[Todos] IAFE: Coloquio: "BLACK HOLES AT THE DAWN OF THE UNIVERSE: COSMOLOGICAL IMPLICATIONS"]

[difusion en iafe.uba.ar]

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                    COLOQUIO EN EL IAFE
               Instituto de Astronomía y Física del Espacio
                    2010 - 40 aniversario IAFE
                         CONICET-UBA
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"BLACK HOLES AT THE DAWN OF THE UNIVERSE: COSMOLOGICAL IMPLICATIONS"
                       Dr. Félix Mirabel
                 Instituto de Astronomía y Física del Espacio
                           (CONICET-UBA)
                        Miercoles 15 de diciembre 2010, 11:00hs.
                         Aula del Edificio IAFE


Abstract:
The so called "dark ages" of the universe began about 400.000 years after
the Big Bang as matter cooled down and space became filled with neutral
hydrogen for hundreds of millions years. How the universe was heated and
reionized during the first billon years after the Big Bang is a question
of topical interest in cosmology. I will show that current theoretical
models on the formation and collapse of primordial stars suggest that a
large fraction of massive stars should have imploded, forming high mass
black hole x-ray binaries. Then, I will review the recent observations of
compact stellar remnants in the near and distant universe that support
this theoretical expectation, showing that the thermal (UV and soft
x-rays) and non-thermal (hard x-rays, winds and jets) emission from a
large population of stellar black holes in high mass binaries heated the
intergalactic medium over large volumes of space, complementing the
reionization by their stellar progenitors. Feedback from accreting stellar
black holes at that epoch would have prevented the formation of the large
quantities of low mass dwarf galaxies that are predicted by the cold dark
matter model of the universe. A large population of black hole binaries
may be important for future observations of gravitational waves as well as
for the existing and future atomic hydrogen radio surveys of HI in the
early universe.