AGILE detection of intense transient gamma-ray activity from Cygnus X-3 emerging from a prolonged quenching state
ATel #15009; G. Piano (INAF/IAPS), F. Verrecchia, C. Pittori (SSDC and INAF/OAR), M. Tavani (INAF/IAPS, and Univ. Roma Tor Vergata), A. Bulgarelli, V. Fioretti, N. Parmiggiani, A. Addis, L. Baroncelli, A. Di Piano (INAF/OAS-Bo), F. Lucarelli (SSDC and INAF/OAR), S. Vercellone (INAF/OA-Brera), M. Cardillo, A. Ursi, C. Casentini (INAF/IAPS), I. Donnarumma (ASI), F. Gianotti, M. Trifoglio (INAF/OAS-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, L. Foffano, I. Lapshov, E. Menegoni, L. Pacciani, P. Soffitta, V. Vittorini (INAF/IAPS), F. Lazzarotto (INAF/OAPD), G. Di Cocco, F. Fuschino, M. Galli, C. Labanti (INAF/OAS-Bo), M. Marisaldi (University of Bergen), A. Pellizzoni, M. Pilia, A. Trois (INAF/OA-Cagliari), G. Barbiellini (INFN Trieste), F. Longo (Univ. Trieste and INFN Trieste), E. Vallazza (INFN Milano Bicocca), 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), L. A. Antonelli (INAF/OAR), P. Giommi, L. Salotti, G. Valentini, and F. D'Amico (ASI)
on 29 Oct 2021; 16:32 UT
Credential Certification: Giovanni Piano (giovanni.piano@inaf.it)
Subjects: Gamma Ray, >GeV, Binary, Black Hole, Transient
Referred to by ATel #: 15018
The microquasar Cyg X-3 recently emerged from a deep and prolonged quenched state, which lasted about 5 months, on October 18, 2021 (Swift/BAT, 15-50 keV; http://swift.gsfc.nasa.gov/results/transients/CygX-3/ ).
AGILE is now detecting intense transient gamma-ray emission above 100 MeV from Cygnus X-3. Integrating from 2021-10-25 UT 00:00:00 to 2021-10-29 UT 00:00:00 (MJD: 59512.0 - 59516.0), a preliminary multi-source likelihood analysis yields a detection with a gamma-ray flux F(>100 MeV) = (2.6 +/- 0.9) x 10^-6 photons/cm^2/s.
Earlier, AGILE found evidence of transient gamma-ray emission from Cyg X-3 at the beginning of the quenched state (2021 May, 24-26, MJD: 59358.875 - 59360.250, ATel #14662) and during the quenched state (2021 July, 11-13, MJD: 59406.0 - 59408.0, ATel #14780).
Recently, the Nasu telescope array reported a strong radio flare of 3.4 Jy at 1.4 GHz (ATel #14989), confirming the well known correlation between gamma-ray and radio flares from Cyg X-3, when emerging from a quenched state (Tavani et al., Nature, 462, 620, 2009). Multifrequency observations of Cyg X-3 during this interesting phase are strongly encouraged.
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.
