Constraints for the Progenitor Masses of Historic Core-Collapse
  Supernovae
  We age-date the stellar populations associated with 12 historic nearby
core-collapse supernovae (CCSNe) and 2 supernova impostors, and from these
ages, we infer their initial masses and associated uncertainties. To do this,
we have obtained new HST imaging covering these CCSNe. Using these images, we
measure resolved stellar photometry for the stars surrounding the locations of
the SNe. We then fit the color-magnitude distributions of this photometry with
stellar evolution models to determine the ages of any young existing
populations present. From these age distributions, we infer the most likely
progenitor mass for all of the SNe in our sample. We find ages between 4 and 50
Myr, corresponding to masses from 7.5 to 59 solar masses. There were no SNe
that lacked a young population within 50~pc. Our sample contains 4 type Ib/c
SNe; their masses have a wide range of values, suggesting that the progenitors
of stripped-envelope SNe are binary systems. Both impostors have masses
constrained to be $\lesssim$7.5 solar masses. In cases with precursor imaging
measurements, we find that age-dating and precursor imaging give consistent
progenitor masses. This consistency implies that, although the uncertainties
for each technique are significantly different, the results of both are
reliable to the measured uncertainties. We combine these new measurements with
those from our previous work and find that the distribution of 25 core-collapse
SNe progenitor masses is consistent with a standard Salpeter power-law mass
function, no upper mass cutoff, and an assumed minimum mass for core-collapse
of 7.5~M$_{\odot}$.
