Probing Galaxy Feedback across Cosmic Time with a 3-Dimensional Census of Quasar Absorption Lines

Lundgren Britt F, New Haven IL

Investigators

Abstract

Dr. Britt Lundgren is awarded an NSF Astronomy and Astrophysics Postdoctoral Fellowship to carry out a program of research and education at the University of Wisconsin-Madison. A longstanding problem in astrophysics is to understand how galaxies form and develop---or evolve---throughout their lifetimes. Such understanding is necessary to uncover how our Universe evolved and to gain insight into the origin of our own Milky Way Galaxy. One important aspect of understanding galaxy evolution is to study how large region of newly forming stars in certain galaxies interact with the massive black holes at the centers (nuclei) of these galaxies, which is the central theme of this fellow's project. By using the largest sample of quasar absorption lines (QALs), the fellow will address outstanding questions regarding the enrichment history of the intergalactic medium and its connection to feedback from star formation and Active Galactic Nuclei (AGN) in galaxies. QALs provide uniquely unbiased probes of galactic environments over vast ranges in redshift, but only recently has the number density of spectroscopically observed high-redshift quasars, combined with the scale of deep galaxy surveys, provided sufficient statistics to study the associations between galaxies and absorption features in proximate quasar sightlines over wide ranges in redshift and galaxy properties. Through her participation in the Sloan Digital Sky Survey III's Baryon Oscillation Spectroscopic Survey (BOSS), which will obtain spectra for 160,000 redshift z > 2.2 quasars over the next three years, the fellow will extract a 3-dimensional census of metal absorption lines in the redshift range z = 0.35 to 4. Using this data set, already one order of magnitude larger than existing samples, she will precisely measure the evolution of the number density and equivalent width distribution for the most prolific metals in the intergalactic medium from redshift z around 4 to present. Leveraging these data with her existing participation in numerous deep galaxy surveys, she will reveal the typical galactic environments of QALs from high redshift and constrain the physical distances to which galaxy and AGN outflows extend as a function of galaxy properties and redshift. Together, these investigations will potentially revolutionize our understanding of feedback from star formation and AGN and its role in the co-evolution of galaxies and the intergalactic medium throughout about 90% of cosmic history. The broader impacts of this project include a significant educational component. The fellow will undertake a program of educational outreach in partnership with the UW Space Place, a well-established astronomy outreach center in Madison. Within this facility she will conduct a series of weekend workshops for students in grades 6 through 8 using a well-tested curriculum of inquiry-based modern astronomy activities that she designed for a previous educational program. The fellow will supplement these student-focussed sessions with a shorter series of evening workshops for local high school science teachers that are designed to familiarize educators with activities using the public interface to the Sloan Digital Sky Survey, the Skyserver. These programs will serve the next generation of scientists by providing students at a critical age with a positive introduction to modern astronomy research in addition to providing their future educators with the tools to foster further explorations in the high school classroom.