The death of massive stars - II. Observational constraints on the progenitors of Type Ibc supernovae

• Published in: Monthly notices of the Royal Astronomical Society 2013-11, Vol.436 (1), p.774-795
• Main Authors: Eldridge, John J., Fraser, Morgan, Smartt, Stephen J., Maund, Justyn R., Crockett, R. Mark
• Format: Article
• Language: English
• Subjects: Comparative analysis; Helium; Hydrogen; Space telescopes; Star & galaxy formation; Supernovae
• ISSN: 0035-8711; 1365-2966
• DOI: 10.1093/mnras/stt1612

The progenitors of many Type II core-collapse supernovae (SNe) have now been identified directly on pre-discovery imaging. Here, we present an extensive search for the progenitors of Type Ibc SNe in all available pre-discovery imaging since 1998. There are 12 Type Ibc SNe with no detections of progenitors in either deep ground-based or Hubble Space Telescope archival imaging. The deepest absolute BVR magnitude limits are between −4 and − 5 mag. We compare these limits with the observed Wolf-Rayet population in the Large Magellanic Cloud and estimate a 16 per cent probability that we have failed to detect such a progenitor by chance. Alternatively, the progenitors evolve significantly before core-collapse or we have underestimated the extinction towards the progenitors. Reviewing the relative rates and ejecta mass estimates from light-curve modelling of Ibc SNe, we find both incompatible with Wolf-Rayet stars with initial masses >25 M being the only progenitors. We present binary evolution models that fit these observational constraints. Stars in binaries with initial masses 20 M lose their hydrogen envelopes in binary interactions to become low-mass helium stars. They retain a low-mass hydrogen envelope until 104 yr before core-collapse; hence, it is not surprising that Galactic analogues have been difficult to identify.