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BEGIN:VEVENT
DTSTART;TZID=Atlantic/Canary:20101104T000000
DTEND;TZID=Atlantic/Canary:20101104T010000
UID:iactalks-222
X-WR-CALNAME: IAC Talks: Open Astronomy Seminars
X-ORIGINAL-URL: /iactalks/Talks/view/222
CREATED:2010-11-04T00:00:00+00:00
X-WR-CALDESC: IAC Talks upcomming talks
SUMMARY:Stellar black holes at the dawn of the Universe: cosmological impli
 cations
DESCRIPTION:Stellar black holes at the dawn of the Universe: cosmological i
 mplications\nDr. Felix Mirabel\n\nThe so called "dark ages" of the univers
 e began about 400.000 years after the Big Bang as matter cooled down and s
 pace became filled with neutral hydrogen for hundreds of millions years. H
 ow the Universe was heated and reionized during the first billion years af
 ter the Big Bang is a question of topical interest in cosmology. I will sh
 ow that current theoretical models on the formation and collapse of primor
 dial stars suggest that a large fraction of massive stars should have impl
 oded, forming high-mass black hole X-ray binaries. Then, I will review the
  recent observations of compact stellar remnants in the near and distant u
 niverse that support this theoretical expectation, showing that the therma
 l (UV and soft X-rays) and non-thermal (hard X-rays, winds and jets) emiss
 ion from a large population of stellar black holes in high mass binaries h
 eated the intergalactic medium over large volumes of space, complementing 
 the reionization by their stellar progenitors. Feedback from accreting ste
 llar black holes at that epoch would have prevented the formation of the l
 arge quantities of low mass dwarf galaxies that are predicted by the cold 
 dark matter model of the universe. A large population of black hole binari
 es 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. 
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