Day 108

Sunday.  Should get the calibration done today.


1109.0998
Testing general relativity on horizon scales and the primordial non-Gaussianity
Yoo, Hamaus, Seljak, Zaldarriaga


GR description on observed galaxy power spectrum is different from standard Newtonian description on large scales: a unique opportunity to test GR on horizon scales.  GR effects classified as two new terms that represent (1) velocity and (2) gravitational potential, coupling to the time evolution of galaxy number density and Hubble parameter.  Compared to the dominant density and velocity redshift-space distortion terms, the former scales as H/k and correlates the real and imaginary parts of the Fourier modes, while the latter scales as (H/k)^2, where k is the comoving wave number and H is the conformal Hubble parameter.  We use the recently developed methods to reduce the sampling variance and shot noise to show that in an all sky galaxy redshift survey at low z, the velocty term can be measured at 10-sigma confidence level, if one can utilize halos of mass M>1e10 Msun, while the gravitational potential term itself can only be marginally detected.  Also demonstrate that the GR effect is not degenerate with the primordial non-Gaussian signature in galaxy bias, and the ability to detect the primordial non-Gaussianity is little compromised.


1109.1033
Modeling techniques for measuring galaxy properties in multi-epoch surveys
Bosch


Advocate Bayesian approach to survey data reduction as a whole; focus specifically on the problem of modeling individual galaxies and stars.  Present MC algorithm that can efficiently sample from posterior probability for a flexible class of galaxy models, and propose a method for constructing and convolving these models using Gauss-Hermite ("shapelet") functions.  These methods designed to be efficient in a multi-epoch modeling ("multifit") sense: where comparing a generative model to each exposure rather than combining the data from multiple exposures in advance.  Also discuss how these methods are important for specific higher-level analysis (in particular, WL), as well as their interaction with the many other aspects of survey reduction pipeline.


* PSF and galaxy modeling: from priors of galaxy models, using shaplet for convolution and construction, working in "multifit" mode.


1109.1121
Cosmology with Gravitational lensing
Heavens


Overview of gravitational lensing: theoretical aspects and derivation of important results.  Topics: determination of surface mass densities of intervening lenses, statistical analysis of distirtions of galaxy images by general inhomogeneities (cosmic shear), both in 2d proejction on the sky, and in 3d where source distance information is available.  3d mass reconstruction and the shear ratio test are also considered; sensitivity of observables to DE is used to show how its equation of state may be determined using WL.  Prospect of testing GR with WL, exploiting the differences in growth rates of perturbations in different models.


1109.1014
Astronomy carrie profiles from the AAS newsletter archives
Metcalfe, et al


A collection of articles that were originally publised in the Newsletter of the AAS between 5/2008 and 9/2011 by the Committe on Employment.  Success in various job sectors: insight and advise from authors representing a wide range of career paths.  Post complete selection here to make them accessible.