The Superluminous (Type I) Supernova ASASSN-15lh : A case for a   Quark-Nova inside an Oxygen-type Wolf-Rayet supernova remnant
  We show that a Quark-Nova (QN; the explosive transition of a neutron star to a quark star) occurring a few days following the supernova explosion of an Oxygen-type Wolf-Rayet (WO) star can account for the intriguing features of ASASSN-15lh, including its extreme energetics, its double-peaked light-curve and the evolution of its photospheric radius and temperature. A two-component configuration of the homologously expanding WO remnant (an extended envelope and a compact core) is used to harness the kinetic energy (>10^52 ergs) of the QN ejecta. The delay between the WO SN and the QN yields a large (~ 10^4 Rsun) envelope which when energized by the QN ejecta/shock gives the first peak in our model. As the envelope's photosphere recedes into the slowly expanding, hot and insulated, denser core (initially heated by the QN shock) a second hump emerges. The spectrum in our model should reflect the composition of an WO SN remnant re-heated by a QN going off in its wake. 
Rachid Ouyed, Denis Leahy, Luis Welbanks, Nico Koning (Department of   Physics and Astronomy, University of Calgary, Calgary...
astro-ph.HE