# The GeV emission in the field of the star-forming region W30 revisited

## TL;DR

This study analyzes a decade of Fermi LAT data to resolve gamma-ray emission in W30, identifying two distinct structures: one linked to a supernova remnant and another to a pulsar wind nebula, each with different spectral characteristics.

## Contribution

It provides a detailed morphological and spectral analysis that distinguishes two gamma-ray sources in W30, clarifying their origins and emission mechanisms.

## Key findings

- One gamma-ray structure overlaps with SNR G8.7-0.1 with a soft spectrum.
- Another aligns with HESS J1804-216, explained by inverse Compton scattering.
- The second source is attributed to the pulsar wind nebula around PSR J1803-2137.

## Abstract

We present a detailed study of the gamma-ray emission from the direction of the star-forming region W30 based on a decade of the Fermi Large Area Telescope data in the 0.3-300 GeV photon energy range. The morphological and spectral analyses allow us to resolve the gamma-ray emission into two extended structures from different origins. One of them mostly overlaps with the supernova remnant (SNR) G8.7-0.1 and has a soft spectrum that resembles with the spectra of other middle-aged SNRs interacting with molecular clouds. The other shows remarkable spatial and spectral consistency with the TeV emission from HESS J1804-216, and its spectrum could be naturally explained by inverse Compton scattering of electrons like a number of TeV gamma-ray emitting pulsar wind nebulae. Thus we attribute this source to the nebula around the pulsar PSR J1803-2137.