Astronomy Colloquium

  Rest-frame optical spectroscopy provides basic insight into the stellar and gaseous contents of galaxies. Until now, our knowledge of the rest-frame optical spectroscopic properties of galaxies at 1.5<=z<=3.5 has been extremely limited, despite the critical importance of this cosmic epoch for the assembly of galaxies and the growth of black holes. The recent commissioning of the MOSFIRE spectrograph on the Keck I telescope represents a major development for the study of the rest-frame optical properties of high-redshift galaxies. The MOSFIRE Deep Evolution Field (MOSDEF) Survey fully exploits the new capabilities of MOSFIRE, charting the evolution of the rest-frame optical spectra for ~2000 galaxies in three distinct redshift intervals spanning 1.5<=z<=3.5 -- more than an order of magnitude improvement over existing surveys. With MOSDEF, we address key questions including: What are the physical processes driving star formation in individual galaxies? How do galaxies exchange gas and heavy elements with the intergalactic medium? How are stellar mass and structure assembled in galaxies (in situ star formation vs. mergers)? What is the nature of the co-evolution of black holes and stellar populations? In this talk I will present early science results from the MOSDEF survey regarding galaxy chemical abundances and the physical conditions in high-redshift star-forming regions.