Improvement of the richness estimates of maxBCG clusters

Eduardo Rozo, Eli S. Rykoff, Benjamin P. Koester, Timothy McKay, Jiangang Hao, August Evrard, Risa H. Wechsler, Sarah Hansen, Erin Sheldon, David Johnston, Matthew Becker, James Annis, Lindsey Bleem, Ryan Scranton

Research output: Contribution to journalArticlepeer-review

78 Scopus citations


Minimizing the scatter between cluster mass and accessible observables is an important goal for cluster cosmology. In this work, we introduce a new matched filter richness estimator, and test its performance using the maxBCG cluster catalog. Our new estimator significantly reduces the variance in the LX -richness relation, from to . Relative to the maxBCG richness estimate, it also removes the strong redshift dependence of the LX -richness scaling relations, and is significantly more robust to photometric and redshift errors. These improvements are largely due to the better treatment of galaxy color data. We also demonstrate the scatter in the LX -richness relation depends on the aperture used to estimate cluster richness, and introduce a novel approach for optimizing said aperture which can easily be generalized to other mass tracers.

Original languageEnglish (US)
Pages (from-to)601-613
Number of pages13
JournalAstrophysical Journal
Issue number1
StatePublished - 2009


  • Cosmology: observations
  • Methods: data analysis

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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