Multifrequency analysis of the radio emission from a post-merger galaxy CGCG 292-057

Abstract

ABSTRACT Galaxies exhibiting a specific large-scale extended radio emission, such as X-shaped radio galaxies, belong to a rare class of winged radio galaxies. The morphological evolution of these radio sources is explained using several theoretical models, including galaxy mergers. However, such a direct link between a perturbed radio morphology and a galaxy merger remains observationally sparse. Here, we investigate a unique radio galaxy J1159+5820, whose host CGCG 292-057 displays the optical signature of a post-merger system with a distinct tidal tail feature, and an X-shaped radio morphology accompanied by an additional pair of inner lobes. We observed the target on a wide range of radio frequencies ranging from 147 to 4959 MHz, using dedicated GMRT and VLA observations, and supplemented it with publicly available survey data for broad-band radio analysis. Particle injection models were fitted to radio spectra of lobes and different parts of the wings. Spectral ageing analysis performed on the lobes and the wings favours a fast jet realignment model with a reorientation time-scale of a few million years. We present our results and discuss the possible mechanisms for the formation of the radio morphology.