TY - JOUR
T1 - Radiative-transfer models for explosions from rotating and non-rotating single WC stars
T2 - Implications for SN 1998bw and LGRB/SNe
AU - Dessart, Luc
AU - John Hillier, D.
AU - Yoon, Sung Chul
AU - Waldman, Roni
AU - Livne, Eli
N1 - Publisher Copyright:
© ESO, 2017.
PY - 2017/7/1
Y1 - 2017/7/1
N2 - Using 1D, non-local thermodynamic equilibrium and time-dependent radiative transfer simulations, we study the ejecta properties required to match the early- and late-time photometric and spectroscopic properties of supernovae (SNe) associated with long-duration γ-ray bursts (LGRBs). Matching the short rise time, narrow light curve peak and extremely broad spectral lines of SN 1998bw requires a model with 3 Mejecta but a high explosion energy of a few 1052 erg and 0.5 M of 56Ni. The relatively high luminosity, presence of narrow spectral lines of intermediate mass elements, and low ionisation at the nebular stage, however, are matched with a more standard C-rich Wolf-Rayet (WR) star explosion, an ejecta of 10 M, an explosion energy 1051 erg, and only 0.1 M of 56Ni. As the two models are mutually exclusive, the breaking of spherical symmetry is essential to match the early- and late-time photometric and spectroscopic properties of SN 1998bw. This conclusion confirms the notion that the ejecta of SN 1998bw is highly aspherical on large scales. More generally, with asphericity, the energetics and 56Ni masses of LGRB/SNe are reduced and their ejecta masses are increased, favouring a massive fast-rotating Wolf-Rayet star progenitor. Contrary to persisting claims in favour of the proto-magnetar model for LGRB/SNe, such progenitor/ejecta properties are compatible with collapsar formation. Ejecta properties of LGRB/SNe inferred from 1D radiative-transfer modelling are fundamentally flawed.
AB - Using 1D, non-local thermodynamic equilibrium and time-dependent radiative transfer simulations, we study the ejecta properties required to match the early- and late-time photometric and spectroscopic properties of supernovae (SNe) associated with long-duration γ-ray bursts (LGRBs). Matching the short rise time, narrow light curve peak and extremely broad spectral lines of SN 1998bw requires a model with 3 Mejecta but a high explosion energy of a few 1052 erg and 0.5 M of 56Ni. The relatively high luminosity, presence of narrow spectral lines of intermediate mass elements, and low ionisation at the nebular stage, however, are matched with a more standard C-rich Wolf-Rayet (WR) star explosion, an ejecta of 10 M, an explosion energy 1051 erg, and only 0.1 M of 56Ni. As the two models are mutually exclusive, the breaking of spherical symmetry is essential to match the early- and late-time photometric and spectroscopic properties of SN 1998bw. This conclusion confirms the notion that the ejecta of SN 1998bw is highly aspherical on large scales. More generally, with asphericity, the energetics and 56Ni masses of LGRB/SNe are reduced and their ejecta masses are increased, favouring a massive fast-rotating Wolf-Rayet star progenitor. Contrary to persisting claims in favour of the proto-magnetar model for LGRB/SNe, such progenitor/ejecta properties are compatible with collapsar formation. Ejecta properties of LGRB/SNe inferred from 1D radiative-transfer modelling are fundamentally flawed.
KW - Hydrodynamics
KW - Radiative transfer
KW - Supernovae: general
UR - http://www.scopus.com/inward/record.url?scp=85022320997&partnerID=8YFLogxK
U2 - 10.1051/0004-6361/201730873
DO - 10.1051/0004-6361/201730873
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AN - SCOPUS:85022320997
SN - 0004-6361
VL - 603
JO - Astronomy and Astrophysics
JF - Astronomy and Astrophysics
M1 - A51
ER -