Towards breaking the Omega-bias degeneracy in density--velocity comparisons

Abstract

I derive a second-order local relation between the REDSHIFT-space mass density field and the REAL-space velocity field. This relation can be useful for comparisons between the cosmic density and peculiar velocity fields, for a number of reasons. First, relating the real-space velocity directly to the redshift-space density enables one to avoid the Omega-dependent reconstruction of the density field in real space. Secondly, the reconstruction of the three-dimensional velocity field in redshift space, questionable because of its vorticity, is also unnecessary. Finally, a similar relation between the GALAXY density field and the velocity field offers a way to break the Omega-bias degeneracy in density--velocity comparisons, when combined with an additional measurement of the redshift-space galaxy skewness. I derive the latter relation under the assumption of nonlinear but local bias; accounting for stochasticity of bias is left for further study.

13 pages, no figures, uses mn.sty. The calculation properly redone for bias in real space, added references. Accepted by MNRAS

References in corpus (6)

• The Bispectrum as a Signature of Gravitational Instability in Redshift-Space
• The Angular Clustering of Lyman-Break Galaxies at Redshift z=3
• The time-evolution of bias
• The nonlinear redshift-space power spectrum of galaxies
• Observational evidence for stochastic biasing
• The Inverse Redshift-Space Operator: Reconstructing Cosmological Density and Velocity Fields

Cited by in corpus (4)

• Large-Scale Structure of the Universe and Cosmological Perturbation Theory
• Constraints on Galaxy Bias, Matter Density, and Primordial Non--Gausianity from the PSCz Galaxy Redshift Survey
• On the vorticity of flow in redshift space
• Comparing the redshift-space density field to the real-space velocity field