Optical observations of Ultra Steep Spectrum radio sources
  In this paper we present follow-up optical observations of Ultra Steep Spectrum sources that were found by matching 150 MHz GMRT sources with either the 74 MHz VLSS or the 1400 MHz NVSS. These sources are possibly high-redshift radio galaxies but optical identification is required for clarification. The follow-up observations were conducted with the Liverpool Telescope; in all cases no sources are detected down to an R magnitude of ~23. By applying models and using the K-z relation we are able to suggest that these sources are possibly at high redshift. We discuss how 2m class telescopes can help with the identification of HzRGs from large-scale, low-frequency surveys. 
Samuel J. George, Ian R. Stevens
astro-ph.CO