TAPIR Seminar

Friday, October 16, 2020
2:00pm to 3:00pm
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Online Event
Going local: the Galactic center as a case study of binaries in a galactic nucleus
Aleksey Generozov, Postodoctoral Research Associate, JILA, University of Colorado, Boulder,

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https://caltech.zoom.us/j/92271559087?pwd=TFQ2YVk2N0FpSzhlR3JvZlFENTUyQT09

In a galactic nucleus, close encounters between stars and compact objects can produce exotic electromagnetic and gravitational wave sources.  As the closest galactic nucleus to Earth, the Galactic center provides a unique window into this dynamics. 

For example, there are approximately a dozen black hole X-ray binaries observed in the central parsec of our Galaxy. I will discuss how tidal capture of stars by a population of ~10,000 black holes can explain these sources. These black holes can accumulate in the central parsec via mass segregation or in-situ star formation. In fact, the latter is presently observed in a young, sub-parsec stellar disk. 

Observations suggest that this disk pushed some of its constituent stellar binaries to tidal disruption shortly after its formation. Such disruptions could explain an observed cluster of stars ~0.01 pc from the central supermassive black hole. I will describe how the present-day orbits of these stars constrain the (resonant) relaxation time in the Galactic center and therefore its population of black holes. I will also discuss how the binary disruption paradigm can be tested by observations of hypervelocity stars. 

For more information, please contact JoAnn Boyd by email at joann@caltech.edu.