The H alpha Galaxy Survey. III. Constraints on supernova progenitors from spatial correlations with H alpha emission

TL;DR

This study uses spatial analysis of supernovae relative to H alpha emission in host galaxies to constrain progenitor types, revealing differences in star formation association and progenitor runaway fractions.

Contribution

It provides new insights into supernova progenitor origins by analyzing their spatial correlations with star formation regions in a large galaxy sample.

Findings

Type II supernovae often originate from regions with low or zero H alpha emission.

Approximately 40% of supernova progenitors are 'runaways' that have moved from their birthplaces.

Type Ib and Ic supernovae closely follow star formation regions, unlike Type II.

Abstract

Aims: We attempt to constrain progenitors of the different types of supernovae from their spatial distributions relative to star formation regions in their host galaxies, as traced by H alpha + NII line emission. Methods: We analyse 63 supernovae which have occurred within galaxies from our H alpha survey of the local Universe. Three statistical tests are used, based on pixel statistics, H alpha radial growth curves, and total galaxy emission-line fluxes. Results: Many more type II supernovae come from regions of low or zero emission line flux than would be expected if the latter accurately traces high-mass star formation. We interpret this excess as a 40% `Runaway' fraction in the progenitor stars. Supernovae of types Ib and Ic do appear to trace star formation activity, with a much higher fraction coming from the centres of bright star formation regions than is the case for the type II supernovae. Type Ia supernovae overall show a weak correlation with locations of current star formation, but there is evidence that a significant minority, up to about 40%, may be linked to the young stellar population. The radial distribution of all core-collapse supernovae (types Ib, Ic and II) closely follows that of the line emission and hence star formation in the their host galaxies, apart from a central deficiency which is less marked for supernovae of types Ib and Ic than for those of type II. Core-collapse supernova rates overall are consistent with being proportional to galaxy total luminosities and star formation rates; however, within this total the type Ib and Ic supernovae show a moderate bias towards more luminous host galaxies, and type II supernovae a slight bias towards lower-luminosity hosts.