J/ApJ/730/128 Spectroscopy of DA WD from the SDSS-DR4 (Tremblay+, 2011)
An improved spectroscopic analysis of DA white dwarfs from the Sloan Digital
Sky Survey Data Release 4.
Tremblay P.-E., Bergeron P., Gianninas A.
<Astrophys. J., 730, 128 (2011)>
=2011ApJ...730..128T 2011ApJ...730..128T
ADC_Keywords: Effective temperatures ; Stars, white dwarf ; Abundances ;
Stars, masses
Keywords: stars: atmospheres - stars: fundamental parameters -
stars: luminosity function, mass function - white dwarfs
Abstract:
We present an improved spectroscopic and photometric analysis of
hydrogen-line DA white dwarfs from the Sloan Digital Sky Survey Data
Release 4 (SDSS DR4) based on model atmospheres that include improved
Stark broadening profiles with non-ideal gas effects. We also perform
a careful visual inspection of all spectroscopic fits with high
signal-to-noise ratios (S/Ns>12) and present improved atmospheric
parameters (Teff and logg) for each white dwarf. Through a
comparison of spectroscopic and photometric temperatures, we report
the discovery of 35 DA+DB/DC double degenerate candidates and two
helium-rich DA stars. We also determine that a cutoff at S/N=15
optimizes the size and quality of the sample for computing the mean
mass of DA white dwarfs, for which we report a value of 0.613M☉.
We compare our results to previous analyses of the SDSS DR4 and find a
good agreement if we account for the shift produced by the improved
Stark profiles. Finally, the properties of DA white dwarfs in the SDSS
are weighed against those of the Villanova White Dwarf Catalog sample
of Gianninas et al. (2009JPhCS.172a2021G 2009JPhCS.172a2021G).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 84 3072 SDSS DR4 sample of DA white dwarfs with S/N>12
table3.dat 82 35 DA+DB/DC binary candidates
table5.dat 88 16 SDSS DR4 sample of DAO white dwarfs with S/N>12
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See also:
J/MNRAS/417/1210 : DA-white dwarfs from SDSS and UKIDSS (Girven+, 2011)
J/ApJS/190/77 : Detailed analysis of cool WDs in the SDSS (Kilic+, 2010)
J/ApJ/714/1037 : White dwarfs from the Kiso survey (Limoges+, 2010)
J/AJ/135/1239 : Spectral distances to DA white dwarfs (Holberg+, 2008)
J/A+A/466/627 : Parameters of DA white dwarfs in SDSS-DR1 (Hu+, 2007)
J/AJ/134/741 : Close binary systems from the SDSS DR5 (Silvestri+, 2007)
J/MNRAS/382/515 : SDSS ultracool and halo WD candidates (Vidrih+, 2007)
J/AJ/132/1221 : VJHK and SDSS photometry of DA WDs (Holberg+, 2006)
J/AJ/131/582 : Cool white dwarfs in the SDSS (Kilic+, 2006)
J/AJ/131/1674 : Close binary systems from SDSS DR4 (Silvestri+, 2006)
J/AJ/132/676 : SDSS hot DB white dwarfs (Eisenstein+, 2006)
J/ApJS/167/40 : SDSS4 confirmed white dwarfs catalog (Eisenstein+, 2006)
J/ApJ/607/426 : Catalog of white dwarfs in SDSS-DR1 (Kleinman+, 2004)
J/AJ/126/1023 : White Dwarfs in the SDSS (Harris+, 2003)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 19 A19 --- SDSS SDSS name (JHHMMSS.ss+DDMMSS.s) (1)
21- 24 I4 --- Plate SDSS plate
25 A1 --- --- [-]
26- 30 I5 d MJD SDSS MJD
31 A1 --- --- [-]
32- 34 I3 --- Fib SDSS fiber
36- 41 I6 K Teff Effective temperature
43- 47 I5 K e_Teff ? Uncertainty in Teff
49- 52 F4.2 [cm/s2] log(g) Log of the surface gravity
54- 57 F4.2 [cm/s2] e_log(g) ? Uncertainty in log(g)
59- 62 F4.2 Msun Mass ? Mass
64- 67 F4.2 Msun e_Mass ? Uncertainty in Mass
69- 73 F5.2 mag VMag ? Absolute V band magnitude
75- 78 F4.2 [yr] logtau ? Log of white dwarf cooling time
80- 84 A5 --- Notes Additional note(s) (2)
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Note (1): For J031858.28+002325.6 we fixed the parameters at Teff=140000K and
log(g)=8 because the object fitted Teff exceeds our models grid.
Note (2): Notes as follows:
1 = Incomplete wavelength coverage or glitches in the Balmer lines;
2 = poor match between the slope of the observed spectra and the ugriz
photometry;
3 = main-sequence companion, one or two lines removed from the fit, and
the line cores also removed due to emission;
4 = same as previous but with no emission;
5 = flagged in our visual inspection with a poor fit but no clear
explanation was found; the atmospheric parameters under the assumption
of a normal single DA should be regarded with caution;
6 = DA with the Balmer-line problem and models with CNO were used;
7 = emission in the line cores but no red excess;
8 = DAZ (both Balmer and metallic lines)
9 = binary DAO+dM.
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 19 A19 --- SDSS SDSS name (JHHMMSS.ss+DDMMSS.s)
21- 24 I4 --- Plate SDSS plate
25 A1 --- --- [-]
26- 30 I5 d MJD SDSS MJD
31 A1 --- --- [-]
32- 34 I3 --- Fib SDSS fiber
36- 40 I5 K Teff Effective temperature; H-comp
42- 45 I4 K e_Teff Teff uncertainty
47- 50 F4.2 [cm/s2] logg Log of the surface gravity; H-comp
52- 55 F4.2 [cm/s2] e_logg ? logg uncertainty
57- 61 I5 K TeffHe Effective temperature; He-comp
63- 66 I4 K e_TeffHe TeffHe uncertainty
68- 71 F4.2 [cm/s2] loggHe Log of the surface gravity; He-comp
73- 76 F4.2 [cm/s2] e_loggHe ? loggHe uncertainty
78- 82 A5 --- Notes Additional note(s) (1)
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Note (1): Notes as follows:
1 = Helium-rich DA, an equally valid possibility;
2 = very faint H lines, difficult to fit in any cases;
3 = could also be a DAB;
4 = also in Limoges & Bergeron (2010, Cat. J/ApJ/714/1037);
5 = average photometric match;
6 = weakly magnetic also a possibility, good photometric fit to a single
star;
7 = cores of the Hα and Hβ lines poorly fitted.
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
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1- 19 A19 --- SDSS SDSS name (JHHMMSS.ss+DDMMSS.s)
20 A1 --- f_SDSS [a] a: Observational glitch
22- 25 I4 --- Plate SDSS plate
26 A1 --- --- [-]
27- 31 I5 d MJD SDSS MJD
32 A1 --- --- [-]
33- 35 I3 --- Fib SDSS fiber
37- 41 I5 K Teff Effective temperature
43- 47 I5 K e_Teff Teff uncertainty
49- 52 F4.2 [cm/s2] logg Log of the surface gravity
54- 57 F4.2 [cm/s2] e_logg logg uncertainty
59- 63 F5.2 [-] logHe/H Log of Helium abundance
65- 68 F4.2 [-] e_logHe/H logHe/H uncertainty
70- 73 F4.2 Msun Mass Mass
75- 78 F4.2 Msun e_Mass Mass uncertainty
80- 83 F4.2 mag VMag Absolute V-band magnitude
85- 88 F4.2 [-] logtau Log of white dwarf cooling time
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 11-Oct-2012