The superluminous supernova PS1-11ap: bridging the gap between low and high redshift

M. McCrum, S. J. Smartt, R. Kotak, A. Rest, A. Jerkstrand, C. Inserra, S. A. Rodney, T.-W. Chen, D. A. Howell, M. E. Huber, A. Pastorello, J. L. Tonry, F. Bresolin, R.-P. Kudritzki, R. Chornock, E. Berger, K. Smith, M. T. Botticella, R. J. Foley, M. FraserD. Milisavljevic, M. Nicholl, A. G. Riess, C. W. Stubbs, S. Valenti, W. M. Wood-Vasey, D. Wright, M. Drout, I. Czekala, W. S. Burgett, K. C. Chambers, P. Draper, H. Flewelling, K. W. Hodapp, N. Kaiser, E. A. Magnier, N. Metcalfe, P. A. Price, W. Sweeney, R. J. Wainscoat

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41 Citations (Scopus)


We present optical photometric and spectroscopic coverage of the superluminous supernova (SLSN) PS1-11ap, discovered with the Pan-STARRS1 Medium Deep Survey at z = 0.524. This intrinsically blue transient rose slowly to reach a peak magnitude of Mu = -21.4 mag and bolometric luminosity of 8 × 1043 erg s-1 before settling on to a relatively shallow gradient of decline. The observed decline is significantly slower than those of the SLSNe-Ic which have been the focus of much recent attention. Spectroscopic similarities with the lower redshift SN2007bi and a decline rate similar to 56Co decay time-scale initially indicated that this transient could be a candidate for a pair instability supernova (PISN) explosion. Overall the transient appears quite similar to SN2007bi and the lower redshift object PTF12dam. The extensive data set, from 30 d before peak to 230 d after, allows a detailed and quantitative comparison with published models of PISN explosions. We find that the PS1-11ap data do not match these model explosion parameters well, supporting the recent claim that these SNe are not pair instability explosions. We show that PS1-11ap has many features in common with the faster declining SLSNe-Ic, and the light-curve evolution can also be quantitatively explained by the magnetar spin-down model. At a redshift of z = 0.524, the observer-frame optical coverage provides comprehensive rest-frame UV data and allows us to compare it with the SLSNe recently found at high redshifts between z = 2 and 4. While these high-z explosions are still plausible PISN candidates, they match the photometric evolution of PS1-11ap and hence could be counterparts to this lower redshift transient.
Original languageEnglish
Pages (from-to)656-674
JournalMonthly Notices of the Royal Astronomical Society
Issue number1
Publication statusPublished - 1 Jan 2014


  • Supernovae: general
  • Supernovae: individual: PS1-11ap


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