The high redshift star-formation history from carbon-monoxide intensity maps

TL;DR

This paper presents a method to measure the cosmic star-formation history using CO intensity maps and one-point statistics, providing competitive constraints on star-formation rates at high redshifts.

Contribution

It introduces a P(D) analysis technique to infer the CO luminosity function and star-formation rate density from intensity maps, addressing noise and foreground effects.

Findings

CO intensity maps can constrain SFRD with about 10% accuracy.

Model uncertainty dominates SFRD error, around 50% for pessimistic estimates.

Combining intensity maps with galaxy data reduces uncertainty to 5-10%.

Abstract

We demonstrate how cosmic star-formation history can be measured with one-point statistics of carbon-monoxide intensity maps. Using a P(D) analysis, the luminosity function of CO-emitting sources can be inferred from the measured one-point intensity PDF. The star-formation rate density (SFRD) can then be obtained, at several redshifts, from the CO luminosity density. We study the effects of instrumental noise, line foregrounds, and target redshift, and obtain constraints on the CO luminosity density of order 10%. We show that the SFRD uncertainty is dominated by that of the model connecting CO luminosity and star formation. For pessimistic estimates of this model uncertainty, we obtain an error of order 50% on SFRD for surveys targeting redshifts between 2 and 7 with reasonable noise and foregrounds included. However, comparisons between intensity maps and galaxies could substantially reduce this model uncertainty. In this case our constraints on SFRD at these redshifts improve to roughly 5-10%, which is highly competitive with current measurements.