Dr. Erin Hicks is awarded an NSF Astronomy and Astrophysics Postdoctoral Fellowship to carry out a program of research and education at the University of Washington (UW). Over the past decade it has become increasingly clear that supermassive black holes (BHs) play a pivotal role in galaxy evolution. This revelation has been driven by the discovery that most, if not all, galaxies harbor a BH, and that the mass of the BH is related to the global properties of the host galaxy, likely as a consequence of the co-evolution of galaxies and their BHs. It is widely accepted that BHs accumulate mass through accretion of material from the host galaxy and that this process is the source of power behind active galactic nuclei (AGN). The massive BHs found in elliptical galaxies are understood to be products of intense quasar AGN activity occurring in the early universe as a result of major galaxy mergers. In contrast, the ongoing BH growth in the local universe occurs primarily in spiral galaxies hosting Seyfert AGN, the driving mechanism(s) of which are not yet known. Despite the significant BH growth occurring in these galaxies, there is no observed correlation of this activity with large-scale phenomena (>100 pc); this indicates that the triggering mechanism of this mode of accretion, and thus its role in galaxy evolution, is hidden on smaller scales. Dr Hicks will conduct the first comparative study of the two-dimensional molecular gas kinematics, as well as stellar kinematics, on scales down to 10 pc in a matched sample of Seyfert and inactive galaxies. Dr. Hicks will interpret the observed kinematic signatures of gas inflow in the context of theoretical models, and will thereby constrain the mechanism(s) responsible for BH growth in the local universe.
Dr. Hicks will also lead two educational activities at UW that aim to excite a diverse population of undergraduate students about the field of astronomy and to encourage these students to pursue astronomy as a career. As a participant in the well-established UW Pre-Major in Astronomy Program (Pre-MAP), which recruits incoming students from groups that are traditionally underrepresented in science and promotes astronomy as an undergraduate major, Dr. Hicks will provide entry level research projects drawn from the proposed galaxy evolution research as well as one-on-one student mentoring throughout the yearlong program. Dr. Hicks will also help to spread the success of Pre-MAP to other STEM departments across UW. A partnership will be formed with the recently created, NSF-funded Pacific Northwest Louis Stokes Alliance for Minority Participation (PNW LSAMP) to assist with the implementation of similar programs in other Science, Technology, Engineering, and Mathematics (STEM) departments across UW. This will include collaboration on new programs in curriculum building, funding acquisition and research project development, and will work toward the PNW LSAMP five-year goal of doubling the number of underrepresented minority students graduating in STEM fields.
Dr. Hicks's second educational activity will be a course entitled "Galaxies: From Black Holes to Superclusters," to be developed and taught within the UW astronomy department. This course will draw directly from Dr. Hicks's research activities and related topics, and will provide the opportunity to share the fascination of extragalactic research with non-science majors. Among the goals of the course will be for students to gain awareness of exciting breakthroughs in the field and understanding of the fundamental principles underlying them, to recognize the applicability of the scientific method in daily life, and to develop a lifelong interest in astronomy that leads to their continued engagement in the field in the future.
Over the past decade it has become increasingly clear that supermassive black holes (BHs) play a pivotal role in galaxy evolution. This revelation has been driven by the discovery that most, if not all, galaxies harbor a BH, and that the mass of the BH is related to the global properties of the host galaxy, likely as a consequence of the co-evolution of galaxies and their BHs. It is widely accepted that BHs accumulate mass through accretion of material from the host galaxy and that this process is the source of power behind active galactic nuclei (AGN). The massive BHs found in elliptical galaxies are understood to be products of intense quasar AGN activity occurring in the early universe as a result of major galaxy mergers. In contrast, the ongoing BH growth in the local universe occurs primarily in spiral galaxies hosting Seyfert AGN, the driving mechanism(s) of which are not yet known. Despite the significant BH growth occurring in these galaxies, there is no observed correlation of this activity with large-scale phenomena; this indicates that the triggering mechanism of this mode of accretion, and thus its role in galaxy evolution, is hidden on smaller scales. In this program the first comparative study of the two-dimensional molecular gas kinematics, as well as stellar kinematics, in a matched sample of Seyfert and inactive galaxies was conducted at unprecedented detail. This program for the first time showed that there are several differences at small radii that are correlated with active galactic nucleus (AGN) activity. Compared to the inactive galaxies, the Seyfert galaxies have (1) a more centrally concentrated nuclear stellar component, (2) nuclear stars in a more disk-like component, (3) a greater amount of molecular gas in the nuclear region, and (4) more centrally concentrated nuclear molecular gas. These observed differences can be interpreted as evidence for Seyfert galaxies having a disk-like nuclear structure composed of a significant gas reservoir and a relatively young stellar population. This structure is undetected (and possibly does not exist) in quiescent galaxies. The presence of such a nuclear structure in Seyfert galaxies provides evidence for inflow of the surrounding interstellar medium since the nuclear stellar population requires a supply of gas from which to form. The fueling of a Seyfert AGN is thus associated with the formation of a disk-like component of gas and stars. Detailed analysis of the kinematics of the nuclear gas and stars, including comparison to simulations, suggests that quiescent galaxies in which some nuclear gas is present are in the early stage of a minor merger that has not yet triggered significant inflow to the nuclear region. In contrast this detailed analysis of the Seyfert galaxies shows that gas inflow and outflow are superimposed on a generally rotating disk component with a variety of inflow mechanisms responsible. This therefore suggests that steady-state inflow is often insufficient to fuel luminous Seyfert activity, and that instead this requires a stochastic process to temporarily increase the inflow toward the BH. This project also supported two educational activities that aimed to excite a diverse population of undergraduate students about the field of astronomy and to encourage these students to pursue astronomy as a career. As a participant in the well-established UW Pre-Major in Astronomy Program (Pre-MAP), which recruits incoming students from groups that are traditionally underrepresented in science and promotes astronomy as an undergraduate major, Dr. Hicks provided entry level research projects drawn from the proposed galaxy evolution research as well as one-on-one student mentoring throughout the yearlong program. Dr. Hicks also help to spread the success of Pre-MAP to other STEM departments across UW and to other interested astronomy departments across the country. In addition, the curriculum for an advance (calculus-based) astronomy survey course was developed and taught at the University of Washington which included the development of hand-on exercises to reinforce and explore the more challenging course topics.
