T-RaMiSu: the Two-meter Radio Mini Survey

I. The Boötes Field^⋆

¹ Leiden Observatory, Leiden University, PO Box 9513 2300 RA, Leiden, The Netherlands
e-mail: wwilliams@strw.leidenuniv.nl
² Netherlands Institute for Radio AStronomy (ASTRON), PO Box 2, 7990 AA Dwingeloo, The Netherlands
³ National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903-2475, USA

Received: 15 August 2012
Accepted: 31 October 2012

Abstract

We present wide area, deep, high-resolution 153 MHz GMRT observations of the NOAO Boötes field, adding to the extensive, multi-wavelength data of this region. The observations, data reduction, and catalogue construction and description are described here. The seven pointings produced a final mosaic covering 30 square degrees with a resolution of 25″. The rms noise is 2 mJy beam^-1 in the centre of the image, rising to 4–5 mJy beam^-1 on the edges, with an average of 3 mJy beam^-1. Seventy-five per cent of the area has an rms <4 mJy beam^-1. The extracted source catalogue contains 1289 sources detected at 5σ, of which 453 are resolved. We estimate the catalogue to be 92 per cent reliable and 95 per cent complete at an integrated flux density limit of 14 mJy. The flux densities and astrometry have been corrected for systematic errors. We calculate the differential source counts, which are in good agreement with those in the literature and provide an important step forward in quantifying the source counts at these low frequencies and low flux densities. The GMRT 153 MHz sources have been matched to the 1.4 GHz NVSS and 327 MHz WENSS catalogues and spectral indices were derived.