Cross-correlation Weak Lensing of SDSS Galaxy Clusters. III. Mass-to-Light Ratios

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 200 ~ 5 X 1012 h -1 M to clusters with M 200 ~ 1015 h -1 M. Using cross-correlat...

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Bibliographic Details
Published in:	The Astrophysical journal 2009-10, Vol.703 (2), p.2232-2248
Main Authors:	Sheldon, Erin S, Johnston, David E, Masjedi, Morad, McKay, Timothy A, Blanton, Michael R, Scranton, Ryan, Wechsler, Risa H, Koester, Benjamin P, Hansen, Sarah M, Frieman, Joshua A, Annis, James
Format:	Article
Language:	eng
Subjects:	Astronomy ASTROPHYSICS, COSMOLOGY AND ASTRONOMY ASYMPTOTIC SOLUTIONS CALIBRATION Earth, ocean, space Exact sciences and technology GALAXIES GALAXY CLUSTERS LUMINOSITY MASS MATHEMATICAL SOLUTIONS MATTER NONLUMINOUS MATTER OPTICAL PROPERTIES PHYSICAL PROPERTIES THREE-DIMENSIONAL CALCULATIONS UNIVERSE
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Summary:	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 200 ~ 5 X 1012 h -1 M to clusters with M 200 ~ 1015 h -1 M. Using cross-correlation weak lensing, we measure the excess mass density profile above the universal mean for clusters in bins of richness and optical luminosity. We also measure the excess luminosity density 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 -1 kpc to 22 h -1 Mpc. From these profiles we calculate the cumulative excess mass Delta DM(r) and excess light Delta DL(r) as a function of separation from the BCG. On small scales, where, the integrated mass-to-light profile ( Delta DM/ Delta DL)(r) may be interpreted as the cluster M/L. We find the ( Delta DM/ Delta DL)200, the M/L within r 200, scales with cluster mass as a power law with index 0.33 +/- 0.02. On large scales, where, the Delta DM/ Delta DL approaches an asymptotic value independent of cluster richness. For small groups, the mean ( Delta DM/ Delta DL)200 is much smaller than the asymptotic value, while for large clusters ( Delta DM/ Delta DL)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/Lb-2 M/L = 362 +/- 54h (statistical). There is additional uncertainty in the overall calibration at the ~10% level. The parameter b 2 M/L is primarily a function of the bias of the L L * galaxies used as light tracers, and should be of order unity. Multiplying by the luminosity density in the same bandpass we find Delta *W m b-2 M/L = 0.20 +/- 0.03, independent of the Hubble parameter.
ISSN:	0004-637X 1538-4357