Cosmological Evolution & Hierarchical Galaxy Formation

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dc.creatorPercival, W. J.
dc.creatorMiller, L.
dc.date1999-06-11
dc.date.accessioned2026-07-07T11:08:29Z
dc.date.available2026-07-07T11:08:29Z
dc.descriptionWe calculate the rate at which dark matter halos merge to form higher mass systems. Two complementary derivations using Press-Schechter theory are given, both of which result in the same equation for the formation rate. First, a derivation using the properties of the Brownian random walks within the framework of Press-Schechter theory is presented. We then use Bayes' theorem to obtain the same result from the standard Press-Schechter mass function. The rate obtained is shown to be in good agreement with results from Monte-Carlo and N-body simulations. We illustrate the usefulness of this formula by calculating the expected cosmological evolution in the rate of star formation that is due to short-lived, merger-induced starbursts. The calculated evolution is well-matched to the observed evolution in ultraviolet luminosity density, in contrast to the lower rates of evolution that are derived from semi-analytic models that do not include a dominant contribution from starbursts. Hence we suggest that the bulk of the observed ultraviolet starlight at z > 1 arises from short-lived, merger-induced starbursts. Finally, we show that a simple merging-halo model can also account for the bulk of the observed evolution in the comoving quasar space density.
dc.description11 pages, 8 figures, accepted for publication in MNRAS
dc.identifierhttps://arxiv.org/abs/astro-ph/9906204
dc.identifierhttp://arxiv.org/abs/astro-ph/9906204
dc.identifierMon.Not.Roy.Astron.Soc.309:823,1999
dc.identifierdoi:10.1046/j.1365-8711.1999.02865.x
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/190149
dc.subjectAstrophysics
dc.titleCosmological Evolution & Hierarchical Galaxy Formation
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