@article{5ef19af961534a07a24f8fbcdf40b1bc,
title = "SUPERLUMINOUS SUPERNOVA SN 2015bn in the NEBULAR PHASE: EVIDENCE for the ENGINE-POWERED EXPLOSION of A STRIPPED MASSIVE STAR",
abstract = "We present nebular-phase imaging and spectroscopy for the hydrogen-poor superluminous supernova (SLSN) SN 2015bn, at redshift z = 0.1136, spanning +250-400 days after maximum light. The light curve exhibits a steepening in the decline rate from 1.4 mag (100 days)-1 to 1.7 mag (100 days)-1, suggestive of a significant decrease in the opacity. This change is accompanied by a transition from a blue continuum superposed with photospheric absorption lines to a nebular spectrum dominated by emission lines of oxygen, calcium, and magnesium. There are no obvious signatures of circumstellar interaction or large 56Ni mass. We show that the spectrum at +400 days is virtually identical to a number of energetic SNe Ic such as SN 1997dq, SN 2012au, and SN 1998bw, indicating similar core conditions and strengthening the link between {"}hypernovae{"}/long gamma-ray bursts and SLSNe. A single explosion mechanism may unify these events that span absolute magnitudes of -22 < M B < -17. Both the light curve and spectrum of SN 2015bn are consistent with an engine-driven explosion ejecting 7-30 M o of oxygen-dominated ejecta (for reasonable choices in temperature and opacity). A strong and relatively narrow O i λ7774 line, seen in a number of these energetic events but not in normal supernovae, may point to an inner shell that is the signature of a central engine.",
keywords = "supernovae: general, supernovae: individual (2015bn)",
author = "M. Nicholl and E. Berger and R. Margutti and R. Chornock and Blanchard, {P. K.} and A. Jerkstrand and Smartt, {S. J.} and I. Arcavi and P. Challis and Chambers, {K. C.} and Chen, {T. W.} and Cowperthwaite, {P. S.} and A. Gal-Yam and G. Hosseinzadeh and Howell, {D. A.} and C. Inserra and E. Kankare and Magnier, {E. A.} and K. Maguire and Mazzali, {P. A.} and C. McCully and D. Milisavljevic and Smith, {K. W.} and S. Taubenberger and S. Valenti and Wainscoat, {R. J.} and O. Yaron and Young, {D. R.}",
note = "Publisher Copyright: {\textcopyright} 2016. The American Astronomical Society. All rights reserved.",
year = "2016",
month = sep,
day = "10",
doi = "10.3847/2041-8205/828/2/L18",
language = "אנגלית",
volume = "828",
journal = "Astrophysical Journal Letters",
issn = "2041-8205",
publisher = "American Astronomical Society",
number = "2",
}