201. SN 2020ank: a bright and fast-evolving H-deficient superluminous supernova
- Author
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Shashi B. Pandey, Amit Kumar, Kuntal Misra, G. C. Anupama, Avinash Singh, A. Aryan, Anirban Dutta, Rahul Gupta, Brajesh Kumar, and D. K. Sahu
- Subjects
High Energy Astrophysical Phenomena (astro-ph.HE) ,Physics ,010308 nuclear & particles physics ,FOS: Physical sciences ,Flux ,Astronomy and Astrophysics ,Astrophysics ,Magnetar ,Kinetic energy ,01 natural sciences ,7. Clean energy ,Spectral line ,Luminosity ,Supernova ,13. Climate action ,Space and Planetary Science ,0103 physical sciences ,Absorption (logic) ,Astrophysics - High Energy Astrophysical Phenomena ,010303 astronomy & astrophysics ,Spin-½ - Abstract
We investigate the observational properties of a hydrogen-deficient superluminous supernova (SLSN) SN 2020ank (at z = 0.2485), with the help of early phase observations carried out between $-$21 and +52 d since $g$-band maximum. Photometrically, SN 2020ank is one of the brightest SLSN ($M_{g,peak}$ $\sim$ $-$21.84 $\pm$ 0.10 mag), having fast pre-peak rising and post-peak decaying rates. The bolometric light curve of SN 2020ank exhibits a higher peak luminosity ($L_{max}$) of $\sim$(3.9 $\pm$ 0.7) $\times$ 10$^{44}$ erg s$^{-1}$ and appears to be symmetric around the peak with $L^{rise}_{max}$/e $\approx$ $L^{fall}_{max}$/e $\approx$ 15 d. The semi-analytical light-curve modelling using the MINIM code suggests a spin down millisecond magnetar with $P_i$ $\sim$2.2 $\pm$ 0.5 ms and $B$ $\sim$(2.9 $\pm$ 0.1) $\times$ $10^{14}$ G as a possible powering source for SN 2020ank. The possible magnetar origin and excess ultraviolet flux at early epochs indicate a central-engine based powering source for SN 2020ank. Near-peak spectra of SN 2020ank are enriched with the W-shaped O II features but with the weaker signatures of C II and Fe III. Using the estimated rise time of $\sim$27.9 d and the photospheric velocity of $\sim$12050 km s$^{-1}$, we constrain the ejecta mass to $\sim$7.2 $M_{\odot}$ and the kinetic energy of $\sim$6.3 $\times$ 10$^{51}$ erg. The near-peak spectrum of SN 2020ank exhibits a close spectral resemblance with that of fast-evolving SN 2010gx. The absorption features of SN 2020ank are blueshifted compared to Gaia16apd, suggesting a higher expansion velocity. The spectral similarity with SN 2010gx and comparatively faster spectral evolution than PTF12dam (a slow-evolving SLSN) indicate the fast-evolving behavior of SN 2020ank., Comment: 17 pages, 13 figures, Accepted in MNRAS, Accepted 2020 December 29. Received in original form 2020 October 06
- Published
- 2021
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