AGILE detects enhanced gamma-ray emission above 100 MeV from the blazar S4 0554+58 region
ATel #7155; F. Lucarelli, C. Pittori and F. Verrecchia (ASDC and INAF/OAR), M. Tavani (INAF/IAPS and Univ. Roma Tor Vergata), G. Piano (INAF/IAPS), A. Bulgarelli, V. Fioretti (INAF/IASF-Bo), E. Striani (CIFS and INAF/IAPS), S. Vercellone (INAF/IASF-Pa), 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, G. Valentini and F. D'Amico (ASI)
on 27 Feb 2015; 17:52 UT
Credential Certification: Fabrizio Lucarelli (fabrizio.lucarelli@asdc.asi.it)
Subjects: Gamma Ray, >GeV, Blazar, Transient
Referred to by ATel #: 7282
AGILE is detecting increased gamma-ray emission above 100 MeV from a source positionally consistent with the flat spectrum radio quasar S4 0554+58 (also known as BZQ J0559+5804), with radio coordinates R.A.: 89.8058092 deg, Dec.: 58.0676239 deg (J2000, A. J. Beasley et al., 2002ApJS..141...13B).
Integrating over 48 hours from 2015-02-25 07:30 UT to 2015-02-27 07:30 UT, a preliminary maximum likelihood analysis yields a detection at a significance level above 5 sigma and a flux F(E>100 MeV)=(2.6+/-0.9)x10^-6 ph cm^-2 s^-1.
This is the first time that gamma-ray emission above 100 MeV from the quasar S4 0554+58 region is reported.
This measurement was obtained with AGILE observing a large portion of the sky in spinning mode. Multifrequency observations of the blazar source are strongly encouraged.
