The new sample of Giant radio sources: I. Radio imaging, optical identification and spectroscopy of selected candidates

TL;DR

This paper presents a new sample of giant radio sources with detailed radio and optical observations, including redshift measurements, to study their size evolution and test analytical models of radio source development.

Contribution

It provides a comprehensive dataset of radio and optical observations for a large sample of giant radio sources, including redshift and size estimates, aiding in understanding their evolution.

Findings

70% of sources with redshift data have sizes over 1 Mpc

Redshift measurements for 15 galaxies, mostly below 0.33

Photometric estimates suggest many sources exceed 1 Mpc in size

Abstract

A new sample of very large angular size radio sources has been selected from the 1.4 GHz VLA surveys: FIRST and NVSS. This sample will be very useful for an observational constraint on the time evolution of double radio sources, especially their size, predicted by numerous analytical models of such evolution (cf. Introduction). In this paper we present radio and optical data for a large fraction of the sample sources. They are: high-frequency VLA maps with very weak radio cores detected, deep optical images showing the identified faint host galaxies not visible on the DSS images, and optical spectra of the identified galaxies brighter than about R ~ 18.5 mag taken with the McDonald Observatory 2.1m telescope. For 15 galaxies (of which 4 do not belong to the complete sample) the redshift has been determined. In the result, 44 per cent of galaxies in the complete sample have redshift data (with one exception all redshifts are less than 0.33), of which 70 per cent have a linear size exceeding 1 Mpc. The photometric redshift estimates for other 11 galaxies with 19 mag<R<21.7 mag (0.3<z<0.5) predict their sizes much over 1 Mpc.