The Extinction Distance of Supernova Remnants in Combination with the CO Line Measurements

TL;DR

This paper introduces a new method combining CO line observations with 3D extinction maps to accurately determine distances to supernova remnants by analyzing associated molecular clouds and extinction jumps.

Contribution

The study presents a novel approach that improves distance measurements to SNRs by integrating CO line data with 3D extinction mapping, enhancing accuracy over previous methods.

Findings

Distances to four SNRs were precisely measured.

Extinction-based distances agree with previous estimates.

Method offers improved accuracy and robustness.

Abstract

Accurate distance measurements to supernova remnants (SNRs) are crucial for understanding their physical properties and evolution. We present a novel method that combines CO line observations with three-dimensional (3D) extinction maps to determine distances to SNRs (G93.7$-$0.2, G109.1$-$1.0, G156.2+5.7, and G166.0+4.3) through their associated molecular clouds. For each SNR, candidate CO velocity components corresponding to interacting molecular clouds are identified based on previous observational evidence with refinements: [$-$19, $-$3] km s$^{-1}$ for G93.7$-$0.2, [$-$51, $-$46] km s$^{-1}$ for G109.1$-$1.0, [$-$10, 0] km s$^{-1}$ for G156.2+5.7, and [$-$27, $-$15] km s$^{-1}$ for G166.0+4.3. By examining extinction-distance profiles along the sightlines and identifying extinction jumps that spatially coincide with CO emission features, we derive distances of 1.82$\pm$0.13 kpc for G93.7$-$0.2, 3.05$\pm$0.15 kpc for G109.1$-$1.0, 0.60$\pm$0.15 kpc for G156.2+5.7, and 3.44$\pm$0.23 kpc for G166.0+4.3. Our extinction-based distances are largely consistent with previous estimates while with better accuracy and robustness.