18 January 2001CfA Colloquium

Title: The 2dF Galaxy Redshift Survey

Speaker: Matthew Colless

Abstract: The 2dF Galaxy Redshift Survey has now measured redshifts for over 140,000 galaxies and provides some of the most detailed information to date on the intrinsic properties of galaxies and the large-scale structure in the local universe. I present results on the luminosity functions of galaxies and their dependence on spectral type and surface brightness. I also report some initial results on the statistical properties on the structure of the galaxy distribution and the implications for cosmological parameters.

The redshift-space anisotropy of the galaxy correlation function is in excellent agreement with the predictions of the gravitational instability paradigm for the growth of large-scale structure. The preliminary estimate of the distortion parameter has significantly higher precision than previous determinations. Allowing for the effective redshift and luminosity of the 2dFGRS sample, this result is in good accord with recent CMB anisotropy results, and favours a universe with a low mass density, Omega~0.3-0.4.

A preliminary measurement of the real-space power spectrum of galaxy clustering, P(k), has been made on scales up to 300 h/Mpc (k>0.02). A comparison is presented between the 2dFGRS power spectrum and previous estimates from the projected galaxy distribution and earlier redshift surveys; the 2dFGRS P(k) is also compared to predictions from the best-fitting cosmological models derived from recent CMB anisotropy measurements. Further work with the 2dFGRS will yield higher-order clustering statistics for the galaxy distribution. Amongst other things, these will test whether the initial density fluctuations were a Gaussian random field, and allow independent measurement of the mass density Omega and the bias parameter b.

Reference for students:

"Redshift Surveys and Cosmology", Colless, M., 1999, astroph-11326

The 2dF Galaxy Redshift Survey Home Page

Lunch with the students will be on Friday, January 19th at 12:00 in A-101.