Large-Scale Investigations of Quasar Wind Variability with the Sloan Digital Sky Survey

A longstanding problem in astrophysics is to understand how galaxies form and develop 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 formation and evolution is to study supermassive black holes (SMBHs) at the centers of galaxies and how these SMBHs are linked to their host galaxies. Quasar winds are fundamentally linked to mass accretion onto rapidly growing SMBHs, and they also likely serve as agents of SMBH feedback into typical massive galaxies. This project will advance understanding of several key aspects of quasar winds using an unprecedentedly large---and still growing---spectroscopic survey of multi-year ultraviolet broad absorption line (BAL) variability in about 2100 BAL quasars. This survey is primarily based on spectra from the ongoing Sloan Digital Sky Survey (SDSS) and is about two orders of magnitude larger than past comparable surveys; supporting targeted spectroscopy is also obtained via Penn State's access to the queue-scheduled Hobby-Eberly Telescope.

The PI's annual summer workshops will serve as a high-leverage way of helping about 50 Pennsylvania high school teachers educate their thousands of students better about space, time, gravity, black holes, and the scientific method. Teachers from underserved rural and urban school districts, including underrepresented minorities and women, will be specifically recruited with scholarship funds. The workshops' programs will include an overview of the project's scientific discoveries and an associated activity, and the postdoctoral research associate will help with workshop planning and presentation. The postdoctoral researcher will also work as a central member of PI's group, thereby developing his or her research, teaching, and outreach skills. He or she will lead much of the analysis as well as many of the high-impact journal articles and presentations. The postdoctoral researcher will also be a primary mentor of the undergraduate researcher, who will develop hands-on research skills via well-defined projects.

More technically, this project will use its database to provide the following specific advances: (1) unmatched large-scale measurements/limits of BAL acceleration and deceleration that constrain BAL-wind feedback into galaxies; (2) measurements of BAL vs. emission-line properties that test the drivers of BAL variability and quasar-wind models; (3) determination of the in-depth relations between BAL disappearance and emergence with associated improvements in direct BAL-lifetime estimates; (4) an understanding of the nature of unusually stable BALs and their possible relation to ongoing large-scale galactic feedback; and (5) determination of whether remarkable redshifted BAL troughs arise from rotationally dominated outflows or high-velocity infalling material. These results will play an important role in transforming the field of multi-year BAL variability studies into one that supplies rigorous, large-sample constraints that can effectively guide models of quasar winds and their feedback. They are expected to be the best such results available for at least a decade.