# Why Are We Not Detecting Any Type Ib Supernova Associated with Long Gamma Ray Bursts?

## TL;DR

This paper investigates why Type Ib supernovae are not associated with gamma-ray bursts by examining how their envelope properties, such as mass and extension, influence jet breakout and observable features.

## Contribution

It proposes that differences in envelope mass and size in Type Ib SNe prevent GRB jet breakout, explaining the lack of observed GRB associations.

## Key findings

- GRB-like jets cannot break out of Type Ib SNe with certain envelope properties
- Type Ib SNe with massive, extended envelopes have light curves compatible with observations
- Envelope differences may be linked to the presence of a helium layer in Type Ib SNe

## Abstract

Core-collapse supernovae (SNe) of Types Ib and Ic arise from hydrogen-stripped stars, while the latter are also stripped of their helium. Both SN types have a similar temporal evolution, suggesting broadly similar progenitors. However, while some Ic SNe are associated with relativistic jets of gamma-ray bursts (GRBs), no GRB has yet been found in association with Type Ib SNe. Here we find that, even if GRB-like central engines operate in both SNe Ib and Ic, different properties of their envelopes may accommodate this potential tension. In particular, we focus on the case of a low-mass, extended envelope surrounding the progenitor star (as produced, for example, by strong mass losses prior to explosion). If the envelopes of Type Ib SNe are sufficiently massive ($M_{\rm ext}\sim(0.3-1)M_\odot$) and extended ($R_{\rm ext}\sim 10^{13}\text{ cm}$), we show that (i) GRB-like jets cannot break out of the star; (ii) the SN light curve is compatible with current observations. Different envelope properties of Type Ib SNe with respect to (at least some) Type Ic SNe may be connected to the presence of a helium layer surrounding the star.

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Source: https://tomesphere.com/paper/1705.00792