The Triggering and Quenching of Star-Formation and Nuclear Activity in Galaxies

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Galaxy surveys in the local universe such as the Sloan Digital Sky Survey have shown that galaxies populate two broad categories: blue, star-forming disk galaxies and red, quiescent spheroidal or early-type galaxies. In the nearby universe, the most luminous and massive galaxies are quiescent, and they are preferentially found in dense environments, such as groups and clusters. In contrast, star-forming galaxies have lower stellar masses and occupy low-density environments. Astronomers also know that star-formation in the universe was significantly more active several billion years ago. The key question that will be answered by this research is the following: what physical processes drive the suppression of star formation and nuclear activity between early times and the present day.This award will enable for the next phase of the Observations of Redshift Evolution in Large Scale Environments (ORELSE) survey of galaxies. This includes a comprehensive, near-IR spectroscopic survey with the Multi-Object Spectrometer For Infra-Red Exploration (MOSFIRE) on the Keck 10-m telescope, together with multi-wavelength (X-ray, radio, and infrared) observations. By correlating with the precise measures of local and global environment afforded by ORELSE, the program will determine the cause and effect of gas-fueling and quenching events that drive galaxy evolution over a critical 3-billion year period where star formation and nuclear activity are rapidly declining.This award will also expand the underrepresented student base by supporting the Mentorship for Undergraduate Research Participants in Physical and Mathematical Sciences (MURPPS) program at the University of California-Davis. The program will increase the number of underrepresented students who can participate in MURPPS by over 30% and is directly aligned with the NSF's commitment to achieve full participation of women, persons with disabilities, and underrepresented minorities in STEM fields.