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Gamma-ray flaring emission from Cygnus X-3 detected by AGILE

ATel #3151; A. Bulgarelli (INAF/IASF Bologna, Italy), C. Pittori (ASDC), E. Striani (Univ. Tor Vergata), M. Tavani (INAF/IASF Roma), F. Gianotti, M. Trifoglio (INAF/IASF Bologna), G. Pooley (Cavendish Lab., Cambridge, UK), M. McCollough (Smithsonian Astrophys. Observatory, USA), Sergei A. Trushkin (Special Astrophysical Observatory, Russia), G. Piano (INAF/IASF Roma), F. Verrecchia, F. Lucarelli (ASDC), M. Cardillo (Univ. Tor Vergata), 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, S. Sabatini (INAF-IASF-Rm), 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), F. D'Ammando, S. Vercellone (IASF-Pa), A. Pellizzoni, M. Pilia (INAF/OA-Cagliari), G. Barbiellini, F. Longo (INFN and Univ. 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, (ASDC), L. Salotti, G. Valentini (ASI)
on 8 Feb 2011; 15:45 UT
Distributed as an Instant Email Notice Transients
Credential Certification: Andrea Bulgarelli (bulgarelli@iasfbo.inaf.it)

Subjects: X-ray, >GeV, Binary, Transient

AGILE continues to detect gamma-ray flaring emission from a source positionally consistent with the microquasar Cygnus X-3.

Integrating during the period 2011-02-06 05:00 UT to 2011-02-08 09:00 UT (MJD= 55598.21-55600.37) the AGILE-GRID multi-source likelihood analysis finds enhanced gamma-ray emission above 100 MeV from a source at Galactic coordinates (l,b) = (79.46, 0.6) +/- 0.7 (stat.) +/- 0.1 (syst.) deg, (R.A.,Dec.) J2000 = (307.91, 40.58) deg, with flux F > 250 e-8 ph/cm2/sec for a 4.8 sigma significance.

On 2011-02-07 (MJD 55599) the Swift/BAT data indicate that Cygnus X-3 experienced a brief (~ 0.2 day) quenching in the hard X-ray. The Swift/BAT data indicate a trend of decreasing hard X-ray emission over the last several weeks.

This gamma ray flaring activity follows the trend already reported in ATel #3141.

In the following link a 1 day integration intensity map (2011-02-07 05:10 - 2011-02-08 05:50 UT) of the Cygnus region is available.

We strongly encourage multifrequency observations of Cygnus X-3.