2011/10/20 by L. Foschini, Foschini, L., G. Ghisellini +7 · 2 citations
Physics and Astronomy · #Astrophysics and Cosmic Phenomena #FOS: Physical sciences #Gamma-ray bursts and supernovae #High Energy Astrophysical Phenomena (astro-ph.HE) #Radio Astronomy Observations and Technology #astro-ph.HE
paper · pdf · doi:10.48550/arxiv.1110.4471
2011 Fermi Symposium proceedings - eConf C110509
openalex publication_date 2011/10/20 · arxiv created 2012/02/13 · arxiv updated 2012/02/14 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
We studied the rapid variability at GeV gamma rays of the flat-spectrum radio quasar PKS 1222+216, which was recently found by the MAGIC Cerenkov telescope to display very short variability (minutes time scale) at hundreds of GeV. We analyzed the time period between 2010 April 29 and June 20, when the source generated a few gamma-ray flares with flux in the MeV-GeV band in excess of 10-5 ph cm-2 s-1 on daily basis. We set tight upper limits on the observed doubling time scale (about 1 hour on 2010 April 30), the smallest measured to date at MeV-GeV energies, which can constrain the size of the gamma-ray emitting region. We also studied the spectra measured during two flares (2010 April 30 and June 17-18). The combination of spectral and variability studies obtained in the present work favors the hypothesis that gamma rays are generally produced inside the broad-line region (BLR), but sometimes the dissipation can occur at larger distances, nearby the infrared torus.