2007ApJ...664L..39P

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 σ. 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_0.3–10keV=7.1^+1.8_–1.4x10^–12 ergs cm^–2 s^–1 and hydrogen column density N_H=(0.70±0.06)x10²² cm^–2 are compatible with previous results, the photon index Γ=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.