J/ApJ/742/89 Relations between spectra and colors of SNe Ia (Foley+, 2011)
Velocity evolution and the intrinsic color of type Ia supernovae.
Foley R.J., Sanders N.E., Kirshner R.P.
<Astrophys. J., 742, 89 (2011)>
=2011ApJ...742...89F 2011ApJ...742...89F
ADC_Keywords: Supernovae ; Photometry, UBV ; Spectroscopy
Keywords: distance scale - dust, extinction - supernovae: general
Abstract:
To understand how best to use observations of Type Ia supernovae
(SNe Ia) to obtain precise and accurate distances, we investigate the
relations between spectra of SNe Ia and their intrinsic colors. Using
a sample of 1630 optical spectra of 255 SNe, based primarily on data
from the CfA Supernova Program, we examine how the velocity evolution
and line strengths of SiII(6355) and CaII H&K are related to the B-V
color at peak brightness. We find that the maximum-light velocity of
SiII6355 and CaII H&K and the maximum-light pseudo-equivalent width of
SiII6355 are correlated with intrinsic color, with intrinsic color
having a linear relation with the SiII6355 measurements. CaII H&K does
not have a linear relation with intrinsic color, but lower-velocity
SNe tend to be intrinsically bluer. Combining the spectroscopic
measurements does not improve intrinsic color inference. The intrinsic
color scatter is larger for higher-velocity SNe Ia - even after
removing a linear trend with velocity - indicating that lower-velocity
SNe Ia are more "standard crayons". Employing information derived from
SN Ia spectra has the potential to improve the measurements of
extragalactic distances and the cosmological properties inferred from
them.
Description:
Our photometric data come, mainly, from two sources: CfA3 (Hicken et
al. 2009, Cat. J/ApJ/700/331) and Lick Observatory Supernova Search
(LOSS; Ganeshalingam et al. 2010, Cat. J/ApJS/190/418). All derived
values presented by Hicken et al. and Ganeshalingam et al. are both K
correct and deredden for Milky Way reddening. We present the combined
derived light-curve parameters in Table 1.
Over the last two decades, the CfA Supernova Program has observed
hundreds of SNe Ia, mostly with the FAST spectrograph mounted on the
1.5m telescope at the F. L. Whipple Observatory. The data have been
reduced in a consistent manner (Matheson et al. 2008, Cat.
J/AJ/135/1598; Blondin et al. 2011A&A...526A..81B 2011A&A...526A..81B; S. Blondin et al.
2012AJ....143..126B 2012AJ....143..126B), producing well-calibrated spectra. The
measurements for each spectrum are listed in Table 2. The reference
for each spectrum is listed in Table 2, but measurements in all cases
were obtained by S. Blondin et al. (2012AJ....143..126B 2012AJ....143..126B).
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 92 252 Object information
table2.dat 74 1630 Spectral properties
snspec.dat 6 16 List of the 16 SNe with spectral properties in
table2 missing in table1 (added by CDS)
refs.dat 68 45 References
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See also:
B/sn : Asiago Supernova Catalogue (Barbon et al., 1999-)
J/ApJS/200/12 : CfA4: light curves for 94 type Ia SNe (Hicken+, 2012)
J/ApJ/731/120 : Intrinsic SN Ia light curves (Mandel+, 2011)
J/MNRAS/410/1262 : Supernova Legacy Survey. Type Ia supernovae (Walker+, 2011)
J/ApJ/730/119 : HST/WFC3 observations of Cepheids in SNIa hosts (Riess+, 2011)
J/ApJS/190/418 : Light curves for 165 SNe (Ganeshalingam+, 2010)
J/A+A/523/A7 : Light curves of type Ia supernovae in SNLS (Guy+, 2010)
J/AJ/137/3731 : ESSENCE high-redshift supernova (Foley+, 2009)
J/ApJ/700/1097 : Light curve parameters of SN Ia (Hicken+, 2009)
J/ApJ/699/L139 : Spectral parameters of SNe Ia (Wang+, 2009)
J/A+A/500/L17 : Spectral flux ratio of SN Ia (Bailey+, 2009)
J/ApJ/700/331 : Light curves of type Ia supernovae (CfA3) (Hicken+, 2009)
J/A+A/507/85 : ESO/VLT 3rd year type Ia supernova data set (Balland+, 2009)
J/AJ/135/1598 : Optical spectroscopy of type Ia supernovae (Matheson+, 2008)
J/AJ/135/1766 : Sloan Digital Sky Survey-II supernova survey (Zheng+, 2008)
J/A+A/477/717 : Spectroscopy of Type Ia supernovae (Bronder+, 2008)
J/MNRAS/377/1531 : Optical + IR photometry of SN 2004eo (Pastorello+, 2007)
J/MNRAS/369/1880 : Photometry of SN 2003cg (Elias-Rosa+, 2006)
J/AJ/131/527 : UBVRI light curves of 44 type Ia supernovae (Jha+, 2006)
J/AJ/131/1648 : Type Ia supernovae at high and low redshifts (Blondin+, 2006)
J/AJ/112/2408 : Light Curves of 29 SNe (Hamuy+ 1996)
http://www.cfa.harvard.edu/supernova/ : CfA Supernova group home page
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 6 A6 --- SN SN identification
8 A1 --- f_SN [d] SN with Cepheid distance (1)
10- 15 F6.4 --- zCMB Redshift relative to the CMB
17- 21 F5.2 mag Vmag ? V band magnitude at maximum; LOSS system (2)
23- 26 F4.2 mag e_Vmag ? Uncertainty in Vmag
28- 31 F4.2 mag Dm15B ? Magnitude decline from peak brightness at
15 days after B band maximum; LOSS system (3)
33- 36 F4.2 mag e_Dm15B ? Uncertainty in Dm15B
38- 42 F5.2 mag B-V ? The (Bmax-Vmax) color index; LOSS system
44- 47 F4.2 mag e_B-V ? Uncertainty in B-V
49- 54 F6.2 Mm/s V(SiII) ? SiII line velocity at maximum (103km/s)
56- 59 F4.2 Mm/s e_V(SiII) ? Uncertainty in V(SiII) (103km/s)
61- 65 F5.1 0.1nm W(SiII) ? Si II line pseudo-equivalent width at
maximum (4)
67- 69 F3.1 0.1nm e_W(SiII) ? Uncertainty in W(SiII) (4)
71- 76 F6.2 Mm/s V(CaII) ? "red" component Ca II H&K line velocity at
maximum ((103km/s)
78- 81 F4.2 Mm/s e_V(CaII) ? Uncertainty in V(CaII) (103km/s)
83- 87 F5.1 0.1nm W(CaII) ? Ca II H&K line pseudo-equivalent width at
maximum (4)
89- 92 F4.1 0.1nm e_W(CaII) ? Uncertainty in W(CaII) (4)
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Note (1):
d = Supernova with redshift z<0.01, but having a Cepheid distance modulus
from Riess et al. (2011, Cat. J/ApJ/730/119). The redshifts listed for
these SNe yield appropriate distance moduli using H0=70.5km/s/Mpc.
Note (2): corrected for Milky Way extinction using the reddening maps of
Schlegel et al. (1998ApJ...500..525S 1998ApJ...500..525S), as performed by Hicken et al.
(2009, Cat. J/ApJ/700/331) and Ganeshalingam et al. (2010, Cat.
J/ApJS/190/418).
Note (3): When color information is available, Δm15(B) has been
corrected for host-galaxy extinction using the method similar to that
of Phillips et al. (1999AJ....118.1766P 1999AJ....118.1766P);
Δm15(B)=Δm15,obs(B)+0.1x((Bmax-Vmax)+0.081)
(see Section 5.2). The values for Bmax-Vmax include a correction for
Milky Way extinction, so that correction is inherent in this process.
Note (4): For the "F11" sample (final sample with photometric and spectroscopic
measurements), the measured SiIIλ6355 FWHMs assume a Gaussian
profile. This has not been attempted for the CaII H&K feature since it
rarely has a Gaussian profile. We performed the analysis described in
section 4 for the FWHM(SiII) measurements, but found pseudo-equivalent
width pEW(SiII) measurements to yield a more robust result. We
therefore only report the pEW results.
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 6 A6 --- SN SN identification
8- 13 F6.2 d Phase Phase (days relative to maximum)
15- 20 F6.2 Mm/s V(SiII) Velocity of Si II line (103km/s)
22- 25 F4.2 Mm/s e_V(SiII) Uncertainty in VSiII (103km/s)
27- 31 F5.1 0.1nm W(SiII) Si II line pseudo-equivalent width in Å
33- 36 F4.1 0.1nm e_W(SiII) Uncertainty in W(SiII) in Å
38- 43 F6.2 Mm/s V(CaII)b ? Velocity of blue Ca II line (103km/s)
45- 48 F4.2 Mm/s e_V(CaII)b ? Uncertainty in VCaIIb (103km/s)
50- 55 F6.2 Mm/s V(CaII)r ? Velocity of red Ca II line (103km/s)
57- 60 F4.2 Mm/s e_V(CaII)r ? Uncertainty in VCaIIr (103km/s)
62- 66 F5.1 0.1nm W(CaII) ? Ca II line pseudo-equivalent width in Å
68- 71 F4.1 0.1nm e_W(CaII) ? Uncertainty in W(CaII) in Å
73- 74 I2 --- Ref Reference (see refs.dat file)
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Byte-by-byte Description of file: snspec.dat
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Bytes Format Units Label Explanations
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1- 6 A6 --- SN SN identification
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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 I2 --- Ref Reference number
4- 22 A19 --- BibCode Bibcode
24- 42 A19 --- Auth Author's name(s)
44- 68 A25 --- Comm Comments
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 22-Apr-2013