A 610-MHz survey of the Lockman Hole with the Giant Metrewave Radio Telescope - I. Observations, data reduction and source catalogue for the central 5 square degrees

TL;DR

This paper reports a detailed 610-MHz survey of the Lockman Hole using GMRT, producing a source catalogue of 2845 objects and analyzing radio source counts to understand galaxy evolution.

Contribution

It presents new high-resolution radio observations, a comprehensive source catalogue, and insights into galaxy evolution through source count analysis.

Findings

Detected 2845 sources above 6 sigma threshold

Radio source counts support pure luminosity evolution models

Combined 610-MHz and 1.4-GHz data explain galaxy evolution

Abstract

We present observations of the Lockman Hole with the Giant Metrewave Radio Telescope (GMRT). Twelve pointings were observed, covering a total area of ~ five square degrees with a resolution of 6 x 5 arcsec, position angle +45deg. The majority of the pointings have an rms noise of 60 microJy/beam before correction for the attenuation of the GMRT primary beam. Techniques used for data reduction and production of a mosaicked image of the region are described, and the final mosaic is presented, along with a catalogue of 2845 sources detected above 6 sigma. Radio source counts are calculated at 610 MHz and combined with existing 1.4-GHz source counts, in order to show that pure luminosity evolution of the local radio luminosity functions for active galactic nuclei and starburst galaxies is sufficient to account for the two source counts simultaneously.