TY - JOUR
A1 - Abramowski, Attila
A1 - Aharonian, Felix
A1 - Benkhali, F. Ait
A1 - Akhperjanian, A. G.
A1 - Anguener, E. O.
A1 - Anton, Gisela
A1 - Backes, M.
A1 - Balenderan, S.
A1 - Balzer, A.
A1 - Barnacka, A.
A1 - Becherini, Y.
A1 - Tjus, J. Becker
A1 - Bernlhr, K.
A1 - Birsin, E.
A1 - Bissaldi, E.
A1 - Biteau, J.
A1 - Boettcher, M.
A1 - Boisson, C.
A1 - Bolmont, J.
A1 - Bordas, P.
A1 - Brucker, J.
A1 - Brun, F.
A1 - Brun, P.
A1 - Bulik, T.
A1 - Carrigan, S.
A1 - Casanova, Sabrina
A1 - Chadwick, P. M.
A1 - Chalme-Calvet, R.
A1 - Chaves, R. C. G.
A1 - Cheesebrough, A.
A1 - Chretien, M.
A1 - Colafrancesco, S.
A1 - Cologna, G.
A1 - Conrad, J.
A1 - Couturier, C.
A1 - Cui, Y.
A1 - Dalton, M.
A1 - Daniel, M. K.
A1 - Davids, I. D.
A1 - Degrange, B.
A1 - Deil, C.
A1 - deWilt, P.
A1 - Dickinson, H. J.
A1 - Djannati-Ataï, A.
A1 - Domainko, W.
A1 - Dubus, G.
A1 - Dutson, K.
A1 - Dyks, J.
A1 - Dyrda, M.
A1 - Edwards, T.
A1 - Egberts, K.
A1 - Eger, P.
A1 - Espigat, P.
A1 - Farnier, C.
A1 - Fegan, S.
A1 - Feinstein, F.
A1 - Fernandes, M. V.
A1 - Fernandez, D.
A1 - Fiasson, A.
A1 - Fontaine, G.
A1 - Foerster, A.
A1 - Fuessling, M.
A1 - Gajdus, M.
A1 - Gallant, Y. A.
A1 - Garrigoux, T.
A1 - Giavitto, G.
A1 - Giebels, B.
A1 - Glicenstein, J. F.
A1 - Grondin, M. -H.
A1 - Grudzinska, M.
A1 - Haeffner, S.
A1 - Hahn, J.
A1 - Harris, J.
A1 - Heinzelmann, G.
A1 - Henri, G.
A1 - Hermann, G.
A1 - Hervet, O.
A1 - Hillert, A.
A1 - Hinton, J. A.
A1 - Hofmann, W.
A1 - Hofverberg, P.
A1 - Holler, M.
A1 - Horns, D.
A1 - Jacholkowska, A.
A1 - Jahn, C.
A1 - Jamrozy, M.
A1 - Janiak, M.
A1 - Jankowsky, F.
A1 - Jung, I.
A1 - Kastendieck, M. A.
A1 - Katarzynski, K.
A1 - Katz, Uli
A1 - Kaufmann, S.
A1 - Khelifi, B.
A1 - Kieffer, M.
A1 - Klepser, S.
A1 - Klochkov, D.
A1 - Kluzniak, W.
A1 - Kneiske, Tanja
A1 - Kolitzus, D.
A1 - Komin, Nu.
A1 - Kosack, K.
A1 - Krakau, S.
A1 - Krayzel, F.
A1 - Krueger, P. P.
A1 - Laffon, H.
A1 - Lamanna, G.
A1 - Lefaucheur, J.
A1 - Lemiere, A.
A1 - Lemoine-Goumard, M.
A1 - Lenain, J. -P.
A1 - Lohse, T.
A1 - Lopatin, A.
A1 - Lu, C. -C.
A1 - Marandon, V.
A1 - Marcowith, A.
A1 - Marx, R.
A1 - Maurin, G.
A1 - Maxted, N.
A1 - Mayer, M.
A1 - McComb, T. J. L.
A1 - Mehault, J.
A1 - Meintjes, P. J.
A1 - Menzler, U.
A1 - Meyer, M.
A1 - Moderski, R.
A1 - Mohamed, M.
A1 - Moulin, E.
A1 - Murach, T.
A1 - Naumann, C. L.
A1 - de Naurois, M.
A1 - Niemiec, J.
A1 - Nolan, S. J.
A1 - Oakes, L.
A1 - Odaka, H.
A1 - Ohm, S.
A1 - Wilhelmi, E. de Ona
A1 - Opitz, B.
A1 - Ostrowski, M.
A1 - Oya, I.
A1 - Panter, M.
A1 - Parsons, R. D.
A1 - Arribas, M. Paz
A1 - Pekeur, N. W.
A1 - Pelletier, G.
A1 - Perez, J.
A1 - Petrucci, P. -O.
A1 - Peyaud, B.
A1 - Pita, S.
A1 - Poon, H.
A1 - Puehlhofer, G.
A1 - Punch, M.
A1 - Quirrenbach, A.
A1 - Raab, S.
A1 - Raue, M.
A1 - Reichardt, I.
A1 - Reimer, A.
A1 - Reimer, Olaf
A1 - Renaud, M.
A1 - de los Reyes, R.
A1 - Rieger, F.
A1 - Rob, L.
A1 - Romoli, C.
A1 - Rosier-Lees, S.
A1 - Rowell, G.
A1 - Rudak, B.
A1 - Rulten, C. B.
A1 - Sahakian, V.
A1 - Sanchez, D. A.
A1 - Santangelo, A.
A1 - Schlickeiser, R.
A1 - Schuessler, F.
A1 - Schulz, A.
A1 - Schwanke, U.
A1 - Schwarzburg, S.
A1 - Schwemmer, S.
A1 - Sol, H.
A1 - Spengler, G.
A1 - Spies, F.
A1 - Stawarz, L.
A1 - Steenkamp, R.
A1 - Stegmann, C.
A1 - Stinzing, F.
A1 - Stycz, K.
A1 - Sushch, I.
A1 - Tavernet, J. -P.
A1 - Tavernier, T.
A1 - Taylor, A. M.
A1 - Terrier, R.
A1 - Tluczykont, M.
A1 - Trichard, C.
A1 - Valerius, K.
A1 - van Eldik, Christopher
A1 - van Soelen, B.
A1 - Vasileiadis, G.
A1 - Venter, C.
A1 - Viana, A.
A1 - Vincent, P.
A1 - Voelk, H. J.
A1 - Volpe, F.
A1 - Vorster, M.
A1 - Vuillaume, T.
A1 - Wagner, S. J.
A1 - Wagner, P.
A1 - Wagner, R. M.
A1 - Ward, M.
A1 - Weidinger, M.
A1 - Weitzel, Q.
A1 - White, R.
A1 - Wierzcholska, A.
A1 - Willmann, P.
A1 - Wrnlein, A.
A1 - Wouters, D.
A1 - Yang, R.
A1 - Zabalza, V.
A1 - Zacharias, M.
A1 - Zdziarski, A. A.
A1 - Zech, A.
A1 - Zechlin, H. -S.
A1 - Finke, J.
A1 - Fortin, P.
A1 - Horan, D.
T1 - The high-energy gamma-ray emission of AP Librae
JF - Astronomy and astrophysics : an international weekly journal
N2 - The gamma-ray spectrum of the low-frequency-peaked BL Lac (LBL) object AP Librae is studied, following the discovery of very-high-energy (VHE; E > 100 GeV) gamma-ray emission up to the TeV range by the H.E.S.S. experiment. Thismakes AP Librae one of the few VHE emitters of the LBL type. The measured spectrum yields a flux of (8.8 +/- 1.5(stat) +/- 1.8(sys)) x 10(-12) cm(-2) s(-1) above 130 GeV and a spectral index of Gamma = 2.65 +/- 0.19(stat) +/- 0.20(sys). This study also makes use of Fermi-LAT observations in the high energy (HE, E > 100 MeV) range, providing the longest continuous light curve (5 years) ever published on this source. The source underwent a flaring event between MJD 56 306-56 376 in the HE range, with a flux increase of a factor of 3.5 in the 14 day bin light curve and no significant variation in spectral shape with respect to the low-flux state. While the H.E.S.S. and (low state) Fermi-LAT fluxes are in good agreement where they overlap, a spectral curvature between the steep VHE spectrum and the Fermi-LAT spectrum is observed. The maximum of the gamma-ray emission in the spectral energy distribution is located below the GeV energy range.
KW - galaxies: active
KW - BL Lacertae objects: individual: AP Librae
KW - gamma rays: galaxies
Y1 - 2015
U6 - http://dx.doi.org/10.1051/0004-6361/201321436
SN - 0004-6361 (print)
SN - 1432-0746 (online)
VL - 573
PB - EDP Sciences
CY - Les Ulis
ER -
TY - JOUR
A1 - Orienti, M.
A1 - Finke, J.
A1 - Raiteri, C. M.
A1 - Hovatta, T.
A1 - Larsson, J.
A1 - Max-Moerbeck, W.
A1 - Perkins, J.
A1 - Readhead, A. C. S.
A1 - Richards, J. L.
A1 - Beilicke, M.
A1 - Benbow, W.
A1 - Berger, K.
A1 - Bird, R.
A1 - Bugaev, V.
A1 - Cardenzana, J. V.
A1 - Cerruti, M.
A1 - Chen, Xuhui
A1 - Ciupik, L.
A1 - Dickinson, H. J.
A1 - Eisch, J. D.
A1 - Errando, M.
A1 - Falcone, A.
A1 - Finley, J. P.
A1 - Fleischhack, H.
A1 - Fortin, P.
A1 - Fortson, L.
A1 - Furniss, A.
A1 - Gerard, L.
A1 - Gillanders, G. H.
A1 - Griffiths, S. T.
A1 - Grube, J.
A1 - Gyuk, G.
A1 - Hakansson, Nils
A1 - Holder, J.
A1 - Humensky, T. B.
A1 - Kar, P.
A1 - Kertzman, M.
A1 - Khassen, Y.
A1 - Kieda, D.
A1 - Krennrich, F.
A1 - Kumar, S.
A1 - Lang, M. J.
A1 - Maier, G.
A1 - McCann, A.
A1 - Meagher, K.
A1 - Moriarty, P.
A1 - Mukherjee, R.
A1 - Nieto, D.
A1 - Ong, R. A.
A1 - Otte, A. N.
A1 - Pohl, Manuela
A1 - Popkow, A.
A1 - Prokoph, H.
A1 - Pueschel, E.
A1 - Quinn, J.
A1 - Ragan, K.
A1 - Reynolds, P. T.
A1 - Richards, G. T.
A1 - Roache, E.
A1 - Rousselle, J.
A1 - Santander, M.
A1 - Sembroski, G. H.
A1 - Smith, A. W.
A1 - Staszak, D.
A1 - Telezhinsky, Igor
A1 - Tucci, J. V.
A1 - Tyler, J.
A1 - Varlotta, A.
A1 - Vassiliev, V. V.
A1 - Wakely, S. P.
A1 - Weinstein, A.
A1 - Welsing, R.
A1 - Williams, D. A.
A1 - Zitzer, B.
T1 - The most powerful flaring activity from the NLSyl PMN J0948+0022
JF - Monthly notices of the Royal Astronomical Society
N2 - We report on multifrequency observations performed during 2012 December-2013 August of the first narrow-line Seyfert 1 galaxy detected in gamma-rays, PMN J0948+0022 (z = 0.5846). A y -ray flare was observed by the Large Area Telescope on board Fermi during 2012 December-2013 January, reaching a daily peak flux in the 0.1-100 GeV energy range of (155 31) x 10 8 ph cm(-2) S-1 on 2013 January 1, corresponding to an apparent isotropic luminosity of similar to 1.5 x 1048 erg s(-1). The y -ray flaring period triggered Swift and Very Energetic Radiation Imaging Telescope Array System (VERITAS) observations in addition to radio and optical monitoring by Owens Valley Radio Observatory, Monitoring Of Jets in Active galactic nuclei with VLBA Experiments, and Catalina Real-time Transient Survey. A strong flare was observed in optical, UV, and X-rays on 2012 December 30, quasi-simultaneously to the y -ray flare, reaching a record flux for this source from optical to y gamma-rays. VERITAS observations at very high energy (E > 100 GeV) during 2013 January 6-17 resulted in an upper limit of F>0.2 Trev < 4.0 x 10(-12) ph cm(-2) s(-1). We compared the spectral energy distribution (SED) of the flaring state in 2013 January with that of an intermediate state observed in 2011. The two SEDs, modelled as synchrotron emission and an external Compton scattering of seed photons from a dust torus, can be modelled by changing both the electron distribution parameters and the magnetic field.
KW - galaxies: active-galaxies: individual: PMN J0948+0022
KW - galaxies: nuclei
KW - galaxies: Seyfert
KW - gamma-rays: general
Y1 - 2015
U6 - http://dx.doi.org/10.1093/mnras/stu2251
SN - 0035-8711 (print)
SN - 1365-2966 (online)
VL - 446
IS - 3
SP - 2456
EP - 2467
PB - Oxford Univ. Press
CY - Oxford
ER -
TY - JOUR
A1 - Aleksic, J.
A1 - Ansoldi, S.
A1 - Antonelli, L. A.
A1 - Antoranz, P.
A1 - Babic, A.
A1 - Bangale, P.
A1 - de Almeida, U. Barres
A1 - Barrio, J. A.
A1 - Gonzalez, J. Becerra
A1 - Bednarek, W.
A1 - Bernardini, E.
A1 - Biasuzzi, B.
A1 - Biland, A.
A1 - Blanch, O.
A1 - Boller, A.
A1 - Bonnefoy, S.
A1 - Bonnoli, G.
A1 - Borracci, F.
A1 - Bretz, T.
A1 - Carmona, E.
A1 - Carosi, A.
A1 - Colin, P.
A1 - Colombo, E.
A1 - Contreras, J. L.
A1 - Cortina, J.
A1 - Covino, S.
A1 - Da Vela, P.
A1 - Dazzi, F.
A1 - De Angelis, A.
A1 - De Caneva, G.
A1 - De Lotto, B.
A1 - Wilhelmi, E. de Ona
A1 - Mendez, C. Delgado
A1 - Prester, Dijana Dominis
A1 - Dorner, D.
A1 - Doro, M.
A1 - Einecke, S.
A1 - Eisenacher, D.
A1 - Elsaesser, D.
A1 - Fonseca, M. V.
A1 - Font, L.
A1 - Frantzen, K.
A1 - Fruck, C.
A1 - Galindo, D.
A1 - Lopez, R. J. Garcia
A1 - Garczarczyk, M.
A1 - Terrats, D. Garrido
A1 - Gaug, M.
A1 - Godinovic, N.
A1 - Munoz, A. Gonzalez
A1 - Gozzini, S. R.
A1 - Hadasch, D.
A1 - Hanabata, Y.
A1 - Hayashida, M.
A1 - Herrera, J.
A1 - Hildebrand, D.
A1 - Hose, J.
A1 - Hrupec, D.
A1 - Hughes, G.
A1 - Idec, W.
A1 - Kadenius, V.
A1 - Kellermann, H.
A1 - Knoetig, M. L.
A1 - Kodani, K.
A1 - Konno, Y.
A1 - Krause, J.
A1 - Kubo, H.
A1 - Kushida, J.
A1 - La Barbera, A.
A1 - Lelas, D.
A1 - Lewandowska, N.
A1 - Lindfors, E.
A1 - Lombardi, S.
A1 - Lopez, M.
A1 - Lopez-Coto, R.
A1 - Lopez-Oramas, A.
A1 - Lorenz, E.
A1 - Lozano, I.
A1 - Makariev, M.
A1 - Mallot, K.
A1 - Maneva, G.
A1 - Mankuzhiyil, N.
A1 - Mannheim, K.
A1 - Maraschi, L.
A1 - Marcote, B.
A1 - Mariotti, M.
A1 - Martinez, M.
A1 - Mazin, D.
A1 - Menzel, U.
A1 - Miranda, J. M.
A1 - Mirzoyan, R.
A1 - Moralejo, A.
A1 - Munar-Adrover, P.
A1 - Nakajima, D.
A1 - Niedzwiecki, A.
A1 - Nilsson, K.
A1 - Nishijima, K.
A1 - Noda, K.
A1 - Orito, R.
A1 - Overkemping, A.
A1 - Paiano, S.
A1 - Palatiello, M.
A1 - Paneque, D.
A1 - Paoletti, R.
A1 - Paredes, J. M.
A1 - Paredes-Fortuny, X.
A1 - Persic, M.
A1 - Moroni, P. G. Prada
A1 - Prandini, E.
A1 - Puljak, I.
A1 - Reinthal, R.
A1 - Rhode, W.
A1 - Ribo, M.
A1 - Rico, J.
A1 - Garcia, J. Rodriguez
A1 - Rugamer, S.
A1 - Saito, T.
A1 - Saito, K.
A1 - Satalecka, K.
A1 - Scalzotto, V.
A1 - Scapin, V.
A1 - Schultz, C.
A1 - Schweizer, T.
A1 - Sun, S.
A1 - Shore, S. N.
A1 - Sillanpaa, A.
A1 - Sitarek, J.
A1 - Snidaric, I.
A1 - Sobczynska, D.
A1 - Spanier, F.
A1 - Stamatescu, V.
A1 - Stamerra, A.
A1 - Steinbring, T.
A1 - Steinke, B.
A1 - Storz, J.
A1 - Strzys, M.
A1 - Takalo, L.
A1 - Takami, H.
A1 - Tavecchio, F.
A1 - Temnikov, P.
A1 - Terzic, T.
A1 - Tescaro, D.
A1 - Teshima, M.
A1 - Thaele, J.
A1 - Tibolla, O.
A1 - Torres, D. F.
A1 - Toyama, T.
A1 - Treves, A.
A1 - Uellenbeck, M.
A1 - Vogler, P.
A1 - Zanin, R.
A1 - Archambault, S.
A1 - Archer, A.
A1 - Beilicke, M.
A1 - Benbow, W.
A1 - Berger, K.
A1 - Bird, R.
A1 - Biteau, J.
A1 - Buckley, J. H.
A1 - Bugaev, V.
A1 - Cerruti, M.
A1 - Chen, Xiaoming
A1 - Ciupik, L.
A1 - Collins-Hughes, E.
A1 - Cui, W.
A1 - Eisch, J. D.
A1 - Falcone, A.
A1 - Feng, Q.
A1 - Finley, J. P.
A1 - Fortin, P.
A1 - Fortson, L.
A1 - Furniss, A.
A1 - Galante, N.
A1 - Gillanders, G. H.
A1 - Griffin, S.
A1 - Gyuk, G.
A1 - Hakansson, Nils
A1 - Holder, J.
A1 - Johnson, C. A.
A1 - Kaaret, P.
A1 - Kar, P.
A1 - Kertzman, M.
A1 - Kieda, D.
A1 - Lang, M. J.
A1 - McArthur, S.
A1 - McCann, A.
A1 - Meagher, K.
A1 - Millis, J.
A1 - Moriarty, P.
A1 - Ong, R. A.
A1 - Otte, A. N.
A1 - Perkins, J. S.
A1 - Pichel, A.
A1 - Pohl, Manuela
A1 - Popkow, A.
A1 - Prokoph, H.
A1 - Pueschel, E.
A1 - Ragan, K.
A1 - Reyes, L. C.
A1 - Reynolds, P. T.
A1 - Richards, G. T.
A1 - Roache, E.
A1 - Rovero, A. C.
A1 - Sembroski, G. H.
A1 - Shahinyan, K.
A1 - Staszak, D.
A1 - Telezhinsky, Igor
A1 - Tucci, J. V.
A1 - Tyler, J.
A1 - Varlotta, A.
A1 - Wakely, S. P.
A1 - Welsing, R.
A1 - Wilhelm, Alina
A1 - Williams, D. A.
A1 - Buson, S.
A1 - Finke, J.
A1 - Villata, M.
A1 - Raiteri, C.
A1 - Aller, H. D.
A1 - Aller, M. F.
A1 - Cesarini, A.
A1 - Chen, W. P.
A1 - Gurwell, M. A.
A1 - Jorstad, S. G.
A1 - Kimeridze, G. N.
A1 - Koptelova, E.
A1 - Kurtanidze, O. M.
A1 - Kurtanidze, S. O.
A1 - Lahteenmaki, A.
A1 - Larionov, V. M.
A1 - Larionova, E. G.
A1 - Lin, H. C.
A1 - McBreen, B.
A1 - Moody, J. W.
A1 - Morozova, D. A.
A1 - Marscher, A. P.
A1 - Max-Moerbeck, W.
A1 - Nikolashvili, M. G.
A1 - Perri, M.
A1 - Readhead, A. C. S.
A1 - Richards, J. L.
A1 - Ros, J. A.
A1 - Sadun, A. C.
A1 - Sakamoto, T.
A1 - Sigua, L. A.
A1 - Smith, P. S.
A1 - Tornikoski, M.
A1 - Troitsky, I. S.
A1 - Wehrle, A. E.
A1 - Jordan, B.
T1 - Unprecedented study of the broadband emission of Mrk 421 during flaring activity in March 2010
JF - Astronomy and astrophysics : an international weekly journal
N2 - Context. Because of its proximity, Mrk 421 is one of the best sources on which to study the nature of BL Lac objects. Its proximity allows us to characterize its broadband spectral energy distribution (SED).
Aims. The goal is to better understand the mechanisms responsible for the broadband emission and the temporal evolution of Mrk 421. These mechanisms may also apply to more distant blazars that cannot be studied with the same level of detail.
Methods. A flare occurring in March 2010 was observed for 13 consecutive days (from MJD 55 265 to MJD 55 277) with unprecedented wavelength coverage from radio to very high energy (VHE; E > 100 GeV) gamma-rays with MAGIC, VERITAS, Whipple, Fermi-LAT, MAXI, RXTE, Swift, GASP-WEBT, and several optical and radio telescopes. We modeled the day-scale SEDs with one-zone and two-zone synchrotron self-Compton (SSC) models, investigated the physical parameters, and evaluated whether the observed broadband SED variability can be associated with variations in the relativistic particle population.
Results. The activity of Mrk 421 initially was high and then slowly decreased during the 13-day period. The flux variability was remarkable at the X-ray and VHE bands, but it was minor or not significant at the other bands. The variability in optical polarization was also minor. These observations revealed an almost linear correlation between the X-ray flux at the 2-10 keV band and the VHE gamma-ray flux above 200 GeV, consistent with the gamma-rays being produced by inverse-Compton scattering in the Klein-Nishina regime in the framework of SSC models. The one-zone SSC model can describe the SED of each day for the 13 consecutive days reasonably well, which once more shows the success of this standard theoretical scenario to describe the SEDs of VHE BL Lacs such as Mrk 421. This flaring activity is also very well described by a two-zone SSC model, where one zone is responsible for the quiescent emission, while the other smaller zone, which is spatially separated from the first, contributes to the daily variable emission occurring at X-rays and VHE gamma-rays. The second blob is assumed to have a smaller volume and a narrow electron energy distribution with 3 x 10(4) < gamma < 6 x 10(5), where. is the Lorentz factor of the electrons. Such a two-zone scenario would naturally lead to the correlated variability at the X-ray and VHE bands without variability at the optical/UV band, as well as to shorter timescales for the variability at the X-ray and VHE bands with respect to the variability at the other bands.
Conclusions. Both the one-zone and the two-zone SSC models can describe the daily SEDs via the variation of only four or five model parameters, under the hypothesis that the variability is associated mostly with the underlying particle population. This shows that the particle acceleration and cooling mechanism that produces the radiating particles might be the main mechanism responsible for the broadband SED variations during the flaring episodes in blazars. The two-zone SSC model provides a better agreement with the observed SED at the narrow peaks of the low-and high-energy bumps during the highest activity, although the reported one-zone SSC model could be further improved by varying the parameters related to the emitting region itself (delta, B and R), in addition to the parameters related to the particle population.
KW - radiation mechanisms: non-thermal
KW - galaxies: active
KW - BL Lacertae objects: individual: Mrk 421
KW - gamma rays: galaxies
Y1 - 2015
U6 - http://dx.doi.org/10.1051/0004-6361/201424811
SN - 0004-6361 (print)
SN - 1432-0746 (online)
VL - 578
PB - EDP Sciences
CY - Les Ulis
ER -