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Title: RECONSTRUCTING THE INITIAL DENSITY FIELD OF THE LOCAL UNIVERSE: METHODS AND TESTS WITH MOCK CATALOGS

Our research objective in this paper is to reconstruct an initial linear density field, which follows the multivariate Gaussian distribution with variances given by the linear power spectrum of the current cold dark matter model and evolves through gravitational instabilities to the present-day density field in the local universe. For this purpose, we develop a Hamiltonian Markov Chain Monte Carlo method to obtain the linear density field from a posterior probability function that consists of two components: a prior of a Gaussian density field with a given linear spectrum and a likelihood term that is given by the current density field. The present-day density field can be reconstructed from galaxy groups using the method developed in Wang et al. Using a realistic mock Sloan Digital Sky Survey DR7, obtained by populating dark matter halos in the Millennium simulation (MS) with galaxies, we show that our method can effectively and accurately recover both the amplitudes and phases of the initial, linear density field. To examine the accuracy of our method, we use N-body simulations to evolve these reconstructed initial conditions to the present day. The resimulated density field thus obtained accurately matches the original density field of the MS in themore » density range 0.3{approx}<{rho}/ {rho}-bar {approx}<20 without any significant bias. In particular, the Fourier phases of the resimulated density fields are tightly correlated with those of the original simulation down to a scale corresponding to a wavenumber of {approx}1 h Mpc{sup -1}, much smaller than the translinear scale, which corresponds to a wavenumber of {approx}0.15 h Mpc{sup -1}.« less
Authors:
 [1] ;  [2] ;  [3] ;  [4]
  1. Key Laboratory for Research in Galaxies and Cosmology, Department of Astronomy, University of Science and Technology of China, Hefei, Anhui 230026 (China)
  2. Department of Astronomy, University of Massachusetts, Amherst, MA 01003-9305 (United States)
  3. Key Laboratory for Research in Galaxies and Cosmology, Shanghai Astronomical Observatory, Shanghai 200030 (China)
  4. Astronomy Department, Yale University, P.O. Box 208101, New Haven, CT 06520-8101 (United States)
Publication Date:
OSTI Identifier:
22121866
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 772; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ACCURACY; AMPLITUDES; CATALOGS; CURRENT DENSITY; DENSITY; GALAXIES; GAUSS FUNCTION; GRAVITATIONAL INSTABILITY; HAMILTONIANS; MANY-BODY PROBLEM; MARKOV PROCESS; MONTE CARLO METHOD; MULTIVARIATE ANALYSIS; NONLUMINOUS MATTER; PROBABILITY; SPECTRA; UNIVERSE