McCann, A. and McCutcheon, M. and Moriarty, P. and Mukherjee, R. and Ong, R. and Otte, A.~N. and Pandel, D. and Perkins, J.~S. and Pichel, A. and Pohl, M. and Quinn, J. and Ragan, K. and Reyes, L.~C. and Reynolds, P.~T. and Roache, E. and Rose, H.~J. and Rovero, A.~C. and Schroedter, M. and Sembroski, G.~H. and Senturk, G.~D. and Steele, D. and Swordy, S.~P. and Te\v si{\'c}, G. and Theiling, M. and Thibadeau, S. and Varlotta, A. and Vincent, S. and Wakely, S.~P. and Ward, J.~E. and Weekes, T.~C. and Weinstein, A. and Weisgarber, T. and Williams, D.~A. and Wood, M. and Zitzer, B. and VERITAS Collaboration and Villata, M. and Raiteri, C.~M. and Aller, H.~D. and Aller, M.~F. and Arkharov, A.~A. and Blinov, D.~A. and Calcidese, P. and Chen, W.~P. and Efimova, N.~V. and Kimeridze, G. and Konstantinova, T.~S. and Kopatskaya, E.~N. and Koptelova, E. and Kurtanidze, O.~M. and Kurtanidze, S.~O. and L{\"a}hteenm{\"a}ki, A. and Larionov, V.~M. and Larionova, E.~G. and Larionova, L.~V. and Ligustri, R. and Morozova, D.~A. and Nikolashvili, M.~G. and Sigua, L.~A. and Troitsky, I.~S. and Angelakis, E. and Capalbi, M. and Carrami{\~n}ana, A. and Carrasco, L. and Cassaro, P. and de la Fuente, E. and Gurwell, M.~A. and Kovalev, Y.~Y. and Kovalev, Y.~A. and Krichbaum, T.~P. and Krimm, H.~A. and Leto, P. and Lister, M.~L. and Maccaferri, G. and Moody, J.~W. and Mori, Y. and Nestoras, I. and Orlati, A. and Pagani, C. and Pace, C. and Pearson III, R. and Perri, M. and Piner, B.~G. and Pushkarev, A.~B. and Ros, E. and Sadun, A.~C. and Sakamoto, T. and Tornikoski, M. and Yatsu, Y. and Zook, A.} } @article {2011ApJ...742...43A, title = {{Observations of the Crab Pulsar between 25 and 100 GeV with the MAGIC I Telescope}}, journal = {The Astrophysical Journal}, volume = {742}, year = {2011}, month = {nov}, pages = {43}, abstract = {We report on the observation of {$\gamma$}-rays above 25 GeV from the Crab pulsar (PSR B0532+21) using the MAGIC I telescope. Two data sets from observations during the winter period 2007/2008 and 2008/2009 are used. In order to discuss the spectral shape from 100 MeV to 100 GeV, one year of public Fermi Large Area Telescope (Fermi-LAT) data are also analyzed to complement the MAGIC data. The extrapolation of the exponential cutoff spectrum determined with the Fermi-LAT data is inconsistent with MAGIC measurements, which requires a modification of the standard pulsar emission models. In the energy region between 25 and 100 GeV, the emission in the P1 phase (from -0.06 to 0.04, location of the main pulse) and the P2 phase (from 0.32 to 0.43, location of the interpulse) can be described by power laws with spectral indices of -3.1 {\plusmn} 1.0$_{stat}$ {\plusmn} 0.3$_{syst}$ and -3.5 {\plusmn} 0.5$_{stat}$ {\plusmn} 0.3$_{syst}$, respectively. Assuming an asymmetric Lorentzian for the pulse shape, the peak positions of the main pulse and the interpulse are estimated to be at phases -0.009 {\plusmn} 0.007 and 0.393 {\plusmn} 0.009, while the full widths at half-maximum are 0.025 {\plusmn} 0.008 and 0.053 {\plusmn} 0.015, respectively.}, keywords = {gamma rays: stars, pulsars: individual: Crab pulsar PSR B0531+21}, doi = {10.1088/0004-637X/742/1/43}, url = {http://adsabs.harvard.edu/abs/2011ApJ...742...43A}, author = {Aleksi{\'c}, J. and Alvarez, E.~A. and Antonelli, L.~A. and Antoranz, P. and Asensio, M. and Backes, M. and Barrio, J.~A. and Bastieri, D. and Becerra Gonz{\'a}lez, J. and Bednarek, W. and Berdyugin, A. and Berger, K. and Bernardini, E. and Biland, A. and Blanch, O. and Bock, R.~K. and Boller, A. and Bonnoli, G. and Borla Tridon, D. and Braun, I. and Bretz, T. and Ca{\~n}ellas, A. and Carmona, E. and Carosi, A. and Colin, P. and Colombo, E. and Contreras, J.~L. and Cortina, J. and Cossio, L. and Covino, S. and Dazzi, F. and De Angelis, A. and De Caneva, G. and De Cea del Pozo, E. and De Lotto, B. and Delgado Mendez, C. and Diago Ortega, A. and Doert, M. and Dom{\'\i}nguez, A. and Dominis Prester, D. and Dorner, D. and Doro, M. and Eisenacher, D. and Elsaesser, D. and Ferenc, D. and Fonseca, M.~V. and Font, L. and Fruck, C. and Garc{\'\i}a L{\'o}pez, R.~J. and Garczarczyk, M. and Garrido, D. and Giavitto, G. and Godinovi{\'c}, N. and Hadasch, D. and H{\"a}fner, D. and Herrero, A. and Hildebrand, D. and H{\"o}hne-M{\"o}nch, D. and Hose, J. and Hrupec, D. and Jogler, T. and Kellermann, H. and Klepser, S. and Kr{\"a}henb{\"u}hl, T. and Krause, J. and Kushida, J. and La Barbera, A. and Lelas, D. and Leonardo, E. and Lindfors, E. and Lombardi, S. and L{\'o}pez, M. and L{\'o}pez-Oramas, A. and Lorenz, E. and Makariev, M. and Maneva, G. and Mankuzhiyil, N. and Mannheim, K. and Maraschi, L. and Marcote, B. and Mariotti, M. and Mart{\'\i}nez, M. and Mazin, D. and Meucci, M. and Miranda, J.~M. and Mirzoyan, R. and Mold{\'o}n, J. and Moralejo, A. and Munar-Adrover, P. and Nieto, D. and Nilsson, K. and Orito, R. and Otte, N. and Oya, I. and Paneque, D. and Paoletti, R. and Pardo, S. and Paredes, J.~M. and Partini, S. and M. A. P{\'e}rez-Torres and Persic, M. and Peruzzo, L. and Pilia, M. and Pochon, J. and Prada, F. and Prada Moroni, P.~G. and Prandini, E. and Puerto Gimenez, I. and Puljak, I. and Reichardt, I. and Reinthal, R. and Rhode, W. and Rib{\'o}, M. and Rico, J. and Rissi, M. and R{\"u}gamer, S. and Saggion, A. and Saito, K. and Saito, T.~Y. and Salvati, M. and Satalecka, K. and Scalzotto, V. and Scapin, V. and Schultz, C. and Schweizer, T. and Shayduk, M. and Shore, S.~N. and Sillanp{\"a}{\"a}, A. and Sitarek, J. and Snidaric, I. and Sobczynska, D. and Spanier, F. and Spiro, S. and Stamatescu, V. and Stamerra, A. and Steinke, B. and Storz, J. and Strah, N. and Suri{\'c}, T. and Takalo, L. and Takami, H. and Tavecchio, F. and Temnikov, P. and Terzi{\'c}, T. and Tescaro, D. and Teshima, M. and Tibolla, O. and Torres, D.~F. and Treves, A. and Uellenbeck, M. and Vankov, H. and Vogler, P. and Wagner, R.~M. and Weitzel, Q. and Zabalza, V. and Zandanel, F. and Zanin, R. and Hirotani, K.} } @article {2011ApJ...729....2A, title = {{Spectral Energy Distribution of Markarian 501: Quiescent State Versus Extreme Outburst}}, journal = {The Astrophysical Journal}, volume = {729}, year = {2011}, month = {mar}, pages = {2}, abstract = {The very high energy (VHE; E {\gt} 100 GeV) blazar Markarian 501 (Mrk 501) has a well-studied history of extreme spectral variability and is an excellent laboratory for studying the physical processes within the jets of active galactic nuclei. However, there are few detailed multiwavelength studies of Mrk 501 during its quiescent state, due to its low luminosity. A short-term multiwavelength study of Mrk 501 was coordinated in 2009 March, focusing around a multi-day observation with the Suzaku X-ray satellite and including {$\gamma$}-ray data from VERITAS, MAGIC, and the Fermi Gamma-ray Space Telescope with the goal of providing a well-sampled multiwavelength baseline measurement of Mrk 501 in the quiescent state. The results of these quiescent-state observations are compared to the historically extreme outburst of 1997 April 16, with the goal of examining variability of the spectral energy distribution (SED) between the two states. The derived broadband SED shows the characteristic double-peaked profile. We find that the X-ray peak shifts by over two orders of magnitude in photon energy between the two flux states while the VHE peak varies little. The limited shift in the VHE peak can be explained by the transition to the Klein-Nishina (KN) regime. Synchrotron self-Compton models are matched to the data and the implied KN effects are explored.}, keywords = {BL Lacertae objects: individual: Markarian 501 = VER J1653+397, galaxies: active, gamma rays: galaxies, radiation mechanisms: non-thermal, X-rays: galaxies}, doi = {10.1088/0004-637X/729/1/2}, url = {http://adsabs.harvard.edu/abs/2011ApJ...729....2A}, author = {Acciari, V.~A. and Arlen, T. and Aune, T. and Beilicke, M. and Benbow, W. and B{\"o}ttcher, M. and Boltuch, D. and Bradbury, S.~M. and Buckley, J.~H. and Bugaev, V. and Cannon, A. and Cesarini, A. and Ciupik, L. and Cui, W. and Dickherber, R. and Duke, C. and Errando, M. and Falcone, A. and Finley, J.~P. and Finnegan, G. and Fortson, L. and Furniss, A. and Galante, N. and Gall, D. and Godambe, S. and Grube, J. and Guenette, R. and Gyuk, G. and Hanna, D. and Holder, J. and Huang, D. and Hui, C.~M. and Humensky, T.~B. and Imran, A. and Kaaret, P. and Karlsson, N. and Kertzman, M. and Kieda, D. and Konopelko, A. and Krawczynski, H. and Krennrich, F. and Madhavan, A.~S. and Maier, G. and McArthur, S. and McCann, A. and Moriarty, P. and Ong, R.~A. and Otte, A.~N. and Pandel, D. and Perkins, J.~S. and Pichel, A. and Pohl, M. and Quinn, J. and Ragan, K. and Reyes, L.~C. and Reynolds, P.~T. and Roache, E. and Rose, H.~J. and Schroedter, M. and Sembroski, G.~H. and Steele, D. and Swordy, S.~P. and Theiling, M. and Thibadeau, S. and Varlotta, A. and Vassiliev, V.~V. and Vincent, S. and Wakely, S.~P. and Ward, J.~E. and Weekes, T.~C. and Weinstein, A. and Weisgarber, T. and Williams, D.~A. and Wood, M. and Zitzer, B. and VERITAS Collaboration and Aleksi{\'c}, J. and Antonelli, L.~A. and Antoranz, P. and Backes, M. and Barrio, J.~A. and Bastieri, D. and Becerra Gonz{\'a}lez, J. and Bednarek, W. and Berdyugin, A. and Berger, K. and Bernardini, E. and Biland, A. and Blanch, O. and Bock, R.~K. and Boller, A. and Bonnoli, G. and Bordas, P. and Borla Tridon, D. and Bosch-Ramon, V. and Bose, D. and Braun, I. and Bretz, T. and Camara, M. and Carmona, E. and Carosi, A. and Colin, P. and Colombo, E. and Contreras, J.~L. and Cortina, J. and Covino, S. and Dazzi, F. and De Angelis, A. and De Cea del Pozo, E. and De Lotto, B. and De Maria, M. and De Sabata, F. and Delgado Mendez, C. and Diago Ortega, A. and Doert, M. and Dom{\'\i}nguez, A. and Dominis Prester, D. and Dorner, D. and Doro, M. and Elsaesser, D. and Errando, M. and Ferenc, D. and Fonseca, M.~V. and Font, L. and Garc{\'\i}a L{\'o}pez, R.~J. and Garczarczyk, M. and Gaug, M. and Giavitto, G. and Godinovi{\'c}, N. and Hadasch, D. and Herrero, A. and Hildebrand, D. and H{\"o}hne-M{\"o}nch, D. and Hose, J. and Hrupec, D. and Jogler, T. and Klepser, S. and Kr{\"a}henb{\"u}hl, T. and Kranich, D. and Krause, J. and La Barbera, A. and Leonardo, E. and Lindfors, E. and Lombardi, S. and Longo, F. and L{\'o}pez, M. and Lorenz, E. and Majumdar, P. and Makariev, M. and Maneva, G. and Mankuzhiyil, N. and Mannheim, K. and Maraschi, L. and Mariotti, M. and Mart{\'\i}nez, M. and Mazin, D. and Meucci, M. and Miranda, J.~M. and Mirzoyan, R. and Miyamoto, H. and Mold{\'o}n, J. and Moralejo, A. and Nieto, D. and Nilsson, K. and Orito, R. and Oya, I. and Paoletti, R. and Paredes, J.~M. and Partini, S. and Pasanen, M. and Pauss, F. and Pegna, R.~G. and M. A. P{\'e}rez-Torres and Persic, M. and Peruzzo, L. and Pochon, J. and Prada, F. and Prada Moroni, P.~G. and Prandini, E. and Puchades, N. and Puljak, I. and Reichardt, I. and Reinthal, R. and Rhode, W. and Rib{\'o}, M. and Rico, J. and Rissi, M. and R{\"u}gamer, S. and Saggion, A. and Saito, K. and Saito, T.~Y. and Salvati, M. and S{\'a}nchez-Conde, M. and Satalecka, K. and Scalzotto, V. and Scapin, V. and Schultz, C. and Schweizer, T. and Shayduk, M. and Shore, S.~N. and Sierpowska-Bartosik, A. and Sillanp{\"a}{\"a}, A. and Sitarek, J. and Sobczynska, D. and Spanier, F. and Spiro, S. and Stamerra, A. and Steinke, B. and Storz, J. and Strah, N. and Struebig, J.~C. and Suri{\'c}, T. and Takalo, L. and Tavecchio, F. and Temnikov, P. and Terzi{\'c}, T. and Tescaro, D. and Teshima, M. and Torres, D.~F. and Vankov, H. and Wagner, R.~M. and Weitzel, Q. and Zabalza, V. and Zandanel, F. and Zanin, R. and MAGIC Collaboration and Paneque, D. and Hayashida, M.} } @article {2010ApJ...721..843A, title = {{Magic Constraints on {$\gamma$}-ray Emission from Cygnus X-3}}, journal = {The Astrophysical Journal}, volume = {721}, year = {2010}, month = {sep}, pages = {843-855}, abstract = {Cygnus X-3 is a microquasar consisting of an accreting compact object orbiting around a Wolf-Rayet star. It has been detected at radio frequencies and up to high-energy {$\gamma$} rays (above 100 MeV). However, many models also predict a very high energy (VHE) emission (above hundreds of GeV) when the source displays relativistic persistent jets or transient ejections. Therefore, detecting such emission would improve the understanding of the jet physics. The imaging atmospheric Cherenkov telescope MAGIC observed Cygnus X-3 for about 70 hr between 2006 March and 2009 August in different X-ray/radio spectral states and also during a period of enhanced {$\gamma$}-ray emission. MAGIC found no evidence for a VHE signal from the direction of the microquasar. An upper limit to the integral flux for energies higher than 250 GeV has been set to 2.2 {\times} 10$^{-12}$ photons cm$^{-2}$ s$^{-1}$ (95\% confidence level). This is the best limit so far to the VHE emission from this source. The non-detection of a VHE signal during the period of activity in the high-energy band sheds light on the location of the possible VHE radiation favoring the emission from the innermost region of the jets, where absorption is significant. The current and future generations of Cherenkov telescopes may detect a signal under precise spectral conditions.}, keywords = {acceleration of particles, binaries: general, gamma rays: general, methods: observational, X-rays: binaries}, doi = {10.1088/0004-637X/721/1/843}, url = {http://adsabs.harvard.edu/abs/2010ApJ...721..843A}, author = {Aleksi{\'c}, J. and Antonelli, L.~A. and Antoranz, P. and Backes, M. and Baixeras, C. and Barrio, J.~A. and Bastieri, D. and Becerra Gonz{\'a}lez, J. and Bednarek, W. and Berdyugin, A. and Berger, K. and Bernardini, E. and Biland, A. and Blanch, O. and Bock, R.~K. and Boller, A. and Bonnoli, G. and Bordas, P. and Borla Tridon, D. and Bosch-Ramon, V. and Bose, D. and Braun, I. and Bretz, T. and Britzger, D. and Camara, M. and Carmona, E. and Carosi, A. and Colin, P. and Contreras, J.~L. and Cortina, J. and Costado, M.~T. and Covino, S. and Dazzi, F. and De Angelis, A. and De Cea del Pozo, E. and De Lotto, B. and De Maria, M. and De Sabata, F. and Delgado Mendez, C. and Doert, M. and Dom{\'\i}nguez, A. and Dominis Prester, D. and Dorner, D. and Doro, M. and Elsaesser, D. and Errando, M. and Ferenc, D. and Fonseca, M.~V. and Font, L. and Garc{\'\i}a L{\'o}pez, R.~J. and Garczarczyk, M. and Gaug, M. and Godinovi{\'c}, N. and G{\"o}ebel, F. and Hadasch, D. and Herrero, A. and Hildebrand, D. and H{\"o}hne-M{\"o}nch, D. and Hose, J. and Hrupec, D. and Hsu, C.~C. and Jogler, T. and Klepser, S. and Kr{\"a}henb{\"u}hl, T. and Kranich, D. and La Barbera, A. and Laille, A. and Leonardo, E. and Lindfors, E. and Lombardi, S. and Longo, F. and L{\'o}pez, M. and Lorenz, E. and Majumdar, P. and Maneva, G. and Mankuzhiyil, N. and Mannheim, K. and Maraschi, L. and Mariotti, M. and Mart{\'\i}nez, M. and Mazin, D. and Meucci, M. and Miranda, J.~M. and Mirzoyan, R. and Miyamoto, H. and Mold{\'o}n, J. and Moles, M. and Moralejo, A. and Nieto, D. and Nilsson, K. and Ninkovic, J. and Orito, R. and Oya, I. and Paiano, S. and Paoletti, R. and Paredes, J.~M. and Partini, S. and Pasanen, M. and Pascoli, D. and Pauss, F. and Pegna, R.~G. and M. A. P{\'e}rez-Torres and Persic, M. and Peruzzo, L. and Prada, F. and Prandini, E. and Puchades, N. and Puljak, I. and Reichardt, I. and Rhode, W. and Rib{\'o}, M. and Rico, J. and Rissi, M. and R{\"u}gamer, S. and Saggion, A. and Saito, K. and Saito, T.~Y. and Salvati, M. and S{\'a}nchez-Conde, M. and Satalecka, K. and Scalzotto, V. and Scapin, V. and Schultz, C. and Schweizer, T. and Shayduk, M. and Shore, S.~N. and Sierpowska-Bartosik, A. and Sillanp{\"a}{\"a}, A. and Sitarek, J. and Sobczynska, D. and Spanier, F. and Spiro, S. and Stamerra, A. and Steinke, B. and Struebig, J.~C. and Suri{\'c}, T. and Takalo, L. and Tavecchio, F. and Temnikov, P. and Terzi{\'c}, T. and Tescaro, D. and Teshima, M. and Torres, D.~F. and Vankov, H. and Wagner, R.~M. and Weitzel, Q. and Zabalza, V. and Zandanel, F. and Zanin, R. and MAGIC Collaboration} } @article {2010ApJ...710..634A, title = {{MAGIC Gamma-ray Telescope Observation of the Perseus Cluster of Galaxies: Implications for Cosmic Rays, Dark Matter, and NGC 1275}}, journal = {The Astrophysical Journal}, volume = {710}, year = {2010}, month = {feb}, pages = {634-647}, abstract = {The Perseus galaxy cluster was observed by the MAGIC Cherenkov telescope for a total effective time of 24.4 hr during 2008 November and December. The resulting upper limits on the {$\gamma$}-ray emission above 100 GeV are in the range of 4.6-7.5 {\times} 10$^{-12}$ cm$^{-2}$ s$^{-1}$ for spectral indices from -1.5 to -2.5, thereby constraining the emission produced by cosmic rays, dark matter annihilations, and the central radio galaxy NGC 1275. Results are compatible with cosmological cluster simulations for the cosmic-ray-induced {$\gamma$}-ray emission, constraining the average cosmic ray-to-thermal pressure to {\l}t}4\% for the cluster core region ({\l}t}8\% for the entire cluster). Using simplified assumptions adopted in earlier work (a power-law spectrum with an index of -2.1, constant cosmic ray-to-thermal pressure for the peripheral cluster regions while accounting for the adiabatic contraction during the cooling flow formation), we would limit the ratio of cosmic ray-to-thermal energy to E $_{CR}$/E $_{th}$ {\l}t} 3\%. Improving the sensitivity of this observation by a factor of about 7 will enable us to scrutinize the hadronic model for the Perseus radio mini-halo: a non-detection of {$\gamma$}-ray emission at this level implies cosmic ray fluxes that are too small to produce enough electrons through hadronic interactions with the ambient gas protons to explain the observed synchrotron emission. The upper limit also translates into a level of {$\gamma$}-ray emission from possible annihilations of the cluster dark matter (the dominant mass component) that is consistent with boost factors of \~{}10$^{4}$ for the typically expected dark matter annihilation-induced emission. Finally, the upper limits obtained for the {$\gamma$}-ray emission of the central radio galaxy NGC 1275 are consistent with the recent detection by the Fermi-LAT satellite. Due to the extremely large Doppler factors required for the jet, a one-zone synchrotron self-Compton model is implausible in this case. We reproduce the observed spectral energy density by using the structured jet (spine-layer) model which has previously been adopted to explain the high-energy emission of radio galaxies.}, keywords = {galaxies: clusters: individual: Perseus, gamma rays: general}, doi = {10.1088/0004-637X/710/1/634}, url = {http://adsabs.harvard.edu/abs/2010ApJ...710..634A}, author = {Aleksi{\'c}, J. and Antonelli, L.~A. and Antoranz, P. and Backes, M. and Baixeras, C. and Balestra, S. and Barrio, J.~A. and Bastieri, D. and Becerra Gonz{\'a}lez, J. and Bednarek, W. and Berdyugin, A. and Berger, K. and Bernardini, E. and Biland, A. and Bock, R.~K. and Bonnoli, G. and Bordas, P. and Borla Tridon, D. and Bosch-Ramon, V. and Bose, D. and Braun, I. and Bretz, T. and Britzger, D. and Camara, M. and Carmona, E. and Carosi, A. and Colin, P. and Commichau, S. and Contreras, J.~L. and Cortina, J. and Costado, M.~T. and Covino, S. and Dazzi, F. and De Angelis, A. and De Cea del Pozo, E. and de los Reyes, R. and De Lotto, B. and De Maria, M. and De Sabata, F. and Delgado Mendez, C. and Doert, M. and Dom{\'\i}nguez, A. and Dominis Prester, D. and Dorner, D. and Doro, M. and Elsaesser, D. and Errando, M. and Ferenc, D. and Fonseca, M.~V. and Font, L. and Galante, N. and Garc{\'\i}a L{\'o}pez, R.~J. and Garczarczyk, M. and Gaug, M. and Godinovi{\'c}, N. and Hadasch, D. and Herrero, A. and Hildebrand, D. and H{\"o}hne-M{\"o}nch, D. and Hose, J. and Hrupec, D. and Hsu, C.~C. and Jogler, T. and Klepser, S. and Kr{\"a}henb{\"u}hl, T. and Kranich, D. and La Barbera, A. and Laille, A. and Leonardo, E. and Lindfors, E. and Lombardi, S. and Longo, F. and L{\'o}pez, M. and Lorenz, E. and Majumdar, P. and Maneva, G. and Mankuzhiyil, N. and Mannheim, K. and Maraschi, L. and Mariotti, M. and Mart{\'\i}nez, M. and Mazin, D. and Meucci, M. and Miranda, J.~M. and Mirzoyan, R. and Miyamoto, H. and Mold{\'o}n, J. and Moles, M. and Moralejo, A. and Nieto, D. and Nilsson, K. and Ninkovic, J. and Orito, R. and Oya, I. and Paiano, S. and Paoletti, R. and Paredes, J.~M. and Partini, S. and Pasanen, M. and Pascoli, D. and Pauss, F. and Pegna, R.~G. and M. A. P{\'e}rez-Torres and Persic, M. and Peruzzo, L. and Prada, F. and Prandini, E. and Puchades, N. and Puljak, I. and Reichardt, I. and Rhode, W. and Rib{\'o}, M. and Rico, J. and Rissi, M. and R{\"u}gamer, S. and Saggion, A. and Saito, T.~Y. and Salvati, M. and S{\'a}nchez-Conde, M.~A. and Satalecka, K. and Scalzotto, V. and Scapin, V. and Schultz, C. and Schweizer, T. and Shayduk, M. and Shore, S.~N. and Sierpowska-Bartosik, A. and Sillanp{\"a}{\"a}, A. and Sitarek, J. and Sobczynska, D. and Spanier, F. and Spiro, S. and Stamerra, A. and Steinke, B. and Struebig, J.~C. and Suri{\'c}, T. and Takalo, L. and Tavecchio, F. and Temnikov, P. and Terzi{\'c}, T. and Tescaro, D. and Teshima, M. and Torres, D.~F. and Vankov, H. and Wagner, R.~M. and Zabalza, V. and Zandanel, F. and Zanin, R. and Zapatero, J. and Pfrommer, C. and Pinzke, A. and En{\ss}lin, T.~A. and Inoue, S. and Ghisellini, G. and MAGIC Collaboration} } @article {2010A\&A...517A...5A, title = {{MAGIC observation of the GRB 080430 afterglow}}, journal = {Astronomy and Astrophysics}, volume = {517}, year = {2010}, month = {jul}, pages = {A5}, abstract = {Context. Gamma-ray bursts are cosmological sources emitting radiation from the gamma-rays to the radio band. Substantial observational efforts have been devoted to the study of gamma-ray bursts during the prompt phase, i.e. the initial burst of high-energy radiation, and during the long-lasting afterglows. In spite of many successes in interpreting these phenomena, there are still several open key questions about the fundamental emission processes, their energetics and the environment.
Aims: Independently of specific gamma-ray burst theoretical recipes, spectra in the GeV/TeV range are predicted to be remarkably simple, being satisfactorily modeled with power-laws, and therefore offer a very valuable tool to probe the extragalactic background light distribution. Furthermore, the simple detection of a component at very-high energies, i.e. at \~{}100 GeV, would solve the ambiguity about the importance of various possible emission processes, which provide barely distinguishable scenarios at lower energies.
Methods: We used the results of the MAGIC telescope observation of the moderate resdhift (z \~{} 0.76) GRB 080430 at energies above about 80 GeV, to evaluate the perspective for late-afterglow observations with ground based GeV/TeV telescopes.
Results: We obtained an upper limit of F$_{95\% CL}$ = 5.5 {\times} 10$^{-11}$ erg cm$^{-2}$ s$^{-1}$ for the very-high energy emission of GRB 080430, which cannot set further constraints on the theoretical scenarios proposed for this object also due to the difficulties in modeling the low-energy afterglow. Nonetheless, our observations show that Cherenkov telescopes have already reached the required sensitivity to detect the GeV/TeV emission of GRBs at moderate redshift (z {\l}sim} 0.8), provided the observations are carried out at early times, close to the onset of their afterglow phase.}, keywords = {gamma-ray burst: individual: GRB 080430, radiation mechanisms: non-thermal}, doi = {10.1051/0004-6361/200913461}, url = {http://adsabs.harvard.edu/abs/2010A\%26A...517A...5A}, author = {Aleksi{\'c}, J. and Anderhub, H. and Antonelli, L.~A. and Antoranz, P. and Backes, M. and Baixeras, C. and Balestra, S. and Barrio, J.~A. and Bastieri, D. and Becerra Gonz{\'a}lez, J. and Becker, J.~K. and Bednarek, W. and Berdyugin, A. and Berger, K. and Bernardini, E. and Biland, A. and Bock, R.~K. and Bonnoli, G. and Bordas, P. and Borla Tridon, D. and Bosch-Ramon, V. and Bose, D. and Braun, I. and Bretz, T. and Britzger, D. and Camara, M. and Carmona, E. and Carosi, A. and Colin, P. and Commichau, S. and Contreras, J.~L. and Cortina, J. and Costado, M.~T. and Covino, S. and Dazzi, F. and De Angelis, A. and De Cea del Pozo, E. and de los Reyes, R. and De Lotto, B. and De Maria, M. and De Sabata, F. and Delgado Mendez, C. and Doert, M. and Dom{\'\i}nguez, A. and Dominis Prester, D. and Dorner, D. and Doro, M. and Elsaesser, D. and Errando, M. and Ferenc, D. and Fern{\'a}ndez, E. and Firpo, R. and Fonseca, M.~V. and Font, L. and Galante, N. and Garc{\'\i}a L{\'o}pez, R.~J. and Garczarczyk, M. and Gaug, M. and Godinovi{\'c}, N. and G{\"o}ebel, F. and Hadasch, D. and Herrero, A. and Hildebrand, D. and H{\"o}hne-M{\"o}nch, D. and Hose, J. and Hrupec, D. and Hsu, C.~C. and Jogler, T. and Klepser, S. and Kr{\"a}henb{\"u}hl, T. and Kranich, D. and La Barbera, A. and Laille, A. and Leonardo, E. and Lindfors, E. and Lombardi, S. and Longo, F. and L{\'o}pez, M. and Lorenz, E. and Majumdar, P. and Maneva, G. and Mankuzhiyil, N. and Mannheim, K. and Maraschi, L. and Mariotti, M. and Mart{\'\i}nez, M. and Mazin, D. and Meucci, M. and Miranda, J.~M. and Mirzoyan, R. and Miyamoto, H. and Mold{\'o}n, J. and Moles, M. and Moralejo, A. and Nieto, D. and Nilsson, K. and Ninkovic, J. and Orito, R. and Oya, I. and Paoletti, R. and Paredes, J.~M. and Pasanen, M. and Pascoli, D. and Pauss, F. and Pegna, R.~G. and M. A. P{\'e}rez-Torres and Persic, M. and Peruzzo, L. and Prada, F. and Prandini, E. and Puchades, N. and Puljak, I. and Reichardt, I. and Rhode, W. and Rib{\'o}, M. and Rico, J. and Rissi, M. and R{\"u}gamer, S. and Saggion, A. and Saito, T.~Y. and Salvati, M. and S{\'a}nchez-Conde, M. and Satalecka, K. and Scalzotto, V. and Scapin, V. and Schweizer, T. and Shayduk, M. and Shore, S.~N. and Sierpowska-Bartosik, A. and Sillanp{\"a}{\"a}, A. and Sitarek, J. and Sobczynska, D. and Spanier, F. and Spiro, S. and Stamerra, A. and Steinke, B. and Strah, N. and Struebig, J.~C. and Suri{\'c}, T. and Takalo, L. and Tavecchio, F. and Temnikov, P. and Tescaro, D. and Teshima, M. and Torres, D.~F. and Turini, N. and Vankov, H. and Wagner, R.~M. and Zabalza, V. and Zandanel, F. and Zanin, R. and Zapatero, J. and de Ugarte-Postigo, A. and MAGIC Collaboration} } @article {2010A\&A...519A..32A, title = {{MAGIC TeV gamma-ray observations of Markarian 421 during multiwavelength campaigns in 2006}}, journal = {Astronomy and Astrophysics}, volume = {519}, year = {2010}, month = {sep}, pages = {A32}, abstract = {Context. Wide-range spectral coverage of blazar-type active galactic nuclei is of paramount importance for understanding the particle acceleration mechanisms assumed to take place in their jets. The Major Atmospheric Gamma Imaging Cerenkov (MAGIC) telescope participated in three multiwavelength (MWL) campaigns, observing the blazar Markarian (Mkn) 421 during the nights of April 28 and 29, 2006, and June 14, 2006.
Aims: We analyzed the corresponding MAGIC very-high energy observations during 9 nights from April 22 to 30, 2006 and on June 14, 2006. We inferred light curves with sub-day resolution and night-by-night energy spectra.
Methods: MAGIC detects {$\gamma$}-rays by observing extended air showers in the atmosphere. The obtained air-shower images were analyzed using the standard MAGIC analysis chain.
Results: A strong {$\gamma$}-ray signal was detected from Mkn 421 on all observation nights. The flux (E {\gt} 250 GeV) varied on night-by-night basis between (0.92{\plusmn}0.11) {\times} 10$^{-10}$ cm$^{-2}$ s$^{-1}$ (0.57 Crab units) and (3.21{\plusmn}0.15) {\times} 10$^{-10}$ cm$^{-2}$ s$^{-1}$ (2.0 Crab units) in April 2006. There is a clear indication for intra-night variability with a doubling time of 36{\plusmn}10\_stat min on the night of April 29, 2006, establishing once more rapid flux variability for this object. For all individual nights {$\gamma$}-ray spectra could be inferred, with power-law indices ranging from 1.66 to 2.47. We did not find statistically significant correlations between the spectral index and the flux state for individual nights. During the June 2006 campaign, a flux substantially lower than the one measured by the Whipple 10-m telescope four days later was found. Using a log-parabolic power law fit we deduced for some data sets the location of the spectral peak in the very-high energy regime. Our results confirm the indications of rising peak energy with increasing flux, as expected in leptonic acceleration models.}, keywords = {BL Lacertae objects: individual: Mkn 421, gamma rays: galaxies, radiation mechanisms: non-thermal}, doi = {10.1051/0004-6361/200913945}, url = {http://adsabs.harvard.edu/abs/2010A\%26A...519A..32A}, author = {Aleksi{\'c}, J. and Anderhub, H. and Antonelli, L.~A. and Antoranz, P. and Backes, M. and Baixeras, C. and Balestra, S. and Barrio, J.~A. and Bastieri, D. and Becerra Gonz{\'a}lez, J. and Becker, J.~K. and Bednarek, W. and Berdyugin, A. and Berger, K. and Bernardini, E. and Biland, A. and Bock, R.~K. and Bonnoli, G. and Bordas, P. and Borla Tridon, D. and Bosch-Ramon, V. and Bose, D. and Braun, I. and Bretz, T. and Britzger, D. and Camara, M. and Carmona, E. and Carosi, A. and Colin, P. and Commichau, S. and Contreras, J.~L. and Cortina, J. and Costado, M.~T. and Covino, S. and Dazzi, F. and De Angelis, A. and De Cea del Pozo, E. and de los Reyes, R. and De Lotto, B. and De Maria, M. and De Sabata, F. and Delgado Mendez, C. and Doert, M. and Dom{\'\i}nguez, A. and Dominis Prester, D. and Dorner, D. and Doro, M. and Elsaesser, D. and Errando, M. and Ferenc, D. and Fonseca, M.~V. and Font, L. and Garc{\'\i}a L{\'o}pez, R.~J. and Garczarczyk, M. and Gaug, M. and Godinovi{\'c}, N. and Hadasch, D. and Herrero, A. and Hildebrand, D. and H{\"o}hne-M{\"o}nch, D. and Hose, J. and Hrupec, D. and Hsu, C.~C. and Jogler, T. and Klepser, S. and Kr{\"a}henb{\"u}hl, T. and Kranich, D. and La Barbera, A. and Laille, A. and Leonardo, E. and Lindfors, E. and Lombardi, S. and Longo, F. and L{\'o}pez, M. and Lorenz, E. and Majumdar, P. and Maneva, G. and Mankuzhiyil, N. and Mannheim, K. and Maraschi, L. and Mariotti, M. and Mart{\'\i}nez, M. and Mazin, D. and Meucci, M. and Miranda, J.~M. and Mirzoyan, R. and Miyamoto, H. and Mold{\'o}n, J. and Moles, M. and Moralejo, A. and Nieto, D. and Nilsson, K. and Ninkovic, J. and Orito, R. and Oya, I. and Paoletti, R. and Paredes, J.~M. and Partini, S. and Pasanen, M. and Pascoli, D. and Pauss, F. and Pegna, R.~G. and M. A. P{\'e}rez-Torres and Persic, M. and Peruzzo, L. and Prada, F. and Prandini, E. and Puchades, N. and Puljak, I. and Reichardt, I. and Rhode, W. and Rib{\'o}, M. and Rico, J. and Rissi, M. and R{\"u}gamer, S. and Saggion, A. and Saito, T.~Y. and Salvati, M. and S{\'a}nchez-Conde, M. and Satalecka, K. and Scalzotto, V. and Scapin, V. and Schweizer, T. and Shayduk, M. and Shore, S.~N. and Sierpowska-Bartosik, A. and Sillanp{\"a}{\"a}, A. and Sitarek, J. and Sobczynska, D. and Spanier, F. and Spiro, S. and Stamerra, A. and Steinke, B. and Strah, N. and Struebig, J.~C. and Suri{\'c}, T. and Takalo, L. and Tavecchio, F. and Temnikov, P. and Tescaro, D. and Teshima, M. and Torres, D.~F. and Vankov, H. and Wagner, R.~M. and Zabalza, V. and Zandanel, F. and Zanin, R. and MAGIC Collaboration} } @article {2010ApJ...725.1629A, title = {{MAGIC Upper Limits for Two Milagro-detected Bright Fermi Sources in the Region of SNR G65.1+0.6}}, journal = {The Astrophysical Journal}, volume = {725}, year = {2010}, month = {dec}, pages = {1629-1632}, abstract = {We report on the observation of the region around supernova remnant G65.1+0.6 with the stand-alone MAGIC-I telescope. This region hosts the two bright GeV gamma-ray sources 1FGL J1954.3+2836 and 1FGL J1958.6+2845. They are identified as GeV pulsars and both have a possible counterpart detected at about 35 TeV by the Milagro observatory. MAGIC collected 25.5 hr of good quality data and found no significant emission in the range around 1 TeV. We therefore report differential flux upper limits, assuming the emission to be point-like ({\l}t}=0fdg1) or within a radius of 0fdg3. In the point-like scenario, the flux limits around 1 TeV are at the level of 3\% and 2\% of the Crab Nebula flux for the two sources, respectively. This implies that the Milagro emission is either extended over a much larger area than our point-spread function or it must be peaked at energies beyond 1 TeV, resulting in a photon index harder than 2.2 in the TeV band.}, keywords = {ISM: supernova remnants, pulsars: individual: PSR J1957+2831 LAT PSR J1954+2836 LAT PSR J1958+2846}, doi = {10.1088/0004-637X/725/2/1629}, url = {http://adsabs.harvard.edu/abs/2010ApJ...725.1629A}, author = {Aleksi{\'c}, J. and Antonelli, L.~A. and Antoranz, P. and Backes, M. and Barrio, J.~A. and Bastieri, D. and Becerra Gonz{\'a}lez, J. and Bednarek, W. and Berdyugin, A. and Berger, K. and Bernardini, E. and Biland, A. and Blanch, O. and Bock, R.~K. and Boller, A. and Bonnoli, G. and Bordas, P. and Borla Tridon, D. and Bosch-Ramon, V. and Bose, D. and Braun, I. and Bretz, T. and Camara, M. and Carmona, E. and Carosi, A. and Colin, P. and Contreras, J.~L. and Cortina, J. and Covino, S. and Dazzi, F. and De Angelis, A. and De Cea del Pozo, E. and De Lotto, B. and De Maria, M. and De Sabata, F. and Delgado Mendez, C. and Diago Ortega, A. and Doert, M. and Dom{\'\i}nguez, A. and Dominis Prester, D. and Dorner, D. and Doro, M. and Elsaesser, D. and Errando, M. and Ferenc, D. and Fonseca, M.~V. and Font, L. and Garc{\'\i}a L{\'o}pez, R.~J. and Garczarczyk, M. and Gaug, M. and Giavitto, G. and Godinovi{\'c}, N. and Hadasch, D. and Herrero, A. and Hildebrand, D. and H{\"o}hne-M{\"o}nch, D. and Hose, J. and Hrupec, D. and Jogler, T. and Klepser, S. and Kr{\"a}henb{\"u}hl, T. and Kranich, D. and Krause, J. and La Barbera, A. and Leonardo, E. and Lindfors, E. and Lombardi, S. and Longo, F. and L{\'o}pez, M. and Lorenz, E. and Majumdar, P. and Maneva, G. and Mankuzhiyil, N. and Mannheim, K. and Maraschi, L. and Mariotti, M. and Mart{\'\i}nez, M. and Mazin, D. and Meucci, M. and Miranda, J.~M. and Mirzoyan, R. and Miyamoto, H. and Mold{\'o}n, J. and Moralejo, A. and Nieto, D. and Nilsson, K. and Orito, R. and Oya, I. and Paoletti, R. and Paredes, J.~M. and Partini, S. and Pasanen, M. and Pauss, F. and Pegna, R.~G. and M. A. P{\'e}rez-Torres and Persic, M. and Peruzzo, L. and Pochon, J. and Prada, F. and Prada Moroni, P.~G. and Prandini, E. and Puchades, N. and Puljak, I. and Reichardt, I. and Reinthal, R. and Rhode, W. and Rib{\'o}, M. and Rico, J. and Rissi, M. and R{\"u}gamer, S. and Saggion, A. and Saito, K. and Saito, T.~Y. and Salvati, M. and S{\'a}nchez-Conde, M. and Satalecka, K. and Scalzotto, V. and Scapin, V. and Schultz, C. and Schweizer, T. and Shayduk, M. and Sierpowska-Bartosik, A. and Sillanp{\"a}{\"a}, A. and Sitarek, J. and Sobczynska, D. and Spanier, F. and Spiro, S. and Stamerra, A. and Steinke, B. and Storz, J. and Strah, N. and Struebig, J.~C. and Suri{\'c}, T. and Takalo, L. and Tavecchio, F. and Temnikov, P. and Terzi{\'c}, T. and Tescaro, D. and Teshima, M. and Torres, D.~F. and Vankov, H. and Wagner, R.~M. and Weitzel, Q. and Zabalza, V. and Zandanel, F. and Zanin, R.} } @article {2010A\&A...524A..77A, title = {{Search for an extended VHE {$\gamma$}-ray emission from Mrk 421 and Mrk 501 with the MAGIC Telescope}}, journal = {Astronomy and Astrophysics}, volume = {524}, year = {2010}, month = {dec}, pages = {A77}, abstract = {Context. Part of the very high energy {$\gamma$}-ray radiation coming from extragalactic sources is absorbed through the pair production process on the extragalactic background light photons. Extragalactic magnetic fields alter the trajectories of these cascade pairs and, in turn, convert cosmic background photons to {$\gamma$}-ray energies by inverse Compton scattering. These secondary photons can form an extended halo around bright VHE sources.
Aims: We searched for an extended emission around the bright blazars Mrk 421 and Mrk 501 using the MAGIC telescope data.
Methods: If extended emission is present, the angular distribution of reconstructed {$\gamma$}-ray arrival directions around the source is broader than for a point-like source. In the analysis of a few tens of hours of observational data taken from Mrk 421 and Mrk 501 we used a newly developed method that provides better angular resolution. This method is based on the usage of multidimensional decision trees. Comparing the measured shapes of angular distributions with those expected from a point-like source one can detect or constrain possible extended emission around the source. We also studied the influence of different types of systematic errors on the shape of the distribution of reconstructed {$\gamma$}-ray arrival directions for a point source.
Results: We present upper limits for an extended emission calculated for both sources for various source extensions and emission profiles. We obtain upper limits on the extended emission around the Mrk 421 (Mrk 501) on the level of {\l}t}5\% ({\l}t}4\%) of the Crab Nebula flux above the energy threshold of 300 GeV. Using these results we discuss possible constraints on the extragalactic magnetic fields strength around a few times 10$^{-15}$ G.}, keywords = {galaxies: active, {$\gamma$}-rays: galaxies}, doi = {10.1051/0004-6361/201014747}, url = {http://adsabs.harvard.edu/abs/2010A\%26A...524A..77A}, author = {Aleksi{\'c}, J. and Antonelli, L.~A. and Antoranz, P. and Backes, M. and Baixeras, C. and Barrio, J.~A. and Bastieri, D. and Becerra Gonz{\'a}lez, J. and Bednarek, W. and Berdyugin, A. and Berger, K. and Bernardini, E. and Biland, A. and Blanch, O. and Bock, R.~K. and Bonnoli, G. and Bordas, P. and Borla Tridon, D. and Bosch-Ramon, V. and Bose, D. and Braun, I. and Bretz, T. and Britzger, D. and Camara, M. and Carmona, E. and Carosi, A. and Colin, P. and Commichau, S. and Contreras, J.~L. and Cortina, J. and Costado, M.~T. and Covino, S. and Dazzi, F. and De Angelis, A. and De Cea del Pozo, E. and de los Reyes, R. and De Lotto, B. and De Maria, M. and De Sabata, F. and Delgado Mendez, C. and Doert, M. and Dom{\'\i}nguez, A. and Dominis Prester, D. and Dorner, D. and Doro, M. and Elsaesser, D. and Errando, M. and Ferenc, D. and Fonseca, M.~V. and Font, L. and Garc{\'\i}a L{\'o}pez, R.~J. and Garczarczyk, M. and Gaug, M. and Godinovi{\'c}, N. and Hadasch, D. and Herrero, A. and Hildebrand, D. and H{\"o}hne-M{\"o}nch, D. and Hose, J. and Hrupec, D. and Hsu, C.~C. and Jogler, T. and Klepser, S. and Kr{\"a}henb{\"u}hl, T. and Kranich, D. and La Barbera, A. and Laille, A. and Leonardo, E. and Lindfors, E. and Lombardi, S. and Longo, F. and L{\'o}pez, M. and Lorenz, E. and Majumdar, P. and Maneva, G. and Mankuzhiyil, N. and Mannheim, K. and Maraschi, L. and Mariotti, M. and Mart{\'\i}nez, M. and Mazin, D. and Meucci, M. and Miranda, J.~M. and Mirzoyan, R. and Miyamoto, H. and Mold{\'o}n, J. and Moles, M. and Moralejo, A. and Nieto, D. and Nilsson, K. and Ninkovic, J. and Orito, R. and Oya, I. and Paiano, S. and Paoletti, R. and Paredes, J.~M. and Partini, S. and Pasanen, M. and Pascoli, D. and Pauss, F. and Pegna, R.~G. and M. A. P{\'e}rez-Torres and Persic, M. and Peruzzo, L. and Prada, F. and Prandini, E. and Puchades, N. and Puljak, I. and Reichardt, I. and Rhode, W. and Rib{\'o}, M. and Rico, J. and Rissi, M. and R{\"u}gamer, S. and Saggion, A. and Saito, T.~Y. and Salvati, M. and S{\'a}nchez-Conde, M. and Satalecka, K. and Scalzotto, V. and Scapin, V. and Schultz, C. and Schweizer, T. and Shayduk, M. and Shore, S.~N. and Sierpowska-Bartosik, A. and Sillanp{\"a}{\"a}, A. and Sitarek, J. and Sobczynska, D. and Spanier, F. and Spiro, S. and Stamerra, A. and Steinke, B. and Struebig, J.~C. and Suri{\'c}, T. and Takalo, L. and Tavecchio, F. and Temnikov, P. and Terzi{\'c}, T. and Tescaro, D. and Teshima, M. and Torres, D.~F. and Vankov, H. and Wagner, R.~M. and Weitzel, Q. and Zabalza, V. and Zandanel, F. and Zanin, R. and Neronov, A. and Semikoz, D.~V.} } @article {2010ApJ...710..828A, title = {{Search for Very High Energy Gamma-ray Emission from Pulsar-Pulsar Wind Nebula Systems with the MAGIC Telescope}}, journal = {The Astrophysical Journal}, volume = {710}, year = {2010}, month = {feb}, pages = {828-835}, abstract = {The MAGIC collaboration has searched for high-energy gamma-ray emission of some of the most promising pulsar candidates above an energy threshold of 50 GeV, an energy not reachable up to now by other ground-based instruments. Neither pulsed nor steady gamma-ray emission has been observed at energies of 100 GeV from the classical radio pulsars PSR J0205+6449 and PSR J2229+6114 (and their nebulae 3C58 and Boomerang, respectively) and the millisecond pulsar PSR J0218+4232. Here, we present the flux upper limits for these sources and discuss their implications in the context of current model predictions.}, keywords = {gamma rays: stars, methods: observational, pulsars: individual: PSR J0205+6449 PSR J2229+6114 PSR J0218+4232, telescopes}, doi = {10.1088/0004-637X/710/1/828}, url = {http://adsabs.harvard.edu/abs/2010ApJ...710..828A}, author = {Anderhub, H. and Antonelli, L.~A. and Antoranz, P. and Backes, M. and Baixeras, C. and Balestra, S. and Barrio, J.~A. and Bastieri, D. and Becerra Gonz{\'a}lez, J. and Becker, J.~K. and Bednarek, W. and Berger, a.~K. and Bernardini, E. and Biland, A. and Bock, R.~K. and Bonnoli, G. and Bordas, P. and Borla Tridon, D. and Bosch-Ramon, V. and Bose, D. and Braun, I. and Bretz, T. and Britzger, D. and Camara, M. and Carmona, E. and Carosi, A. and Colin, P. and Commichau, S. and Contreras, J.~L. and Cortina, J. and Costado, M.~T. and Covino, S. and Dazzi, F. and De Angelis, A. and De Cea del Pozo, E. and de los Reyes, R. and De Lotto, B. and De Maria, M. and De Sabata, F. and Delgado Mendez, C. and Dom{\'\i}nguez, A. and Dominis Prester, D. and Dorner, D. and Doro, M. and Elsaesser, D. and Errando, M. and Ferenc, D. and Fern{\'a}ndez, E. and Firpo, R. and Fonseca, M.~V. and Font, L. and Galante, N. and Garc{\'\i}a L{\'o}pez, R.~J. and Garczarczyk, M. and Gaug, M. and Godinovi{\'c}, N. and G{\"o}ebel, F. and Hadasch, D. and Herrero, A. and Hildebrand, D. and H{\"o}hne-M{\"o}nch, D. and Hose, J. and Hrupec, D. and Hsu, C.~C. and Jogler, T. and Klepser, S. and Kranich, D. and La Barbera, A. and Laille, A. and Leonardo, E. and Lindfors, E. and Lombardi, S. and Longo, F. and L{\'o}pez, M. and Lorenz, E. and Majumdar, P. and Maneva, G. and Mankuzhiyil, N. and Mannheim, K. and Maraschi, L. and Mariotti, M. and Mart{\'\i}nez, M. and Mazin, D. and Meucci, M. and Miranda, J.~M. and Mirzoyan, R. and Miyamoto, H. and Mold{\'o}n, J. and Moles, M. and Moralejo, A. and Nieto, D. and Nilsson, K. and Ninkovic, J. and Orito, R. and Oya, I. and Paoletti, R. and Paredes, J.~M. and Pasanen, M. and Pascoli, D. and Pauss, F. and Pegna, R.~G. and M. A. P{\'e}rez-Torres and Persic, M. and Peruzzo, L. and Prada, F. and Prandini, E. and Puchades, N. and Puljak, I. and Reichardt, I. and Rhode, W. and Rib{\'o}, M. and Rico, J. and Rissi, M. and Robert, A. and R{\"u}gamer, S. and Saggion, A. and Saito, T.~Y. and Salvati, M. and S{\'a}nchez-Conde, M. and Satalecka, K. and Scalzotto, V. and Scapin, V. and Schweizer, T. and Shayduk, M. and Shore, S.~N. and Sierpowska-Bartosik, A. and Sillanp{\"a}{\"a}, A. and Sitarek, J. and Sobczynska, D. and Spanier, F. and Spiro, S. and Stamerra, A. and Stark, L.~S. and Suri{\'c}, T. and Takalo, L. and Tavecchio, F. and Temnikov, P. and Tescaro, D. and Teshima, M. and Torres, D.~F. and Turini, N. and Vankov, H. and Wagner, R.~M. and Zabalza, V. and Zandanel, F. and Zanin, R. and Zapatero, J. and Cognard, I.} } @article {2010A\&A...515A..76A, title = {{Simultaneous multi-frequency observation of the unknown redshift blazar PG 1553+113 in March-April 2008}}, journal = {Astronomy and Astrophysics}, volume = {515}, year = {2010}, month = {jun}, pages = {A76}, abstract = {The blazar PG 1553+113 is a well known TeV {$\gamma$}-ray emitter. In this paper we determine its spectral energy distribution through simultaneous multi-frequency data to study its emission processes. An extensive campaign was carried out between March and April 2008, where optical, X-ray, high-energy (HE) {$\gamma$}-ray, and very-high-energy (VHE) {$\gamma$}-ray data were obtained with the KVA, Abastumani, REM, RossiXTE/ASM, AGILE and MAGIC telescopes, respectively. We combine the data to derive the source{\textquoteright}s spectral energy distribution and interpret its double-peaked shape within the framework of a synchrotron self-Compton model.}, keywords = {BL Lacertae objects: individual: PG 1553+113, galaxies: active, gamma rays: galaxies, X-rays: galaxies}, doi = {10.1051/0004-6361/200913607}, url = {http://adsabs.harvard.edu/abs/2010A\%26A...515A..76A}, author = {Aleksi{\'c}, J. and Anderhub, H. and Antonelli, L.~A. and Antoranz, P. and Backes, M. and Baixeras, C. and Balestra, S. and Barrio, J.~A. and Bastieri, D. and Becerra Gonz{\'a}lez, J. and Becker, J.~K. and Bednarek, W. and Berdyugin, A. and Berger, K. and Bernardini, E. and Biland, A. and Bock, R.~K. and Bonnoli, G. and Bordas, P. and Borla Tridon, D. and Bosch-Ramon, V. and Bose, D. and Braun, I. and Bretz, T. and Britzger, D. and Camara, M. and Carmona, E. and Carosi, A. and Colin, P. and Commichau, S. and Contreras, J.~L. and Cortina, J. and Costado, M.~T. and Covino, S. and Dazzi, F. and De Angelis, A. and De Cea del Pozo, E. and de los Reyes, R. and De Lotto, B. and De Maria, M. and De Sabata, F. and Delgado Mendez, C. and Dom{\'\i}nguez, A. and Dominis Prester, D. and Dorner, D. and Doro, M. and Elsaesser, D. and Errando, M. and Ferenc, D. and Fern{\'a}ndez, E. and Firpo, R. and Fonseca, M.~V. and Font, L. and Galante, N. and Garc{\'\i}a L{\'o}pez, R.~J. and Garczarczyk, M. and Gaug, M. and Godinovi{\'c}, N. and G{\"o}ebel, F. and Hadasch, D. and Herrero, A. and Hildebrand, D. and H{\"o}hne-M{\"o}nch, D. and Hose, J. and Hrupec, D. and Hsu, C.~C. and Jogler, T. and Klepser, S. and Kr{\"a}henb{\"u}hl, T. and Kranich, D. and La Barbera, A. and Laille, A. and Leonardo, E. and Lindfors, E. and Lombardi, S. and Longo, F. and L{\'o}pez, M. and Lorenz, E. and Majumdar, P. and Maneva, G. and Mankuzhiyil, N. and Mannheim, K. and Maraschi, L. and Mariotti, M. and Mart{\'\i}nez, M. and Mazin, D. and Meucci, M. and Miranda, J.~M. and Mirzoyan, R. and Miyamoto, H. and Mold{\'o}n, J. and Moles, M. and Moralejo, A. and Nieto, D. and Nilsson, K. and Ninkovic, J. and Orito, R. and Oya, I. and Paoletti, R. and Paredes, J.~M. and Pasanen, M. and Pascoli, D. and Pauss, F. and Pegna, R.~G. and M. A. P{\'e}rez-Torres and Persic, M. and Peruzzo, L. and Prada, F. and Prandini, E. and Puchades, N. and Puljak, I. and Reichardt, I. and Rhode, W. and Rib{\'o}, M. and Rico, J. and Rissi, M. and R{\"u}gamer, S. and Saggion, A. and Saito, T.~Y. and Salvati, M. and S{\'a}nchez-Conde, M. and Satalecka, K. and Scalzotto, V. and Scapin, V. and Schweizer, T. and Shayduk, M. and Shore, S.~N. and Sierpowska-Bartosik, A. and Sillanp{\"a}{\"a}, A. and Sitarek, J. and Sobczynska, D. and Spanier, F. and Spiro, S. and Stamerra, A. and Steinke, B. and Strah, N. and Struebig, J.~C. and Suri{\'c}, T. and Takalo, L. and Tavecchio, F. and Temnikov, P. and Tescaro, D. and Teshima, M. and Torres, D.~F. and Turini, N. and Vankov, H. and Wagner, R.~M. and Zabalza, V. and Zandanel, F. and Zanin, R. and Zapatero, J. and Pian, E. and Bianchin, V. and D{\textquoteright}Ammando, F. and Di Cocco, G. and Fugazza, D. and Ghisellini, G. and Kurtanidze, O.~M. and Raiteri, C.~M. and Tosti, G. and Treves, A. and Vercellone, S. and Villata, M. and MAGIC Collaboration} }