http://arxiv.org/abs/1408.2566
We present a Bayesian reconstruction algorithm to generate unbiased samples of the underlying dark matter field from galaxy redshift data. Our new contribution consists of implementing a non-Poisson likelihood including a deterministic non-linear and scale-dependent bias. In particular we present the Hamiltonian equations of motions for the negative binomial (NB) probability distribution function. This permits us to efficiently sample the posterior distribution function of density fields given a sample of galaxies using the Hamiltonian Monte Carlo technique implemented in the Argo code. We have tested our algorithm with the Bolshoi N-body simulation, inferring the underlying dark matter density field from a subsample of the halo catalogue. Our method shows that we can draw closely unbiased samples (compatible within 1-$\sigma$) from the posterior distribution up to scales of about k~1 h/Mpc in terms of power-spectra and cell-to-cell correlations. We find that a Poisson likelihood yields reconstructions with power spectra deviating more than 10% at k=0.2 h/Mpc. Our reconstruction algorithm is especially suited for emission line galaxy data for which a complex non-linear stochastic biasing treatment beyond Poissonity becomes indispensable.
M. Ata, F. Kitaura and V. Muller
Wed, 13 Aug 14
10/57
Comments: 8 pages, 4 figures
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