Emission from Pair-Instability Supernovae with Rotation

TL;DR

This study models rotating pair-instability supernovae using radiation hydrodynamics and transport calculations, revealing their spectral properties and the effects of metallicity and rotation, with implications for identifying such events.

Contribution

It provides detailed radiation hydrodynamics and spectral models for rotating pair-instability supernovae across different parameters, highlighting the impact of rotation and metallicity.

Findings

Supernovae have intrinsically red colors inconsistent with super-luminous observations.

Spectroscopic properties are similar regardless of progenitor metallicity and rotation.

Mass-loss and ejecta properties primarily influence the spectral features.

Abstract

Pair Instability Supernovae have been suggested as candidates for some Super Luminous Supernovae, such as SN 2007bi, and as one of the dominant types of explosion occurring in the early Universe from massive, zero-metallicity Population III stars. The progenitors of such events can be rapidly rotating, therefore exhibiting different evolutionary properties due to the effects of rotationally-induced mixing and mass-loss. Proper identification of such events requires rigorous radiation hydrodynamics and radiative transfer calculations that capture not only the behavior of the light curve but also the spectral evolution of these events. We present radiation hydrodynamics and radiation transport calculations for 90-300 Msun rotating pair-instability supernovae covering both the shock break-out and late light curve phases. We also investigate cases of different initial metallicity and rotation rate to determine the impact of these parameters on the detailed spectral characteristics of these events. In agreement with recent results on non-rotating pair instability supernovae, we find that for a range of progenitor masses and rotation rates these events have intrinsically red colors in contradiction with observations of super-luminous supernovae. The spectroscopic properties of rotating pair instability supernovae are similar to those of non-rotating events with stripped hydrogen and helium envelopes. We find that the progenitor metallicity and rotation rate properties are erased after the explosion and cannot be identified in the resulting model spectra. It is the combined effects of pre-supernova mass-loss and the basic properties of the supernova ejecta such as mass, temperature and velocity that have the most direct impact in the model spectra of pair instability supernovae.