Oral, Saturday, January 9, 1999, 10:00-11:30am, Ballroom A

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*Y. Wang, D.N. Spergel, M.A. Strauss (Princeton)*

The existence of primordial adiabatic Gaussian random-phase
density fluctuations is a generic prediction of inflation.
The properties of these fluctuations are completely
specified by their power spectrum A_{S}^{2}(k). The basic
cosmological parameters and the primordial power spectrum
together completely specify predictions for the cosmic
microwave background radiation anisotropy and large scale
structure. Here we show how we can strongly constrain both
A_{S}^{2}(k) and the cosmological parameters by combining the
data from the Microwave Anisotropy Probe (MAP) and the
galaxy redshift survey from the Sloan Digital Sky Survey
(SDSS). We allow A_{S}^{2}(k) to be a free function, and thus
probe features in the primordial power spectrum on all
scales. If we assume that the cosmological parameters are
known *a priori* and that galaxy bias is linear and
scale-independent, and neglect non-linear redshift
distortions, the primordial power spectrum in 20 steps in
\log k to k\leq 0.5hMpc^{-1} can be determined to
~16% accuracy for k~0.01hMpc^{-1}, and to
~1% accuracy for k~0.1hMpc^{-1}. The
uncertainty in the primordial power spectrum increases by a
factor up to 3 on small scales if we solve simultaneously
for the dimensionless Hubble constant h, the cosmological
constant {\Lambda}, the baryon fraction \Omega_{b}, the
reionization optical depth \tau_{ri}, and the effective
bias between the matter density field and the redshift space
galaxy density field b_{\it eff}. Alternately, if we
restrict A_{S}^{2}(k) to be a power law, we find that
inclusion of the SDSS data breaks the degeneracy between the
amplitude of the power spectrum and the optical depth
inherent in the MAP data, significantly reduces the
uncertainties in the determination of the matter density and
the cosmological constant, and allows a determination of the
galaxy bias parameter. Thus, combining the MAP and SDSS data
allows the independent measurement of important cosmological
parameters, and a measurement of the primordial power
spectrum independent of inflationary models, giving us
valuable information on physics in the early Universe, and
providing clues to the correct inflationary model.

If you would like more information about this abstract, please follow the link to http://www.astro.princeton.edu/~ywang. This link was provided by the author. When you follow it, you will leave the Web site for this meeting; to return, you should use the Back comand on your browser.