Detection of Gamma-Ray Emission from the Eta-Carinae Region
Antonelli, L. A.; Pian, E.; Costa, E.; Mereghetti, S.; Corcoran, M. F.; Barbiellini, G.; Longo, F.; Morselli, A.; Chen, A. W.; Colafrancesco, S.; Giommi, P.; Di Cocco, G.; Pellizzoni, A.; Pilia, M.; Gianotti, F.; Feroci, M.; D'Ammando, F.; Del Monte, E.; Donnarumma, I.; Evangelista, Y.; Soffitta, P.; Trois, A.; Moretti, E.; Vercellone, S.; Pacciani, L.; Verrecchia, F.; Vittorini, V.; Tavani, M.; Bulgarelli, A.; Giuliani, A.; Pucella, G.; Argan, A.; Caraveo, P.; Cattaneo, P. W.; Ferrari, A.; Fiorini, M.; Fuschino, F.; Galli, M.; Labanti, C.; Lapshov, I.; Lazzarotto, F.; Lipari, P.; Marisaldi, M.; Morelli, E.; Perotti, F.; Piano, G.; Picozza, P.; Prest, M.; Rapisarda, M.; Rappoldi, A.; Rubini, A.; Sabatini, S.; Trifoglio, M.; Vallazza, E.; Zanello, D.; Pittori, C.; Santolamazza, P.; Salotti, L.; DeParis, G.; Zambra, A.; Boffelli, F.; Cocco, V.; Froysland, T.; Mastropietro, M.; Porrovecchio, G.; Viotti, R. F.
Italy, United States
Abstract
We present the results of extensive observations by the gamma-ray AGILE satellite of the Galactic region hosting the Carina nebula and the remarkable colliding wind binary Eta Carinae (η Car) during the period 2007 July-2009 January. We detect a gamma-ray source (1AGL J1043-5931) consistent with the position of η Car. If 1AGL J1043-5931 is associated with the Car system, our data provide the long sought first detection above 100 MeV of a colliding wind binary. The average gamma-ray flux above 100 MeV and integrated over the preperiastron period 2007 July-2008 October is F γ = (37 ± 5) × 10-8 ph cm-2 s-1 corresponding to an average gamma-ray luminosity of L γ = 3.4 × 1034 erg s-1 for a distance of 2.3 kpc. We also report a two-day gamma-ray flaring episode of 1AGL J1043-5931 on 2008 October 11-13 possibly related to a transient acceleration and radiation episode of the strongly variable shock in the system.