RC J0311+0507: A Candidate for Superpowerful Radio Galaxies in the Early Universe at Redshift z=4.514

TL;DR

This paper reports the discovery of a candidate superpowerful radio galaxy at redshift 4.514, characterized by ultrasteep spectrum and ultrahigh radio luminosity, indicating a massive black hole in the early universe.

Contribution

It identifies a new high-redshift radio galaxy with extreme luminosity, providing insights into black hole formation in the early universe.

Findings

Detected a strong emission line at 6703A likely Lyα at z=4.514

Classified as an ultrahigh radio luminosity galaxy

Suggests presence of a ~10^9 solar mass black hole at early cosmic times

Abstract

A strong emission line at 6703A has been detected in the optical spectrum for the host galaxy (R=23.1) of the radio source RC J0311+0507 (4C+04.11). This radio galaxy, with a spectral index of 1.31 in the frequency range 365-4850 MHz, is one of the ultrasteep spectrum objects from the deep survey of a sky strip conducted with RATAN-600 in 1980-1981. We present arguments in favor of the identification of this line with Ly\alpha at redshift z=4.514. In this case, the object belongs to the group of extremely distant radio galaxies of ultrahigh radio luminosity (P_{1400}=1.3 x 10^{29}W Hz^{-1}). Such power can be provided only by a fairly massive black hole (~10^9M_\sun}) that formed in a time less than the age of the Universe at the observed z(1.3 Gyr) or had a primordial origin.