J/ApJ/708/661 SDSS-II SN Survey: SNe II-P standardization (D'Andrea+, 2010)
Type II-P supernovae from the SDSS-II Supernova Survey and the Standardized
Candle Method.
D'Andrea C.B., Sako M., Dilday B., Frieman J.A., Holtzman J., Kessler R.,
Konishi K., Schneider D.P., Sollerman J., Wheeler J.C., Yasuda N.,
Cinabro D., Jha S., Nichol R.C., Lampeitl H., Smith M., Atlee D.W.,
Bassett B., Castander F.J., Goobar A., Miquel R., Nordin J., Ostman L.,
Prieto J.L., Quimby R., Riess A.G., Stritzinger M.
<Astrophys. J., 708, 661-674 (2010)>
=2010ApJ...708..661D 2010ApJ...708..661D
ADC_Keywords: Supernovae ; Photometry, SDSS ; Spectroscopy ; Surveys
Keywords: cosmology: observations - distance scale - supernovae: general -
surveys
Abstract:
We apply the Standardized Candle Method (SCM) for Type II Plateau
supernovae (SNe II-P), which relates the velocity of the ejecta of a
SN to its luminosity during the plateau, to 15 SNe II-P discovered
over the three season run of the Sloan Digital Sky Survey-II Supernova
Survey. The redshifts of these SNe - 0.027<z<0.144 - cover a range
hitherto sparsely sampled in the literature; in particular, our SNe
II-P sample contains nearly as many SNe in the Hubble flow (z>0.01) as
all of the current literature on the SCM combined. We find that the
SDSS SNe have a very small intrinsic I-band dispersion (0.22mag),
which can be attributed to selection effects. When the SCM is applied
to the combined SDSS-plus-literature set of SNe II-P, the dispersion
increases to 0.29mag, larger than the scatter for either set of SNe
separately. We show that the standardization cannot be further
improved by eliminating SNe with positive plateau decline rates, as
proposed in Poznanski et al. (2009ApJ...694.1067P 2009ApJ...694.1067P). We thoroughly
examine all potential systematic effects and conclude that for the SCM
to be useful for cosmology, the methods currently used to determine
the FeII velocity at day 50 must be improved, and spectral templates
able to encompass the intrinsic variations of Type II-P SNe will be
needed.
Description:
The SDSS-SNS (Sloan Digital Sky Survey-II Supernova Survey
(SDSS-II SN; Frieman et al. 2008AJ....135..338F 2008AJ....135..338F) repeatedly surveyed
the 300deg2 Southern Equatorial Stripe (designated stripe 82; see
Stoughton et al. 2002AJ....123..485S 2002AJ....123..485S) during the Fall seasons
(September 1-November 30) of 2005-2007 using a dedicated 2.5m
telescope at Apache Point Observatory, New Mexico.
The SDSS-SNS spectroscopically confirmed a total of 34 SNe II-P. Our
Standardized Candle Method (SCM) sample is composed of the SDSS-SNS
SNe II-P that pass three cuts (see section 2.1). In the end, we find
15 of the 34 spectroscopically confirmed SNe II-P have sufficient data
for the SCM analysis, and thus form our SCM sample.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 107 21 Rest-frame day 50 magnitudes of SNe II-P from
the SDSS-II SN Survey (and FeII velocities for
the 15 SCM sample from table 3)
sn.dat 44 34 List of SNe with photometry and spectroscopy
phot/* . 34 *Individual SNe photometry files
spec/* . 73 *Individual fits spectra for the 34 confirmed
Type II-P SNe from the SDSS-II
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Notes on phot/*: These files contain results of the scene modelling
photometry for each of the spectroscopically confirmed Type II-P supernovae
from the full three season run of the SDSS supernova survey. Each file
contains a header section that gives information about the particular
supernova: its designation, coordinates, redshift, the derived galaxy
brightness underneath the supernova as derived from the scene modelling
photometry, and the foreground extinction. The header also contains a few
notes on the units used.
Notes on spec/*: This folder contains all spectra taken of the 34
spectroscopically confirmed Type II-P SNe from the SDSS-II Supernova Survey.
Note that the SN is not necessarily visible in each spectra; for every object
that was eventually identified as a SN II-P, all spectra taken are included.
The name of each file is the SDSS Candidate Identification Number (CID)
followed by the date the spectrum was taken in MMDDYYYY format. Each file is
in the format obtained from the observers. Spectra have not been corrected for
reddening and are presented in the observer frame.
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See also:
B/sn : Asiago Supernova Catalogue (Barbon et al., 1999-)
J/A+A/526/A28 : SDSS-II supernovae NTT and NOT spectroscopy (Oestman+, 2011)
J/ApJS/185/32 : First-year SDSS-II SN results (Kessler+, 2009)
J/AJ/136/2306 : SDSS-II Supernova survey, 2005 (Holtzman+, 2008)
J/AJ/135/348 : SDSS-II SNe survey: search and follow-up (Sako+, 2008)
J/AJ/135/1766 : Sloan Digital Sky Survey-II supernova survey (Zheng+, 2008)
http://sdssdp62.fnal.gov/sdsssn/snlist_confirmed_updated.php : SDSS-II SNe
http://www.sdss.org/ : SDSS 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 IAU name (YYYYaa) (except flagged) (1)
7 A1 --- f_SN [a] a: SDSS-II SN number
9- 14 F6.4 --- z Redshift (2)
16- 21 F6.4 --- e_z Redshift uncertainty
23- 27 F5.2 mag Bmag Bessell B-band magnitude (Vega) (3)
29- 32 F4.2 mag e_Bmag Bmag uncertainty
34- 38 F5.2 mag Vmag Bessell V-band magnitude (Vega) (3)
40- 43 F4.2 mag e_Vmag Vmag uncertainty
45- 49 F5.2 mag Rmag Bessell R-band magnitude (Vega) (3)
51- 54 F4.2 mag e_Rmag Rmag uncertainty
56- 60 F5.2 mag Imag Bessell I-band magnitude (Vega) (3)
62- 65 F4.2 mag e_Imag Imag uncertainty
67- 71 F5.2 mag gmag SDSS g-band AB magnitude (3)
73- 76 F4.2 mag e_gmag gmag uncertainty
78- 82 F5.2 mag rmag SDSS r-band AB magnitude (3)
84- 87 F4.2 mag e_rmag rmag uncertainty
89- 93 F5.2 mag imag SDSS i-band AB magnitude (3)
95- 98 F4.2 mag e_imag imag uncertainty
100-103 I4 km/s FeIIvel ? FeII velocity (νFeII) from table 3 (2)
105-107 I3 km/s e_FeIIvel ? FeIIvel uncertainty from table 3 (2)
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Note (1): The 21 SNe listed here include the 15 SCM (Standardized Candle Method)
sample SNe, as well as those that only fail our spectroscopy cut
(described in Section 2.1).
Note (2): An additional uncertainty of σpec=300km/s is added in
quadrature to both the redshift z and the velocity derived from the
FeII5169 absorption feature before applying the SCM to this sample.
Note (3): Magnitudes listed here are derived for 50 days after the explosion,
and have been both K-corrected and corrected for MW extinction along
the line of sight. Bessell BVRI magnitudes are calculated in the Vega
system and have been S-corrected from the observed filters; SDSS gri
magnitudes are standard log10 magnitudes (not asinh, as in Holtzman et
al. 2008, Cat. J/AJ/136/2306), and are in the AB system. We model the
plateau as an exponential in flux space, and fold into our photometric
corrections the uncertainties in observed flux, explosion epoch and
redshift.
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Byte-by-byte Description of file: sn.dat
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Bytes Format Units Label Explanations
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1- 2 I2 h RAh Simbad hour of right ascension (J2000)
4- 5 I2 min RAm Simbad minute of right ascension (J2000)
7- 10 F4.1 s RAs Simbad second of right ascension (J2000)
12 A1 --- DE- Simbad sign of declination (J2000)
13- 14 I2 deg DEd Simbad degree of declination (J2000)
16- 17 I2 arcmin DEm Simbad arcminute of declination (J2000)
19- 20 I2 arcsec DEs Simbad arcsecond of declination (J2000)
22- 31 A10 --- --- [SDSS-II SN]
33- 37 I5 --- SDSS-II SDSS-II number (<SDSS-II SN NNNNN> in Simbad)
39- 44 A6 --- SN IAU SN designation (YYYYaa) if any
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Byte-by-byte Description of file(#): phot/*
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Bytes Format Units Label Explanations
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1- 4 I4 --- Flag [0/1469] Photometry flags for each measurement (1)
6- 17 F12.6 d MJD Modified Julian Date of the measurement
20 I1 --- Filt [0/4] Filter in which the measurement was
obtained: [01234] corresponds to [ugriz]
23- 28 F6.3 mag mag The asinh magnitude of the supernova for this
epoch and filter in the native SDSS photometric
system
31- 36 F6.3 mag e_mag Error on the magnitude
39- 44 F6.3 mag e_sky Estimate of possible systematic error from
uncertainty in sky determination
47- 52 F6.3 mag e_gal Estimate of possible systematic error from
uncertainty in galaxy background determination
54- 63 E10.4 uJy Flux Derived flux using the SDSS/AB correction from
the paper
66- 74 E9.4 uJy e_Flux Error in the flux
77- 85 E9.4 uJy e_sky2 Estimate of possible systematic error from
uncertainty in sky determination in flux units
88- 96 E9.4 uJy e_gal2 Estimate of possible systematic error from
uncertainty in galaxy background determination
in flux units
100-101 I2 --- Npre [1/27] The number of available SDSS frames before
2005, which constrain the total brightness of
the underlying galaxy
103-106 A4 --- Tel [sdss] The telescope used for the measurement,
always sdss here
110-113 I4 --- run [5566/7202] The SDSS run number in which the
observation was obtained
115-117 A3 --- strip [82N/82S] SDSS strip 82N or 82S
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Note (1): Flag as follows:
0 = there are no lines on the measurement.
>1024 = the measurement is likely bad.
0<FLAG<1024 = the measurement is likely OK, but there was some line on the
frames so it was not used to constrain the galaxy background.
See paper for more details.
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 10-Feb-2012