Search for X/Z-shaped radio sources from TGSS ADR 1

TL;DR

This paper presents a systematic search for X-shaped and Z-shaped radio galaxies in the TGSS ADR 1 survey, identifying 58 sources and analyzing their properties, morphology, and spectral characteristics to enhance understanding of these rare radio galaxy subclasses.

Contribution

The study provides the first large sample of 58 XRGs and ZRGs from TGSS data, including detailed morphological and spectral analysis, and compares their properties with previously known sources.

Findings

58 new winged radio galaxies identified from TGSS data

Most XRGs exhibit steep spectral indices, while a significant fraction of ZRGs show flat spectra

Approximately one-third of the sources are classified as FR-I and over half as FR-II

Abstract

A small sub-class of radio galaxies that exhibit a pair of secondary low surface brightness radio lobes oriented at an angle to the primary high surface brightness lobes are known as X-shaped radio galaxies (XRGs). In cases, it is seen that the less luminous secondary lobes emerge from the edges of the primary high brightened lobes and give a Z-symmetric morphology. These are known as Z-shaped radio galaxies (ZRGs). From the TIFR GMRT Sky Survey at 150 MHz, we present a systematic search result for XRGs and ZRGs. We identified a total of 58 radio sources, out of which 40 are XRGs and 18 are ZRGs. Taking advantage of the large sample size of the XRGs and ZRGs reported in the current paper, different properties of XRGs and ZRGs are studied. Out of 58 XRGs and ZRGs presented in the current paper, 19 (32 per cent) are FR-I and 33 (57 per cent) are FR-II radio galaxies. For four XRGs and three ZRGs, the morphology is so complex that they could not be classified. We have estimated radio luminosity and spectral index of newly discovered winged radio galaxies and made a comparative study with previously detected XRGs and ZRGs. Most of the XRGs show a steep spectral index between 150 MHz and 1400 MHz and only 14 per cent of the sources show a flat spectrum but for ZRGs, a good fraction of the sources (36 per cent) show a flat spectrum.