The XMM Cluster Survey: The Halo Occupation Number of BOSS galaxies in X-ray clusters

Research output: Contribution to journalArticle

  • External authors:
  • Nicola Mehrtens
  • A Kathy Romer
  • Robert C. Nichol
  • Chris A Collins
  • Martin Sahlén
  • Philip J. Rooney
  • Julian A. Mayers
  • A. Bermeo-Hernandez
  • Martyn Bristow
  • Diego Capozzi
  • L Christodoulou
  • Johan Comparat
  • Matt Hilton
  • Ben Hoyle
  • Andrew R Liddle
  • Robert G. Mann
  • Karen Masters
  • Christopher J Miller
  • John K. Parejko
  • Francisco Prada
  • Ashley J. Ross
  • Donald P. Schneider
  • John P Stott
  • Alina Streblyanska
  • Pedro T P Viana
  • Martin White
  • Harry Wilcox
  • Idit Zehavi

Abstract

We present a direct measurement of the mean halo occupation distribution (HOD) of galaxies taken from the eleventh data release (DR11) of the Sloan Digital Sky Survey-III Baryon Oscillation Spectroscopic Survey (BOSS). The HOD of BOSS low-redshift (LOWZ: 0.2 < z < 0.4) and Constant-Mass (CMASS: 0.43 < z < 0.7) galaxies is inferred via their association with the dark matter haloes of 174 X-ray-selected galaxy clusters drawn from the XMM Cluster Survey (XCS). Halo masses are determined for each galaxy cluster based on X-ray temperature measurements, and range between log10(M180/M⊙) = 13 and 15. Our directly measured HODs are consistent with the HOD-model fits inferred via the galaxy-clustering analyses of Parejko et al. for the BOSS LOWZ sample and White et al. for the BOSS CMASS sample. Under the simplifying assumption that the other parameters that describe the HOD hold the values measured by these authors, we have determined a best-fitting alpha-index of 0.91 ± 0.08 and 1.27+0.03−0.04 1.27−0.04+0.03 for the CMASS and LOWZ HOD, respectively. These alpha-index values are consistent with those measured by White et al. and Parejko et al. In summary, our study provides independent support for the HOD models assumed during the development of the BOSS mock-galaxy catalogues that have subsequently been used to derive BOSS cosmological constraints.

Bibliographical metadata

Original languageEnglish
JournalMonthly Notices of the Royal Astronomical Society
Volume463
Issue number2
Early online date30 Aug 2016
DOIs
StatePublished - 1 Dec 2016