Integrated Light Spectra of Globular Clusters: A New Frontier in Chemical Abundance Studies

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Dr. Janet Colucci is awarded an NSF Astronomy and Astrophysics Postdoctoral Fellowship to carry out a program of research and education at the University of California, Santa Cruz (UCSC). Precisely how galaxies initially form and how they change throughout their lifetimes are among the least understood problems in astrophysics. Many projects are centered on unraveling these mysteries. In this project the fellow will study the detailed chemical evolution of galaxies beyond the Local Group by obtaining chemical abundances of over 20 individual chemical elements from integrated light spectra of star clusters. The fellow's technique enables chemical abundance measurements in galaxies as distant as 13 million light-years that were previously only possible in galaxies within a half million light-years distance, i.e., our own Milky Way Galaxy and its nearby satellite galaxies. Bridging the fields of stellar astronomy and extragalactic astronomy, this technique will allow the assembly of a large sample of detailed chemical abundances in galaxies across all galaxy types, and it will provide the basis for reconsideration of a wide range of classic questions in galaxy formation.Specifically, the fellow will measure chemical abundances in a total sample of about 40 globular clusters residing in both the nearest massive early-type (E/S0) galaxy, NGC 5128, and in the starbursting M82 galaxy, which she will add to her previous work in M31, the Large Magellanic Cloud, and the Milky Way, to address galaxy and globular cluster formation questions. Detailed chemical analyses of this scope---comparable to standard optical abundance analyses of local Milky Way stars---have never been performed before for either an early-type or a starburst galaxy. The broader impacts of this project include a significant educational component. The fellow will undertake a program of educational outreach that focuses on bringing astronomy outreach programs to underrepresented groups. With the Expanding Your Horizons (EYH) program at UCSC, the fellow will develop and present hands-on astronomy workshops to groups of high school girls in Santa Cruz and Monterey counties. The goal of EYH is to encourage young women to engage in science, technology, engineering, and mathematics (STEM) fields early in their education to enable their pursuit of STEM careers. An important part of this endeavor is to provide female role models and mentors who are in STEM careers. The fellow will also expand outreach efforts through EYH at UCSC by organizing traveling workshops to bring astronomy and other STEM fields to underserved communities. She will establish an infrastructure to facilitate continuing involvement of the UCSC Astronomy Department with EYH as well as other STEM-field departments.