Type Ibc supernovae in disturbed galaxies: evidence for a top-heavy IMF

TL;DR

This study finds that disturbed galaxies have a central excess of high-mass star supernovae, suggesting a top-heavy initial mass function in these environments, based on the distribution of supernova types.

Contribution

It provides evidence for a top-heavy initial mass function in the central regions of disturbed galaxies through supernova distribution analysis.

Findings

Disturbed galaxies show a central excess of Type Ib, Ic, and Ib/c supernovae.

Type II supernovae dominate in undisturbed environments.

The results suggest a top-heavy initial mass function in disturbed galaxy centers.

Abstract

We compare the radial locations of 178 core-collapse supernovae to the R-band and H alpha light distributions of their host galaxies. When the galaxies are split into `disturbed' and `undisturbed' categories, a striking difference emerges. The disturbed galaxies have a central excess of core-collapse supernovae, and this excess is almost completely dominated by supernovae of types Ib, Ic and Ib/c, whereas type II supernovae dominate in all other environments. The difference cannot easily be explained by metallicity or extinction effects, and thus we propose that this is direct evidence for a stellar initial mass function that is strongly weighted towards high mass stars, specifically in the central regions of disturbed galaxies.