The very young resolved stellar populations around stripped-envelope
  supernovae
  The massive star origins for Type IIP supernovae (SNe) have been established
through direct detection of their red supergiants progenitors in pre-explosion
observations; however, there has been limited success in the detection of the
progenitors of H-deficient SNe. The final fate of more massive stars, capable
of undergoing a Wolf-Rayet phase, and the origins of Type Ibc SNe remains
debated, including the relative importance of single massive star progenitors
or lower mass stars stripped in binaries. We present an analysis of the ages
and spatial distributions of massive stars around the sites of 23
stripped-envelope SNe, as observed with the Hubble Space Telescope, to probe
the possible origins of the progenitors of these events. Using a Bayesian
stellar populations analysis scheme, we find characteristic ages for the
populations observed within $150\,\mathrm{pc}$ of the target Type IIb, Ib and
Ic SNe to be $\log (t) = 7.20$, $7.05$ and $6.57$, respectively. The Type Ic
SNe in the sample are nearly all observed within $100\,\mathrm{pc}$ of young,
dense stellar populations. The environment around SN 2002ap is an important
exception both in terms of age and spatial properties. These findings may
support the hypothesis that stars with $M_{init} > 30M_{\odot}$ produce a
relatively large proportion of Type Ibc SNe, and that these SN subtypes arise
from progressively more massive progenitors. Significantly higher extinctions
are derived towards the populations hosting these SNe than previously used in
analysis of constraints from pre-explosion observations. The large initial
masses inferred for the progenitors are in stark contrast with the low ejecta
masses estimated from SN light curves.
