Tentative evidence of spatially extended GeV emission from SS433/W50. (arXiv:1904.05127v1 [astro-ph.HE])

Tentative evidence of spatially extended GeV emission from SS433/W50. (arXiv:1904.05127v1 [astro-ph.HE])
<a href="http://arxiv.org/find/astro-ph/1/au:+Sun_X/0/1/0/all/0/1">Xiao-Na Sun</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Yang_R/0/1/0/all/0/1">Rui-Zhi Yang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Liu_B/0/1/0/all/0/1">Bing Liu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Xi_S/0/1/0/all/0/1">Shao-Qiang Xi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Wang_X/0/1/0/all/0/1">Xiang-Yu Wang</a>

We analyze 10 years of Fermi-LAT data towards the SS433/W50 region. With the
latest source catalog and diffuse background models, the gamma-ray excess from
SS433/W50 is detected with a significance of 5.5{sigma} in the photon energy
range of 500 MeV – 10 GeV. Our analysis indicates that an extended flat disk
morphology is preferred over a point-source description, suggesting that the
GeV emission region is much larger than that of the TeV emission detected by
HAWC. The size of the GeV emission is instead consistent with the extent of the
radio nebula W50, a supernova remnant being distorted by the jets, so we
suggest that the GeV emission may originate from this supernova remnant. The
spectral result of the GeV emission is also consistent with an supernova
remnant origin. We also derive the GeV flux upper limits on the TeV emission
region, which put moderate constrains on the leptonic models to explain the
multiwavelength data.

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