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Astrophysics Seminar

Tuesday May 13, 14.30, HPF G6

Professor John Peacock, University of Edinburgh

"Studying large-scale structure with the 2dF Galaxy Redshift Survey"

Abstract:

The 2dF Galaxy Redshift Survey was the first to observe more
than 100,000 redshifts, making possible precise measurements of
many aspects of galaxy clustering. The spatial distribution of galaxies
can be studied as a function of galaxy spectral type, and also of
broad-band colour. This talk concentrates on measurements of the
clustering power spectrum, and how this allows us to measure the
matter content of the universe. In combination with measurements
of aniostropies in the microwave background, all the main cosmological
parameters can be measured - breaking the degeneracies inherent in
a CMB-only analysis. This analysis proves that the universe is very
close to flat. The matter content is accurately consistent with
pure Cold Dark Matter, with about 25\% of the critical density,
and fluctuations that are scalar-only, adiabatic and scale-invariant.
It is demonstrated that these conclusions cannot be evaded by
adjusting either the equation of state of the vacuum, or the total
relativistic density.

There will also be a broadly related Theoretical Physics Seminar later
the same afternoon (1630 HPZ E9)

Professor Neil Turok, University of Cambridge

`Beyond Inflation: Developing a Cyclic Model of the Universe'