http://arxiv.org/abs/2204.08427
Odd Radio Circles or ORCs are recently discovered low surface brightness diffuse radio sources, whose progenitors and astrophysical processes responsible for their origins are presently debated. Some ORCs appear to be hosted in distant galaxies and some are host-less. Two plausible scenarios consider ORCs as either nearby supernovae remnants of sizes a few hundred pc in the intragroup medium of the local group of galaxies or alternatively shocked halos of sizes a few hundred kpc around distant galaxies. The input energy for shocks, required to create ORCs of a few hundred kpc size is estimated to be $10^{56} – 10^{59}$ erg. It is shown here that the energy released in shocks with a rate of $10^{41} – 10^{44}$ erg s$^{-1}$ due to multiple ($10^{3} – 10^{6}$) tidal disruption events in a short span of time (a few tens of Myr) in a merger galaxy system, hosting a massive black hole can supply required energy to generate ORCs around distant galaxies. The most plausible and abundant hosts for ORCs can be post-starburst galaxies at intermediate redshifts. The presently observed dominance of tidal disruption events in post-starburst galaxies, redshift evolution and environments of post-starburst galaxies at intermediate redshifts favourably support the current observations.
A. Omar
Tue, 19 Apr 22
38/52
Comments: 5 pages, submitted to MNRAS Letters; comments welcome