SLAC Publication SLAC-PUB-13728
SLAC Release Date: August 3, 2009
An Improved Cluster Richness Estimator
Rozo, Eduardo (Ohio State U.); Rykoff, Eli S. (UC, Santa Barbara); Koester, Benjamin P. (Chicago U.; KICP, Chicago); McKay, Timothy (Michigan U.); Hao, Jiangang (Michigan U.); Evrard, August (Michigan U.); Wechsler, Risa H. (SLAC); Hansen, Sarah (Chicago U.; KICP, Chicago); Sheldon, Erin (New York U.); Johnston, David (Houston U.); Becker, Matthew R. (Chicago U.; KICP, Chicago); Annis, James T. (Fermilab); Bleem, Lindsey (Chicago U.); Scranton, Ryan (Pittsburgh U.)
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 L_X-richness relation, from \sigma_{\ln L_X}^2=(0.86\pm0.02)^2 to \sigma_{\ln L_X}^2=(0.69\pm0.02)^2. Relative to the maxBCG richness estimate, it also removes the strong redshift dependence of the ... Show Full Abstract
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 L_X-richness relation, from \sigma_{\ln L_X}^2=(0.86\pm0.02)^2 to \sigma_{\ln L_X}^2=(0.69\pm0.02)^2. Relative to the maxBCG richness estimate, it also removes the strong redshift dependence of the richness scaling relations, and is significantly more robust to photometric and redshift errors. These improvements are largely due to our more sophisticated treatment of galaxy color data. We also demonstrate the scatter in the L_X-richness relation depends on the aperture used to estimate cluster richness, and introduce a novel approach for optimizing said aperture which can be easily generalized to other mass tracers. Show Partial Abstract
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  • Published in Astrophysical Journal
  • Interest Categories: Other
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