A multiwavelength study of the thermal composite SNR Kes41 confined in a molecular cavity

We revisited the archival XMM-Newton and Chandra data of the thermal composite SNR Kes 41(G337.8-0.1), performed a millimeter observation toward this source in the ¹²CO, ¹³CO, and C¹⁸O lines, and explored the 5.6-yr Fermi observational data. The X-ray emission, mainly concentrated toward the southwestern part of the SNR, is characterized by distinct S and Ar He-like lines in the spectra. The overabundance of the two elements strongly indicates the presence of a substantial ejecta component in the X-ray-emitting plasma of this SNR. Kes 41 is found to be associated with a giant molecular cloud (MC) at a systemic local standard of rest velocity of -50 km/s and confined in a cavity delineated by a northern molecular shell, a western concave MC that features a discernible shell, and an HI cloud seen toward the southeast of the SNR. The scenario of gas reheating by the shock reflected from the cavity wall is quantitatively consistent with the observations. We also found a gamma-ray source, with a significance of 24σ in 0.2-300 GeV, projectively on the northwest of the SNR, with a power-law photon index $2.38\pm0.03$ and a 0.2-300 GeV luminosity ~1.6*10³⁶ erg/s at an assumed distance 12 kpc. This emission may arise from the SNR-MC hadronic interaction.