TITLE:
Density profiles of galaxy groups and clusters from SDSS galaxy-galaxy weak lensing.
AUTHOR(S):
Rachel Mandelbaum (Princeton), Uros Seljak (ICTP), Richard J. Cool (Arizona), Michael Blanton (NYU), Christopher M. Hirata (IAS), Jonathan Brinkmann
(APO).
DATE:
2006 May 18 (arXiv, v1, posted); 2006 May 18 (MNRAS, submitted); 2006 Jul 24 (revised);
2006 Jul 28 (MNRAS, accepted); 2006 Aug 02 (arXiv, v2, posted); 2006 Sep 19 (MNRAS, published).
AVAILABILITY:
arXiv astro-ph/0605476 (free);
Blackwell-Synergy (requires subscription).
PUBLICATION INFORMATION:
Mon. Not. R. Astron. Soc., 372, 758--776, 2006
ABSTRACT:
We present results of a measurement of the shape of the density
profile of galaxy groups and clusters
traced by 43,335 Luminous Red Galaxies (LRGs) with
spectroscopic redshifts from the Sloan Digital Sky Survey (SDSS). The
galaxies are selected such that they are the brightest within a
cylindrical aperture, split into two luminosity samples, and modeled
as the sum of stellar and dark matter
components. We present a detailed investigation of many possible systematic
effects that could contaminate our signal and develop methods to remove them,
including a detected intrinsic alignment
for galaxies within 100 h-1 kpc of LRGs which we remove using photometric
redshift information. The resulting lensing signal is consistent with NFW
profile dark matter halos; the SIS profile is ruled out at the 96
(conservatively) and 99.96 per cent confidence level (CL) for the
fainter and brighter
lens samples (respectively) when we fit using lensing data between 40
h-1 kpc and 2 h-1 Mpc with total signal-to-noise of 19 and 25 for the
two lens samples. The lensing signal amplitude suggests that the faint
and bright sample galaxies typically reside in haloes of mass (2.9+/-0.4)x1013 h-1Msun
and (6.7+/-0.8)x1013 h-1Msun
respectively, in good agreement with predictions based on
halo spatial density with normalization lower than the 'concordance'
sigma8=0.9. When fitting for the concentration parameter in the NFW
profile, we find c=5.0+/-0.6(stat)+/-1(sys), and c=5.6+/-0.6(stat)+/-1(sys)
for the faint and bright
samples, consistent with LambdaCDM simulations. We also split the
bright sample further to determine masses and concentrations for
cluster-mass halos, finding mass (1.3+/-0.2)x1014 h-1Msun
for the sample of LRGs brighter than -22.6 in r.
We establish that on average there is a correlation between
the halo mass and central galaxy
luminosity relation that scales as M~L2.
ADS BIBLIOGRAPHIC CODE: 2006MNRAS.372..758M
COMMENTS: SDSS Publication #640.