Measurement of the core-collapse progenitor mass distribution of the
  Small Magellanic Cloud
  The physics of core-collapse (CC) supernovae (SNe) and how the explosions
depend on progenitor properties are central questions in astronomy. For only a
handful of SNe, the progenitor star has been identified in pre-explosion
images. Supernova remnants (SNRs), which are observed long after the original
SN event, provide a unique opportunity to increase the number of progenitor
measurements. Here, we systematically examine the stellar populations in the
vicinities of 23 known SNRs in the Small Magellanic Cloud (SMC) using the star
formation history (SFH) maps of Harris & Zaritsky (2004). We combine the
results with constraints on the SNR metal abundances and environment from X-ray
and optical observations. We find that 22 SNRs in the SMC have local SFHs and
properties consistent with a CC explosion, several of which are likely to have
been high-mass progenitors. This result supports recent theoretical findings
that high-mass progenitors can produce successful explosions. We estimate the
mass distribution of the CC progenitors and find that this distribution is
similar to a Salpeter IMF (within the uncertainties), while this result is
shallower than the mass distribution found in M31 and M33 by Jennings et al.
(2014) and D\'{\i}az-Rodr\'{\i}guez et al. (2018) using a similar approach.
Additionally, we find that a number of the SMC SNRs exhibit a burst of star
formation between 50-200 Myr ago. As these sources are likely CC, this
signature may be indicative of massive stars undergoing delayed CC as a
consequence of binary interaction, rapid rotation, or low metallicity. In
addition, the lack of Type Ia SNRs in the SMC is possibly a result of the short
visibility times of these sources as they may fall below the sensitivity limits
of current radio observations.
