Type I Superluminous Supernovae as Explosions Inside Non-Hydrogen Circumstellar Envelopes

Abstract

A number of Type I (hydrogenless) superluminous supernova (SLSN) events have been discovered recently. However, their nature remains debatable. One of the most promising ideas is the shockinteraction mechanism, but only simplified semi-analytical models have been applied so far. We simulate light curves for several Type I SLSN (SLSN-I) models enshrouded by dense, non-hydrogen circumstellar (CS) envelopes, using a multi-group radiation hydrodynamics code that predicts not only bolometric, but also multicolor light curves. We demonstrate that the bulk of SLSNe-I including those with relatively narrow light curves like SN 2010gx or broad ones like PTF09cnd can be explained by the interaction of the SN ejecta with the CS envelope, though the range of parameters for these models is rather wide. Moderate explosion energy (∼ (2−4)·10 51 ergs) is sufficient to explain both narrow and broad SLSN I light curves, but ejected mass and envelope mass differ for those two cases. Only 5 to 10 M ⊙ of non-hydrogen material is needed to reproduce the light curve of SN 2010gx, while the best model for PTF09cnd is very massive: it contains almost 50 M ⊙ in the CS envelope and only 5 M ⊙ in the ejecta. The CS envelope for each case extends from 10R ⊙ to ∼ 10 5 R ⊙ (7 · 10 15 cm), which is about an order of magnitude larger than typical photospheric radii of standard SNe near the maximum light. We briefly discuss possible ways to form such unusual envelopes.

The two promising scenarios to explode core collapse supernovae

“…But even its supporters admit that this mechanism cannot yield CCSN explosion (kinetic) energies of E exp 2×10 51 erg (e.g., Fryer 2006;Fryer et al 2012;, and hence cannot account for super-energetic CCSNe. Super-energetic CCSNe can reach energies of well above 10 52 erg, and their study is a hot topic (e.g., Gal-Yam 2012; Moriya et al 2015;Wang et al 2016;Arcavi et al 2016;Sorokina et al 2016;Abbott et al 2017). In the delayed neutrino mechanism there is a need for an additional energy source.…”

Radiation Hydrodynamical Models for Type I Superluminous Supernovae

“…Sorokina et al [16] calculated radiation-hydrodynamical models of circumstellar interaction to reproduce LCs of both SN 2010gx and PTF09cnd for optically thick CSM. PTF09cnd and SN 2010gx reach peak luminosities too high to be explained by the 56 Ni production allowed by their late time photometric limits [13].…”

“…In the models by [16], when the shock wave structure starts to form due to collision between the ejecta and the CSM, the envelope is cool and transparent. Then the emission from the shock front heats the gas in the envelope, thus making it opaque, and the photosphere moves to the outermost layers rather quickly.…”

“…2. Synthetic light curves for SN 2010gx, in r, g, B, and u filters compared with Pan-STARRS and PTF observations [16]. Pan-STARRS points are designated with open squares (u, g, and R bands), PTF points, with filled circles (B and r bands).…”

“…Observed (dots) and synthetic (lines) light curves for PTF09cnd in r and B filters . The solid, dashed, and dash-dotted lines correspond to the models with the static outer envelope, expanding envelope, and faster expanding envelope, repectively [16]. stellar cluster, the (multiple) collision of massive stars (in particular, Wolf-Rayet stars) can make a massive C+O star surrounded by a massive non-Hydrogen CSM [14,17].…”