학술논문
SN 2018hti: a nearby superluminous supernova discovered in a metal-poor galaxy
Document Type
Working Paper
Author
Lin, W. L.; Wang, X. F.; Li, W. X.; Zhang, J. J.; Mo, J.; Sai, H. N.; Zhang, X. H.; Filippenko, A. V.; Zheng, W. K.; Brink, T. G.; Baron, E.; DerKacy, J. M.; Ehgamberdiev, S. A.; Mirzaqulov, D.; Li, X.; Zhang, J. C.; Yan, S. Y.; Xi, G. B.; Hsiao, Y.; Zhang, T. M.; Wang, L. J.; Liu, L. D.; Xiang, D. F.; Wu, C. Y.; Rui, L. M.; Chen, Z. H.
Source
MNRAS, 497, 318 (2020)
Subject
Language
Abstract
SN 2018hti is a Type I superluminous supernova (SLSN~I) with an absolute $g$-band magnitude of $-22.2$ at maximum brightness, discovered in a metal-poor galaxy at a redshift of 0.0612. We present extensive photometric and spectroscopic observations of this supernova, covering the phases from $\sim -35$ days to more than +340 days from the $r$-band maximum. Combining our $BVgri$-band photometry with {\it Swift} UVOT optical/ultraviolet photometry, we calculated the peak luminosity as $\sim 3.5\times10^{44}$ erg s$^{-1}$. Modeling the observed light curve reveals that the luminosity evolution of SN 2018hti can be produced by an ejecta mass of 5.8 $M_\odot$ and a magnetar with a magnetic field of $B=1.8\times10^{13}$~G having an initial spin period of $P_0=1.8$ ms. Based on such a magnetar-powered scenario and a larger sample, a correlation between the spin of the magnetar and the kinetic energy of the ejecta can be inferred for most SLSNe~I, suggesting a self-consistent scenario. Like for other SLSNe~I, the host galaxy of SN 2018hti is found to be relatively faint ($M_{g} = -17.75$ mag) and of low metallicity ($Z=0.3~Z_\odot$), with a star-formation rate of 0.3 $M_\odot$ yr$^{-1}$. According to simulation results of single-star evolution, SN 2018hti could originate from a massive, metal-poor star with a zero-age main sequence (ZAMS) mass of 25--40 $M_\odot$, or from a less massive rotating star with $M_\mathrm{ZAMS} \approx 16$--25 $M_\odot$. For the case of a binary system, its progenitor could also be a star with $M_\mathrm{ZAMS} \gtrsim 25$ $M_\odot$.
Comment: 26 pages, 12 figures, 7 tables, published in MNRAS
Comment: 26 pages, 12 figures, 7 tables, published in MNRAS