The diffuse gamma-ray emission toward the Galactic mini starburst W43

TL;DR

This paper reports the detection and analysis of gamma-ray emission from the star-forming region W43, revealing insights into cosmic-ray acceleration mechanisms linked to stellar winds rather than star formation rate.

Contribution

It provides the first detailed gamma-ray analysis of W43, estimating cosmic-ray energy and highlighting stellar wind as a primary acceleration source.

Findings

Gamma-ray emission detected with 16 sigma significance.

Cosmic-ray proton energy estimated at ~10^{48} erg.

CR luminosity correlates with wind power over SFR.

Abstract

In this paper we report the Fermi Large Area Telescope (LAT) detection of the gamma-ray emission toward the young star forming region W43. Using the latest source catalog and diffuse background models, the extended gamma-ray excess is detected with a significance of about 16 $\sigma$. The gamma-ray emission has a spectrum with a photon index of $2.3 \pm 0.1$. We also performed a detailed analysis of the gas content in this region by taking into account the opacity correction to the HI gas column density. The total cosmic-ray (CR) proton energy is estimated to be on the order of $10^{48}\ \rm erg,$ assuming the gamma-ray are produced from the interaction of the accelerated protons and nuclei with the ambient gas. Comparing this region to the other star formation regions in our Galaxy, we find that the CR luminosity is better correlated with the wind power than the star formation rate (SFR). This result suggests that CRs are primarily accelerated by stellar wind in these systems