Bibcode
Ackermann, M.; Ajello, M.; Allafort, A.; Antolini, E.; Barbiellini, G.; Bastieri, D.; Bellazzini, R.; Bissaldi, E.; Bonamente, E.; Bregeon, J.; Brigida, M.; Bruel, P.; Buehler, R.; Buson, S.; Caliandro, G. A.; Cameron, R. A.; Caraveo, P. A.; Cavazzuti, E.; Cecchi, C.; Chaves, R. C. G.; Chekhtman, A.; Chiang, J.; Chiaro, G.; Ciprini, S.; Claus, R.; Cohen-Tanugi, J.; Conrad, J.; Cutini, S.; D'Ammando, F.; de Palma, F.; Dermer, C. D.; Silva, E. do Couto e.; Donato, D.; Drell, P. S.; Favuzzi, C.; Finke, J.; Focke, W. B.; Franckowiak, A.; Fukazawa, Y.; Fusco, P.; Gargano, F.; Gasparrini, D.; Gehrels, N.; Giglietto, N.; Giordano, F.; Giroletti, M.; Godfrey, G.; Grenier, I. A.; Guiriec, S.; Hayashida, M.; Hewitt, J. W.; Horan, D.; Hughes, R. E.; Iafrate, G.; Johnson, A. S.; Knödlseder, J.; Kuss, M.; Lande, J.; Larsson, S.; Latronico, L.; Longo, F.; Loparco, F.; Lovellette, M. N.; Lubrano, P.; Mayer, M.; Mazziotta, M. N.; McEnery, J. E.; Michelson, P. F.; Mizuno, T.; Monzani, M. E.; Morselli, A.; Moskalenko, I. V.; Murgia, S.; Nemmen, R.; Nuss, E.; Ohsugi, T.; Orienti, M.; Orlando, E.; Perkins, J. S.; Pesce-Rollins, M.; Piron, F.; Pivato, G.; Porter, T. A.; Rainò, S.; Razzano, M.; Reimer, A.; Reimer, O.; Sanchez, D. A.; Schulz, A.; Sgrò, C.; Siskind, E. J.; Spandre, G.; Spinelli, P.; Stawarz, Ł.; Takahashi, H.; Takahashi, T.; Thayer, J. G.; Thayer, J. B.; Thompson, D. J.; Tinivella, M. et al.
Referencia bibliográfica
The Astrophysical Journal, Volume 786, Issue 2, article id. 157, 17 pp. (2014).
Fecha de publicación:
5
2014
Revista
Número de citas
34
Número de citas referidas
31
Descripción
The discovery of rapidly variable Very High Energy (VHE; E > 100 GeV)
γ-ray emission from 4C +21.35 (PKS 1222+216) by MAGIC on 2010
June 17, triggered by the high activity detected by the Fermi Large Area
Telescope (LAT) in high energy (HE; E > 100 MeV) γ-rays, poses
intriguing questions on the location of the γ-ray emitting region
in this flat spectrum radio quasar. We present multifrequency data of 4C
+21.35 collected from centimeter to VHE during 2010 to investigate the
properties of this source and discuss a possible emission model. The
first hint of detection at VHE was observed by MAGIC on 2010 May 3, soon
after a γ-ray flare detected by Fermi-LAT that peaked on April 29.
The same emission mechanism may therefore be responsible for both the HE
and VHE emission during the 2010 flaring episodes. Two optical peaks
were detected on 2010 April 20 and June 30, close in time but not
simultaneous with the two γ-ray peaks, while no clear connection
was observed between the X-ray and γ-ray emission. An increasing
flux density was observed in radio and mm bands from the beginning of
2009, in accordance with the increasing γ-ray activity observed by
Fermi-LAT, and peaking on 2011 January 27 in the mm regime (230 GHz). We
model the spectral energy distributions (SEDs) of 4C +21.35 for the two
periods of the VHE detection and a quiescent state, using a one-zone
model with the emission coming from a very compact region outside the
broad line region. The three SEDs can be fit with a combination of
synchrotron self-Compton and external Compton emission of seed photons
from a dust torus, changing only the electron distribution parameters
between the epochs. The fit of the optical/UV part of the spectrum for
2010 April 29 seems to favor an inner disk radius of
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