The bias field of dark matter haloes |
| |
| Authors: | Paolo Catelan Francesco Lucchin Sabino Matarrese & Cristiano Porciani |
| |
| Institution: | Theoretical Astrophysics Center, Juliane Maries Vej 30, DK-2100 Copenhagen Ø, Denmark,;Department of Physics, Astrophysics, Nuclear Physics Laboratory, Keble Road, Oxford OX1 3RH,;Dipartimento di Astronomia, Universitàdi Padova, vicolo dell'Osservatorio 5, I-35122 Padova, Italy,;Dipartimento di Fisica Galileo Galilei, Universitàdi Padova, via Marzolo 8, I-35131 Padova, Italy,;SISSA, Scuola Internazionale di Studi Superiori Avanzati, via Beirut 2-4, I-34014 Trieste, Italy |
| |
| Abstract: | Accepted 1998 January 26. Received 1998 January 26; in original form 1997 August 13This paper presents a stochastic approach to the clustering evolution of dark matter haloes in the Universe. Haloes, identified by a Press–Schechter-type algorithm in Lagrangian space, are described in terms of 'counting fields', acting as non-linear operators on the underlying Gaussian density fluctuations. By ensemble-averaging these counting fields, the standard Press–Schechter mass function as well as analytic expressions for the halo correlation function and corresponding bias factors of linear theory are obtained, extending the recent results by Mo & White. The non-linear evolution of our halo population is then followed by solving the continuity equation, under the sole hypothesis that haloes move by the action of gravity. This leads to an exact and general formula for the bias field of dark matter haloes, defined as the local ratio between their number density contrast and the mass density fluctuation. Besides being a function of position and 'observation' redshift, this random field depends upon the mass and formation epoch of the objects and is both non-linear and non-local. The latter features are expected to leave a detectable imprint on the spatial clustering of galaxies, as described, for instance, by statistics like the bispectrum and the skewness. Our algorithm may have several interesting applications, among which is the possibility of generating mock halo catalogues from low-resolution N -body simulations. |
| |
| Keywords: | galaxies: clusters: general galaxies: evolution galaxies: formation galaxies: haloes cosmology: theory large-scale structure of Universe |
|
|
