How Did the Cosmic Dark Age End?
Zoltan Haiman (Columbia ) - Mar 14 at 12:00 noon
In the currently favored cosmological paradigm, the first non-linear
objects are small dark matter halos that formed at redshift z ~ 30.
The pristine primordial gas in these halos can dissipate its energy by
excitations of molecular hydrogen, and contract to high densities to
form the first generation of stars and black holes. These objects
subsequently evolve into the population of well-studied galaxies and
quasars at redshift z<6. The first stars and black holes, however,
can have a significant impact on the rest of the universe as soon as
they appear, by photo-ionizing most of the baryons. The cosmic
microwave background anisotropies (measured by the Wilkinson Microwave
Anisotropy Probe), and the spectra of the most distant quasars
(discovered in the Sloan Digital Sky Survey), have recently provided
the first glimpses of the early ionization history of the universe. I
will discuss plausible interpretations of these recent observations.
In the next decade, new instruments should characterize the ionization
history and tomography in detail, and allow us to infer the abundance,
spectrum, and other properties of the first generation of
astrophysical objects.
The seminar will be held in 544 Campbell Hall.
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