Close Galaxy Counts as a Probe of Hierarchical Structure Formation

Details Close Galaxy Counts as a Probe of Hierarchical Structure Formation Close Galaxy Counts as a Probe of Hierarchical Structure Formation

2006-04-24

arxiv.org/abs/astro-ph/0604506v3

Astrophys.J.652:56-70,2006

Astronomy and Astrophysics

Astrophysics

16 pages, 16 figures, minor change to figure 10, figure captions updated, typos corrected, Figure 4 corrected, version accepte

Scientific paper

10.1086/507573

Standard LCDM predicts that the major merger rate of galaxy-size dark matter halos rises rapidly with redshift. The average number of close companions per galaxy, Nc, is often used to infer the galaxy merger rate, however, recent observational studies suggest that Nc evolves very little with redshift. Here we use a "hybrid" N- body simulation plus analytic substructure model to predict Nc directly. We identify dark matter subhalos with galaxies and show that the observed lack of close pair count evolution arises because the high merger rate per halo at early times is counteracted by a decrease in the number of halos massive enough to host a galaxy pair. We compare our results to data compiled from the DEEP2, SSRS2, and the UZC redshift surveys. Observed pair counts match our predictions if we assume a monotonic mapping between galaxy luminosity and the maximum circular velocity that each subhalo had when it was first accreted onto its host halo. This suggests that satellite galaxies are significantly more resilient to destruction than are dissipationless dark matter subhalos. We argue that while Nc does not provide a direct measure of the halo merger rate, it offers a powerful means to constrain the Halo Occupation Distribution and the spatial distribution of galaxies within halos. Interpreted in this way, close pair counts provide a useful test of galaxy formation processes on < 100 kpc scales.

Affiliated with

Also associated with

No associations

Rating

Close Galaxy Counts as a Probe of Hierarchical Structure Formation does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Close Galaxy Counts as a Probe of Hierarchical Structure Formation, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Close Galaxy Counts as a Probe of Hierarchical Structure Formation will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-433083