Connecting CO Intensity Mapping to Molecular Gas and Star Formation in z > 2 Galaxies

Mon, November 16, 2015

Intensity mapping, which images a single spectral line from unresolved galaxies across cosmological volumes, is a promising technique for probing the early universe. I will present predictions for the intensity map and power spectrum of the CO(1-0) line from z~2.4-2.8 galaxies, based on a parameterized model for the galaxy-halo connection, and then demonstrate the extent to which properties of high-redshift galaxies can be directly inferred from such observations. Our fiducial prediction should be detectable by a realistic experiment, but motivated by significant modeling uncertainties, we demonstrate the effect of varying model parameters on the observed CO power spectrum. Using simulated observations, we then infer constraints on our model parameter space with an MCMC procedure, showing corresponding constraints on the LIR-LCO relation and the CO luminosity function. These constraints would be complementary to current high-redshift galaxy observations, which can detect the brightest galaxies but not complete samples from fainter galaxy populations. By probing these populations in aggregate, CO intensity mapping could be a valuable tool for probing molecular gas and its relation to star formation in high-redshift galaxies.