Evolution features of giant sources with linear and break steep radio spectra

TL;DR

This paper investigates the evolution and activity cycles of giant radio sources with steep spectra, estimating their ages and analyzing emission ratios to understand their transient injection and periodic activity.

Contribution

It provides new estimates of the ages of giant radio sources with steep spectra and analyzes their emission ratios to reveal periodic activity patterns.

Findings

Estimated galaxy and quasar ages range from 10^7 to 10^8 years.

Steep spectra may result from transient injection and synchrotron losses.

Evidence suggests periodic activity in giant low-frequency steep spectrum radio sources.

Abstract

In the framework of the cosmological model LambdaCDM the features of properties of giant radio sources with steep low-frequency spectra of linear (S) and break (C+) types are examined. Our estimates of characteristic age of galaxies and quasars with steep spectrum from the UTR-2 catalogue have values 10E7-10E8 years. We consider that steep radio spectra may be formed at the transient injection by synchrotron losses of relativistic electrons. To further examination of evolution features of giant sources with steep spectra we consider ratio of emission of radio lobes and accretion disk (and disk crown) versus velocity of jet propagation and characteristic age of these objects. Analysis of obtained relations testifies to periodical activity of giant low-frequency steep spectrum radio sources.