Day 730

Tuesday.

1408.5435
Tests of streaming models for redshift-space distortions
White, Reid, Chuang, Tinker, McBride, Prada, Samushia

Observations of redshift-space distortions in spectroscopic galaxy surveys offer an attractive method for observing the build-up for cosmological structure, which depends both on the expansion rate of the Universe and our theory of gravity.  In preparation for analysis of BOSS final data release, compare a number of analytic and phenomenological 'streaming' models, specified in configuration space, to mock catalogs derived in different ways from several N-body simulations.  The galaxies in each mock analog have properties similar to those of the higher redshift galaxies measured by BOSS but differ in the details of how small-scale velocities and halo occupancy are determined.  Find that all of the analytic models fit the simulations over a limited range of scales while failing at small scales.  Discuss which models are most robust and on which scales they return reliable estimates of the rate of growth of structure: find that models based on some form of resumption can fit the N-body data for BOSS-like galaxies above 30 Mpc/h well enough to return unbiased parameter estimates.

1408.5633
Measuring cluster masses with CMB lensing: a statistical approach
Melin, Bartlett

Present a method for measuring the masses of galaxy clusters using the imprint of their gravitational lensing signal on the CMB temperature anisotropies.  The method first reconstructs the projected gravitational potential with a quadratic estimator and then applies a matched filter to extract cluster mass.  The approach is well-suited for statistical analyses that bin clusters according to other mass proxies.  Find that current experiments such as Planck, SPT and ACT, can practically implement such a statistical methodology, and that future experiments will reach sensitivities sufficient for individual measurements of massive systems.  As illustration, use simulations of Planck observations to demonstrate that it tis possible to constrain the mass scale of a set of 62 massive clusters with prior information from X-ray observations, similar to the published Planck ESZ-XMM sample.  Examine the effect of the tSZ and kSZ signals, finding that the impact of kSZ remains small in this context.  The stronger tSZ signal, however, must be actively removed from the CMB maps by component separation techniques prior to reconstruction of the gravitational potential.  Study of 2 such methods highlights the importance of broad frequency coverage for this purpose.  A companion paper presents application to the Planck data on the ESZ-XMM sample.

1408.5790
Accretion history of the Milky Way dark matter halo and the origin of its angular momentum
Peebles

The flow of Dm into the MW and LMC in a model for the gravitational field of the neighboring galaxies yields a growth history of the DM halo of the MW that ends up with angular momentum roughly in the observed direction, and it produces a DM stream around the LMC that resembles the Magellanic Stream.