Dissecting Stars and Gas in High-redshift Cluster Galaxies with ALMA+HST+VLT

Arizona State University, Scottsdale AZ

Investigators

Abstract

An overarching goal of astrophysics is to better understand the processes that drive the evolution of galaxies. This understanding requires spatially resolved properties of a galaxy's dust and stellar components, as well as its gas reservoir. The Principal Investigator (PI) has used deep observations with the Atacama Large Sub/Millimeter Array (ALMA), the Hubble Space Telescope (HST), and the Very Large Telescope (VLT) of the European Southern Observatory to carry out a spatially resolved study of moderate redshift cluster galaxies. This will allow the PI and her team to map star formation efficiency and measure baryon fractions, evaluate the gravitational stability of disks, determine a spatially resolved star formation law, and identify the dominant star formation "quenching" mechanisms and their timescales, all during cosmic "high noon" - the epoch when star formation reached its peak intensity. These results will be compared with cosmological simulations of galaxy formation and evolution. This work will support the research activities of a graduate student, as well as a program involving undergraduate students in the development of interactive visualizations related to the project's science goals. This research program features the first observational study of molecular gas distribution and kinematics on kiloparsec scales for cluster galaxies beyond z > 0.1. Together with the HST and VLT observations, the combined multi-wavelength data set will allow the researchers to fully dissect the baryonic components of moderate redshift cluster galaxies. This study will be complementary to state-of-the-art surveys of spatially resolved molecular gas and star formation at low redshift in both sparsely populated fields (PHANGS, ALMA-QUEST) and in dense cluster (VERTICO) environments, but at significantly higher redshifts, and at the epoch of peak cosmic star formation and cluster assembly, when many important environmental effects are likely occurring. Moreover, it will serve as a direct comparison to the next generation of hydrodynamic simulations (e.g., COLIBRE) to model the kinematics of cold gas directly for the first time. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.