Description:

Colloquium abstract: Tidal disruption events, or TDEs, are a dramatic type of electromagnetic transient.  TDEs are triggered by the death throes of unlucky stars that pass too close to massive black holes (MBHs).  Stellar tidal disruption initiates a complex chain of events that culminates in the production of super-luminous, multi-wavelength flares of radiation, rising and decaying over a period of weeks to months.  TDEs hold exceptional promise for measuring the bottom end of the MBH mass function, potentially answering old questions about the origins of supermassive black holes.  However, this promise can only be achieved with larger samples of TDEs and better theoretical models that are robust for parameter estimation.  I will discuss how near future time domain surveys, particularly Rubin and ULTRASAT, will expand our TDE sample by two orders of magnitude.  I will then describe my group's recent and ongoing efforts to solve the challenging "circularization problem" for TDEs, a longstanding theoretical bottleneck that has finally been cracked open with the use of moving-mesh radiation-hydrodynamics.  I will conclude with a discussion of late-time TDE emission, a phase of the TDE that is harder to observe but which may facilitate MBH mass measurement.

Speaker: Nick Stone, Assistant Professor, University of Wisconsin-Madison

Host: Fred Rasio