iPTF 16asu Revisited: A Rapidly Evolving Superluminous Broad-Lined Ic Supernova?

TL;DR

This study re-analyzes the supernova iPTF 16asu, revealing it as a rapidly evolving superluminous Ic-BL supernova with a peak luminosity exceeding typical thresholds, and demonstrates that a magnetar plus nickel model best explains its light curve.

Contribution

It provides a detailed spectral energy distribution fitting and bolometric light curve reconstruction, proposing iPTF 16asu as a new class of rapidly evolving superluminous SNe Ic-BL.

Findings

The peak luminosity exceeds 10^44 erg s^-1, classifying it as superluminous.

The magnetar plus nickel model fits the observed light curves well.

iPTF 16asu and similar SNe form a new class of rapidly evolving SLSNe Ic-BL.

Abstract

In this paper, we fit the spectral energy distributions (SEDs) of iPTF 16asu that has so far been classified as a luminous rapidly evolving broad-lined Ic supernova (SN Ic-BL), and re-construct its post-peak bolometric light curve. We find that the luminosity of the post-peak bolometric light curve of iPTF 16asu is about 3 times that of the pseudo-bolometric light curve derived in the literature, and the extrapolated peak luminosity exceeds $\sim 10^{44}$ erg s$^{-1}$, which is higher than the threshold of superluminous SNe (SLSNe). We then use the $^{56}$Ni model and the magnetar plus $^{56}$Ni model to fit the multi-band light curves of iPTF 16asu, and construct the theoretical bolometric light curve using the best-fitting theoretical multi-band light curves. We find that the magnetar plus $^{56}$Ni model can account for the photometry of iPTF~16asu, and the peak luminosity of its theoretical bolometric light curve is $\sim 1.06\times 10^{44}$ erg s$^{-1}$. We suggest that iPTF~16asu and similar SNe (e.g., SN 2018gep) constitute the class of rapidly evolving SLSNe Ic-BL.