[Todos] IAFE- COLOQUIOS CIENTÍFICOS: Lunes 21 de Marzo de 2016 a las 14:00 hs.

["Area Difusión IAFE"]

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                        COLOQUIOS CIENTÍFICOS
               Instituto de Astronomía y Física del Espacio
                             CONICET-UBA
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"BLACK HOLE BINARIES OF LOW MASS AS PROLIFIC SOURCES OF GRAVITATIONAL WAVES."
                           I. F. Mirabel
          Instituto de Astronomía y Física del Espacio (CONICET-UBA)
                      Lunes 21 de Marzo de 2016 a las 14:00 hs.
                         Aula del Edificio IAFE
The detection of the gravitational-wave transient GW150914 from a merger
of two black holes with masses as large as 30 solar masses caused surprise
and raised the question on whether could exist binary black holes with
components having masses lower than 30 solar masses that would contribute
significantly to a stochastic gravitational-wave background. One of the
most critical parameters to answer that question is the range of masses of
black holes that may form by direct collapse, namely, with no energetic
supernova kicks that would unbound the massive stellar binary progenitors.
Although theoretical models set mass ranges and limits for black hole
formation through the complete collapse of the progenitor star,
observational constraints for those mass limits have been elusive. I will
show that the kinematics of black hole X-ray binaries in the Galaxy
encodes the history of their formation and evolution, and provide
observational constraints on the strength of kicks by supernova explosions
in the process of black hole formation. Based on the velocities in three
dimensions of five black hole binaries in our Galaxy it was found that
three black holes with < 10 solar masses are runaway black hole binaries
due to kicks imparted by natal supernovae, whereas two black holes with
masses in the range of 10-15 solar masses remained in their birth place
and must have been form by complete or almost complete collapse of the
progenitor star. Despite the low number statistics, the observations I
will reviewed show that binary black holes could be form with components
having masses as low as 10 solar masses. Together with the case for
missing progenitors of core-collapse supernovae with > 18 solar masses
(Smartt 2015), these two approaches of observational constraints for black
hole formation suggest that a significant fraction of massive stellar
binaries in the universe end as black hole binaries.