Optical Observations and Modeling of the Superluminous Supernova 2018lfe

TL;DR

This paper reports optical observations and modeling of the superluminous supernova SN 2018lfe, analyzing its light curve, spectra, and host galaxy to understand its properties and underlying engine.

Contribution

It provides detailed optical data and modeling of SN 2018lfe, including magnetar engine parameters and host galaxy characteristics, expanding knowledge of SLSNe diversity.

Findings

SN 2018lfe is a bright SLSN-I at z=0.3501 with M_r ≈ -22.1 mag.

The magnetar model suggests an ejecta mass of 3.8 M_sun, spin period of 2.9 ms, and magnetic field of 2.8×10^14 G.

Host galaxy has M_r ≈ -17.85, low metallicity, and moderate star formation rate.

Abstract

We present optical imaging and spectroscopy of SN\,2018lfe, which we classify as a Type I superluminous supernova (SLSN-I) at a redshift of $z = 0.3501$ with a peak absolute magnitude of $M_r\approx -22.1$ mag, one of the brightest SLSNe discovered. SN\,2018lfe was identified for follow-up using our FLEET machine learning pipeline. Both the light curve and the spectra of SN\,2018lfe are consistent with the broad population of SLSNe. We fit the light curve with a magnetar central engine model and find an ejecta mass of $M_{\rm ej}\approx 3.8$ M$_\odot$, a magnetar spin period of $P\approx 2.9$ ms and a magnetic field strength of $B_{\perp}\approx 2.8\times 10^{14}$ G. The magnetic field strength is near the top of the distribution for SLSNe, while the spin period and ejecta mass are near the median values of the distribution for SLSNe. From late-time imaging and spectroscopy we find that the host galaxy of SN\,2018lfe has an absolute magnitude of $M_r\approx -17.85$, ($L_B \approx 0.029$ $L^*$), and an inferred metallicity of $Z\approx 0.3$ Z$_\odot$, and star formation rate of $\approx 0.8$ M$_\odot$ yr$^{-1}$.