Understanding the shape of the galaxy two-point correlation function at z~1 in the COSMOS field
Abstract
We investigate how the shape of the galaxy two-point correlation function as measured in the zCOSMOS survey depends on local environment, quantified in terms of the density contrast on scales of 5 Mpc/h. We show that the flat shape previously observed at redshifts between z=0.6 and z=1 can be explained by this volume being simply 10% over-abundant in high-density environments, with respect to a Universal density probability distribution function. When galaxies corresponding to the top 10% tail of the distribution are excluded, the measured w_p(r_p) steepens and becomes indistinguishable from LCDM predictions on all scales. This is the same effect recognised by Abbas & Sheth in the SDSS data at z~0 and explained as a natural consequence of halo-environment correlations in a hierarchical scenario. Galaxies living in high-density regions trace dark matter halos with typically higher masses, which are more correlated. If the density probability distribution function of the sample is particularly rich in high-density regions because of the variance introduced by its finite size, this produces a distorted two-point correlation function. We argue that this is the dominant effect responsible for the observed "peculiar" clustering in the COSMOS field.
Keywords
Cite
@article{arxiv.1007.1984,
title = {Understanding the shape of the galaxy two-point correlation function at z~1 in the COSMOS field},
author = {S. de la Torre and L. Guzzo and K. Kovac and C. Porciani and U. Abbas and B. Meneux and C. M. Carollo and T. Contini and J. -P. Kneib and O. Le Fevre and S. J. Lilly and V. Mainieri and A. Renzini and D. Sanders and M. Scodeggio and N. Scoville and G. Zamorani and S. Bardelli and M. Bolzonella and A. Bongiorno and K. Caputi and G. Coppa and O. Cucciati and L. de Ravel and P. Franzetti and B. Garilli and A. Iovino and P. Kampczyk and C. Knobel and A. M. Koekemoer and F. Lamareille and J. -F. Le Borgne and V. Le Brun and C. Maier and M. Mignoli and R. Pello and Y. Peng and E. Perez-Montero and E. Ricciardelli and J. Silverman and M. Tanaka and L. Tasca and L. Tresse and D. Vergani and N. Welikala and E. Zucca and D. Bottini and A. Cappi and P. Cassata and A. Cimatti and M. Fumana and O. Ilbert and A. Leauthaud and D. Maccagni and C. Marinoni and H. J. McCracken and P. Memeo and P. Nair and P. Oesch and L. Pozzetti and V. Presotto and R. Scaramella},
journal= {arXiv preprint arXiv:1007.1984},
year = {2015}
}
Comments
6 pages, 3 figures, accepted for publication in MNRAS