Radio Properties of High-Redshift Galaxies at

• Published in: Astrophysical bulletin Vol. 78; no. 4; pp. 443 - 463
• Main Authors: Khabibullina, M. L., Mikhailov, A. G., Sotnikova, Yu. V., Mufakharov, T. V., Mingaliev, M. G., Kudryashova, A. A., Bursov, N. N., Stolyarov, V. A., Udovitskiy, R. Y.
• Format: Journal Article
• Language: English
• Published: Moscow Pleiades Publishing 2023; Springer Nature B.V
• Subjects: Active galactic nuclei; Astronomy; Astrophysics and Cosmology; Broadband; Compact galaxies; Elliptical galaxies; Galactic evolution; Loudness; Luminosity; Physics; Physics and Astronomy; Quasars; Radio emission; Radio galaxies; Radio spectra; Red shift; Spectra; galaxies: active—galaxies: high-redshift—quasars: general—radio continuum: galaxies
• ISSN: 1990-3413; 1990-3421
• DOI: 10.1134/S1990341323700190

Study of high-redshift radio galaxies (HzRGs) can shed light on the active galactic nuclei (AGNs) evolution in massive elliptical galaxies. The vast majority of observed high-redshift AGNs are quasars, and there are very few radio galaxies at redshifts . We present the radio properties of 173 sources optically identified with radio galaxies at with flux densities mJy. Literature data were collected for compilation of broadband radio spectra, estimation of radio variability, radio luminosity, and radio loudness. Almost 60 of the galaxies have steep or ultra-steep radio spectra; 22 have flat, inverted, upturn, and complex spectral shapes, and 18 have peaked spectra (PS). The majority of the PS sources in the sample (20/31) are megahertz-peaked spectrum source candidates, i.e. possibly very young and compact radio galaxies. The median values of the variability indices at 11 and 5 GHz are and , which generally indicates a weak or moderate character of the long-term variability of the studied galaxies. The typical radio luminosity and radio loudness are erg s and respectively. We have found less prominent features of the bright compact radio cores in our sample compared to high-redshift quasars at . The variety of the obtained radio properties shows the different conditions for the formation of radio emission sources in galaxies.