Optical photometry and spectroscopy of the 1987A-like supernova 2009mw

TL;DR

This paper reports detailed optical photometry and spectroscopy of supernova 2009mw, a 1987A-like event, and estimates its physical parameters, revealing a blue supergiant progenitor with specific explosion characteristics.

Contribution

It provides the first comprehensive observational and hydrodynamical analysis of SN 2009mw, expanding understanding of 1987A-like supernovae and their progenitors.

Findings

SN 2009mw has an explosion energy of 1 foe.

Progenitor was a blue supergiant with 19 solar masses.

Host environment has slightly sub-solar metallicity.

Abstract

We present optical photometric and spectroscopic observations of the 1987A-like supernova (SN) 2009mw. Our $BVRI$ and $g'r'i'z'$ photometry covers 167 days of evolution, including the rise to the light curve maximum, and ends just after the beginning of the linear tail phase. We compare the observational properties of SN 2009mw with those of other SNe belonging to the same subgroup, and find that it shows similarities to several objects. The physical parameters of the progenitor and the SN are estimated via hydrodynamical modelling, yielding an explosion energy of $1$ foe, a pre-SN mass of $19\,{\rm M_{\odot}}$, a progenitor radius as $30\,{\rm R_{\odot}}$ and a $^{56}$Ni mass as $0.062\,{\rm M_{\odot}}$. These values indicate that the progenitor of SN 2009mw was a blue supergiant star, similar to the progenitor of SN 1987A. We examine the host environment of SN 2009mw and find that it emerged from a population with slightly sub-solar metallicty.