J/MNRAS/454/3816 Cobalt emission in nebular phase spectra (Childress+, 2015)
Measuring nickel masses in Type Ia supernovae using cobalt emission in nebular
phase spectra.
Childress M.J., Hillier D.J., Seitenzahl I., Sullivan M., Maguire K.,
Taubenberger S., Scalzo R., Ruiter A., Blagorodnova N., Camacho Y.,
Castillo J., Elias-Rosa N., Fraser M., Gal-Yam A., Graham M., Howell D.A.,
Inserra C., Jha S.W., Kumar S., Mazzali P.A., McCully C.,
Morales-Garoffolo A., Pandya V., Polshaw J., Schmidt B., Smartt S.,
Smith K.W., Sollerman J., Spyromilio J., Tucker B., Valenti S., Walton N.,
Wolf C., Yaron O., Young D.R., Yuan F., Zhang B.
<Mon. Not. R. Astron. Soc., 454, 3816-3842 (2015)>
=2015MNRAS.454.3816C 2015MNRAS.454.3816C (SIMBAD/NED BibCode)
ADC_Keywords: Supernovae ; Nebulae ; Redshifts ; Photometry, UBV ; Spectroscopy
Keywords: supernovae: general
Abstract:
The light curves of Type Ia supernovae (SNe Ia) are powered by the
radioactive decay of 56Ni to 56Co at early times, and the decay of
56Co to 56Fe from ∼60 d after explosion. We examine the evolution of
the [CoIII] λ5893 emission complex during the nebular phase for
SNe Ia with multiple nebular spectra and show that the line flux
follows the square of the mass of 56Co as a function of time. This
result indicates both efficient local energy deposition from positrons
produced in 56Co decay and long-term stability of the ionization state
of the nebula. We compile SN Ia nebular spectra from the literature
and present 21 new late-phase spectra of 7 SNe Ia, including SN 2014J.
From these we measure the flux in the [CoIII] λ5893 line and
remove its well-behaved time dependence to infer the initial mass of
56Ni (MNi) produced in the explosion. We then examine 56Ni yields
for different SN Ia ejected masses (Mej - calculated using the
relation between light-curve width and ejected mass) and find that the
56Ni masses of SNe Ia fall into two regimes: for narrow light curves
(low stretch s∼0.7-0.9), MNi is clustered near MNi∼0.4M☉ and
shows a shallow increase as Mej increases from ∼1 to 1.4M☉; at
high stretch, Mej clusters at the Chandrasekhar mass (1.4M☉)
while MNi spans a broad range from 0.6 to 1.2M☉. This could
constitute evidence for two distinct SN Ia explosion mechanisms.
Description:
The analysis in this work relies on a compilation of SN Ia nebular
spectra from the literature as well as new observations. We obtained
new late-phase (+50=<t=<+150 d) and nebular (t≥+150 d) spectra of several
nearby SNe Ia from numerous telescopes. Several late-phase spectra of
very nearby SNe Ia were collected with the Wide Field Spectrograph
(WiFeS; Dopita et al. 2007Ap&SS.310..255D 2007Ap&SS.310..255D, 2010Ap&SS.327..245D 2010Ap&SS.327..245D) on the
Australian National University (ANU) 2.3 m telescope at Siding Spring
Observatory in northern New South Wales, Australia. New nebular
spectra for three nearby SNe Ia were collected with DEIMOS (Faber et al.
2003SPIE.4841.1657F 2003SPIE.4841.1657F) on the Keck-II telescope on Mauna Kea, Hawaii.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
tableb1.dat 160 32 Nebular SN Ia host information
tableb2.dat 140 32 Light-curve fit results and sources
tableb3.dat 82 77 Late-phase photometry
tableb4.dat 55 73 Co line fluxes from spectra
--------------------------------------------------------------------------------
See also:
B/sn : Asiago Supernova Catalogue (Barbon et al., 1999-)
J/AJ/131/527 : UBVRI light curves of 44 type Ia supernovae (Jha+, 2006)
J/MNRAS/376/1301 : UBVRI light-curves of SN 2005cf (Pastorello+, 2007)
J/MNRAS/377/1531 : Optical + infrared photometry of SN 2004eo
(Pastorello+, 2007)
J/AJ/135/1598 : Optical spectroscopy of type Ia supernovae (Matheson+, 2008)
J/ApJ/700/331 : Light curves of type Ia supernovae (CfA3) (Hicken+, 2009)
J/AJ/139/519 : Carnegie supernova project. SNe Ia (Contreras+, 2010)
J/ApJS/190/418 : Light curves for 165 SNe (Ganeshalingam+, 2010)
J/PASP/122/1 : BVRI light curves of SN 2007gi (Zhang+, 2010)
J/AJ/142/156 : The CSP (DR2): photometry of SNe Ia (Stritzinger+, 2011)
J/ApJ/730/119 : HST/WFC3 observations of Cepheids in SN Ia hosts
(Riess+, 2011)
J/ApJS/200/12 : CfA4: light curves for 94 type Ia SNe (Hicken+, 2012)
J/AJ/148/1 : Optical and ultraviolet photometry of SN 2012fr
(Zhang+, 2014)
J/A+A/585/A19 : SN 2014J BV light curves (Bonanos+, 2016)
J/AJ/151/125 : Optical and UV photometry of SN 2013dy (Zhai+, 2016)
Byte-by-byte Description of file: tableb1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 A2 --- --- [SN]
4- 9 A6 --- SN SN name
11- 22 A12 --- Host Host galaxy name
24- 31 F8.6 --- z Redshift of host galaxy
33- 37 F5.2 mag DM [] Distance modulus of the SN host galaxy
39- 42 F4.2 mag e_DM Uncertainty in DM (1)
44- 54 A11 --- Meth Method used to derive the distance (2)
56-112 A57 --- r_z Reference for z
115-160 A46 --- r_DM Reference for DM
--------------------------------------------------------------------------------
Note (1): For hosts with redshift-based µ, uncertainty includes a peculiar
velocity term of 300 km/s.
Note (2): Distances for SNe Ia in our sample are preferentially derived from
Cepheid distances from Riess et al. (2011, J/ApJ/730/119) where
available, and from host redshift with the Riess et al. (2011,
J/ApJ/730/119) Hubble constant value (H0=73.8 km/s/Mpc). Generally,
we avoid other distance indicators such as Tully-Fisher, surface
brightness fluctuations, and planetary nebula luminosity functions.
The one exception to this is SN 2012cg, for which we use the
Cortes, Kenney & Hardy (2008ApJ...683...78C 2008ApJ...683...78C) Tully-Fisher distance
modulus, as was done in Silverman et al. (2012ApJ...756L...7S 2012ApJ...756L...7S).
--------------------------------------------------------------------------------
Byte-by-byte Description of file: tableb2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 A2 --- --- [SN]
4- 9 A6 --- SN SN name
11- 18 F8.2 d MJD Modified Julian Date for B-band maximum
magnitude
20- 25 F6.3 mag Brest Rest frame B-band maximum magnitude
27- 31 F5.3 mag e_Brest Uncertainty in Brest
33- 37 F5.3 --- s SN light-curve stretch
39- 43 F5.3 --- e_s Uncertainty in s
45- 50 F6.3 --- c Colour correction
52- 56 F5.3 --- e_c Uncertainty in c
58-140 A83 --- Ref Light-curve reference(s) (G1)
--------------------------------------------------------------------------------
Byte-by-byte Description of file: tableb3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 A2 --- --- [SN]
4- 9 A6 --- SN SN name (1)
11- 13 I3 d Phase [144/430] Phase
15- 24 A10 "date" Date Observation date
26- 31 F6.3 mag Bmag B-band magnitude
33- 37 F5.3 mag e_Bmag Uncertainty in Bmag
39- 82 A44 --- Ref Photometry reference (G1)
--------------------------------------------------------------------------------
Note (1): For SNe with poor late-time photometric coverage, the late light curve
of a surrogate SN is employed.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: tableb4.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 A2 --- --- [SN]
4- 9 A6 --- SN SN name
11- 20 A10 "date" Date Observation date
22- 27 F6.3 [mW/m2] logCoF Measured [Co III] λ5893 line flux
(in erg/cm2/s)
29- 33 F5.3 [mW/m2] e_logCoF Uncertainty in logCoF
35- 41 F7.3 --- Resc Spectrum rescale (1)
43- 48 F6.1 0.1nm WaveMin ? Minimum wavelength integration bound for
the [Co III] λ5893 flux measurement
(Å)
50- 55 F6.1 0.1nm WaveMax ? Maximum wavelength integration bound for
the [Co III] λ5893 flux measurement
(Å)
--------------------------------------------------------------------------------
Note (1): Factor applied to spectrum to enforce consistency with observed B-band
magnitude.
--------------------------------------------------------------------------------
Global note:
Note (G1): Reference as follows:
CfA = Riess et al. (1999AJ....117..707R 1999AJ....117..707R), Jha et al. (2006, J/AJ/131/527),
Hicken et al. (2009, J/ApJ/700/331; 2012, J/ApJS/200/12);
LOSS = Ganeshalingam et al. (2010, J/ApJS/190/418);
CSP = Contreras et al. (2010, J/AJ/139/519), Stritzinger et al. (2011,
J/AJ/142/156);
LCOGT = Brown et al. (2013PASP..125.1031B 2013PASP..125.1031B);
T15b = Taubenberger et al. (in preparation).
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Tiphaine Pouvreau [CDS] 19-Jan-2018