DES15E2mlf: A Spectroscopically Confirmed Superluminous Supernova that Exploded 3.5 Gyr After the Big Bang

TL;DR

This paper reports the discovery and spectroscopic confirmation of the most distant superluminous supernova, DES15E2mlf, observed at a redshift of 1.861, providing insights into its ultraviolet properties and host galaxy characteristics.

Contribution

It presents the first spectroscopic confirmation of a superluminous supernova at such a high redshift, expanding understanding of SLSNe in the early universe.

Findings

Confirmed DES15E2mlf as the most distant SLSN-I at z=1.861

Observed UV spectral features and velocity changes around maximum light

Host galaxy is more massive than typical SLSN-I hosts

Abstract

We present the Dark Energy Survey (DES) discovery of DES15E2mlf, the most distant superluminous supernova (SLSN) spectroscopically confirmed to date. The light curves and Gemini spectroscopy of DES15E2mlf indicate that it is a Type I superluminous supernova (SLSN-I) at z = 1.861 (a lookback time of ~10 Gyr) and peaking at M_AB = -22.3 +/- 0.1 mag. Given the high redshift, our data probe the rest-frame ultraviolet (1400-3500 A) properties of the SN, finding velocity of the C III feature changes by ~5600 km/s over 14 days around maximum light. We find the host galaxy of DES15E2mlf has a stellar mass of 3.5^+3.6_-2.4 x 10^9 M_sun, which is more massive than the typical SLSN-I host galaxy.