MACHO Messages from the Big Bang

  • George Chapline
  • James Barbieri U.S. Navy
Keywords: gravitational collapse, cosmology, dark matter, vacuum energy, CMB.


The present day mass spectrum for MACHOs is calculated based on the assumption that a population of
compact objects was created at a definite redshift with a uniform mass mass and that the mass spectrum
evolved due to gravitational radiation. The resulting spectrum extends over many decades of mass and
allows one to connect the abundance of galactic halo objects to the abundance of galactic seeds. Present day
astrophysical constraints on the abundance of compact objects appear to be consistent with an assumption
that present day dark matter originated time ~ 10~4 seconds after the big bang as a population of compact
objects with masses ~ 0.1M. This raises the question as to what form matter took before this time. A
possible clue is that in a quantum theory of gravity massive black holes would release their entropy at a
time when the radiation temperature ~ 300 MeV.