CROSS-CORRELATION WEAK LENSING OF SDSS GALAXY CLUSTERS. III. MASS-TO-LIGHT RATIOS
- Brookhaven National Laboratory, Upton, NY 11973 (United States)
- Department of Astronomy, 105-24, California Institute of Technology, 1201 East California Boulevard, Pasadena, CA 91125 (United States)
- Center for Cosmology and Particle Physics, Department of Physics, New York University, 4 Washington Place, New York, NY 10003 (United States)
- Department of Physics, University of Michigan, 500 East University, Ann Arbor, MI 48109-1120 (United States)
- Department of Physics and Astronomy, University of Pittsburgh, 3941 O'Hara Street, Pittsburgh, PA 15260 (United States)
- Kavli Institute for Particle Astrophysics and Cosmology, Physics Department, and Stanford Linear Accelerator Center, Stanford University, Stanford, CA 94305 (United States)
- Kavli Institute for Cosmological Physics, University of Chicago, 5640 South Ellis Avenue Chicago, IL 60637 (United States)
- Fermi National Accelerator Laboratory, P.O. Box 500, Batavia, IL 60510 (United States)
We present measurements of the excess mass-to-light ratio (M/L) measured around MaxBCG galaxy clusters observed in the Sloan Digital Sky Survey. This red-sequence cluster sample includes objects from small groups with M {sub 200} approx 5 x 10{sup 12} h {sup -1} M {sub sun} to clusters with M {sub 200} approx 10{sup 15} h {sup -1} M {sub sun}. Using cross-correlation weak lensing, we measure the excess mass density profile above the universal mean DELTArho(r)=rho(r)-rho-bar for clusters in bins of richness and optical luminosity. We also measure the excess luminosity density DELTAl(r)=l(r)-l-bar measured in the z = 0.25 i band. For both mass and light, we de-project the profiles to produce three-dimensional mass and light profiles over scales from 25 h {sup -1} kpc to 22 h {sup -1} Mpc. From these profiles we calculate the cumulative excess mass DELTAM(r) and excess light DELTAL(r) as a function of separation from the BCG. On small scales, where rho(r)>>rho-bar, the integrated mass-to-light profile (DELTAM/DELTAL)(r) may be interpreted as the cluster M/L. We find the (DELTAM/DELTAL){sub 200}, the M/L within r {sub 200}, scales with cluster mass as a power law with index 0.33 +- 0.02. On large scales, where rho(r)approxrho-bar, the DELTAM/DELTAL approaches an asymptotic value independent of cluster richness. For small groups, the mean (DELTAM/DELTAL){sub 200} is much smaller than the asymptotic value, while for large clusters (DELTAM/DELTAL){sub 200} is consistent with the asymptotic value. This asymptotic value should be proportional to the mean M/L of the universe (M/L). We find (M/L)b{sup -2} {sub M/L} = 362 +- 54h (statistical). There is additional uncertainty in the overall calibration at the approx10% level. The parameter b {sup 2} {sub M/L} is primarily a function of the bias of the L approx< L {sub *} galaxies used as light tracers, and should be of order unity. Multiplying by the luminosity density in the same bandpass we find OMEGA {sub m}b{sup -2} {sub M/L} = 0.20 +- 0.03, independent of the Hubble parameter.
- OSTI ID:
- 21371819
- Journal Information:
- Astrophysical Journal, Vol. 703, Issue 2; Other Information: DOI: 10.1088/0004-637X/703/2/2232; ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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