Streaming velocities as a dynamical estimator of Omega

(1998)

Authors:

PG Ferreira, R Juszkiewicz, HA Feldman, M Davis, AH Jaffe

Streaming velocities as a dynamical estimator of Omega

ArXiv astro-ph/9812456 (1998)

Authors:

PG Ferreira, R Juszkiewicz, HA Feldman, M Davis, AH Jaffe

Abstract:

It is well known that estimating the pairwise velocity of galaxies, v_{12}, from the redshift space galaxy correlation function is difficult because this method is highly sensitive to the assumed model of the pairwise velocity dispersion. Here we propose an alternative method to estimate v_{12} directly from peculiar velocity samples, which contain redshift-independent distances as well as galaxy redshifts. In contrast to other dynamical measures which determine beta = sigma_8 x Omega^{0.6}, our method can provide an estimate of (sigma_8)^2 x Omega^{0.6} for a range of sigma_8 (here Omega is the cosmological mass density parameter while sigma_8 is the standard normalization parameter for the spectrum of matter density fluctuations). We demonstrate how to measure this quantity from realistic catalogues.

Evidence for non-Gaussianity in the CMB

ArXiv astro-ph/9810414 (1998)

Authors:

J Magueijo, P Ferreira, K Gorski

Abstract:

In a recent Letter we have shown how COBE-DMR maps may be used to disprove Gaussianity at a high confidence level. In this report we digress on a few issues closely related to this Letter. We present the general formalism for surveying non-Gaussianity employed. We present a few more tests for systematics. We wonder about the theoretical implications of our result.

The 2dF QSO Redshift Survey

ArXiv astro-ph/9810127 (1998)

Authors:

SM Croom, T Shanks, BJ Boyle, RJ Smith, L Miller, NS Loaring

Abstract:

We present preliminary results from the 2-degree Field (2dF) QSO Redshift Survey currently under way at the Anglo-Australian Telescope. This survey aims to determine the redshifts of >25000 QSOs over a redshift range of 0.3

The galaxy halo formation rate

ArXiv astro-ph/9809330 (1998)

Authors:

WJ Percival, L Miller

Abstract:

The rate at which galaxy halos form is thought to play a key role in explaining many observable cosmological phenomena such as the initial epoch at which luminous matter forms and the distribution of active galaxies. Here we show how Press-Schechter theory can be used to provide a simple, completely analytic model of the halo formation rate. This model shows good agreement with both Monte-Carlo and N-body simulation results.