Giant Metrewave Radio Telescope Observations of Head-Tail Radio Galaxies

TL;DR

This study uses GMRT observations at 240 and 610 MHz to analyze the morphology and spectral index distribution of seven head-tail radio galaxies, revealing insights into their dynamics, magnetic fields, and plasma aging.

Contribution

It provides detailed morphological and spectral analysis of head-tail radio galaxies, highlighting the effects of host galaxy motion, jet precession, and synchrotron aging.

Findings

Radio tails show steepening of spectral index with distance

Magnetic field strength decreases along the tails

Dynamical ages are approximately 100 million years

Abstract

We present results from a study of seven large known head-tail radio galaxies based on observations using the Giant Metrewave Radio Telescope at 240 and 610 MHz. These observations are used to study the radio morphologies and distribution of the spectral indices across the sources. The overall morphology of the radio tails of these sources is suggestive of random motions of the optical host around the cluster potential. The presence of the multiple bends an d wiggles in several head-tail sources is possibly due to the precessing radio jets. We find steepening of the spectral index along the radio tails. The prevailing equipartition magnetic field also decreases a long the radio tails of these sources. These steepening trends are attributed to the synchrotron aging of plasma toward the ends of the tails. The dynamical ages of these sample sources have been estimated to be ~100 Myr, which is a factor of six more than the age estimates from the radiative losses due to synchrotron cooling.