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AGILE confirmation of enhanced gamma-ray activity from NGC 1275

ATel #9934; F. Lucarelli, C. Pittori, F. Verrecchia (ASDC and INAF/OAR), S. Vercellone (INAF/OA-Brera), A. Bulgarelli (INAF/IASF-Bo), M. Tavani (INAF/IAPS, and Univ. Roma Tor Vergata), P. Munar-Adrover, G. Minervini, G. Piano, A. Ursi (INAF/IAPS), I. Donnarumma (INAF/IAPS), V. Fioretti, A. Zoli (INAF/IASF-Bo), E. Striani (CIFS and 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, M. Pilia, A. Trois (INAF/OA-Cagliari), 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), F. Paoletti (East Windsor RSD Hightstown and INAF/IAPS), A. Antonelli (ASDC and INAF/OAR), P. Giommi (ASDC), L. Salotti, G. Valentini, and F. D'Amico (ASI)
on 4 Jan 2017; 15:40 UT
Credential Certification: Fabrizio Lucarelli (fabrizio.lucarelli@asdc.asi.it)

Subjects: Gamma Ray, >GeV, Transient

Following the detection of a VHE gamma-ray flare by MAGIC on Dec. 31st, 2016 from the radio galaxy NGC 1275 (ATel #9929) and the subsequent confirmation by VERITAS (ATel #9931), we performed a dedicated analysis at the source location with AGILE-GRID data.

Integrating from 2016-12-29 23:00 UT to 2016-12-31 23:00 UT, AGILE detected the source with a preliminary significance of about 4 sigma and a flux F(E>100 MeV)=(3.0 +/- 1.2) x 10^-6 ph cm^-2 s^-1, which is about a factor of 12 larger than the most significant flux reported in the 1AGLR Catalogue (Verrecchia et al., A&A 558, 137 (2013)).

During this time period, the source is close to the region not accessible to observations due to the solar panel constraints; this might limit the significance of the detection.

This measurement was obtained with AGILE observing a large portion of the sky in spinning mode. Further multifrequency observations of NGC 1275 are strongly encouraged.