Deep GMRT 150 MHz observations of the DEEP2 fields: Searching for High Red-shift Radio Galaxies Revisited

TL;DR

This study uses deep low-frequency GMRT observations to identify ultra-steep spectrum radio sources as potential high-redshift radio galaxies, reaching fainter than previously known populations.

Contribution

It presents a new method of selecting high-redshift radio galaxy candidates using ultra-steep spectrum sources from deep 150 MHz GMRT data, extending the search to much fainter sources.

Findings

Identified approximately 100 steep spectrum radio sources as high-redshift galaxy candidates.

Demonstrated the effectiveness of low-frequency surveys in finding faint high-redshift radio galaxies.

Correlated GMRT data with high-frequency catalogs to select candidate sources.

Abstract

High red-shift radio galaxies are best searched at low radio frequencies, due to its steep radio spectra. Here we present preliminary results from our programme to search for high red-shift radio galaxies to ~ 10 to 100 times fainter than the known population till date. We have extracted ultra-steep spectrum (USS) samples from deep 150 MHz Giant Meter-wave Radio Telescope (GMRT) observations from one of the three well-studied DEEP2 fields to this affect. From correlating these radio sources w.r.t to the high-frequency catalogues such as VLA, FIRST, and NVSS at 1.4 GHz, we find ~ 100 steep spectrum (spectral index, $\alpha$ $>$ 1) radio sources, which are good candidates for high red-shift radio galaxies.