A 20 Year Radio Light Curve for the Young Supernova Remnant G1.9+0.3

TL;DR

This study presents a 20-year radio light curve of the youngest known Galactic supernova remnant G1.9+0.3, revealing a steady increase in flux density indicative of magnetic field amplification.

Contribution

The paper provides the first long-term radio flux measurements of G1.9+0.3, showing a consistent flux increase over two decades at a single frequency.

Findings

Flux density increased by approximately 1.22% per year.

G1.9+0.3 is undergoing magnetic field amplification.

The observations span 20 years at 843 MHz.

Abstract

The radio source G1.9+0.3 has recently been identified as the youngest known Galactic supernova remnant, with a putative age of ~100 years. We present a radio light curve for G1.9+0.3 based on 25 epochs of observation with the Molonglo Observatory Synthesis Telescope, spanning 20 years from 1988 to 2007. These observations are all at the same frequency (843 MHz) and comparable resolutions (43" x 91" or 43" x 95") and cover one fifth of the estimated lifetime of the supernova remnant. We find that the flux density has increased at a rate of 1.22 +0.24/-0.16 per cent per year over the last two decades, suggesting that G1.9+0.3 is undergoing a period of magnetic field amplification.