# Tentative evidence of spatially extended GeV emission from SS433/W50

## TL;DR

This study analyzes a decade of Fermi-LAT data revealing extended GeV gamma-ray emission from SS433/W50, likely originating from the supernova remnant, with implications for understanding its morphology and emission mechanisms.

## Contribution

First detection of spatially extended GeV emission from SS433/W50, suggesting a supernova remnant origin and providing constraints on emission models.

## Key findings

- Gamma-ray excess detected with 6σ significance.
- Extended flat disk morphology preferred over point source.
- GeV emission size matches radio nebula W50.

## Abstract

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 6{\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.