Interpreting the Observed Clustering of Red Galaxies at z~3

Details Interpreting the Observed Clustering of Red Galaxies at z~3 Interpreting the Observed Clustering of Red Galaxies at z~3

2003-07-01

arxiv.org/abs/astro-ph/0307030v2

Astrophys.J.610:61-68,2004

Astronomy and Astrophysics

Astrophysics

16 pages, 2 figures. To appear in ApJ (July 20th, 2004). Minor revisions to match the version in press

Scientific paper

10.1086/421542

Daddi et al. have recently reported strong clustering of a population of red galaxies at z~3 in the Hubble Deep Field-South. Fitting the observed angular clustering with a power law of index -0.8, they infer a comoving correlation length r_0~8 Mpc/h; for a standard cosmology, this r_0 would imply that the red galaxies reside in rare, M>10^{13} Msun/h halos, with each halo hosting ~100 galaxies to match the number density of the population. Using the framework of the halo occupation distribution (HOD) in a $\Lambda$CDM universe, we show that the Daddi et al. data can be adequately reproduced by less surprising models, e.g., models with galaxies residing in halos of mass M>M_min=6.3x10^{11} Msun/h and a mean occupation Navg(M)=1.4(M/M_min)^{0.45} above this cutoff. The resultant correlation functions do not follow a strict power law, showing instead a clear transition from the 1-halo dominated regime, where the two galaxies of each pair reside in the same dark matter halo, to the 2-halo dominated regime, where the two galaxies of each pair are from different halos. The observed high-amplitude data points lie in the one-halo-dominated regime, so these HOD models are able to explain the observations despite having smaller correlation lengths, r_0~5 Mpc/h. HOD parameters are only loosely constrained by the current data because of large sample variance and the lack of clustering information on scales that probe the 2-halo regime. If our explanation of the data is correct, then future observations covering a larger area should show that the large scale correlations lie below a \theta^{-1.8} extrapolation of the small scale points. Our models of the current data suggest that the red galaxies are somewhat more strongly clustered than UV-selected Lyman-break galaxies and have a greater tendency to reside in small groups.

Affiliated with

Also associated with

No associations

Rating

Interpreting the Observed Clustering of Red Galaxies at z~3 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 Interpreting the Observed Clustering of Red Galaxies at z~3, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Interpreting the Observed Clustering of Red Galaxies at z~3 will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-629953