Astrophysics

A number of ground based CMB surveys that will survey large fractions of the sky to high sensitivity are currently in the planning stages.  I will give an overview of what can be learned from these surveys about the Universe since recombination, focussing on gravitational lensing science.  I will also discuss some new CMB observables that would be accessible with even more futuristic surveys.

Cosmology has seen great progress thanks to precision measurements and is bound to greatly benefit from upcoming Large Scale Structure and Cosmic Microwave Background data. I will point out a number of interesting directions. In particular, I discuss how the microphysics of inflation may be tested in galaxy surveys through “fossil” signatures originating from squeezed primordial correlations. I further elaborate on the constraining power of CMB spectral distortions on small-scale cosmological fluctuations and on particle decays in the very early Universe in relation to reheating. I also describe some of the possible constraints on inflation and reheating from future B-mode observations.

I will describe the Dark Energy Spectroscopic Instrument (DESI), an instrument currently being built to carry out a large galaxy redshift survey.  DESI is the next step beyond the SDSS and BOSS surveys, mapping over 30 million galaxies.  I will focus in particular on the amazing engineering challenges of the DESI instrument itself, which includes a 5,000-robot army and 250 kilometers of fiber optics.  I will conclude by briefly describing the work I am personally involved in: a large imaging survey that will measure the galaxies from which DESI will select targets for follow-up spectroscopic observation.