The Molonglo Galactic Plane Survey (MGPS-2): Compact Source Catalogue

TL;DR

The MGPS-2 survey provides a high-resolution radio source catalogue of the southern Galactic plane, revealing that source density is consistent with extragalactic expectations, and updates the SUMSS data with improved cataloguing.

Contribution

This paper presents the first data release of MGPS-2, a high-resolution radio survey of the southern Galactic plane, and updates the SUMSS catalogue with new data and improved processing methods.

Findings

48,850 compact sources identified in MGPS-2

Galactic source density matches extragalactic expectations

SUMSS catalogue updated with 210,412 sources and improved data

Abstract

We present the first data release from the second epoch Molonglo Galactic Plane Survey (MGPS-2). MGPS-2 was carried out with the Molonglo Observatory Synthesis Telescope at a frequency of 843 MHz and with a restoring beam of 45 arcsec x 45 arcsec cosec(dec), making it the highest resolution large scale radio survey of the southern Galactic plane. It covers the range |b| < 10 deg and 245 deg < l < 365 deg and is the Galactic counterpart to the Sydney University Molonglo Sky Survey (SUMSS) which covers the whole southern sky with dec <= -30 deg (|b| > 10 deg). In this paper we present the MGPS-2 compact source catalogue. The catalogue has 48,850 sources above a limiting peak brightness of 10 mJy/beam. Positions in the catalogue are accurate to 1 arcsec - 2 arcsec. A full catalogue including extended sources is in preparation. We have carried out an analysis of the compact source density across the Galactic plane and find that the source density is not statistically higher than the density expected from the extragalactic source density alone. We also present version 2.0 of the SUMSS image data and catalogue which are now available online. The data consists of 629 4.3 deg x 4.3 deg mosaic images covering the 8100 deg^2 of sky with dec <= -30 deg and |b| > 10 deg. The catalogue contains 210,412 radio sources to a limiting peak brightness of 6 mJy/beam at dec <= -50 deg and 10 mJy/beam at dec > -50 deg. We describe the updates and improvements made to the SUMSS cataloguing process.