A1 Refereed original research article in a scientific journal
On the diversity of superluminous supernovae: ejected mass as the dominant factor
Authors: Nicholl M, Smartt SJ, Jerkstrand A, Inserra C, Sim SA, Chen TW, Benetti S, Fraser M, Gal-Yam A, Kankare E, Maguire K, Smith K, Sullivan M, Valenti S, Young DR, Baltay C, Bauer FE, Baumont S, Bersier D, Botticella MT, Childress M, Dennefeld M, Della Valle M, Elias-Rosa N, Feindt U, Galbany L, Hadjiyska E, Le Guillou L, Leloudas G, Mazzali P, McKinnon R, Polshaw J, Rabinowitz D, Rostami S, Scalzo R, Schmidt BP, Schulze S, Sollerman J, Taddia F, Yuan F
Publisher: OXFORD UNIV PRESS
Publication year: 2015
Journal: Monthly Notices of the Royal Astronomical Society
Journal name in source: MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
Journal acronym: MON NOT R ASTRON SOC
Volume: 452
Issue: 4
First page : 3869
Last page: 3893
Number of pages: 25
ISSN: 0035-8711
DOI: https://doi.org/10.1093/mnras/stv1522
We assemble a sample of 24 hydrogen-poor superluminous supernovae (SLSNe). Parameterizing the light-curve shape through rise and decline time-scales shows that the two are highly correlated. Magnetar-powered models can reproduce the correlation, with the diversity in rise and decline rates driven by the diffusion time-scale. Circumstellar interaction models can exhibit a similar rise-decline relation, but only for a narrow range of densities, which may be problematic for these models. We find that SLSNe are approximately 3.5 mag brighter and have light curves three times broader than SNe Ibc, but that the intrinsic shapes are similar. There are a number of SLSNe with particularly broad light curves, possibly indicating two progenitor channels, but statistical tests do not cleanly separate two populations. The general spectral evolution is also presented. Velocities measured from Fe II are similar for SLSNe and SNe Ibc, suggesting that diffusion time differences are dominated by mass or opacity. Flat velocity evolution in most SLSNe suggests a dense shell of ejecta. If opacities in SLSNe are similar to other SNe Ibc, the average ejected mass is higher by a factor 2-3. Assuming. = 0.1 cm(2) g(-1), we estimate a mean (median) SLSN ejecta mass of 10 M-circle dot (6 M-circle dot), with a range of 3-30 M-circle dot. Doubling the assumed opacity brings the masses closer to normal SNe Ibc, but with a high-mass tail. The most probable mechanism for generating SLSNe seems to be the core collapse of a very massive hydrogen-poor star, forming a millisecond magnetar.
