Publication Date:
2009-11-26
Description:
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 Cygnus X-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 100 MeV from the microquasar Cygnus X-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 Cygnus X-3, particle energies during the flares can be thousands of times higher than during quiescent states.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉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 -- Pittori, C -- Verrecchia, F -- Giommi, P -- Colafrancesco, S -- Santolamazza, P -- Antonelli, A -- Salotti, L -- England -- Nature. 2009 Dec 3;462(7273):620-3. doi: 10.1038/nature08578. Epub 2009 Nov 22.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉INAF-IASF Roma, Via del Fosso del Cavaliere 100, I-00133 Roma, Italy. pi.agile@iasf-roma.inaf.it〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19935645" target="_blank"〉PubMed〈/a〉
Print ISSN:
0028-0836
Electronic ISSN:
1476-4687
Topics:
Biology
,
Chemistry and Pharmacology
,
Medicine
,
Natural Sciences in General
,
Physics
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