0 Assigned ID: 313 ----- Attempting Submission 1 (Fri Apr 10 00:17:40 GMT 2015) ----- HST Phase I Proposal 313 (m33_archive.apt) successfully submitted. Receipt: # 313-1 ----- Attempting Submission 2 (Fri Apr 10 19:40:36 GMT 2015) ----- We propose to find the optical counterparts for at least 40 high-mass X-ray binaries (HMXBs) in M33 using archival HST imaging data. We will align the data to the deep Chandra X-ray catalog to search for optical counterpart candidates to the X-ray sources. The optical morphology and photometry of these counterparts will identify which X-ray sources are most likely to be HMXBs. The colors of the counterpart stars will allow each HMXB to be typed. Because HMXBs are young systems, we will measure the recent star formation histories (SFHs) of their surrounding populations to determine their ages. We will then compare the distribution of ages to those we've measured for other nearby galaxies to look for patterns with metallicity and star formation rate, and we will compare the distribution to those predicted by binary formation and evolution models. This project will yield state-of-the-art observational constraints on population synthesis models for interacting binary stars. RESOLVED STELLAR POPULATIONS 0 Regular false false false false false SUPPORTED