Chandra observations of the gamma-ray binary LS I +61 303 : extended X-ray structure?

Josep M. Paredes ... [et al.].

J. M. Paredes investigador correspondiente del IAR.

Resumen: We present a 50 ks observation of the gamma-ray binary LS I +61 303 carried out with the ACIS-I array aboard the Chandra X-Ray Observatory. This is the highest resolution X-ray observation of the source conducted so far. Possible evidence of an extended structure at a distance between 5" and 12" toward the north of LS I +61 303 has been found at a significance level of 3.2 sigma. The asymmetry of the extended emission excludes an interpretation in the context of a dust-scattered halo, suggesting an intrinsic nature. On the other hand, while the obtained source flux of F[sub]0.3-10keV=7.1[elevado a la]+1.8[sub]-1.4×10[elevado a la]-12 ergs cm[elevado a la]-2 s[elevado a la]-1 and hydrogen column density N[sub]H=(0.70+/-0.06)×10[elevado a la]22 cm[elevado a la]-2 are compatible with previous results, the photon index Gamma=1.25+/-0.09 is the hardest ever found. In light of these new results, we briefly discuss the physics behind the X-ray emission, the location of the emitter, and the possible origin of the extended emission 0.1 pc away from LS I +61 303