DETECTION OF GAMMA-RAY EMISSION FROM THE ETA-CARINAE REGION
Tavani, M. ; Sabatini, S. ; Pian, E. ; Giommi, P. ; Colafrancesco, S. ; Salotti, L.
Jun - 2009
ISSN : 0004-637X ;
journal : The Astrophysical Journal

Issue : 2
type: Article Journal

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 (· Car) during the period 2007 July-2009 January. We detect a gamma-ray source (1AGL J10435931) consistent with the position of · Car. If 1AGL J10435931 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 ³ = (37 ± 5) × 108 ph cm2 s1 corresponding to an average gamma-ray luminosity of L ³ = 3.4 × 1034 erg s1 for a distance of 2.3 kpc. We also report a two-day gamma-ray flaring episode of 1AGL J10435931 on 2008 October 11-13 possibly related to a transient acceleration and radiation episode of the strongly variable shock in the system.

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