Previous   |   Session 147   |   Next

[147.06] Measurements of the Clustering of Mass in the Universe by Weak Lensing of SDSS Galaxy Clusters

D. Johnston (Princeton University), E. Sheldon (KICP University of Chicago), B. Koester (University of Michigan), R. Wechsler (KICP University of Chicago), T. McKay (University of Michigan), J. Frieman (University of Chicago), J. Annis (Fermilab), A. Evrard (University of Michigan), I. Zehavi (University of Arizona), R. Scranton (University of Pittsburgh), R. Nichol (University of Portsmouth), A. Connolly (University of Pittsburgh), T. Budavari (Johns Hopkins University), A. Tasitsiomi (University of Chicago), SDSS Collaboration

We present measurements of the weak lensing distortion from over 200,000 groups and clusters of galaxies from the Sloan Digital Sky Survey. These measurements are inverted to obtain the density profile or cluster-mass correlation function for different stacked samples with a technique akin to that of galaxy-galaxy lensing. This method allows us to directly measure the density structure of dark matter halos that are well predicted by CDM simulations. Furthermore we measure the mean virial mass of the clusters in a model independent way. This mass calibration combined with the shear size of the data set will allow us to measure the mass function of halos to unprecedented statistical accuracy and with greater control over systematic effects than previous attempts and so should allow a tight constraint on the cosmological parameters affecting the mass power spectrum including \Omega_m and \sigma₈. The combination of this measurement and the cluster-cluster correlation function will allow us to measure the mass autocorrelation function on scales approximately 2 Mpc/h to 20 Mpc/h with possible future extension into linear scales above 30 Mpc/h. This leads to another separate constraint on cosmological parameters which combines well with the constraints through the mass function. These constraints should be limited only by our knowledge of the cluster selection function and the appropriate way of comparing this data with dark matter simulations. We are studying these issues with simulated data sets consisting of dark matter simulations with galaxies added in a way constrained to fit various observations. These measurements when combined with CMB anisotropy data will provide a stringent test of the consistency of the CDM structure formation paradigm.

The author(s) of this abstract have provided an email address for comments about the abstract: davej@astro.princeton.edu

Previous   |   Session 147   |   Next

Bulletin of the American Astronomical Society, 36 5
© 2004. The American Astronomical Society.