J/MNRAS/491/2902 Sub-Chandrasekhar progenitors for Type Ia SNe (Flors+, 2020)
Sub-Chandrasekhar progenitors favoured for Type Ia supernovae:
evidence from late-time spectroscopy.
Flors A., Spyromilio J., Taubenberger S., Blondin S., Cartier R.,
Leibundgut B., Dessart L., Dhawan S., Hillebrandt W.
<Mon. Not. R. Astron. Soc., 491, 2902-2918 (2020)>
=2020MNRAS.491.2902F 2020MNRAS.491.2902F (SIMBAD/NED BibCode)
ADC_Keywords: Supernovae ; Spectra, optical ; Spectra, infrared ;
Abundances, peculiar
Keywords: line: formation - line: identification -
radiation mechanisms: thermal - supernovae: general -
supernovae: individual: SN 2015F, SN 2017bzc
Abstract:
A non-local-thermodynamic-equilibrium level population model of the
first and second ionization stages of iron, nickel, and cobalt is used
to fit a sample of XShooter optical + near-infrared (NIR) spectra of
Type Ia supernovae (SNe Ia). From the ratio of the NIR lines to the
optical lines limits can be placed on the temperature and density of
the emission region. We find a similar evolution of these parameters
across our sample. Using the evolution of the FeII 12570-7155Å line
as a prior in fits of spectra covering only the optical wavelengths we
show that the 7200Å feature is fully explained by [FeII] and [NiII]
alone. This approach allows us to determine the abundance of NiII/FeII
for a large sample of 130 optical spectra of 58 SNe Ia with
uncertainties small enough to distinguish between Chandrasekhar mass
(MCh) and sub-Chandrasekhar mass (sub-MCh) explosion models. We
conclude that the majority (85 per cent) of normal SNe Ia have a Ni/Fe
abundance that is in agreement with predictions of sub-MCh explosion
simulations of ∼Z☉ progenitors. Only a small fraction (11 per
cent) of objects in the sample have a Ni/Fe abundance in agreement
with MCh explosion models.
Description:
We extend the XShooter sample of nearby SNe Ia in the nebular phase
from Maguire et al. (2018MNRAS.477.3567M 2018MNRAS.477.3567M) with SN 2015F (PI M.
Sullivan, program ID 095.A-0316; PI R. Cartier, program IDs
096.D-0829, 097.D-0967, and 098.D-0692) and SN 2017bzc (PI L. Dessart,
program ID 0100.D-0285). The epochs of the additional spectra range
from ∼200 to ∼420d after the explosion.
XShooter is an Echelle spectrograph with three arms (UVB, VIS, and
NIR) covering the wavelength range of ∼3000-25000Å located at the
Very Large Telescope (VLT). The resolution of the individual arms
depends on the slit widths. For the observations presented in this
work slit widths of 1.0 (UVB), 0.9 (VIS), and 0.9 (NIR) arcsec have
been used. The corresponding resolution of the three arms is therefore
5400, 8900, and 5600, respectively.
The spectra were reduced using the ESO pipeline with the XShooter
module, producing flux-calibrated one-dimensional spectra in each of
the three arms (Modigliani et al. 2010SPIE.7737E..28M 2010SPIE.7737E..28M; Freudling et
al. 2013A&A...559A..96F 2013A&A...559A..96F). We also used a custom post-processing
pipeline to combine the rectified 2D-images, perform the
sky-subtraction and extract the spectrum
(https://github.com/jselsing/xsh-postproc).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tableb1.dat 105 130 Overview of spectra observations
refs.dat 64 42 References for Table B1
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Byte-by-byte Description of file: tableb1.dat
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Bytes Format Units Label Explanations
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1- 11 A11 --- Name Supernova name
13- 20 A8 --- Subtype Supernova subtype (Ia-norm or 91T-like)
22- 27 F6.4 mag E(B-V) B-V colour excess
29- 36 F8.6 --- z Redshift
38- 49 A12 --- Datemax Date of B-band maximum
51- 56 F6.1 d Epoch Epoch of the observation
58- 70 A13 --- Tel Telescope used for the observation
72- 81 A10 --- Inst Instrument used for the observation
83- 84 A2 --- Refsp Reference for the spectra
86- 87 A2 --- Refext ? Other reference
89- 93 F5.3 --- Ni/Feinf Ni/Fe mass ratio in the limit t->∞
95- 99 F5.3 --- E_Ni/Feinf Upper error on Ni/Feinf
101-105 F5.3 --- e_Ni/Feinf Lower error on Ni/Feinf
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Byte-by-byte Description of file: refs.dat
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Bytes Format Units Label Explanations
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1- 2 A2 --- Ref Reference code
4- 22 A19 --- BibCode BibCode
24- 42 A19 --- Author Author's name
44- 64 A21 --- Comments Comments
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History:
From electronic version of the journal
(End) Ana Fiallos [CDS] 16-Feb-2023