The Exceptionally Luminous Type II-L SN 2008es

TL;DR

SN 2008es is an extremely luminous Type II-L supernova with a peak magnitude of -22.3, showing rapid decline and likely powered by interaction with dense circumstellar material, contributing to understanding of superluminous supernovae.

Contribution

This paper presents early photometric and spectroscopic observations of SN 2008es, highlighting its extreme luminosity and suggesting a different powering mechanism than typical supernovae.

Findings

SN 2008es is the second most luminous supernova observed.

Its luminosity is likely powered by interaction with dense circumstellar medium.

The supernova radiated over 10^51 ergs in ultraviolet and optical wavelengths.

Abstract

We report on our early photometric and spectroscopic observations of the extremely luminous Type II supernova (SN) 2008es. With an observed peak optical magnitude of m_V = 17.8 and at a redshift z = 0.213, SN 2008es had a peak absolute magnitude of M_V = -22.3, making it the second most luminous SN ever observed. The photometric evolution of SN 2008es exhibits a fast decline rate (~0.042 mag d^-1), similar to the extremely luminous Type II-L SN 2005ap. We show that SN 2008es spectroscopically resembles the luminous Type II-L SN 1979C. Although the spectra of SN 2008es lack the narrow and intermediate-width line emission typically associated with the interaction of a SN with the circumstellar medium of its progenitor star, we argue that the extreme luminosity of SN 2008es is powered via strong interaction with a dense, optically thick circumstellar medium. The integrated bolometric luminosity of SN 2008es yields a total radiated energy at ultraviolet and optical wavelengths of >10^51 ergs. Finally, we examine the apparently anomalous rate at which the Texas Supernova Search has discovered rare kinds of supernovae, including the five most luminous supernovae observed to date, and find that their results are consistent with those of other modern SN searches.