Optical and HI observations of IC 443 and G189.6+3.3 in a complex environment

TL;DR

This study uses optical and HI observations to analyze the complex environment of supernova remnants IC 443 and G189.6+3.3, revealing filamentary structures, density estimates, and possible HI shells.

Contribution

It provides new optical imaging and spectroscopic data, confirming the SNR nature of G189.6+3.3 and identifying HI shell-like features associated with these remnants.

Findings

Confirmed G189.6+3.3 as an SNR via [SII]/H_alpha ratios

Estimated electron and pre-shock cloud densities indicating complex surroundings

Discovered shell-like HI structures possibly linked to G189.6+3.3

Abstract

The supernova remnant (SNR) IC 443 is one of the best-studied Galactic SNRs at many wavelengths. It is interacting with a very complex environment, including the SNR G189.6+3.3 and HII regions. In this paper, we observed IC 443 and G189.6+3.3 using 1.5- and 1-m telescopes to better understand the nature of these SNRs in the optical band. We perform H_alpha images showing both filamentary and diffuse structures, and long-slit spectra from many locations with Balmer and forbidden lines detected for IC 443 and G189.6+3.3. The [SII]/ H_alpha ratios confirm the SNR nature of G189.6+3.3. The ranges of our estimated electron density and pre-shock cloud density clearly indicate the complex structure surrounding IC 443 and G189.6+3.3. We also investigated the archival HI data and newly found some shell-like distributions of HI that are possibly associated with G189.6+3.3.