Extreme particle acceleration in the microquasar CygnusX-3
Author(s)
Tavani, M.
Bulgarelli, A.
Piano, G.
Sabatini, S.; Striani, E.; Evangelista, Y.; Trois, A.; Pooley, G.; Trushkin, S.; Nizhelskij, N. A.; McCollough, M.; Koljonen, K. I. I.; Pucella, G.; Giuliani, A.; Chen, A. W.; Costa, E.; Vittorini, V.; Trifoglio, M.; Gianotti, F.; Argan, A.; Barbiellini, G.; Caraveo, P.; Cattaneo, P. W.; Cocco, V.; Contessi, T.; D'Ammando, F.; Del Monte, E.; de Paris, G.; Di Cocco, G.; di Persio, G.; Donnarumma, I.; Feroci, M.; Ferrari, A.; Fuschino, F.; Galli, M.; Labanti, C.; Lapshov, I.; Lazzarotto, F.; Lipari, P.; Longo, F.; Mattaini, E.; Marisaldi, M.; Mastropietro, M.; Mauri, A.; Mereghetti, S.; Morelli, E.; Morselli, A.; Pacciani, L.; Pellizzoni, A.; Perotti, F.; Picozza, P.; Pilia, M.; Prest, M.; Rapisarda, M.; Rappoldi, A.; Rossi, E.; Rubini, A.; Scalise, E.; Soffitta, P.; Vallazza, E.; Vercellone, S.; Zambra, A.; Zanello, D.;
Date Issued
2009-12-01
Mission(s)
Other
Abstract
Super-massive black holes in active galaxies can accelerate particles to relativistic energies, producing jets with associated gamma-ray emission. Galactic `microquasars', which are binary systems consisting of a neutron star or stellar-mass black hole accreting gas from a companion star, also produce relativistic jets, generally together with radio flares. Apart from an isolated event detected in CygnusX-1, there has hitherto been no systematic evidence for the acceleration of particles to gigaelectronvolt or higher energies in a microquasar, with the consequence that we are as yet unsure about the mechanism of jet energization. Here we report four gamma-ray flares with energies above 100MeV from the microquasar CygnusX-3 (an exceptional X-ray binary that sporadically produces radio jets). There is a clear pattern of temporal correlations between the gamma-ray flares and transitional spectral states of the radio-frequency and X-ray emission. Particle acceleration occurred a few days before radio-jet ejections for two of the four flares, meaning that the process of jet formation implies the production of very energetic particles. In CygnusX-3, particle energies during the flares can be thousands of times higher than during quiescent states.