Early-type galaxies with core collapse supernovae

TL;DR

This study investigates the unexpected occurrence of core collapse supernovae in early-type galaxies, revealing most are misclassified spirals or interacting systems with recent star formation, challenging traditional views.

Contribution

It provides a detailed morphological reclassification and analysis of early-type galaxy hosts of core collapse supernovae, highlighting the role of interactions and mergers in star formation.

Findings

Most 'early type' hosts are misclassified spirals or irregulars.

Some genuine early types show signs of recent star formation due to interactions.

Core collapse SNe can occur in galaxies with recent star formation, even if classified as early type.

Abstract

It is widely accepted that the progenitors of core collapse SNe are young massive stars and therefore their host galaxies are mostly spiral or irregular galaxies dominated by a young stellar population. Surprisingly, among morphologically classified hosts of core collapse SNe, we find 22 cases where the host has been classified as an Elliptical or S0 galaxy. To clarify this apparent contradiction, we carry out a detailed morphological study and an extensive literature search for additional information on the sample objects. Our results are as follows: 1. Of 22 "early type" objects, 17 are in fact misclassified spiral galaxies, one is a misclassified irregular, and one is a misclassified ring galaxy. 2. Of the 3 objects maintaining the early type classification, one (NGC2768) is a suspected merger remnant, another (NGC4589) is definitely a merger, and the third (NGC2274) is in close interaction. The presence of some amount of young stellar population in these galaxies is therefore not unexpected. These results confirm the presence of a limited, but significant, number of core collapse SNe in galaxies generally classified of early type. In all cases, anyway, there are independent indicators of the presence in host galaxies of recent star formation due to merging or gravitational interaction.