Interaction Between Supernova Remnant G22.7-0.2 And The Ambient Molecular Clouds

TL;DR

This study investigates the interaction between supernova remnant G22.7-0.2 and surrounding molecular clouds using CO observations, revealing evidence of shock interactions and establishing the remnant's distance and association with nearby structures.

Contribution

The paper provides new observational evidence of SNR G22.7-0.2 interacting with molecular clouds and clarifies its distance and association with nearby remnants and HII regions.

Findings

Detection of filamentary molecular gas surrounding the remnant.

Evidence of shocked molecular gas at the southeastern boundary.

Association of the remnant with molecular clouds at 75-79 km/s and a distance of 4.0-4.8 kpc.

Abstract

We have carried out 12CO (J=1-0 and 2-1), 13CO (J=1-0), and C18O (J=1-0) observations in the direction of the supernova remnant (SNR) G22.7-0.2. A filamentary molecular gas structure, which is likely part of a larger molecular complex with VLSR~75-79 km/s, is detected and is found to surround the southern boundary of the remnant. In particular, the high-velocity wing (77-110 km/s) in the 12CO (J=1-0 and J=2-1) emission shows convincing evidence of the interaction between SNR G22.7-0.2 and the 75-79 km/s molecular clouds (MCs). Spectra with redshifted profiles, a signature of shocked molecular gas, are seen in the southeastern boundary of the remnant. The association between the remnant and the 77 km/s MCs places the remnant at the near distance of 4.0-4.8 kpc, which agrees with a location on the Scutum-Crux arm. We suggest that SNR G22.7-0.2, SNR W41, and HII region G022.760-0.485 are at the same distance and are associated with GMC G23.0-0.4.