Understanding the extreme luminosity of DES14X2fna

Abstract

We present DES14X2fna, a high-luminosity, fast-declining type IIb supernova (SN IIb) at redshift $z=0.0453$, detected by the Dark Energy Survey (DES). DES14X2fna is an unusual member of its class, with a light curve showing a broad, luminous peak reaching $M_r\simeq -19.3$ mag 20 days after explosion. This object does not show a linear decline tail in the light curve until $\simeq$60 days after explosion, after which it declines very rapidly (4.38$\pm$0.10 mag 100 d${}^{-1}$ in $r$-band). By fitting semi-analytic models to the photometry of DES14X2fna, we find that its light curve cannot be explained by a standard ${}^{56}$Ni decay model as this is unable to fit the peak and fast tail decline observed. Inclusion of either interaction with surrounding circumstellar material or a rapidly-rotating neutron star (magnetar) significantly increases the quality of the model fit. We also investigate the possibility for an object similar to DES14X2fna to act as a contaminant in photometric samples of SNe Ia for cosmology, finding that a similar simulated object is misclassified by a recurrent neural network (RNN)-based photometric classifier as a SN Ia in $\sim$1.1-2.4 per cent of cases in DES, depending on the probability threshold used for a positive classification.

References in corpus (22)

• Improving the full spectrum fitting method: accurate convolution with Gauss-Hermite functions
• Evolutionary Stellar Population Synthesis with MILES. Part I: The Base Models and a New Line Index System
• An Analysis of the Shapes of Interstellar Extinction Curves. V. The IR-Through-UV Curve Morphology
• A systematic variation of the stellar initial mass function in early-type galaxies
• The magnetar model for Type I superluminous supernovae I: Bayesian analysis of the full multicolour light curve sample with MOSFiT
• SOUSA: the Swift Optical/Ultraviolet Supernova Archive
• Energetic eruptions leading to a peculiar hydrogen-rich explosion of a massive star
• The type IIb SN 2008ax: spectral and light curve evolution
• Investigating the properties of stripped-envelope supernovae, what are the implications for their progenitors?
• Uncovering the Putative B-Star Binary Companion of the SN 1993J Progenitor
• OzDES multifibre spectroscopy for the Dark Energy Survey: Three year results and first data release
• A Blue Point Source at the Location of Supernova 2011dh
• OzDES multi-object fibre spectroscopy for the Dark Energy Survey: Results and second data release
• SN 2013df, a double-peaked IIb supernova from a compact progenitor and an extended H envelope
• Constraints on the Progenitor of SN 2016gkg From Its Shock-Cooling Light Curve
• The progenitor and early evolution of the Type IIb SN 2016gkg
• DES13S2cmm: The First Superluminous Supernova from the Dark Energy Survey
• Type II Supernova Light Curves and Spectra From the CfA
• Optical photometry and spectroscopy of the type Ibn supernova SN 2006jc until the onset of dust formation
• The Host Galaxies of Rapidly Evolving Transients in the Dark Energy Survey
• Evidence for magnetar formation in broad-lined type Ic supernovae 1998bw and 2002ap
• SN 2018gjx reveals that some SNe Ibn are SNe IIb exploding in dense circumstellar material

Cited by in corpus (7)

• The Dark Energy Survey 5-year photometrically identified Type Ia Supernovae
• Core-collapse Supernovae in the Dark Energy Survey: Luminosity Functions and Host Galaxy Demographics
• SN 2018gk Revisited: the Photosphere, the Central Engine, And the Putative Dust
• A puzzle solved after two decades: SN 2002gh among the brightest of superluminous supernovae
• SN2017ckj: A linearly declining Type IIb supernova with a relatively massive hydrogen envelope
• SN 2017ati: A luminous type IIb explosion from a massive progenitor
• Spectral Dataset of Stripped-Envelope Supernovae from the Tsinghua Supernova Group