Testing Bayesian reconstruction methods from peculiar velocities

Abstract

Reconstructing the large scale density and velocity fields from surveys of galaxy distances, is a major challenge for cosmography. The data is very noisy and sparse. Estimated distances, and thereby peculiar velocities, are strongly affected by the Malmquist-like lognormal bias. Two algorithms have been recently introduced to perform reconstructions from such data: the Bias Gaussian correction coupled with the Wiener filter (BGc/WF) and the HAMLET implementation of the Hamiltonian Monte Carlo forward modelling. The two methods are tested here against mock catalogs that mimic the Cosmicflows-3 data. Specifically the reconstructed cosmography and moments of the velocity field (monopole, dipole) are examined. A comparison is made to the ``exact'' wiener filter as well - namely the Wiener Filter in the unrealistic case of zero observational errors. This is to understand the limits of the WF method. The following is found. In the nearby regime ($d\lesssim 40\mathrm{Mpc}/h$) the two methods perform roughly equally well. HAMLET does slightly better in the intermediate regime ($40\lesssim d\lesssim 120\mathrm{Mpc}/h$). The main differences between the two appear in the most distant regime ($d\gtrsim 120\mathrm{Mpc}/h$), close to the edge of the data. The HAMLET outperforms the BGc/WF in terms of better and tighter correlations, yet in the distant regime the HAMLET yields a somewhat biased reconstruction. Such biases are missing from the BGc/WF reconstruction. In sum, both methods perform well and create reliable reconstructions with significant differences apparent when details are examined.

13 pages, 12 figures

References in corpus (14)

• The Laniakea supercluster of galaxies
• Cosmological parameters from the comparison of peculiar velocities with predictions from the 2M++ density field
• The Hestia project: simulations of the Local Group
• The peculiar velocity field up to $z\sim 0.05$ by forward-modeling Cosmicflows-3 data
• Deriving accurate peculiar velocities (even at high redshift)
• The Redshift Space Momentum Power Spectrum II: measuring the growth rate from the combined 2MTF and 6dFGSv surveys
• Constrained realizations of 2MRS density and peculiar velocity fields: growth rate and local flow
• Minimization of Biases in Galaxy Peculiar Velocity Catalogs
• The need for accurate redshifts in supernova cosmology
• An estimation of the Local growth rate from Cosmicflows-3 peculiar velocities
• Hamiltonian Monte Carlo reconstruction from peculiar velocities
• From Cosmicflows distance moduli to unbiased distances and peculiar velocities
• Reconstructing dark matter distribution with peculiar velocities: Bayesian forward modelling with corrections for inhomogeneous Malmquist bias
• An Inconsistency in standard Maximum Likelihood Estimation of Bulk Flows

Cited by in corpus (5)

• Identification of Basins of Attraction in the Local Universe
• Generalized framework for likelihood-based field-level inference of growth rate from velocity and density fields
• Modeling the Cosmic Dispersion Measure in the D < 120 Mpc Local Universe
• Evaluating the variance of individual halo properties in constrained cosmological simulations
• Peculiar Velocity Reconstruction From Simulations and Observations Using Deep Learning Algorithms