Properties of the observed Lyα forest

Authors

  • M. Demiański,

    1. Institute of Theoretical Physics, University of Warsaw, 00–681 Warsaw, Poland
    2. Department of Astronomy, Williams College, Williamstown, MA 01267, USA
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  • A. G. Doroshkevich,

    Corresponding author
    1. Theoretical Astrophysics Center, Juliane Maries Vej 30, DK–2100 Copenhagen Ø, Denmark
    2. Keldysh Institute of Applied Mathematics, Russian Academy of Sciences, 125047 Moscow, Russia
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  • V. Turchaninov

    1. Keldysh Institute of Applied Mathematics, Russian Academy of Sciences, 125047 Moscow, Russia
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★ E-mail: dorr@tac.dk

Abstract

The main observed properties of Lyα absorbers are investigated on the basis of a theoretical model of formation and evolution of dark matter (DM) structure elements. This model is generally consistent with simulations of absorber formation and with the statistical description of structure evolution based on the Zel'dovich theory. The analysis of redshift variations of comoving linear number density of absorbers was performed in our previous paper.

We show that the observed characteristics of the Doppler parameter can be related to the size of DM structure elements that allow us to explain the observed distribution of the Doppler parameter. This distribution is found to be consistent with the Gaussian initial perturbations. The observed characteristics of entropy and column density Ni confirm that the merging of pancakes is the main evolutionary process at redshifts zgeqslant R: gt-or-equal, slanted2. The observed sample of absorbers mainly characterizes the matter distribution within large low-density regions and therefore it is difficult to reconstruct the density field from the distribution of absorbers.

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