Gaia16apd - a link between fast and slowly declining type I superluminous supernovae

Journal
Date Issued
2017
Author(s)
Kangas, T.
•
Blagorodnova, N.
•
Mattila, S.
•
Lundqvist, P.
•
Fraser, M.
•
Burgaz, U.
•
•
Carrasco Martínez, J. M.
•
•
Hardy, L. K.
•
Harmanen, J.
•
Hsiao, E. Y.
•
Isern, J.
•
Kankare, E.
•
Kołaczkowski, Z.
•
Nielsen, M. B.
•
Reynolds, T. M.
•
Rhodes, L.
•
Somero, A.
•
Stritzinger, M. D.
•
Wyrzykowski, Ł.
DOI
Abstract
We present ultraviolet (UV), optical and infrared photometry and optical spectroscopy of the type Ic superluminous supernova (SLSN) Gaia16apd (=SN 2016eay), covering its evolution from 26 d before the g-band peak to 234.1 d after the peak. Gaia16apd was followed as a part of the NOT Unbiased Transient Survey (NUTS). It is one of the closest SLSNe known (z = 0.102 ± 0.001), with detailed optical and UV observations covering the peak. Gaia16apd is a spectroscopically typical type Ic SLSN, exhibiting the characteristic blue early spectra with O II absorption, and reaches a peak Mg = -21.8 ± 0.1 mag. However, photometrically it exhibits an evolution intermediate between the fast and slowly declining type Ic SLSNe, with an early evolution closer to the fast-declining events. Together with LSQ12dlf, another SLSN with similar properties, it demonstrates a possible continuum between fast and slowly declining events. It is unusually UV-bright even for an SLSN, reaching a non-K-corrected Muvm2 ≃ -23.3 mag, the only other type Ic SLSN with similar UV brightness being SN 2010gx. Assuming that Gaia16apd was powered by magnetar spin-down, we derive a period of P = 1.9 ± 0.2 ms and a magnetic field of B = 1.9 ± 0.2 × 1014 G for the magnetar. The estimated ejecta mass is between 8 and 16 M☉, and the kinetic energy between 1.3 and 2.5 × 1052 erg, depending on opacity and assuming that the entire ejecta is swept up into a thin shell. Despite the early photometric differences, the spectra at late times are similar to slowly declining type Ic SLSNe, implying that the two subclasses originate from similar progenitors.
Volume
469
Issue
1
Start page
1246
Uri
Url
Issn Identifier
0035-8711
Ads BibCode
2017MNRAS.469.1246K
Rights
open.access
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