Luminosity distribution of Type II supernova progenitors

TL;DR

This study analyzes the luminosity distribution of Type II supernova progenitors, finding strong correlations to estimate luminosities and confirming they are consistent with red supergiants, while addressing the RSG problem.

Contribution

It introduces new correlations to estimate progenitor luminosities with high precision and provides the first comprehensive luminosity distribution analysis of SN II progenitors.

Findings

Progenitor luminosities are consistent with RSG populations in nearby galaxies.

Strong correlations enable luminosity estimates with 20-24% accuracy.

The RSG problem is confirmed at a 5.2 sigma significance level.

Abstract

I present progenitor luminosities ($L$) for a sample of 112 Type II supernovae (SNe II), computed directly from progenitor photometry and the bolometric correction technique, or indirectly from empirical correlations between progenitor luminosity and [OI] $\lambda\lambda$6300, 6364 line luminosity at 350 d since explosion, $^{56}$Ni mass, or absolute $V$-band magnitude at 50 d since explosion. To calibrate these correlations, I use twelve SNe II with progenitor luminosities measured from progenitor photometry. I find that the correlations mentioned above are strong and statistically significant, and allow to estimate progenitor luminosities to a precision between 20 and 24 per cent. I correct the SN sample for selection bias and define a subsample of 112 SNe II with progenitor luminosities between $\log(L/L_{\odot})=4.6$ dex, corresponding to the completeness limit of the corrected sample, and the maximum observed progenitor luminosity of $\log(L/L_{\odot})=5.091$ dex. The luminosity distribution for this subsample is statistically consistent with those for red supergiants (RSGs) in LMC, SMC, M31, and M33 with $4.6\leq\log(L/L_{\odot})\leq5.091$. This supports that SN II progenitors correspond to RSGs. The conspicuous absence of SN II progenitors with $\log(L/L_{\odot})>5.1$ dex with respect to what is observed in RSG luminosity distributions, known as the RSG problem, is significant at a $5.2\pm0.5\,\sigma$ level.