Optical observations of Ultra Steep Spectrum radio sources

TL;DR

This study conducts optical follow-up observations of Ultra Steep Spectrum radio sources to identify potential high-redshift radio galaxies, utilizing models and the K-z relation to estimate their redshifts.

Contribution

It demonstrates how 2-meter class telescopes can aid in identifying high-redshift radio galaxies from large-scale low-frequency surveys.

Findings

No optical counterparts detected down to R~23 magnitude.

Sources are likely at high redshift based on models and K-z relation.

Optical follow-up can help confirm high-redshift candidates.

Abstract

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.