LEAPS-MPS: Massive Binary Stellar Evolution in Early Universe Analogs

Massive binary stars form some of the brightest X-ray sources in the universe. Multiwavelength observations are crucial for understanding the complex process of massive binary stellar evolution. This project will use archival multiwavelength observations of nearby low metallicity dwarf galaxies, similar to galaxies in the early universe, to identify and characterize populations of massive stellar binaries comprised of a black hole or neutron star and a massive star (high mass X-ray binaries; HMXBs). The project will also develop a near-peer mentoring program that connects first and second year undergraduate and new transfer students with more experienced undergraduate physics majors and masters students. Peer mentors will also serve as research mentors for a new research skills course that will be created for students in their first two years on campus who do not have prior coursework in computer programming and/or scientific research experience. Understanding the contribution of isolated binary evolution to the production rates of gravitational wave events in the early universe hinges upon understanding of the complex process of massive binary stellar evolution at low metallicity. The project will use archival X-ray and optical/ultraviolet data to identify and characterize ~40 high mass X-ray binaries (HMXBs) in nearby low metallicity dwarf galaxies, which serve as analogs to galaxies in the early universe. SED-fitting of multi-band photometry will derive physical properties of the companion star candidates including their effective temperatures, luminosities, and radii. The age distribution for the HMXB candidates will be measured by using spatially resolved recent star formation history maps of the galaxies in the sample. This project will lay the groundwork for future observing campaigns to obtain optical spectroscopy for HMXB companion star candidates in nearby low metallicity dwarf galaxies. 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.