Oral Presentation

AS2COSPEC - an ALMA spectroscopic survey of the bright dusty star-forming galaxies at cosmic noon and beyond

Author(s): Chian-Chou Chen (ASIAA)

Presenter: Chian-Chou Chen (tc) (ASIAA)

One main objective of the Wideband Sensitivity Upgrade (WSU) is to be able to perform more efficient spectroscopic surveys on high-redshift galaxies. To preview what can be achieved with such a capability, we present AS2COSPEC, a benchmark ALMA spectroscppic survey on a sample of 54 850 micron selected, flux-limited, dusty star-forming galaxies (DSFGs), or the submillimeter galaxies (SMGs). This major effort of >60 hours of 12m time investment has yielded a >95% line (100% in continuum) detection rate, allowing us to unambiguously establish the positive correlation between submillimeter brighteness and rddshift distributions, contrasting predictions from state-of-the-art physical models. Their ISM properties revealed by the detected line emissions suggest that the major challenge for the models could lie in the observed high dust-to-stellar mass ratios, which in turn could suggest that the SMGs in the models, or massive DSFGs at z=2-5 in general, may have experienced too much feedback that has expelled too much dust or impeded efficient dust grain grown in the early times. The talk will briefly summarize our results and give some forecasts on what we can look forward to in the era of WSU.