Progenitor masses of M33 SNRs using PHATTER obs.

We constrained the progenitor masses for 60 of these SNRs, finding that the remaining 25 remnants had no local star formation in the last 56Myr, consistent with core-collapse supernovae, making them potential Type Ia candidates.

We then infer a progenitor mass distribution from the age distribution, assuming single star evolution. We find that the progenitor mass distribution is consistent with being drawn from a power law with an index of -2.9_-1.0_^+1.2^. Additionally, we infer a minimum progenitor mass of 7.1_-0.2_^+0.1^M_{sun}_ from this sample, consistent with several previous studies, providing further evidence that stars with ages older than the lifetimes of single 8M_{sun}_ stars are producing supernovae.