J/ApJ/714/1037 White dwarfs from the Kiso survey (Limoges+, 2010)
A spectroscopic analysis of white dwarfs in the Kiso survey.
Limoges M.-M., Bergeron P.
<Astrophys. J., 714, 1037-1051 (2010)>
=2010ApJ...714.1037L 2010ApJ...714.1037L
ADC_Keywords: Stars, white dwarf ; Ultraviolet ; Spectroscopy ; Stars, masses
Keywords: stars: fundamental parameters -
stars: luminosity function, mass function - white dwarfs
Abstract:
We present a spectroscopic analysis of white dwarfs found in the Kiso
survey. Spectroscopic observations at high signal-to-noise ratio have
been obtained for all DA and DB stars in the Kiso Schmidt ultraviolet
excess survey (KUV stars). These observations led to the
reclassification of several KUV objects, including the discovery of
three unresolved DA+DB double-degenerate binaries. The atmospheric
parameters (Teff and logg) are obtained from detailed model
atmosphere fits to optical spectroscopic data. The mass distribution
of our sample is characterized by a mean value of 0.606M☉ and a
dispersion of 0.135M☉ for DA stars, and 0.758M☉ and a
dispersion of 0.192M☉ for DB stars. Absolute visual magnitudes
obtained from our spectroscopic fits allow us to derive an improved
luminosity function for the DA and DB stars identified in the Kiso
survey. Our luminosity function is found to be significantly different
from earlier estimates based on empirical photometric calibrations of
MV for the same sample. The results for the DA stars now appear
entirely consistent with those obtained for the PG survey using the
same spectroscopic approach. The space density for DA stars with
MV≤12.75 is 2.80x10-4pc-3 in the Kiso survey, which is 9.6%
smaller than the value found in the PG survey.
Description:
The Kiso Schmidt ultraviolet excess survey (KUV) is a photometric
search for UV-excess objects, performed with the 105cm Schmidt
telescope at the Kiso Observatory. A total of 1186 objects were found
in 44 fields in a belt from the northern to the southern galactic pole
at a galactic longitude of 180°.
Our final spectroscopic sample is the combination of the 219 hot white
dwarf candidates from Darling (1994PhDT........26D 1994PhDT........26D), minus 30
misclassified objects, to which we add seven additional white dwarfs,
for a total of 196 spectroscopically confirmed white dwarfs, three of
which are unresolved double degenerates (thus a total of 199 white
dwarfs). In summary, we thus have 175 DA stars (including one DAO and
four magnetics), 23 DB stars, and one DO star.
Optical spectra for the majority of the objects in this sample were
obtained with the Steward Observatory 2.3m telescope with a spectral
coverage of λ3200-5300 at an intermediate resolution of ∼6Å
FWHM. The spectra for the remaining southern objects were obtained
with the Carnegie Observatories' 2.5m du Pont telescope at Las
Campanas (Chile) with a spectral coverage of λ3500-6600 at a
resolution of ∼3Å FWHM.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 96 175 Atmospheric parameters of DA stars from the KUV
sample
table4.dat 94 23 Atmospheric parameters of DB stars from the KUV
sample
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See also:
B/wd : Spectroscopically identified white dwarfs (McCook+, 2014)
III/235 : Spectroscopically Identified White Dwarfs (McCook+, 2008)
II/106 : Kiso Ultraviolet Catalog (KUV) (Noguchi+ 1980-1984)
J/MNRAS/417/1210 : DA-white dwarfs from SDSS and UKIDSS (Girven+, 2011)
J/MNRAS/411/2770 : Hot white dwarfs in GALEX-DR5 (Bianchi+, 2011)
J/AJ/135/1239 : Spectral distances to DA white dwarfs (Holberg+, 2008)
J/AJ/132/676 : SDSS hot DB white dwarfs (Eisenstein+, 2006)
J/AJ/131/582 : Cool white dwarfs in the SDSS (Kilic+, 2006)
J/ApJS/147/145 : IUE low-dispersion spectra of white dwarfs (Holberg+, 2003)
J/ApJS/133/413 : BVRIJHK photometry of cool white dwarfs (Bergeron+, 2001)
J/A+A/363/1040 : DB white dwarfs from the Hamburg/ESO survey (Friedrich+, 2000)
J/ApJS/119/207 : IUE echelle spectra of hot white dwarfs (Holberg+, 1998)
J/ApJS/61/569 : KPD UV-excess objects (Downes+, 1986)
Byte-by-byte Description of file: table[34].dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- KUV KUV identification (HHMMm+DDMM; B1950) (1)
12- 20 A9 --- WD WD identification (HHMM+DDdA; B1950) (2)
22- 26 I5 K Teff Effective temperature
28- 31 I4 K e_Teff Teff uncertainty
33- 36 F4.2 [cm/s2] logg Surface gravity
38- 41 F4.2 [cm/s2] e_logg logg uncertainty
43- 47 F5.2 --- logH/He ? Hydrogen abundance (only for DBA stars)
49- 52 F4.2 Msun Mass Stellar mass
54- 57 F4.2 Msun e_Mass Mass uncertainty
59- 63 F5.2 mag VMag Absolute visual magnitude (MV)
65- 69 F5.2 [Lsun] logL Log of luminosity
71- 75 F5.2 mag Vmag Apparent V-band magnitude from McCook & Sion
(2008, Cat. III/235)
77- 79 I3 pc Dist Distance
81- 87 E7.3 0.5/pc3/mag 1/vmax ? The 1/vmax value (3)
89- 92 F4.2 [yr] logt The WD cooling time (logτ)
94- 96 A3 --- Notes [1-8, ] Individual note(s) (4)
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Note (1): KUV 08473+3838 is KUV 08473+3839 in the Kiso Ultraviolet Catalog (KUV)
(Noguchi et al., 1980-1984, Cat. II/106), idem for KUV 23220+0921
which is 23223+0921 and KUV 23223+0953 which is 23220+0953; table3
corrected at CDS.
Note (2): WD 2306+124 and WD 2306+130 are very likely associated to
KUV 23061+1229 and KUV 23060+1303, respectively
(inverted in the table); note added by CDS.
Note (3): The 1/vmax value corresponds to the maximum volume in which it is
possible to find a particular white dwarf given a limiting apparent V
magnitude of the survey; see Section 4.1 for further explanations.
Note (4): Notes as follows:
1 = DA+dM;
2 = unresolved double degenerate;
3 = magnetic, B=12MG (Jordan 1993wdao.conf..333J), Teff from Schmidt et
al. 2003ApJ...595.1101S 2003ApJ...595.1101S;
4 = not in Darling 1994PhDT........26D 1994PhDT........26D;
5 = DAO star;
6 = magnetic, B=9MG (Angel et al. (1974ApJ...194L..47A 1974ApJ...194L..47A), Teff from Jordan
2001ASPC..226..269J 2001ASPC..226..269J;
7 = magnetic, B=29MG and Teff from Liebert et al. (1985PASP...97..158L 1985PASP...97..158L);
8 = magnetic, B (2.3MG), Teff and logg from Bergeron et al. 2001,
Cat. J/ApJS/133/413.
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History:
From electronic version of the journal
(End) Emmanuelle Perret [CDS] 18-Apr-2012