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Merging history as a function of halo environment

Stefan Gottloeber·Anatoly Klypin·Andrey Kravtsov
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Abstract

According to the hierarchical scenario, galaxies form via merging and accretion of small objects. Using N-body simulations, we study the frequency of merging events in the history of the halos. We find that at z<~2 the merging rate of the overall halo population can be described by a simple power law (1+z)^3. The main emphasis of the paper is on the effects of environment of halos at the present epoch (z=0). We find that the halos located inside clusters have formed earlier (dz \approx 1) than isolated halos of the same mass. At low redshifts (z<1), the merger rate of cluster halos is 3 times lower than that of isolated halos and 2 times lower than merger rate of halos that end up in groups by z=0. At higher redshifts (z~1-4), progenitors of cluster and group halos have 3--5 times higher merger rates than isolated halos. We briefly discuss implications of our results for galaxy evolution in different environments.

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Stefan Gottloeber, Anatoly Klypin, Andrey Kravtsov. 2000-04-11. Merging history as a function of halo environment. https://doi.org/10.1086/318248

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