J/AJ/131/582 Cool white dwarfs in the SDSS (Kilic+, 2006)
Cool white dwarfs in the Sloan Digital Sky Survey.
Kilic M., Munn J.A., Harris H.C., Liebert J., von Hippel T., Williams K.A.,
Metcalfe T.S., Winget D.E., Levine S.E.
<Astron. J., 131, 582-599 (2006)>
=2006AJ....131..582K 2006AJ....131..582K
ADC_Keywords: Stars, white dwarf ; Photometry, SDSS ; Proper motions
Keywords: atmospheres - stars: evolution - white dwarfs
Abstract:
A reduced proper motion diagram utilising Sloan Digital Sky Survey
(SDSS) photometry and astrometry and USNO-B plate astrometry is used
to separate cool white dwarf candidates from metal-weak,
high-velocity, main-sequence Population II stars (subdwarfs) in the
SDSS Data Release 2 imaging area. Follow-up spectroscopy using the
Hobby-Eberly Telescope, the MMT, and the McDonald 2.7m telescope is
used to demonstrate that the white dwarf and subdwarf loci separate
cleanly in the reduced proper motion diagram and that the
contamination by subdwarfs is small near the cool white dwarf locus.
Description:
Follow-up spectroscopy of the cool white dwarf candidates was obtained
at the Hobby-Eberly Telescope (HET), the MMT, and the McDonald 2.7m
Harlan Smith Telescope between 2003 September and 2004 October (an
additional observing run with the Kitt Peak 4m telescope was
completely lost due to weather). We used the HET equipped with the
Marcario Low Resolution Spectrograph (LRS) to obtain low-resolution
spectroscopy of 22 cool white dwarf candidates. Grism 2 with a
1.5" slit produced spectra with a resolution of 6Å over the
range 4280-7340Å. Spectroscopy for 56 additional stars was obtained at
the MMT with the Blue Channel Spectrograph and the 500lines/mm
grating, which produced spectra with a resolution of 3.6Å over the
range 3640-6800Å. In addition, we obtained spectroscopy for 89 stars
at the McDonald 2.7m telescope with the Large Cassegrain Spectrograph
and TI1 camera using grating 43 (600lines/mm), which produced
spectra with a resolution of 5.2Å over the range 3870-5260Å.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 106 112 Spectroscopically identified white dwarfs
table2.dat 72 55 Spectroscopically identified subdwarf stars
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See also:
http://www.sdss.org : SDSS Home Page
III/70 : Luyten's White Dwarf Catalogues (Luyten, 1970-77)
III/235 : Spectroscopically Identified White Dwarfs (McCook+ 2006)
J/AJ/126/1023 : White Dwarfs in the SDSS (Harris+, 2003)
J/ApJ/607/426 : Catalog of white dwarfs in SDSS-DR1 (Kleinman+, 2004)
J/AJ/128/1825 : Photometry identification of cool white dwarfs (Kilic+, 2004)
J/ApJS/133/413 : BVRIJHK photometry of cool white dwarfs (Bergeron+ 2001)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 18 A18 --- SDSSJ SDSS designation (HHMMSS.ss+DDMMSS)
20- 24 F5.2 mag gmag SDSS g band magnitude
26- 29 F4.2 mag u-g SDSS (u-g) color index
31- 35 F5.2 mag g-r SDSS (g-r) color index
37- 41 F5.2 mag r-i SDSS (r-i) color index
43- 47 F5.2 mag i-z SDSS (i-z) color index
49- 52 F4.2 mag Au Interstellar absorption in the SDSS u band (G1)
54- 57 I4 mas/yr pmRA Proper motion in Right Ascension
59- 62 I4 mas/yr pmDE Proper motion in Declination
64 I1 --- nEp Number of epochs in which object is detected
66- 69 A4 --- SpType WD spectral type
71- 75 I5 K Teff Model atmosphere effective temperature
77- 81 F5.2 mag Mbol Predicted bolometric magnitude
83- 87 F5.2 mag gMAG Absolute SDSS g band magnitude
89- 94 F6.2 pc Dist Photometric distance
96-101 F6.2 km/s Vtan Estimated tangential velocity
103-106 A4 --- Tel Source telescope for spectroscopy (G2)
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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- 18 A18 --- SDSSJ SDSS designation (HHMMSS.ss+DDMMSS.s)
20- 24 F5.2 mag gmag SDSS g magnitude
26- 29 F4.2 mag u-g g-u color index
31- 34 F4.2 mag g-r g-r color index
36- 39 F4.2 mag r-i r-i color index
41- 45 F5.2 mag i-z i-z color index
47- 50 F4.2 mag Au Interstellar absorption in the SDSS u band (G1)
52- 55 I4 mas/yr pmRA Proper motion in Right Ascension
57- 60 I4 mas/yr pmDE Proper motion in Declination
62 I1 --- nEp Number of epochs in which the object is detected
64- 67 F4.1 --- Dist Distance
69- 72 A4 --- Tel Source telescope for spectroscopy (G2)
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Global Notes:
Note (G1): From Schlegel, Finkbeiner & Davis (1998ApJ...500..525S 1998ApJ...500..525S).
Note (G2): The source telescope for spectroscopy is defined as follows:
HET = Hobby-Eberly Telescope
MMT = Multi Mirror Telescope
2.7m = McDonald 2.7m Harlan Smith Telescope
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Marianne Brouty [CDS] 03-Nov-2006