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

Abstract

We build H I absorption spectra toward 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 7–16 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 toward G16.7+0.1 and find obvious CO emission at the 20 km s−1 OH 1720 MHz maser site. This supports Reynoso & Mangum 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.