Dust Formation by Supernovae

The large quantities of dust found in a number of high redshift galaxies has led to suggestions that core-collapse supernovae (CCSNe) are the main sources of their dust and has motivated the measurement of the dust masses formed by local and extragalactic CCSNe. A widely used technique for CCSN dust mass determination, namely the fitting of their optical-IR spectral energy distributions, is restricted to warmer dust emitting shortwards of 30 microns by the lack of sufficiently sensitive facilities operating at longer wavelengths. However, an alternative technique for measuring total dust masses is available, one which is insensitive to dust temperature. This method relies on the spectral modelling of the red-blue asymmetries in late-epoch optical emission line profiles, produced by dust within the ejecta that selectively absorbs red-shifted photons emitted from the far side of the ejecta. After reviewing earlier work on CCSN dust masses, I will report on dust masses obtained from line profile fitting for a large VLT and Gemini spectral survey of extragalactic CCSNe, some observed at epochs up to 60 years after outburst. Evidence will be presented for a slow growth in CCSN ejecta dust masses with time, taking approximately 30 years to saturate at a mean dust mass of 0.4 solar masses per CCSN.