Expansion of the Youngest Galactic Supernova Remnant G1.9+0.3

TL;DR

This study measures the expansion and brightening of the youngest Galactic supernova remnant G1.9+0.3 using Chandra X-ray data, estimating its age around 110 years and highlighting its unique flux increase.

Contribution

It provides the first detailed measurement of G1.9+0.3's expansion and brightening, offering new insights into its age and shock wave physics.

Findings

Expansion rate of 0.642% per year

Flux increase of 1.7% per year

Estimated remnant age of about 110 years

Abstract

We present a measurement of the expansion and brightening of G1.9+0.3, the youngest Galactic supernova remnant, comparing Chandra X-ray images obtained in 2007 and 2009. A simple uniform expansion model describes the data well, giving an expansion rate of 0.642 +/- 0.049 % yr^-1, and a flux increase of 1.7 +/- 1.0 % yr^-1. Without deceleration, the remnant age would then be 156 +/- 11 yr, consistent with earlier results. Since deceleration must have occurred, this age is an upper limit; we estimate an age of about 110 yr, or an explosion date of about 1900. The flux increase is comparable to reported increases at radio wavelengths. G1.9+0.3 is the only Galactic supernova remnant increasing in flux, with implications for the physics of electron acceleration in shock waves