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Probing Gravity: Galaxies, CMB Lensing, and Intensity Mapping

We discuss recent work exploring the use of large-scale structure to probe gravity.  We first consider using CMB lensing and galaxy surveys to probe E_G, the ratio between curvature and velocity perturbations. This quantity is independent of galaxy clustering bias and is distinct for various gravity models, breaking the degeneracy in current cosmological probes of gravity and dark energy. We present our constraints to E_G using CMB data from Planck and galaxy data from the SDSS BOSS survey, which are in tension with general relativity (GR). We also forecast gravity constraints for upcoming galaxy and CMB surveys.  Next, we consider intensity mapping (IM) as a gravity probe.  We start by discussing our recent work probing intensities at high redshifts of IM lines from star formation lines, i.e. CO, Ly-a.  We then consider how IM lines can probe gravity by measuring E_G.

Cody Hall

Anthony Pullen (Carnegie Mellon)

January 15, 2016
14:00 - 15:00