AGILE detection of a gamma-ray flare from the blazar 4C+21.35 (PKS 1222+21)

ATel #2686; E. Striani (Univ. Roma Tor Vergata and INFN Roma), F. Verrecchia (ASDC), I. Donnarumma (INAF/IASF-Rm), S. Vercellone (INAF/IASF-Pa), M. Tavani (INAF/IASF-Rm, and Univ. Tor Vergata), A. Bulgarelli, F. Gianotti, M. Trifoglio (INAF/IASF-Bo), A. Chen, A. Giuliani, S. Mereghetti, P. Caraveo, F. Perotti (INAF/IASF-Mi), F. D'Ammando (INAF/IASF-Pa), E. Del Monte, Y. Evangelista, M. Feroci, F. Lazzarotto, L. Pacciani, P. Soffitta, E. Costa, I. Lapshov, M. Rapisarda, A. Argan, G. Piano, G. Pucella, S. Sabatini, A. Trois, V. Vittorini (INAF/IASF-Rm), F. Fuschino, M. Galli, C. Labanti, M. Marisaldi, G. Di Cocco (INAF/IASF-Bo), A. Pellizzoni, M. Pilia (INAF/OA-Cagliari), G. Barbiellini, F. Longo, E. Moretti, E. Vallazza (INFN Trieste), A. Morselli, P. Picozza (INFN and Univ. Roma Tor Vergata), M. Prest (Universita` dell'Insubria), P. Lipari, D. Zanello (INFN and Univ. Roma Sapienza), P. W. Cattaneo, A. Rappoldi (INFN Pavia), C. Pittori, F. Lucarelli, P. Santolamazza, S. Colafrancesco, P. Giommi (ASDC), L. Salotti (ASI)
on 19 Jun 2010; 15:35 UT
Distributed as an Instant Email Notice Request For Observations
Credential Certification: Francesco Verrecchia (francesco.verrecchia@asdc.asi.it)

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AGILE is detecting intense gamma-ray emission above 100 MeV from a source consistent with the Flat Spectrum Radio Quasar PKS 1222+21 (R.A.=186.2, Dec.=21.4).

Integrating from 2010-06-17 09:20 UT to 2010-05-19 09:30 UT, a maximum likelihood analysis yields a detection at a significance level of about 9 sigma, and a flux F = (6.5+/-1.3) 10-6 ph/cm2/s (E > 100 MeV), which correspond to an increase of about a factor of 2 with respect to the previous 48 hours.

This detection followed an activity in VHE reported by MAGIC collaboration in ATel #2684. An increased gamma-ray activity from a source consistent with the blazar PKS 1222+21 was previously reported by AGILE/GRID (ATel #2641, #2348) and Fermi/LAT (ATel #2584, #2349).

The AGILE-GRID detection was obtained while AGILE is observing in spinning mode, surveying a large fraction of the sky each day.

Multifrequency observations of PKS 1222+21 are strongly encouraged.