A1 Refereed original research article in a scientific journal
Understanding the extreme luminosity of DES14X2fna
Authors: Grayling M, Gutierrez CP, Sullivan M, Wiseman P, Vincenzi M, Gonzalez-Gaitan S, Tucker BE, Galbany L, Kelsey L, Lidman C, Swann E, Smith M, Frohmaier C, Carollo D, Glazebrook K, Lewis GF, Moller A, Hinton SR, Uddin SA, Abbott TMC, Aguena M, Avila S, Bertin E, Bhargava S, Brooks D, Rosell AC, Kind MC, Carretero J, Costanzi M, da Costa LN, De Vicente J, Desai S, Diehl HT, Doel P, Everett S, Ferrero I, Fosalba P, Frieman J, Garcia-Bellido J, Gaztanaga E, Gruen D, Gruendl RA, Gschwend J, Gutierrez G, Hoyle B, Kuehn K, Kuropatkin N, Lima M, MacCrann N, Marshall JL, Martini P, Miquel R, Morgan R, Palmese A, Paz-Chinchon F, Plazas AA, Romer AK, Sanchez C, Sanchez E, Scarpine V, Serrano S, Sevilla-Noarbe I, Soares-Santos M, Suchyta E, Tarle G, Thomas D, To C, Varga TN, Walker AR, Wilkinson RD
Publisher: OXFORD UNIV PRESS
Publication year: 2021
Journal: Monthly Notices of the Royal Astronomical Society
Journal name in source: MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
Journal acronym: MON NOT R ASTRON SOC
Volume: 505
Issue: 3
First page : 3950
Last page: 3967
Number of pages: 18
ISSN: 0035-8711
eISSN: 1365-2966
DOI: https://doi.org/10.1093/mnras/stab1478
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 similar or equal to -19.3 mag 20 d after explosion. This object does not show a linear decline tail in the light curve until similar or equal to 60 d after explosion, after which it declines very rapidly (4.30 +/- 0.10 mag 100 d(-1) in the r band). By fitting semi-analytic models to the photometry of DES14X2fna, we find that its light curve cannot be explained by a standard Ni-56 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 an SN Ia in similar to 1.1-2.4 percent of cases in DES, depending on the probability threshold used for a positive classification.
