Discovery of a small diameter young supernova remnant G354.4+0.0

TL;DR

This paper reports the discovery of a young supernova remnant G354.4+0.0, characterized by a shell structure with polarized emission, indicating a recent supernova event within a larger HII region, located over 5 kpc away.

Contribution

The discovery of a new young supernova remnant with detailed radio observations and analysis of its morphology and spectrum, adding to the understanding of early supernova remnant evolution.

Findings

Shell-like structure with polarized emission identified

Estimated age of 100-500 years for the remnant

Located more than 5 kpc from the Sun

Abstract

We report discovery of a shell like structure G354.4+0.0 of size 1.6' that shows morphology of a shell supernova remnant. Part of the structure show polarized emission in NRAO VLA sky survey (NVSS) map. Based on 330 MHz, 1.4 GHz Giant Metrewave Radio Telescope (GMRT) observations and existing observations at higher frequencies, we conclude the partial shell structure showing synchrotron emission is embedded in an extended HII region of size ~4'. The spectrum of the diffuse HII region turns over between 1.4 GHz and 330 MHz. HI absorption spectrum shows it to be located more than 5 kpc away from Sun. Based on morphology, non-thermal polarized emission and size, this object is one of the youngest supernova remnants discovered in the Galaxy with an estimated age of about 100-500 years.