Dust masses for a large sample of core-collapse supernovae from optical
  emission line asymmetries: dust formation on 30-year timescales
  Modelling the red-blue asymmetries seen in the broad emission lines of
core-collapse supernovae (CCSNe) is a powerful technique to quantify total dust
mass formed in the ejecta at late times ($>5$ years after outburst) when ejecta
dust temperatures become too low to be detected by mid-IR instruments.
Following our success in using the Monte Carlo radiative transfer code DAMOCLES
to measure the dust mass evolution in SN~1987A and other CCSNe, we present the
most comprehensive sample of dust mass measurements yet made with DAMOCLES, for
CCSNe aged between four and sixty years after outburst. Our sample comprises of
multi-epoch late-time optical spectra taken with the Gemini GMOS and VLT
X-Shooter spectrographs, supplemented by archival spectra. For the fourteen
CCSNe that we have modelled, we confirm a dust mass growth with time that can
be fit by a sigmoid curve which is found to saturate beyond an age of $\sim30$
years, at a mass of 0.23$^{+0.17}_{-0.12}$ M$_\odot$. An expanded sample
including dust masses found in the literature for a further eleven CCSNe and
six CCSN remnants, the dust mass at saturation is found to be
0.42$^{+0.09}_{-0.05}$~M$_\odot$. Uncertainty limits for our dust masses were
determined from a Bayesian analysis using the affine invariant Markov Chain
Monte Carlo ensemble sampler emcee with DAMOCLES. The best-fitting line profile
models for our sample all required grain radii between 0.1 and 0.5 $\mu$m. Our
results are consistent with CCSNe forming enough dust in their ejecta to
significantly contribute to the dust budget of the Universe.
