GMRT detection of a new wide-angle tail (WAT) radio source associated with the galaxy PGC 1519010

TL;DR

This paper reports the discovery of a new Wide-Angle-Tail radio galaxy associated with galaxy PGC 1519010 using GMRT observations, linking radio morphology with galaxy group environment and X-ray emission.

Contribution

First detection of a WAT radio source at 240 and 610 MHz associated with PGC 1519010, linking radio structure with galaxy group and filament environment.

Findings

WAT is hosted by a galaxy in a galaxy group with a filament extending 2.6 Mpc.

Faint diffuse X-ray emission suggests hot intra-cluster gas.

Radio morphology correlates with galaxy environment and models of WAT formation.

Abstract

We report the serendipitous detection of a Wide-Angle-Tail (WAT) radio galaxy at 240 and 610 MHz, using the Giant Metrewave Radio Telescope (GMRT). This WAT is hosted by a cD galaxy PGC 1519010 whose photometric redshift given in the SDSS DR6 catalog is close to the spectroscopic redshifts (0.105, 0.106 and 0.107) of three galaxies found within 4' of the cD. Using the SDSS DR6 we have identified a total of 37 galaxies within 15' of the cD, whose photometric redshifts are between 0.08 and 0.14. This strongly suggests that the cD is associated with a group of galaxies whose conspicuous feature is a north-south chain of galaxies (filament) extending to at least 2.6 Mpc. The $ROSAT$ All-Sky Survey shows a faint, diffuse X-ray source in this direction, which probably marks the hot intra-cluster gas in the potential well of this group. We combine the radio structural information for this WAT with the galaxy clustering in that region to check its overall consistency with the models of WAT formation. The bending of the jet before and after its disruption forming the radio plume, are found to be correlated in this WAT, as seen from the contrasting morphological patterns on the two sides of the core. Probable constraints imposed by this on the models of WAT formation are pointed out. We also briefly report on the other interesting radio sources found in the proximity of the WAT. These include a highly asymmetric double radio source and an ultra-steep spectrum radio source for which no optical counterpart is detected in the SDSS.