# The kinematic distances of SNR G16.7+0.1 and G15.9+0.2 by analyzing HI absorption spectra

## TL;DR

This study determines the distances to SNRs G16.7+0.1 and G15.9+0.2 using HI absorption spectra, resolving previous ambiguities and analyzing associated molecular emissions to understand their physical properties.

## Contribution

The paper provides new distance estimates for the SNRs using HI absorption spectra and resolves the near/far ambiguity for G16.7+0.1, incorporating CO emission analysis.

## Key findings

- G15.9+0.2 is 7-16 kpc away.
- G16.7+0.1 is approximately 14 kpc distant.
- CO emission supports shock acceleration at the maser site.

## Abstract

We build HI absorption spectra towards Supernova Remnant (SNRs) G16.7+0.1 and G15.9+0.2 using the THOR survey data. With the absorption spectra, we give a new distance range of 7 to 16 kpc for G15.9+0.2. We also resolve the near/far-side distance ambiguity of G16,7+0.1 and confirm its kinematic distance of about 14 kpc. In addition, we analyze the CO (J=3-2) spectra towards G16.7+0.1 and find obvious CO emission at the 20 kms$^{-1}$ OH 1720 MHz maser site. This supports Reynoso and Mangum (2000)'s suggestions that the velocity difference between the maser and southern molecular cloud is caused by the shock acceleration. We discuss the impact of the distances on other physical parameters of the two SNRs.