A sample of ultra steep spectrum sources selected from the Westerbork In the Southern Hemisphere (WISH) survey

Abstract

The 352 MHz Westerbork In the Southern Hemisphere (WISH) survey is the southern extension of the WENSS, covering 1.60 sr between −9 ◦ <δ< −26 ◦ to a limiting flux density of ∼18 mJy (5σ). Due to the very low elevation of the observations, the survey has a much lower resolution in declination than in right ascension (54 �� × 54 �� cosec δ). A correlation with the 1.4 GHz NVSS shows that the positional accuracy is less constrained in declination than in right ascension, but there is no significant systematic error. We present a source list containing 73570 sources. We correlate this WISH catalogue with the NVSS to construct a sample of faint Ultra Steep Spectrum (USS) sources, which is accessible for follow-up studies with large optical telescopes in the southern hemisphere. This sample is aimed at increasing the number of known high redshift radio galaxies to allow detailed follow-up studies of these massive galaxies and their environments in the early Universe.