2013A&A...549A..55W

We present wide area, deep, high-resolution 153 MHz GMRT observations of the NOAO Booetes 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 2mJy/beam in the centre of the image, rising to 4-5mJy/beam on the edges, with an average of 3mJy/beam. Seventy-five per cent of the area has an rms<4mJy/beam. 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 14mJy. 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 153MHz sources have been matched to the 1.4GHz NVSS and 327MHz WENSS catalogues and spectral indices were derived.