AGILE detection of enhanced gamma-ray emission from Cygnus X-3
ATel #12677; G. Piano (INAF/IAPS), M. Tavani (INAF/IAPS, and Univ. Roma Tor Vergata), F. Verrecchia, C. Pittori, F. Lucarelli (SSDC and INAF/OAR), M. Cardillo, A. Ursi, C. Casentini (INAF/IAPS), A. Bulgarelli, V. Fioretti, N. Parmiggiani (INAF/IASF-Bo), I. Donnarumma (ASI), S. Vercellone (INAF/OA-Brera), 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, V. Vittorini (INAF/IAPS), G. Di Cocco, F. Fuschino, M. Galli, C. Labanti (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), A. Ferrari (Univ. Torino and CIFS), F. Paoletti (East Windsor RSD Hightstown and INAF/IAPS), A. Antonelli, P. Giommi, L. Salotti, G. Valentini, and F. D'Amico (ASI)
on 20 Apr 2019; 19:31 UT
Distributed as an Instant Email Notice Transients
Credential Certification: Giovanni Piano (giovanni.piano@iaps.inaf.it)
Subjects: Gamma Ray, >GeV, Binary, Black Hole, Transient
AGILE is detecting gamma-ray emission above 100 MeV from a source positionally consistent with the microquasar Cygnus X-3. Integrating from 2019-04-15 UT 15:00:00 to 2019-04-20 UT 15:00:00, a preliminary multi-source likelihood analysis yields a detection with a gamma-ray flux F(>100 MeV) = (1.7 +/- 0.6) x 10^-6 photons/cm^2/s.
On February 2019, the microquasar entered (ATel #12510) in a prolonged quenched/hypersoft state (Swift/BAT, 15-50 keV; http://swift.gsfc.nasa.gov/results/transients/CygX-3/ ) that usually precedes strong radio/gamma-ray flares. A radio flare (ATel #12668) was previously reported on April 18, when Cyg X-3 was emerging from that state.
The AGILE-GRID detection was obtained while AGILE is observing in spinning mode, surveying a large fraction of the sky each day. The source can be monitored with the public mobile application "AGILEScience" developed by the AGILE Team, available for both Android and iOS devices.
Multifrequency observations of Cyg X-3 are strongly encouraged.
