1. |
- Andrews, Jennifer E., et al.
(author)
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SN 2017gmr : An Energetic Type II-P Supernova with Asymmetries
- 2019
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In: Astrophysical Journal. - : American Astronomical Society. - 0004-637X .- 1538-4357. ; 885:1
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Journal article (peer-reviewed)abstract
- We present high-cadence UV, optical, and near-infrared data on the luminous Type II-P supernova SN;2017gmr from hours after discovery through the first 180 days. SN;2017gmr does not show signs of narrow, high-ionization emission lines in the early optical spectra, yet the optical light-curve evolution suggests that an extra energy source from circumstellar medium (CSM) interaction must be present for at least 2 days after explosion. Modeling of the early light curve indicates a ?500 R progenitor radius, consistent with a rather compact red supergiant, and late-time luminosities indicate that up to 0.130;;0.026 M of Ni-56 are present, if the light curve is solely powered by radioactive decay, although the Ni-56 mass may be lower if CSM interaction contributes to the post-plateau luminosity. Prominent multipeaked emission lines of H? and [O i] emerge after day 154, as a result of either an asymmetric explosion or asymmetries in the CSM. The lack of narrow lines within the first 2 days of explosion in the likely presence of CSM interaction may be an example of close, dense, asymmetric CSM that is quickly enveloped by the spherical supernova ejecta.
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2. |
- Gangopadhyay, Anjasha, et al.
(author)
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Optical studies of two stripped-envelope supernovae – SN 2015ap (Type Ib) and SN 2016P (Type Ic)
- 2020
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In: Monthly notices of the Royal Astronomical Society. - : Oxford University Press (OUP). - 0035-8711 .- 1365-2966. ; 497:3, s. 3770-3789
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Journal article (peer-reviewed)abstract
- We present the photometric and spectroscopic studies of a Type Ib SN 2015ap and a Type Ic SN 2016P. SN 2015ap is one of the bright (MV = −18.04 mag) Type Ib while SN 2016P lies at an average value among the Type Ic SNe (MV = −17.53 mag). Bolometric light-curve modelling of SNe 2015ap and 2016P indicates that both the SNe are powered by 56Ni + magnetar model with 56Ni masses of 0.01 and 0.002 M⊙, ejecta masses of 3.75 and 4.66 M⊙, spin period P0 of 25.8 and 36.5 ms, and magnetic field Bp of 28.39 × 1014 and 35.3 × 1014 G, respectively. The early spectra of SN 2015ap show prominent lines of He with a ‘W’ feature due to Fe complexes while other lines of Mg ii, Na i, and Si ii are present in both SNe 2015ap and 2016P. Nebular phase [O i] profile indicates an asymmetric profile in SN 2015ap. The [O i]/[Ca ii] ratio and nebular spectral modelling of SN 2015ap hint towards a progenitor mass between 12 and 20 M⊙.
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