Fermi-LAT detection of gamma-ray emission in the vicinity of the star forming regions W43 and Westerlund 2

TL;DR

This paper investigates gamma-ray emissions near star-forming regions W43 and Westerlund 2, exploring various particle acceleration mechanisms in massive star clusters using multi-wavelength data, including recent Fermi-LAT and HESS observations.

Contribution

It provides new insights into the origins of gamma-ray emissions in these regions, analyzing potential acceleration processes and their observational signatures.

Findings

Gamma-ray emission is potentially linked to particle acceleration in star clusters.

Multi-wavelength data supports the association between gamma-ray sources and star-forming regions.

Evidence suggests multiple acceleration mechanisms may operate in these environments.

Abstract

Particle acceleration in massive star forming regions can proceed via a large variety of possible emission scenarios, including high-energy gamma-ray production in the colliding wind zone of the massive Wolf-Rayet binary (here WR 20a and WR 121a), collective wind scenarios, diffusive shock acceleration at the boundaries of wind-blown bubbles in the stellar cluster, and outbreak phenomena from hot stellar winds into the interstellar medium. In view of the recent Fermi-LAT detection of HESS J1023-575 (in the vicinity of Westerlund 2), we examine another very high energy (VHE) gamma-ray source, HESS J1848-0145 (in the vicinity of W43), possibly associated with a massive star cluster. Considering multi-wavelength data, in particular TeV gamma-rays, we examine the available evidence that the gamma-ray emission coincident with Westerlund 2 and W43 could originate in particles accelerated by the above-mentioned mechanisms in massive star clusters.