A model for infall around virialized haloes
Abstract
Motivated by the recent direct detection of cosmological gas infall, we develop an analytical model for calculating the mean density profile around an initial overdensity that later forms a dark matter halo. We account for the problem of peaks within peaks; when considering a halo of a given mass we ensure that this halo is not a part of a larger virialized halo. For haloes that represent highsigma fluctuations we recover the usual result that such haloes preferentially lie within highly overdense regions; in the limit of very lowsigma fluctuations, on the other hand, we show that haloes tend to lie within voids. Combined with spherical collapse, our results yield the typical density and velocity profiles of the gas and dark matter that surround virialized haloes.
 Publication:

Monthly Notices of the Royal Astronomical Society
 Pub Date:
 January 2004
 DOI:
 10.1111/j.13652966.2004.07177.x
 arXiv:
 arXiv:astroph/0212458
 Bibcode:
 2004MNRAS.347...59B
 Keywords:

 methods: analytical;
 galaxies: formation;
 cosmology: theory;
 largescale structure of Universe;
 Astrophysics
 EPrint:
 9 pages, 5 figures, submitted to MNRAS. Figure added, calculations slightly modified