Yin-Zhe Ma, Enzo Branchini, Douglas Scott
We constructed a hyper-parameter statistical method to quantify the difference between predicted velocities derived from the observed galaxy distribution in the IRAS-PSCz redshift survey and peculiar velocities measured using different distance indicators. In our analysis we find that the model-data comparison becomes unreliable beyond 70 Mpc/h because of the inadequate sampling of prominent, distant superclusters like the Shapley Concentration by IRAS galaxies. On the other hand, the analysis of the velocity residuals show that the PSCz gravity field provides an adequate model to the local, <= 70 Mpc/h, peculiar velocity field. The hyper-parameter combination of ENEAR, SN, A1SN and SFI++ catalogues constrains the amplitude of the linear flow to \beta=0.53 \pm 0.01. For an rms density fluctuations in the PSCz galaxy number density \sigma_8^{\rm gal}=0.42\pm0.03, we obtain an estimate of the growth rate of density fluctuations $f\sigma_{8}(z\sim0) = 0.42 \pm 0.03$, which is in excellent agreement with independent estimates based on different techniques.
View original:
http://arxiv.org/abs/1205.4237
No comments:
Post a Comment