PS1-10afx at z=1.388: Pan-STARRS1 Discovery of a New Type of Superluminous Supernova

Feb, 2013
17 pages
Published in:
  • Astrophys.J. 767 (2013) 162
e-Print:

Citations per year

20132016201920222024024681012
Abstract: (IOP)
We present the Pan-STARRS1 discovery of PS1-10afx, a unique hydrogen-deficient superluminous supernova (SLSN) at redshift z = 1.388. The light curve peaked at z (P1) = 21.7 mag, making PS1-10afx comparable to the most luminous known SNe, with M(u) = –22.3 mag. Our extensive optical and near-infrared observations indicate that the bolometric light curve of PS1-10afx rose on the unusually fast timescale of ~12 days to the extraordinary peak luminosity of 4.1 × 10(44) erg s(–)(1) (M (bol) = –22.8 mag) and subsequently faded rapidly. Equally important, the spectral energy distribution is unusually red for an SLSN, with a color temperature of ~6800 K near maximum light, in contrast to previous hydrogen-poor SLSNe, which are bright in the ultraviolet (UV). The spectra more closely resemble those of a normal SN Ic than any known SLSN, with a photospheric velocity of ~11, 000 km s(–)(1) and evidence for line blanketing in the rest-frame UV. Despite the fast rise, these parameters imply a very large emitting radius (gsim 5 × 10(15) cm). We demonstrate that no existing theoretical model can satisfactorily explain this combination of properties: (1) a nickel-powered light curve cannot match the combination of high peak luminosity with the fast timescale, (2) models powered by the spindown energy of a rapidly rotating magnetar predict significantly hotter and faster ejecta, and (3) models invoking shock breakout through a dense circumstellar medium cannot explain the observed spectra or color evolution. The host galaxy is well detected in pre-explosion imaging with a luminosity near L*, a star formation rate of ~15 M (☉) yr(–)(1), and is fairly massive (~2 × 10(10) M (☉)), with a stellar population age of ~10(8) yr, also in contrast to the young dwarf hosts of known hydrogen-poor SLSNe. PS1-10afx is distinct from known examples of SLSNe in its spectra, colors, light-curve shape, and host galaxy properties, suggesting that it resulted from a different channel than other hydrogen-poor SLSNe.
Note:
  • 17 pages, 12 figures, accepted to ApJ, minor revisions, including expanded discussion of lensing hypothesis
  • supernovae: individual
  • surveys