Stephane Corbel (CEA)

Title:Discovery of gamma-ray activity from a microquasar by Fermi-LAT

Abstract:

Cygnus X-3 is a high-mass X-ray binary with a Wolf-Rayet star
companion and with a short orbital period.  It occasionnaly becomes
one of the brightest radio source among the Galactic binary systems,
with major flares from its relativistic jets. In the 1970's and early
1980's, it was postulated to be a source of high and very high energy
gamma rays, that generated considerable excitements in the field of
gamma-ray astronomy.  With its unprecedented sensitivity, the Large
Area Telescope (LAT) aboard the Fermi Gamma-Ray Space Telescope
continuously scans the entire sky every ~ 3 hours and is ideally
suited to probe the high energy emission of binary systems. Here, I
will report the results of one year of observations with the LAT of
the very crowded Cygnus region, with specific focus on the microquasar
Cygnus X-3.


The Fermi Large Area Telescope has for the first time discovered high
energy emission from a microquasar, and associated with the activity
from the relativistic jets of Cygnus X-3.  The gamma-ray emission
likely originates from within the binary system, opening new areas in
which to study the formation of relativistic jets.



Reference: LAT Collaboration, Science, Dec 2009, 326, 1512