Spectroscopy of "Big Trio" objects using the "Scorpio" spectrograph of the 6-m telescope of the Special astrophysical observatory

TL;DR

This study presents spectroscopic observations of 71 steep-spectrum radio sources from the 'Big Trio' project, determining redshifts and other parameters to understand their properties and distribution across cosmic time.

Contribution

First spectroscopic analysis of a large sample of 'Big Trio' objects, providing redshifts and physical parameters for steep-spectrum radio sources.

Findings

Redshifts determined for 54 objects, ranging from z=0.2 to z=4.51.

Identified several high-redshift quasars and radio galaxies.

17 objects showed no detectable spectral lines.

Abstract

We present the results of spectroscopy of 71 objects with steep and ultra-steep spectra ($\alpha<-0.9$, $S\propto\nu^\alpha$) from the "Big Trio" (RATAN-600-VLA-BTA) project, performed with the "Scorpio" spectrograph on the 6-m telescope of the Special Astrophysical Observatory (Russian Academy of Sciences). Redshifts were determined for these objects. We also present several other parameters of the sources, such as their R-magnitudes, maximum radio sizes in seconds of arc, flux densities at 500, 1425, and 3940 MHz, radio luminosities at 500 and 3940 MHz, and morphology. Of the total number of radio galaxies studied, four have redshifts 1<z<2, three have 2<z<3, one has 3<z<4, and one has z=4.51. Thirteen sources have redshifts 0.7<z<1 and 15 have 0.2<z<0.7. Of all the quasars studied, five have redshifts 0.7<z<1, seven have 1<z<2, four have 2<z<3, and one has z=3.57. We did not detect any spectral lines for 17 objects.