Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published December 2010 | Published
Journal Article Open

Understanding the shape of the galaxy two-point correlation function at z ≃ 1 in the COSMOS field


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 h^(−1) Mpc. We show that the flat shape previously observed at redshifts between z= 0.6 and 1 can be explained by this volume being simply 10 per cent overabundant in high-density environments, with respect to a universal density probability distribution function. When galaxies corresponding to the top 10 per cent tail of the distribution are excluded, the measured w_(p)(r_(p)) steepens and becomes indistinguishable from Lambda cold dark matter (ΛCDM) predictions on all scales. This is the same effect recognized by Abbas & Sheth in the Sloan Digital Sky Survey (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 haloes 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.

Additional Information

© 2010 The Authors. Journal compilation © 2010 RAS. Accepted 2010 July 12. Received 2010 July 7; in original form 2010 May 21. Article first published online: 6 Sep. 2010. We thank Ravi Sheth for helpful comments on the manuscript, and M. Kitzbichler and S. White for providing us with the COSMOS mock surveys. LG thanks D. Sanders and the University of Hawaii for hospitality at the Institute for Astronomy, where this work was initiated. Financial support from INAF and ASI through grants PRIN-INAF–2007 and ASI/COFIS/WP3110 I/026/07/0 is gratefully acknowledged. This work is based on observations undertaken at the ESO–VLT under Large Programme 175.A-0839. Also based on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, operated by the Association of Universities for Research in Astronomy, Inc. (AURA), under NASA contract NAS 5Y26555, with the Subaru Telescope, operated by the National Astronomical Observatory of Japan, with the telescopes of the National Optical Astronomy Observatory, operated by the Association of Universities for Research in Astronomy, Inc. (AURA), under cooperative agreement with the National Science Foundation and the Canada–France–Hawaii Telescope, operated by the National Research Council of Canada, the Centre National de la Recherche Scientifique de France and the University of Hawaii.

Attached Files

Published - delaTorre2010p12121Mon_Not_R_Astron_Soc.pdf


Files (718.7 kB)
Name Size Download all
718.7 kB Preview Download

Additional details

August 22, 2023
October 21, 2023