Super-luminous supernovae at redshifts of 2.05 and 3.90

TL;DR

This paper reports the discovery of two super-luminous supernovae at high redshifts, demonstrating their potential to probe early star deaths and extending the observable redshift range for supernovae.

Contribution

First detection of super-luminous supernovae at redshifts 2.05 and 3.90, indicating higher event rates at early cosmic times and extending supernova observational limits.

Findings

Super-luminous supernovae are more common at high redshifts.

Detected supernovae have slowly evolving light curves.

Extended the redshift limit for supernova detection to 3.90.

Abstract

A rare class of `super-luminous' supernovae that are about ten or more times more luminous at their peaks than other types of luminous supernovae has recently been found at low to intermediate redshifts. A small subset of these events have luminosities that evolve slowly and result in radiated energies of around 10^51 ergs or more. Therefore, they are likely examples of `pair-instability' or `pulsational pair-instability' supernovae with estimated progenitor masses of 100 - 250 times that of the Sun. These events are exceedingly rare at low redshift, but are expected to be more common at high redshift because the mass distribution of the earliest stars was probably skewed to high values. Here we report the detection of two super-luminous supernovae, at redshifts of 2.05 and 3.90, that have slowly evolving light curves. We estimate the rate of events at redshifts of 2 and 4 to be approximately ten times higher than the rate at low redshift. The extreme luminosities of super-luminous supernovae extend the redshift limit for supernova detection using present technology, previously 2.36, and provide a way of investigating the deaths of the first generation of stars to form after the Big Bang.