The structure at the centre of the giant radio galaxy GRS J0844+4627: a compact symmetric object?

TL;DR

This study uses high-resolution radio observations to identify a compact symmetric object within the core of the giant radio galaxy GRS J0844+4627, suggesting it is a young, recently restarted active galaxy with a complex, triple-double structure.

Contribution

The paper presents the first high-resolution imaging evidence that the core of GRS J0844+4627 contains a CSO, indicating a new understanding of its structure and evolutionary state.

Findings

The core consists of two components separated by 2.7 kpc.

One component resembles a compact symmetric object (CSO).

The overall structure may be a triple-double radio galaxy.

Abstract

We observed the core region of the giant radio galaxy GRS J0844+4627 with e-MERLIN at 1.52 and 5.07 GHz. These observations revealed that the apparent single feature at the centre of GRS J0844+4627, as seen by GMRT, consists of two components separated by 2.7 kpc in projection. Follow-up observations at 1.66 GHz using the EVN unveiled the complex morphologies of the two components. In particular, the south-western component identified with the SDSS J084408.85+462744.2 galaxy morphologically resembles a compact symmetric object (CSO) with a projected linear size of 115 pc. If the CSO hypothesis turns out to be correct, then the overall radio structure of GRS J0844+4627 is triple-double. Given that CSOs are considered young objects, GRS J0844+4627 would appear as a recently restarted active galaxy.