Multifrequency study of a double-double radio galaxy J0028+0035

TL;DR

This study presents a detailed multi-frequency radio analysis of the double-double radio galaxy J0028+0035, revealing its age, jet activity cycle, and structural properties, and clarifying its classification as a DDRS despite a coincident compact object.

Contribution

It provides the first comprehensive multi-frequency radio analysis of J0028+0035, elucidating its dynamical evolution and confirming its nature as a double-double radio source.

Findings

Outer lobes are approximately 245 Myr old.

Jet activity resumed about 3.6 Myr ago after 11 Myr of quiescence.

Inner and outer lobes have similar injection spectral indices and jet powers.

Abstract

We report the discovery of a double-double radio source (DDRS) J0028+0035. We observed it with LOFAR, GMRT, and the VLA. By combining our observational data with those from the literature, we gathered an appreciable set of radio flux density measurements covering the range from 74 MHz to 14 GHz. This enabled us to carry out an extensive review of physical properties of the source and its dynamical evolution analysis. In particular, we found that, while the age of the large-scale outer lobes is about 245 Myr, the renewal of the jet activity, which is directly responsible for the double-double structure, took place only about 3.6 Myr ago after about 11 Myr long period of quiescence. Another important property typical for DDRSs and also present here is that the injection spectral indices for the inner and the outer pair of lobes are similar. The jet powers in J0028+0035 are similar too. Both these circumstances support our inference that it is, in fact, a DDRS which was not recognized as such so far because of the presence of a coincident compact object close to the inner double so that the centre of J0028+0035 is apparently a triple.