@article {2012A\&A...539A.118A, title = {{Discovery of VHE {$\gamma$}-ray emission from the BL Lacertae object B3 2247+381 with the MAGIC telescopes}}, journal = {Astronomy and Astrophysics}, volume = {539}, year = {2012}, month = {mar}, pages = {A118}, abstract = {
Aims: We study the non-thermal jet emission of the BL Lac object B3 2247+381 during a high optical state.
Methods: The MAGIC telescopes observed the source during 13 nights between September 30th and October 30th 2010, collecting a total of 14.2 h of good quality very high energy (VHE) {$\gamma$}-ray data. Simultaneous multiwavelength data was obtained with X-ray observations by the Swift satellite and optical R-band observations at the KVA-telescope. We also use high energy {$\gamma$}-ray (HE, 0.1-100 GeV) data from the Fermi satellite.
Results: The BL Lac object B3 2247+381 (z = 0.119) was detected, for the first time, at VHE {$\gamma$}-rays at a statistical significance of 5.6{$\sigma$}. A soft VHE spectrum with a photon index of -3.2 {\plusmn} 0.6 was determined. No significant short term flux variations were found. We model the spectral energy distribution using a one-zone SSC-model, which can successfully describe our data.}, keywords = {BL Lacertae objects: individual: B3 2247+381, galaxies: active}, doi = {10.1051/0004-6361/201117967}, url = {http://adsabs.harvard.edu/abs/2012A\%26A...539A.118A}, 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 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 Huber, B. and Jogler, T. and Kellermann, H. and Klepser, S. and Kr{\"a}henb{\"u}hl, T. and Krause, 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 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 Munar-Adrover, P. and Nieto, D. and Nilsson, K. and Orito, R. and Oya, I. and Paneque, D. and Paoletti, R. and Pardo, S. and Paredes, J.~M. and Partini, S. and Pasanen, M. and Pauss, F. 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 Puljak, I. and Reichardt, I. and Reinthal, R. and Rhode, W. and Rib{\'o}, M. and Rico, J. 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 Kadenius, V. and Weidinger, M. and Buson, S.} } @article {2012A\&A...544A.142A, title = {{Discovery of VHE {$\gamma$}-rays from the blazar 1ES 1215+303 with the MAGIC telescopes and simultaneous multi-wavelength observations}}, journal = {Astronomy and Astrophysics}, volume = {544}, year = {2012}, month = {aug}, pages = {A142}, abstract = {Context. We present the discovery of very high energy (VHE, E {\gt} 100 GeV) {$\gamma$}-ray emission from the BL Lac object 1ES 1215+303 by the MAGIC telescopes and simultaneous multi-wavelength data in a broad energy range from radio to {$\gamma$}-rays.
Aims: We study the VHE {$\gamma$}-ray emission from 1ES 1215+303 and its relation to the emissions in other wavelengths.
Methods: Triggered by an optical outburst, MAGIC observed the source in 2011 January - February for 20.3 h. The target was monitored in the optical R-band by the KVA telescope that also performed optical polarization measurements. We triggered target of opportunity observations with the Swift satellite and obtained simultaneous and quasi-simultaneous data from the Fermi Large Area Telescope and from the Mets{\"a}hovi radio telescope. We also present the analysis of older MAGIC data taken in 2010.
Results: The MAGIC observations of 1ES 1215+303 carried out in 2011 January - February resulted in the first detection of the source at VHE with a statistical significance of 9.4{$\sigma$}. Simultaneously, the source was observed in a high optical and X-ray state. In 2010 the source was observed in a lower state in optical, X-ray, and VHE, while the GeV {$\gamma$}-ray flux and the radio flux were comparable in 2010 and 2011. The spectral energy distribution obtained with the 2011 data can be modeled with a simple one zone SSC model, but it requires extreme values for the Doppler factor or the electron energy distribution.}, keywords = {BL Lacertae objects: individual: 1ES 1215+303, gamma-rays: galaxies}, doi = {10.1051/0004-6361/201219133}, url = {http://adsabs.harvard.edu/abs/2012A\%26A...544A.142A}, author = {Aleksi{\'c}, J. and Alvarez, E.~A. and Antonelli, L.~A. and Antoranz, P. and Ansoldi, S. and Asensio, M. and Backes, M. and Barres de Almeida, U. and Barrio, J.~A. and Bastieri, D. and Becerra Gonz{\'a}lez, J. and Bednarek, W. 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 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 Da Vela, P. 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 Terrats, D. and Gaug, M. and Giavitto, G. and Godinovi{\'c}, N. and Gonz{\'a}lez Mu{\~n}oz, A. and Gozzini, S.~R. and Hadasch, D. and H{\"a}fner, D. and Herrero, A. and Hildebrand, D. and Hose, J. and Hrupec, D. and Huber, B. and Jankowski, F. and Jogler, T. and Kadenius, V. and Kellermann, H. and Klepser, S. and Kr{\"a}henb{\"u}hl, T. and Krause, J. and La Barbera, A. and Lelas, D. and Leonardo, E. and Lewandowska, N. and Lindfors, E. and Lombardi, S. and L{\'o}pez, M. and L{\'o}pez-Coto, R. 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 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 Niedzwiecki, A. and Nieto, D. and Nilsson, K. and Nowak, N. and Orito, R. and Paiano, S. 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 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 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 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 Sun, S. 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 Vogler, P. and Wagner, R.~M. and Weitzel, Q. and Zabalza, V. and Zandanel, F. and Zanin, R. and Berdyugin, A. and Buson, S. and J{\"a}rvel{\"a}, E. and Larsson, S. and L{\"a}hteenm{\"a}ki, A. and Tammi, J.} } @article {2012ApJ...748...46A, title = {{PG 1553+113: Five Years of Observations with MAGIC}}, journal = {The Astrophysical Journal}, volume = {748}, year = {2012}, month = {mar}, pages = {46}, abstract = {We present the results of five years (2005-2009) of MAGIC observations of the BL Lac object PG 1553+113 at very high energies (VHEs; E {\gt} 100 GeV). Power-law fits of the individual years are compatible with a steady mean photon index {$\Gamma$} = 4.27 {\plusmn} 0.14. In the last three years of data, the flux level above 150 GeV shows a clear variability (probability of constant flux {\l}t} 0.001\%). The flux variations are modest, lying in the range from 4\% to 11\% of the Crab Nebula flux. Simultaneous optical data also show only modest variability that seems to be correlated with VHE gamma-ray variability. We also performed a temporal analysis of (all available) simultaneous Fermi/Large Area Telescope data of PG 1553+113 above 1 GeV, which reveals hints of variability in the 2008-2009 sample. Finally, we present a combination of the mean spectrum measured at VHEs with archival data available for other wavelengths. The mean spectral energy distribution can be modeled with a one-zone synchrotron self-Compton model, which gives the main physical parameters governing the VHE emission in the blazar jet.}, keywords = {BL Lacertae objects: individual: PG 1553+113, gamma rays: galaxies, radiation mechanisms: non-thermal}, doi = {10.1088/0004-637X/748/1/46}, url = {http://adsabs.harvard.edu/abs/2012ApJ...748...46A}, 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 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 Huber, B. and Jogler, T. and Kellermann, H. and Klepser, S. and Kr{\"a}henb{\"u}hl, T. and Krause, 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 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 Munar-Adrover, P. and Nieto, D. and Nilsson, K. and Orito, R. and Oya, I. and Paneque, D. and Paoletti, R. and Pardo, S. and Paredes, J.~M. and Partini, S. and Pasanen, M. and Pauss, F. 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 Puljak, I. and Reichardt, I. and Reinthal, R. and Rhode, W. and Rib{\'o}, M. and Rico, J. 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 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 Buson, S. and Horan, D. and Larsson, S. and D{\textquoteright}Ammando, F.} } @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...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...730L...8A, title = {{MAGIC Discovery of Very High Energy Emission from the FSRQ PKS 1222+21}}, journal = {The Astrophysical Journal Letters}, volume = {730}, year = {2011}, month = {mar}, pages = {L8}, abstract = {{Very high energy (VHE) {$\gamma$}-ray emission from the flat spectrum radio quasar (FSRQ) PKS 1222+21 (4C 21.35}, keywords = {cosmic background radiation, galaxies: active, galaxies: jets, gamma rays: galaxies, quasars: individual: PKS 1222+21}, doi = {10.1088/2041-8205/730/1/L8}, url = {http://adsabs.harvard.edu/abs/2011ApJ...730L...8A}, 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 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 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 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 Huber, B. and Jogler, T. and Klepser, S. and Kr{\"a}henb{\"u}hl, T. and Krause, J. and La Barbera, A. and Lelas, D. and Leonardo, E. and Lindfors, E. and Lombardi, S. and L{\'o}pez, M. and Lorenz, E. 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 Paneque, D. and Paoletti, R. and Pardo, S. and Paredes, J.~M. and Partini, S. and Pasanen, M. and Pauss, F. 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 Puljak, I. and Reichardt, I. and Reinthal, R. and Rhode, W. and Rib{\'o}, M. and Rico, J. 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 Sobczynska, D. and Spanier, F. and Spiro, S. and Stamerra, A. and Steinke, B. and Storz, J. and Strah, N. and Suri{\'c}, T. and Takalo, L. and Tavecchio, F. and Temnikov, P. and Terzi{\'c}, T. and Tescaro, D. and Teshima, M. and Thom, M. and Tibolla, O. and Torres, D.~F. and Treves, A. and Vankov, H. and Vogler, P. and Wagner, R.~M. and Weitzel, Q. and Zabalza, V. and Zandanel, F. and Zanin, R. and MAGIC Collaboration and Tanaka, Y.~T. and Wood, D.~L. and Buson, S.} }