IMPROVEMENT OF THE RICHNESS ESTIMATES OF maxBCG CLUSTERS

Journal Article · Sun Sep 20 04:00:00 EDT 2009 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/703/1/601· OSTI ID:21371978

Rozo, Eduardo ^[1]; Rykoff, Eli S ^[2]; Koester, Benjamin P; Hansen, Sarah; Becker, Matthew; Bleem, Lindsey ^[3]; McKay, Timothy; Jiangang, Hao; Evrard, August ^[4]; Wechsler, Risa H ^[5]; Sheldon, Erin ^[6]; Johnston, David ^[7]; Annis, James ^[8]; Scranton, Ryan ^[9]

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1. Center for Cosmology and Astro-Particle Physics (CCAPP), Ohio State University, Columbus, OH 43210 (United States)
2. Physics Department, University of California at Santa Barbara, 2233B Broida Hall, Santa Barbara, CA 93106 (United States)
3. Department of Astronomy and Astrophysics, University of Chicago, Chicago, IL 60637 (United States)
4. Physics Department, University of Michigan, Ann Arbor, MI 48109 (United States)
5. Kavli Institute for Particle Astrophysics and Cosmology, Physics Department, and Stanford Linear Accelerator Center, Stanford University, Stanford, CA 94305 (United States)
6. Center for Cosmology and Particle Physics, Physics Department, New York University, New York, NY 10003 (United States)
7. Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States)
8. Fermi National Accelerator Laboratory, P.O. Box 500, Batavia, IL 60510 (United States)
9. Department of Physics and Astronomy, University of Pittsburgh, 3941 O'Hara St., Pittsburgh, PA 15260 (United States)

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 lnLx}{sup 2} = (0.86+-0.02){sup 2} to sigma{sub lnLx}{sup 2} = (0.69+-0.02){sup 2}. Relative to the maxBCG richness estimate, it also removes the strong redshift dependence of the L{sub X} -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 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 easily be generalized to other mass tracers.

• OSTI ID: 21371978
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 703; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
COLOR
COSMOLOGY
DATA ANALYSIS
GALAXIES
IMAGES
MASS
OPTICAL PROPERTIES
ORGANOLEPTIC PROPERTIES
PHYSICAL PROPERTIES
RED SHIFT