A UV census of the environments of stripped-envelope supernovae

TL;DR

This study analyzes the environments of 41 stripped-envelope supernovae using Hubble Space Telescope ultraviolet-optical images, revealing insights into their progenitor masses and mass-loss mechanisms through age distribution comparisons.

Contribution

It provides the first detailed environmental analysis of a large, uniformly-selected sample of SESNe, highlighting the role of different mass-loss processes in their progenitors.

Findings

Type Ic progenitors are more massive than Type IIb and Ib.

Progenitor ages suggest a hybrid envelope-stripping mechanism.

Diverse mass-loss processes are crucial in SESN origins.

Abstract

This paper reports an environmental analysis of 41 uniformly-selected stripped-envelope supernovae (SESNe) based on deep ultraviolet-optical images acquired by the Hubble Space Telescope. Young stellar populations are detected in most SN environments and their ages are derived with a hierarchical Bayesian approach. The age distributions are indistinguishable between Type IIb and Type Ib while that for Type Ic is systematically younger. This suggests that the Type Ic SN progenitors are more massive while the Type IIb and Type Ib SNe have very similar progenitor masses. Our result supports a hybrid envelope-stripping mechanism, in which the hydrogen envelopes of the SESN progenitors are stripped via a mass-insensitive process (e.g. binary interaction) while the helium envelopes are stripped via a mass-sensitive process (e.g. stellar wind of the post-binary interaction progenitor). We also provide progenitor constraints for three Type Ibn SNe and two broad-lined Type Ic SNe. All these results demonstrate the importance of the very diverse mass-loss processes in the origins of SESNe.