AGILE detection of enhanced gamma-ray emission from Cygnus X-3
ATel #11804; G. Piano (INAF/IAPS), M. Tavani (INAF/IAPS, and Univ. Roma Tor Vergata), S. Vercellone (INAF/OA-Brera), F. Verrecchia, C. Pittori, F. Lucarelli (SSDC and INAF/OAR), A. Ursi, M. Cardillo, G. Minervini (INAF/IAPS), A. Bulgarelli, V. Fioretti, N. Parmiggiani (INAF/IASF-Bo), P. Munar-Adrover (UAB), I. Donnarumma (ASI), E. Striani (CIFS and INAF/IAPS), M. Cardillo (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), 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 2 Jul 2018; 13:14 UT
Distributed as an Instant Email Notice Transients
Credential Certification: Giovanni Piano (giovanni.piano@iaps.inaf.it)
Subjects: Gamma Ray, >GeV, Request for Observations, Binary, Black Hole, Transient
AGILE is detecting gamma-ray emission above 100 MeV from a source positionally consistent with the microquasar Cygnus X-3, at (l, b) = (79.4, 1.1) +/- 0.9 (stat) +/- 0.1 (syst). Integrating from 2018-06-29 UT 11:00:00 to 2018-07-01 UT 11:00:00, a preliminary multi-source likelihood analysis detects a gamma-ray flux F(>100 MeV) = (2.6 +/- 1.2) x 10^-6 photons/cm^2/s.
Hard X-ray emission from the microquasar is at a very-low/undetectable level (Swift/BAT, 15-50 keV; http://swift.gsfc.nasa.gov/results/transients/CygX-3/ ).
As previously detected, this X-ray spectral state may precede plasmoid ejection (Tavani et al., Nature, 462, 620, (2009); Abdo et al., Science, 326, 1512 (2009); Piano et al., A&A, 545, A110 (2012)). Therefore, Cygnus X-3 might produce radio flares in the next few days.
We strongly encourage multi-frequency observations of Cygnus X-3.
