J/MNRAS/451/1973 Type Ia supernovae high-velocity features (Silverman+, 2015)
High-velocity features of calcium and silicon in the spectra of
Type Ia supernovae.
Silverman J.M., Vinko J., Marion G.H., Wheeler J.C., Barna B., Szalai T.,
Mulligan B.W., Filippenko A.V.
<Mon. Not. R. Astron. Soc., 451, 1973-2014 (2015)>
=2015MNRAS.451.1973S 2015MNRAS.451.1973S (SIMBAD/NED BibCode)
ADC_Keywords: Supernovae ; Spectroscopy
Keywords: methods: data analysis - techniques: spectroscopic -
supernovae: general
Abstract:
'High-velocity features' (HVFs) are spectral features in Type Ia
supernovae (SNe Ia) that have minima indicating significantly higher
(by greater than about 6000km/s) velocities than typical
'photospheric-velocity features' (PVFs). The PVFs are absorption
features with minima indicating typical photospheric (i.e. bulk
ejecta) velocities (usually∼9000-15000km/s near B-band maximum
brightness). In this work, we undertake the most in-depth study of
HVFs ever performed. The data set used herein consists of 445
low-resolution optical and near-infrared (NIR) spectra (at epochs up
to 5d past maximum brightness) of 210 low-redshift SNe Ia that follow
the 'Phillips relation'. A series of Gaussian functions is fit to the
data in order to characterize possible HVFs of CaII H&K, SiII
λ6355, and the CaII NIR triplet. The temporal evolution of the
velocities and strengths of the PVFs and HVFs of these three spectral
features is investigated, as are possible correlations with other SN
Ia observables. We find that while HVFs of CaII are regularly observed
(except in underluminous SNe Ia, where they are never found), HVFs of
Siii λ6355 are significantly rarer, and they tend to exist at
the earliest epochs and mostly in objects with large photospheric
velocities. It is also shown that stronger HVFs of SiII λ6355
are found in objects that lack CII absorption at early times and that
have red ultraviolet/optical colours near maximum brightness. These
results lead to a self-consistent connection between the presence and
strength of HVFs of SiII λ6355 and many other mutually
correlated SN Ia observables, including photospheric velocity.
Description:
The majority of the SN Ia spectra used in this study come from the
Berkeley SN Ia Program (BSNIP) and have been published in BSNIP I
(Silverman et al., 2012, Cat. J/MNRAS/425/1789). Most of these data
were obtained with the Shane 3 m telescope at Lick Observatory using
the Kast double spectrograph. The typical wavelength coverage of
3300-10400Å (with resolutions of ∼11 and ∼6Å on the red and blue
sides, respectively) allows us to observe the CaHK and CaIR3 features
simultaneously. All objects have z<0.1 with a median redshift of 0.02.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 205 210 Summary of SNe Ia
tablea2.dat 108 126 CaHK fit results
tablea3.dat 84 422 SiII6355 fit results
tablea4.dat 89 382 CaIR3 fit results
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See also:
J/MNRAS/425/1789 : Berkeley supernova Ia program. I. (Silverman+, 2012)
Byte-by-byte Description of file: tablea1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 A10 --- SN SN name
12 A1 --- n_SN [ghi] Note on SN (G1)
14-165 A152 d Phases Phases are in rest-frame days
167-170 F4.2 mag Dm15(B) ?=- Delta m15 (decline in B after 15 days)
172 A1 --- --- [(]
173-174 I2 0.01mag e_Dm15(B) ? rms uncertainty on Dm15(B)
175 A1 --- --- [)]
177-182 F6.3 mag (B-V)0 ?=- Deredenned B-V colour index
184 A1 --- --- [(]
185-187 I3 0.001mag e_(B-V)0 ? rms uncertainty on (B-V)0
188 A1 --- --- [)]
190-196 A7 --- SNID (Sub)Type (1)
198-202 A5 --- BType Classification based on the velocity
gradient of the SiII6355 line
(Benetti et al., 2005ApJ...623.1011B 2005ApJ...623.1011B) (2)
204-205 A2 --- WType Classification based on the velocity of the
SiII 6355 line (Wang et al. 2009) (3)
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Note (1): Spectral classification using the SuperNova IDentification code
(SNID; Blondin & Tonry 2007ApJ...666.1024B 2007ApJ...666.1024B) as implemented in BSNIP I
(Silverman et al., 2012, Cat. J/MNRAS/425/1789).
Note (2): Classification as follows:
HVG = high-velocity gradient
LVG = low-velocity gradient
INT = faint/underluminous
Note (3): Classification as follows:
HV = high velocity
N = normal
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Byte-by-byte Description of file: tablea2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 A10 --- SN SN name
12 A1 --- n_SN [h] Note on SN (G1)
13- 17 F5.1 d Phase Phase in rest-frame days
19- 23 F5.2 10+3km/s HVFv ?=- High-velocity feature velocity
26- 29 F4.2 10+3km/s e_HVFv ? rms uncertainty on HVFv
32- 36 F5.1 0.1nm HVFpEW ? High-velocity feature
pseudo equivalent width
39- 42 F4.1 0.1nm e_HVFpEW ? rms uncertainty on HVFpEW
47- 51 F5.2 10+3km/s PVFv ? Photospheric-velocity feature velocity
54- 57 F4.2 10+3km/s e_PVFv ? rms uncertainty on PVFv
60- 64 F5.1 0.1nm PVFpEW ? Photospheric-velocity feature
pseudo equivalent width
67- 70 F4.1 0.1nm e_PVFpEW ? rms uncertainty on PVFpEW
73- 77 F5.2 --- RCaHK ? RCaHK index (1)
80- 83 F4.2 --- e_RCaHK ? rms uncertainty on RCaHK
87- 91 F5.2 10+3km/s SiII3858v ?=- SiII3858 line velocity
94- 97 F4.2 10+3km/s e_SiII3858v ? rms uncertainty on SiII3858v
100-103 F4.1 0.1nm SiII3858pEW ? SiII3858 pseudo equivalent width
106-108 F3.1 0.1nm e_SiII3858pEW ? rms uncertainty on SiII3858pEW
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Note (1): RCaHK is the ratio of the pEW of the HVF to the pEW of the PVF, as
defined by Childress et al. (2014MNRAS.437..338C 2014MNRAS.437..338C).
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Byte-by-byte Description of file: tablea3.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 A10 --- SN SN name
11 A1 --- n_SN [ghi] Note on SN (G1)
12- 16 F5.1 d Phase Phases are in rest-frame days
18- 22 F5.2 10+3km/s HVFv ? High-velocity feature velocity
25- 28 F4.2 10+3km/s e_HVFv ? rms uncertainty on HVFv
31- 35 F5.1 0.1nm HVFpEW ? High-velocity feature
pseudo equivalent width
38- 40 F3.1 0.1nm e_HVFpEW ? rms uncertainty on HVFpEW
45- 49 F5.2 10+3km/s PVFv ? Photospheric-velocity feature velocity
52- 55 F4.2 10+3km/s e_PVFv ? rms uncertainty on PVFv
59- 63 F5.1 0.1nm PVFpEW ? Photospheric-velocity feature
pseudo equivalent width
65- 68 F4.1 0.1nm e_PVFpEW ? rms uncertainty on PVFpEW
74- 78 F5.2 --- RSi ?=0 RSi index (1)
81- 84 F4.2 --- e_RSi ? rms uncertainty on RSi
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Note (1): RSi is the ratio of the pEW of the HVF to the pEW of the PVF,
as defined by Childress et al. (2014MNRAS.437..338C 2014MNRAS.437..338C).
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Byte-by-byte Description of file: tablea4.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 A10 -- SN SN name
12 A1 --- n_SN [ghi] Note on SN (G1)
13- 17 F5.1 d Phase Phase in rest-frame days
20- 24 F5.2 10+3km/s HVFv ?=- High-velocity feature velocity
27- 30 F4.2 10+3km/s e_HVFv ? rms uncertainty on HVFv
35- 39 F5.1 0.1nm HVFpEW ?=- High-velocity feature
pseudo equivalent width
43- 46 F4.1 0.1nm e_HVFpEW ? rms uncertainty on HVFpEW
50- 54 F5.2 10+3km/s PVFv ?=- Photospheric-velocity feature velocity
57- 60 F4.2 10+3km/s e_PVFv ? rms uncertainty on PVFv
64- 68 F5.1 0.1nm PVFpEW ?=- Photospheric-velocity feature
pseudo equivalent width
71- 75 F5.1 0.1nm e_PVFpEW ? rms uncertainty on PVFpEW
79- 83 F5.2 --- RCaIR3 ?=- RCaIR3 index
86- 89 F4.2 --- e_RCaIR3 ? rms uncertainty on RCaIR3 (1)
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Note (1): RCaIR3 is the ratio of the pEW of the HVF to the pEW of the PVF, as
defined by Childress et al. (2014MNRAS.437..338C 2014MNRAS.437..338C).
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Global notes:
Note (G1): Notes as follows:
g = SN 2007s1 also known as SNF20071021-000
h = SN 2008s1 also known as SNF20080514-002
i = SN 2008s5 also known as SNF20080909-030
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 12-Jan-2016