0 Assigned ID: 314 ----- Attempting Submission 1 (Fri Apr 10 00:18:22 GMT 2015) ----- HST Phase I Proposal 314 (m83.apt) successfully submitted. Receipt: # 314-1 ----- Attempting Submission 2 (Fri Apr 10 20:06:32 GMT 2015) ----- We propose to measure the progenitor masses for a large sample of supernova remnants (SNRs) in M83. With a high supernova rate (6-7 per century) and more identified SNRs (>300) than any other galaxy, the nearby grand-design spiral M83 is an ideal target for the study of SNR progenitors. Deep HST images obtained recently with ACS and WFC3 cover most of the galaxy. Using these images, we will age-date the stellar population associated with each SNR and derive a corresponding progenitor mass. We have used the same technique previously to measure the progenitor masses for 17 historic SNe, 82 SNRs in M31, and 33 SNRs in M33. The M31 and M33 studies suggested a derth of progenitors with initial masses >20 solar masses. M83 has a much higher SFR than the galaxies used in our earlier studies, which greatly increases the chances of finding progenitors of higher mass, and will provide much better constraints on the distribution of high-mass progenitors than was possible previously. RESOLVED STELLAR POPULATIONS 0 Regular false false false false false SUPPORTED