ALMA Observations of z~3 star forming galaxies: No Change in Global Star Formation Process out to z > 3

Brent Groves

The observed evolution of the gas fraction and its associated depletion timein main sequence (MS) galaxies provides insights on how star formation proceeds over cosmic time. I will present ALMA detections of the rest-frame ~300umcontinuum observed at 240 GHz for 45 massive ( = 10.7), nor-mal star forming ( = −8.6), i.e. MS, galaxies at z ~ 3.2 inthe COSMOS field. We use these observations and multiwavelength data to derive stellar & gas masses and SFRs for our sample. We obtain a median gas fraction of Mgas/M* = 1.65 and a median gas depletion gas depletion time of Mgas/SFR = 0.68 Gyr. These results are fully consistent with the expected flattening of the redshift evolution from the 2-SFM (2 star formation mode) framework, and demonstrate that the global star formation process has not evolved from z~1 to z~3.