A GRB and Broad-lined Type Ic Supernova from a Single Central Engine

TL;DR

This paper demonstrates that a central engine responsible for long gamma-ray bursts can also produce broad-lined Type Ic supernovae with high velocities and energies, with observable effects depending on viewing angle.

Contribution

It introduces a model linking gamma-ray burst engines to broad-lined Type Ic supernovae, supported by relativistic hydrodynamics and radiation transport simulations.

Findings

Relativistic jets with ~10^51 ergs can produce SN Ic-BL.

Synthetic light curves and spectra match observations during the photospheric phase.

Viewing angle significantly affects early spectral features and light curve brightness.

Abstract

Unusually high velocities (< ~0.1c) and correspondingly high kinetic energies have been observed in a subset of Type Ic supernovae (so-called "broad-lined Ic" supernovae; SNe Ic-BL), prompting a search for a central engine model capable of generating such energetic explosions. A clue to the explosion mechanism may lie in the fact that all supernovae that accompany long-duration gamma-ray bursts belong to the SN Ic-BL class. Using a combination of two-dimensional relativistic hydrodynamics and radiation transport calculations, we demonstrate that the central engine responsible for long gamma-ray bursts can also trigger a SN Ic-BL. We find that a reasonable gamma-ray burst engine injected into a stripped Wolf-Rayet progenitor produces a relativistic jet with energy ~10^51 ergs, as well as a SN whose synthetic light curves and spectra are fully consistent with observed SNe Ic-BL during the photospheric phase. As a result of the jet's asymmetric energy injection, the SN spectra and light curves depend on viewing angle. The impact of viewing angle on the spectrum is particularly pronounced at early times, while the viewing angle dependence for the light curves (~10% variation in bolometric luminosity) persists throughout the photospheric phase.