Radio Emission and Jets from Tidal Disruption Events, and the origin of Ultra High Energy Cosmic Rays

by Prof. Tsvi Piran

The Hebrew University of Jerusalem

at Physics Colloquium

Tue, 09 Jan 2024, 15:15
Ilse Katz Institute for Nanoscale Science & Technology (51), room 015

Abstract

Sw 1644 was one of the most surprising tidal disruption events (TDEs). Its prompt emission in soft gamma-rays triggered Swift. Later on, this was followed by X-ray and Radio afterglows. The energy implied by the radio afterglow increased by a factor of 10 over a period of a few hundred days, ultimately reaching a few times 10^52 erg. This is much higher than what was observed in other TDEs. The combination of initial gamma-rays and strong afterglow makes Sw 1644 the prototype of “jetted” TDEs. Other TDEs have shown radio emission that was much weaker and very different. Those are naturally explained as arising from the interaction of the unbound debris with the surrounding matter. Recently, several TDEs have shown a delayed radio emission that began a few years after the event. These led us to reconsider Sw 1644 and suggest that Sw 1644 as well as the delayed emission events, are relativistic jets viewed off-axis. This requires an initially relativistic jet with 10^53 erg, making those events among the most energetic transient events. I will speculate on the origin of these events, as compared with regular TDEs that are significantly weaker, and on implications to other phenomena and in particular, to the origin of
Ultra High Energy Cosmic Rays.

Created on 24-08-2023 by Maniv, Eran (eranmaniv)
Updaded on 07-01-2024 by Maniv, Eran (eranmaniv)