T-RaMiSu: The Two-meter Radio Mini Survey I. The Bootes Field

TL;DR

This paper presents deep, wide-area 153 MHz GMRT radio observations of the Bootes field, producing a detailed source catalogue and analyzing source counts and spectral indices to enhance low-frequency radio sky understanding.

Contribution

It provides the first extensive 153 MHz survey of the Bootes field, including a high-resolution catalogue and analysis of source counts and spectral properties, advancing low-frequency radio astronomy data.

Findings

Catalogue contains 1289 sources with 92% reliability

Source counts agree with existing literature at low frequencies

Spectral indices derived from cross-matching with other surveys

Abstract

We present wide area, deep, high-resolution 153 MHz GMRT observations of the NOAO Bootes 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 in the centre of the image, rising to 4-5 mJy/beam on the edges, with an average of 3 mJy/beam. Seventy-five per cent of the area has an rms < 4 mJy/beam. The extracted source catalogue contains 1289 sources detected at 5\sigma, 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.