Close, bright and boxy: the superluminous SN 2018hti
: Fiore A., Benetti S., Nicholl M., Reguitti A., Cappellaro E., Campana S., Bose S., Paraskeva E., Berger E., Bravo T. M., Burke J., Cai Y.-Z., Chen T.-W., Chen P., Ciolfi R., Dong S., Gomez S., Gromadzki M., Gutiérrez C. P., Hiramatsu D., Hosseinzadeh G., Howell D. A., Jerkstrand A., Kankare E., Kozyreva A., Maguire K., McCully C., Ochner P., Pellegrino C., Pignata G., Post R. S., Rosa N. E., Shahbandeh M., Schuldt S., Thomas B. P., Tomasella L., Vinkó J., Vogl C., Wheeler J. C., Young D. R.
: 2022
: Monthly Notices of the Royal Astronomical Society
: 512
: 3
: 4484
: 4502
: 1365-2966
DOI: https://doi.org/10.1093/mnras/stac744
: https://academic.oup.com/mnras/article-abstract/512/3/4484/6549929
: https://research.utu.fi/converis/portal/detail/Publication/68078955
SN~2018hti was a very nearby (z=0.0614) superluminous supernova with an exceedingly bright absolute magnitude of -22.2 mag in r-band at maximum. The densely sampled pre-maximum light curves of SN~2018hti show a slow luminosity evolution and constrain the rise time to ~50 rest-frame days. We fitted synthetic light curves to the photometry to infer the physical parameters of the explosion of SN 2018hti for both the magnetar and the CSM-interaction scenarios. We conclude that one of two mechanisms could be powering the luminosity of SN 2018hti; interaction with ~10 Msun of circumstellar material or a magnetar with a magnetic field of B_p~1.3e13 G and initial period of P_spin~1.8 ms. From the nebular spectrum modelling we infer that SN 2018hti likely results from the explosion of a ~40 Msun progenitor star.
