Speaker
Description
The cosmic star-forming activity peaked at redshifts z=1-4 in the so-called "Cosmic Noon". This vigorous star production is driven by massive galaxies with star-formation rates 100-1000x higher than the Milky Way. However, it has long been unclear what causes these immense star formation: were early galaxies forming stars very efficiently, or are they simply more gas-rich than present-day galaxies?
Over the last decade, extensive surveys of cold gas in early galaxies have established that they are indeed very gas-rich. However, most of their cold gas resides in diffuse, extended reservoirs, contributing little to the observed star confirmation. Maybe early galaxies have significantly enhanced star-forming efficiency after all? To answer this question, we need to study the dense gas from which stars actually form.To do so, we need to target emission lines of "complex" molecules such as HCN, HCO+, and HNC.
Unfortunately, as these lines are very faint, dense gas at Cosmic Noon remains almost completely unexplored. I will showcase PRUSSIC: a comprehensive census of dense gas at high redshift with ALMA, NOEMA, and VLA. Over the last two years, PRUSSIC has detected dense gas in >20 early galaxies. We find that high-z galaxies contain surprisingly little dense gas and have an enhanced star-forming efficiency, a direct contradiction to previous models.
| Talk category | NOVA Network 1 |
|---|---|
| Preference for a talk or poster | Talk |
