by Dr. Ramana Athreya, IISER Pune

Abstract :

Radio galaxies are the largest structures associated with a physical
phenomenon in the Universe. These linear structures, some of which
span more than 25 million light-years, are powered by a pair of
ultra-relativistic jets of ions originating from the vicinity of a
massive black hole at the very centre of the galaxy hosting the radio
source. Most of the tens of thousands of radio galaxies studied till
date seem to become active only once in the lifetime of the galaxy;
only 6 of them have shown evidence of three episodes of jet activity.

I will present the first discovery of a radio galaxy with 4 episodes
of jet activity, describing it in terms of the physics of radio
sources. I will also discuss the role of these multi-episodic radio
sources in taking us to a better understanding of the phenomena of
radio galaxies.

This work has been accepted for publication in The Astrophysical Journal.
Authors; Pavan Khadekar, Dharam Vir Lal and Ramana Athreya