Extragalactic sources towards the central region of the Galaxy

TL;DR

This study systematically investigates the radio polarization of 64 sources near the Galactic Center, primarily extragalactic, to understand the Faraday rotation measure, revealing new background sources and Galactic HII regions.

Contribution

First systematic polarization study of background sources near the Galactic Center, significantly increasing known extragalactic sources in this region.

Findings

Identified 59 extragalactic sources in the sample.

Discovered four Galactic HII regions based on morphology and spectral data.

Provided initial polarization measurements for sources near the Galactic Center.

Abstract

We have observed a sample of 64 small diameter sources towards the central -6 degree < l< 6 degree, -2 degree < b < 2 degree of the Galaxy with the aim of studying the Faraday rotation measure near the Galactic Centre (GC) region. All the sources were observed at 6 and 3.6 cm wavelengths using the ATCA and the VLA. Fifty nine of these sources are inferred to be extragalactic. The observations presented here constitute the first systematic study of the radio polarisation properties of the background sources towards this direction and increases the number of known extragalactic radio sources in this part of the sky by almost an order of magnitude. Based on the morphology, spectral indices and lack of polarised emission, we identify four Galactic HII regions in the sample.