Cosmological Constraints from a Combination of Galaxy Clustering and Lensing -- III. Application to SDSS Data

We simultaneously constrain cosmology and galaxy bias using measurements of galaxy abundances, galaxy clustering and galaxy-galaxy lensing taken from the Sloan Digital Sky Survey. We use the conditional luminosity function (which describes the halo occupation statistics as function of galaxy luminosity) combined with the halo model (which describes the non-linear matter field in terms of its halo building blocks) to describe the galaxy-dark matter connection. We explicitly account for residual redshift space distortions in the projected galaxy-galaxy correlation functions, and marginalize over uncertainties in the scale dependence of the halo bias and the detailed structure of dark matter haloes. Under the assumption of a spatially flat, vanilla {\Lambda}CDM cosmology, we focus on constraining the matter density, {\Omega}m, and the normalization of the matter power spectrum, {\sigma}8, and we adopt WMAP7 priors for the spectral index, the Hubble parameter, and the baryon density. We obtain that \Omegam = 0.278_{-0.026}^{+0.023} and {\sigma}8 = 0.763_{-0.049}^{+0.064} (95% CL). These results are robust to uncertainties in the radial number density distribution of satellite galaxies, while allowing for non-Poisson satellite occupation distributions results in a slightly lower value for {\sigma}8 (0.744_{-0.047}^{+0.056}). These constraints are in excellent agreement (at the 1{\sigma} level) with the cosmic microwave background constraints from WMAP. This demonstrates that the use of a realistic and accurate model for galaxy bias, down to the smallest non-linear scales currently observed in galaxy surveys, leads to results perfectly consistent with the vanilla {\Lambda}CDM cosmology.Comment: 21 pages, 9 figures, 5 tables, submitted to MNRA

Estimating cosmological parameters from future gravitational lens surveys

Upcoming ground and space based observatories such as the DES, the LSST, the JDEM concepts and the SKA, promise to dramatically increase the size of strong gravitational lens samples. A significant fraction of the systems are expected to be time delay lenses. Many of the existing lensing degeneracies become less of an issue with large samples since the distributions of a number of parameters are predictable, and can be incorporated into an analysis, thus helping to lessen the degeneracy. Assuming a mean galaxy density profile that does not evolve with redshift, a Lambda-CDM cosmology, and Gaussian distributions for bulk parameters describing the lens and source populations, we generate synthetic lens catalogues and examine the relationship between constraints on the Omega_m - Omega_Lambda plane and H_0 with increasing lens sample size. We find that, with sample sizes of ~400 time delay lenses, useful constraints can be obtained for Omega_m and Omega_Lambda with approximately similar levels of precision as from the best of other methods. In addition, sample sizes of ~100 time delay systems yield estimates of H_0 with errors of only a couple of percent, exceeding the level of precision from current best estimates such as the HST Key Project. We note that insufficient prior knowledge of the lens samples employed in the analysis, via under or overestimates in the mean values of the sample distributions, results in broadening of constraints. This highlights the need for sound prior knowledge of the sample before useful cosmological constraints can be obtained from large time delay samples (abridged).Comment: 10 pages, 3 figures, 1 table. Accepted for publication in MNRA

Architecture and utopia, 2015

No abstract available

Proof of impact and pipeline planning: directions and challenges for social audit in the health sector

Social audits are typically observational studies, combining qualitative and quantitative uptake of evidence with consultative interpretation of results. This often falters on issues of causality because their cross-sectional design limits interpretation of time relations and separation out of other indirect associations

Density, crowding, and satisfaction with the residential environment

The relationships between a set of measures of various components of environmental density and perceived crowding are examined in a data set from a sample of residents of a large metropolitan area. While there are meaningful patterns observed among the correlations, the primary finding is the weakness of the relationships between density and crowding. The implications of the weak relationship between objective and subjective measures intended to measure components of the quality of life, of which the present findings are an example, are discussed; the usefulness of subjective measures may lie primarily in their capacity to define what aspects of society should be monitored and included in a system of social accounting.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43679/1/11205_2004_Article_BF00287219.pd

Population issues and social indicators of well-being

Relating demographers' measures of various population characteristics (size, growth/decline, density, age/sex structures, migration, et cetera) to measures of well-being recently developed within the social indicators movement promises to provide new knowledge about the linkage of population and well-being that can enhance decision making about important population issues.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43515/1/11111_2005_Article_BF01363887.pd