Type Ib/c Supernovae with and without Gamma-Ray Bursts

TL;DR

This study investigates the differences between Type Ib/c supernovae with and without gamma-ray bursts by analyzing their spectral velocities and environmental metallicities, revealing distinct metallicity preferences linked to explosion types.

Contribution

It provides the first comprehensive analysis of expansion velocities and environmental metallicities for a large sample of SNe Ib/c, highlighting key differences related to GRB association.

Findings

SNe Ic occur in more metal-rich environments than SNe Ib.

SNe Ic-bl with GRBs are found in more metal-poor environments than those without GRBs.

The study triples the number of well-observed Stripped SNe with spectroscopic data.

Abstract

While the connection between Long Gamma-Ray Bursts (GRBs) and Type Ib/c Supernovae (SNe Ib/c) from stripped stars has been well-established, one key outstanding question is what conditions and factors lead to each kind of explosion in massive stripped stars. One promising line of attack is to investigate what sets apart SNe Ib/c with GRBs from those without GRBs. Here, I briefly present two observational studies that probe the SN properties and the environmental metallicities of SNe Ib/c (specifically broad-lined SNe Ic) with and without GRBs. I present an analysis of expansion velocities based on published spectra and on the homogeneous spectroscopic CfA data set of over 70 SNe of Types IIb, Ib, Ic and Ic-bl, which triples the world supply of well-observed Stripped SNe. Moreover, I demonstrate that a meta-analysis of the three published SN Ib/c metallicity data sets, when including only values at the SN positions to probe natal oxygen abundances, indicates at very high significance that indeed SNe Ic erupt from more metal-rich environments than SNe Ib, while SNe Ic-bl with GRBs still prefer, on average, more metal-poor sites than those without GRBs.