Colloquium Abstract - Alexander - 2024Mar08

March 8, 2024

11:00am Mountain

Kate Alexander (Univ. of Arizona)

 

Tidal Disruption Events: Unique probes of outflows and accretion in supermassive black holes

 

Abstract

Supermassive black holes (SMBHs) lie at the centers of most galaxies, but the processes by which they grow and launch outflows that shape the galaxies around them remain poorly understood. In this talk, I will discuss tidal disruption events (TDEs) as probes of relativistic processes powered by SMBHs. A TDE occurs when a star passes too close to a SMBH and is torn apart by tidal forces from the strong gravitational field, injecting a large amount of gas close to the event horizon. TDEs therefore provide a valuable opportunity to test theories of SMBH accretion and to study the formation of relativistic jets and outflows. Mass ejection in TDEs is best characterized via radio observations, which reveal synchrotron radiation produced in the shock formed between fast-moving outflows and the ambient interstellar medium. Radio monitoring of TDE outflows allows us to (1) determine the properties of outflowing material (energy, size, expansion velocity) and (2) trace the ambient density profile around previously-dormant SMBHs on scales of a few light years. I will discuss my exciting recent observations of TDEs in the local Universe, including the first results from my ongoing VLA Large Program. The increased sample size now being realized by new wide-field multi-wavelength (and multi-messenger) surveys is revealing a surprisingly diverse population and will shed further light on the physical conditions required for jet and outflow formation in TDEs.


Local Host: Dillon Dong

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