An Improved Cluster Richness Estimator

Journal Article · Mon Aug 03 00:00:00 EDT 2009 · Submitted to Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/703/1/601· OSTI ID:962094

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

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{sub X}-richness relation, from {sigma}{sub lnL{sub X}}{sup 2} = (0.86 {+-} 0.02){sup 2} to {sigma}{sub lnL{sub X}}{sup 2} = (0.69 {+-} 0.02){sup 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{sub 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.

• Research Organization: Stanford Linear Accelerator Center (SLAC)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC02-76SF00515
• OSTI ID: 962094
• Report Number(s): SLAC-PUB-13728; arXiv:0809.2797
• Journal Information: Submitted to Astrophysical Journal, Journal Name: Submitted to Astrophysical Journal
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
APERTURES
Astrophysics
COLOR
COSMOLOGY
PERFORMANCE