Near-Infrared Spectroscopy of Young Galactic Supernova Remnants

TL;DR

This paper reviews near-infrared [Fe II] observations of young Galactic supernova remnants, highlighting recent spectroscopic findings including the detection of strong [P II] lines in Cas A, to explore supernova ejecta and interactions.

Contribution

It presents a review of NIR [Fe II] observations in SNRs and reports new spectroscopic detection of [P II] lines in Cas A, advancing understanding of supernova remnants.

Findings

[Fe II] lines are prominent in SNRs, useful for NIR studies.

Detected strong [P II] lines in Cas A.

Reviewed existing NIR [Fe II] observations of SNRs.

Abstract

Young Galactic supernova remnants (SNRs) are where we can observe closely the supernova (SN) ejecta and its interaction with circumstellar/interstellar medium. Therefore, they provide an opportunity to explore the explosion and the final stage of the evolution of massive stars. Near-infrared (NIR) emission lines in SNRs mostly originate from shocked dense material. In shocked SN ejecta, forbidden lines from heavy ions are prominent, while in shocked circumstellar/interstellar medium, [Fe II] and H2 lines are prominent. [Fe II] lines are strong in both media, and therefore [Fe II] line images provide a good starting point for the NIR study of SNRs. There are about twenty SNRs detected in [Fe II] lines, some of which have been studied in NIR spectroscopy. We will review the NIR [Fe II] observations of SNRs and introduce our recent NIR spectroscopic study of the young core-collapse SNR Cas A where we detected strong [P II] lines.