Relativistic supernovae have shorter-lived central engines or more extended progenitors: The case of SN 2012ap

R. Margutti*, D. Milisavljevic, A. M. Soderberg, C. Guidorzi, B. J. Morsony, N. Sanders, S. Chakraborti, A. Ray, A. Kamble, M. Drout, J. Parrent, A. Zauderer, L. Chomiuk

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

95 Scopus citations


Deep, late-time X-ray observations of the relativistic, engine-driven, type Ic SN 2012ap allow us to probe the nearby environment of the explosion and reveal the unique properties of relativistic supernova explosions (SNe). We find that on a local scale of ∼0.01 pc the environment was shaped directly by the evolution of the progenitor star with a pre-explosion mass-loss rate of M <5 × 10-6 M⊙ yr-1, in line with gamma-ray bursts (GRBs) and the other relativistic SN 2009bb. Like sub-energetic GRBs, SN 2012ap is characterized by a bright radio emission and evidence for mildly relativistic ejecta. However, its late-time (δt ≈ 20 days) X-ray emission is ∼100 times fainter than the faintest sub-energetic GRB at the same epoch, with no evidence for late-time central engine activity. These results support theoretical proposals that link relativistic SNe like 2009bb and 2012ap with the weakest observed engine-driven explosions, where the jet barely fails to break out. Furthermore, our observations demonstrate that the difference between relativistic SNe and sub-energetic GRBs is intrinsic and not due to line-of-sight effects. This phenomenology can either be due to an intrinsically shorter-lived engine or to a more extended progenitor in relativistic SNe.

Original languageEnglish (US)
Article number107
JournalAstrophysical Journal
Issue number2
StatePublished - Dec 20 2014


  • Gamma-ray burst: General
  • Supernovae: Individual (SN 2012ap)

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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