X-ray Luminosity of Decades-Old Supernovae

TL;DR

This study extends the X-ray light curves of old supernovae to better understand their transition to supernova remnants, revealing luminosity trends over time and the influence of surrounding media.

Contribution

It provides new long-term X-ray observations of ancient supernovae, bridging the knowledge gap between supernovae and supernova remnants.

Findings

X-ray luminosity decreases over time in wind medium environments.

Luminosity is expected to increase during the Sedov phase in constant density media.

All supernovae with multiple data points show similar decreasing X-ray luminosity.

Abstract

The transition from supernovae (SNe) to supernova remnants (SNRs) remains poorly understood, given the age gap between well-studied examples of the two. In order to bridge this gap, we analysed archival Chandra data for some of the oldest supernovae detected in X-rays, in order to extend their light curves out to late times. We fitted the spectra with thermal models. All the SNe with multiple X-ray data points were found to have similar X-ray luminosity, which was decreasing with time. The X-ray luminosity will likely continue to decrease while the SNe are evolving in a wind medium, but is anticipated to increase in the Sedov phase when the SNe are interacting with a constant density interstellar medium, bringing it in line with observed SNRs.