[SEMINARI] Radio transients from stellar tidal disruption by supermassive black holes, Dimitrios Giannios

[Enric Marco]

Dimitrios Giannios
Department of Astrophysical Sciences, Peyton Hall, Princeton University,
Princeton, USA

dimecres 13 de Juliol 2011
12:00

seminari del Departament Astronomia i Astrofísica

Títol:
Radio transients from stellar tidal disruption by supermassive black holes

Resum:
The tidal disruption of a star by a supermassive black hole provides us
with a rare glimpse of these otherwise dormant beasts. It has long been
predicted that the disruption will be accompanied by a thermal `flare',
powered by the accretion of bound stellar debris. Several candidate
disruptions have been discovered in this manner at optical, UV and X-ray
wavelengths. Here we explore the observational consequences if a modest
fraction of the accretion power is channeled into an ultra relativistic
outflow. We show that a relativistic jet decelerates due to its
interaction with the interstellar medium at sub-parsec distances from
the black hole. Synchrotron radiation from electrons accelerated by the
reverse shock powers a bright radio-infrared transient that peaks on a
timescale ~1 yr after disruption. Emission from the forward shock may be
detectable for several years after the peak. Deep radio follow-up
observations of tidal disruption candidates at late times can test for
the presence of relativistic ejecta. Upcoming radio transient surveys
may independently discover tens to hundreds of tidal disruptions per
year, complimenting searches at other wavelengths. Non-thermal emission
from tidal disruption probes the physics of jet formation under
relatively clean conditions, in which the flow parameters are
independently constrained.

http://celeste.uv.es/daa/seminari.php?id=1041

-- 
/------------------------------------\
 Dr. Enric Marco
 Departament d'Astronomia i Astrofísica
 Facultat de Física
 Universitat de València
 C/  Dr. Moliner, 50
 46100 Burjassot, Spain
 Phone: (34)-96-354-3069
 Fax:(34)-96-354-3084
 enric.marco en uv.es
 http://www.uv.es/marco
 http://www.uv.es/aulaastronomia
 http://www.uv.es/daa
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