Catalog of One-side Head-Tail Galaxies in the FIRST Survey

TL;DR

This paper presents a systematic catalog of 69 one-side head-tail radio galaxies identified in the FIRST survey, revealing their distribution and properties in galaxy clusters.

Contribution

It introduces an automatic method for identifying OHT galaxies and provides the first comprehensive catalog with analysis of their cluster-related characteristics.

Findings

Most OHT galaxies are near cluster centers.

Tail length weakly anticorrelates with cluster richness.

Tail length inversely relates to radial velocity differences.

Abstract

One-side head-tail (OHT) galaxies are radio galaxies with a peculiar shape. They usually appear in galaxy clusters, but they have never been cataloged systematically. We design an automatic procedure to search for them in the Faint Images of the Radio Sky at Twenty-Centimeters source catalog and compile a sample with 115 HT candidates. After cross-checking with the Sloan Digital Sky Survey photometric data and catalogs of galaxy clusters, we find that 69 of them are possible OHT galaxies. Most of them are close to the center of galaxy clusters. The lengths of their tails do not correlate with the projection distance to the center of the nearest galaxy clusters, but show weak anticorrelation with the cluster richness, and are inversely proportional to the radial velocity differences between clusters and host galaxies. Our catalog provides a unique sample to study this special type of radio galaxies.