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AGILE detection of intense gamma-ray emission above 100 MeV from the blazar 4C+21.35 (PKS 1222+21)

ATel #6733; F. Verrecchia, F. Lucarelli and C. Pittori (ASDC and INAF/OAR), A. Bulgarelli, V. Fioretti (INAF/IASF-Bo), M. Tavani (INAF/IAPS and Univ. Roma Tor Vergata), E. Striani (CIFS and INAF/IAPS), S. Vercellone (INAF/IASF-Pa), G. Piano, I. Donnarumma (INAF/IAPS), M. Cardillo (INAF/OA-Arcetri and INAF/IAPS), F. Gianotti, M. Trifoglio (INAF/IASF-Bo), A. Giuliani, S. Mereghetti, P. Caraveo, F. Perotti (INAF/IASF-Mi), A. Chen (Wits University), A. Argan, E. Costa, E. Del Monte, Y. Evangelista, M. Feroci, F. Lazzarotto, I. Lapshov, L. Pacciani, P. Soffitta, S. Sabatini, V. Vittorini (INAF/IAPS), G. Pucella, M. Rapisarda (ENEA-Frascati), G. Di Cocco, F. Fuschino, M. Galli, C. Labanti, M. Marisaldi (INAF/IASF-Bo), A. Pellizzoni, A. Trois (INAF/OA-Cagliari), M. Pilia (ASTRON, the Netherlands), G. Barbiellini, E. Vallazza (INFN Trieste), F. Longo (Univ. Trieste and INFN Trieste), A. Morselli, P. Picozza (INFN and Univ. Roma Tor Vergata), M. Prest (Univ. dell'Insubria), P. Lipari, D. Zanello (INFN and Univ. Roma Sapienza), P. W. Cattaneo, A. Rappoldi (INFN Pavia), S. Colafrancesco (INAF/OAR and Wits University), N. Parmiggiani (University of Modena and Reggio Emilia), A. Ferrari (Univ. Torino and CIFS), P. Giommi (ASDC), L. Salotti, and G. Valentini (ASI)
on 22 Nov 2014; 22:09 UT
Distributed as an Instant Email Notice Transients
Credential Certification: Carlotta Pittori (carlotta.pittori@asdc.asi.it)

Subjects: Gamma Ray, >GeV, Blazar

AGILE is detecting an increasing gamma-ray flux from a source positionally consistent with 4C +21.35 (also known as PKS 1222+21 (R.A.=186.2, Dec.=21.4).

Integrating from 2014-11-20 01:00 UT to 2014-11-22 05:00 UT, a maximum likelihood analysis yields a detection at a significance level of about 6 sigma, and a flux F = (3.2+/-0.9) 10-6 ph/cm2/s (E > 100 MeV), which corresponds to an increase of about a factor of 2 with respect to the previous 48 hours.

An increased gamma-ray activity from a source consistent with the blazar PKS 1222+21 was previously reported by AGILE/GRID (ATel #2686, #2641, #2348).

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.