GMRT observations of the XMM large scale structure survey field^*

¹ Leiden Observatory, University of Leiden, PO Box 9513, 2300 RA Leiden, The Netherlands e-mail: tasse@strw.leidenuniv.nl
² SUPA, Institute for Astronomy, Royal Observatory Edinburgh, Blackford Hill, Edinburgh EH9 3HJ, UK
³ US Naval Research Laboratory, Remote Sensing Division, 4555 Overlook Avenue, SW, Code 7213, Washington, DC 20375, USA
⁴ CEA/DSM/DAPNIA, Service d'Astrophysique, Saclay, 91191 Gif-sur-Yvette, France
⁵ Department of Physics, Durham University, South Road, Durham, DH1 3LE, UK

Received: 20 December 2006
Accepted: 11 May 2007

Abstract

The low-frequency radio survey of the XMM-Large Scale Structure (XMM-LSS) field aims to study the connection between the extragalactic radio source populations and their environment as traced by X-ray and optical emission. In this paper we present new radio observations of the XMM-LSS field carried out using the Giant Meterwave Radio Telescope at 240 and 610 MHz. These observations complement the observations presented by Cohen at al. (2003, ApJ, 591, 640) and Tasse et al. (2006, A&A, 456, 791) at 74 and 325 MHz with the Very Large Array. At 240 and 610 MHz, we reach noise levels of ~2.5 and ~0.3 mJy/beam, leading to the detection of 466 and 769 sources over 18.0 and 12.7 degree² with resolutions of and respectively. Combining these data with the available source lists at 74, 325 (Tasse et al. 2006, A&A, 456, 791) and 1400 MHz (NVSS), we build a multifrequency catalogue containing 1611 radio sources. We check for consistency of the astrometry and flux density estimates. We fit a simple synchrotron radiation model to the flux density measurements of the 318 radio sources being detected in at least 4 bands. While ~ of them show signature of spectral ageing, ~ show self absorption.