AGILE detection of gamma-ray emission from 4C+21.35 (PKS 1222+21)

ATel #2641; A. Bulgarelli, F. Gianotti, M. Trifoglio (INAF/IASF Bologna), M. Tavani (INAF/IASF Roma), S. Vercellone (INAF/IASF Palermo), E. Striani (Univ. Tor Vergata), C. Pittori, F. Verrecchia (ASDC), S. Sabatini, G. Piano (INAF/IASF Roma), F. D'Ammando (INAF/IASF Palermo), A. Argan, A. Trois, G. De Paris, V. Vittorini, E. Costa, I. Donnarumma, M. Feroci, L. Pacciani, E. Del Monte, F. Lazzarotto, P. Soffitta, Y. Evangelista, I. Lapshov (INAF/IASF Roma), A. Chen, A. Giuliani (INAF/IASF Milano), M. Marisaldi, G. Di Cocco, C. Labanti, F. Fuschino, M. Galli (INAF/IASF Bologna), P. Caraveo, S. Mereghetti, F. Perotti (INAF/IASF Milano), G. Pucella, M. Rapisarda (ENEA-Roma), A. Pellizzoni, M. Pilia (INAF/OA-Cagliari), G. Barbiellini, F. Longo (INFN Trieste), P. Picozza, A. Morselli (INFN and Univ. Tor Vergata), M. Prest (Universita` dell'Insubria), P. Lipari, D. Zanello (INFN Roma-1), P. W. Cattaneo, A. Rappoldi (INFN Pavia), P. Giommi, P. Santolamazza, F. Lucarelli, S. Colafrancesco, (ASDC), L. Salotti (ASI).
on 26 May 2010; 12:44 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 an increasing gamma-ray flux above 100 MeV from a source positionally consistent with the blazar 4C+21.35 (RA: 185.597558, Dec: 21.656435).

Integrating from 2010-05-23 14:30 UT to 2010-05-26 05:22 UT, a quicklook maximum likelihood analysis yields a detection centered at Galactic coordinates (l,b) = (255.07, 81.7) ± 0.4 deg (stat.) ± 0.1 deg (syst.) (R.A. = 12h 25m 1.72s, Dec. = 21h 24m 29.8s ) with a significance level above 7 sigma and gamma-ray flux above 300 e-8 ph/cm2/sec for photon energies larger than 100 MeV.

This detection of PKS 1222+21 turns out to be the most significant one since the beginning of operations of AGILE in spinning mode (early November 2009). The source may start a phase of rising gamma-ray emission as previously detected in recent months (ATel #2021, #2348, #2349, #2584, #2617, #2626).

Multifrequency observations of PKS 1222+21 are strongly encouraged.