Power Spectrum of Cosmic Momentum Field Measured from the SFI Galaxy Sample

Details Power Spectrum of Cosmic Momentum Field Measured from the SFI Galaxy Sample Power Spectrum of Cosmic Momentum Field Measured from the SFI Galaxy Sample

2005-09-24

arxiv.org/abs/astro-ph/0509740v1

Astrophys.J.637:1-11,2006

Astronomy and Astrophysics

Astrophysics

12 pages, 9 figures, accepted for publication in ApJ

Scientific paper

10.1086/498258

We have measured the cosmic momentum power spectrum from the peculiar velocities of galaxies in the SFI sample. The SFI catalog contains field spiral galaxies with radial peculiar velocities derived from the I-band Tully-Fisher relation. As a natural measure of the large-scale peculiar velocity field, we use the cosmic momentum field that is defined as the peculiar velocity field weighted by local number of galaxies. We have shown that the momentum power spectrum can be derived from the density power spectrum for the constant linear biasing of galaxy formation, which makes it possible to estimate \beta_S = \Omega_m^{0.6} / b_S parameter precisely where \Omega_m is the matter density parameter and b_S is the bias factor for optical spiral galaxies. At each wavenumber k we estimate \beta_S(k) as the ratio of the measured to the derived momentum power over a wide range of scales (0.026 h^{-1}Mpc <~ k <~ 0.157 h^{-1}Mpc) that spans the linear to the quasi-linear regimes. The estimated \beta_S(k)'s have stable values around 0.5, which demonstrates the constancy of \beta_S parameter at scales down to 40 h^{-1}Mpc. We have obtained \beta_S=0.49_{-0.05}^{+0.08} or \Omega_m = 0.30_{-0.05}^{+0.09} b_S^{5/3}, and the amplitude of mass fluctuation as \sigma_8\Omega_m^{0.6}=0.56_{-0.21}^{+0.27}. The 68% confidence limits include the cosmic variance. We have also estimated the mass density power spectrum. For example, at k=0.1047 h Mpc^{-1} (\lambda=60 h^{-1}Mpc) we measure \Omega_m^{1.2} P_{\delta}(k)=(2.51_{-0.94}^{+0.91})\times 10^3 (h^{-1}Mpc)^3, which is lower compared to the high-amplitude power spectra found from the previous maximum likelihood analyses of peculiar velocity samples like Mark III, SFI, and ENEAR.

Affiliated with

Also associated with

No associations

Rating

Power Spectrum of Cosmic Momentum Field Measured from the SFI Galaxy Sample does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Power Spectrum of Cosmic Momentum Field Measured from the SFI Galaxy Sample, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Power Spectrum of Cosmic Momentum Field Measured from the SFI Galaxy Sample will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-553263