J/AJ/128/1825 Photometry identification of cool white dwarfs (Kilic+, 2004)
Photometric identification of cool white dwarfs.
Kilic M., Winget D.E., von Hippel T., Claver C.F.
<Astron. J., 128, 1825-1833 (2004)>
=2004AJ....128.1825K 2004AJ....128.1825K
ADC_Keywords: Photometry, ugriz ; Stars, white dwarf
Keywords: stars: evolution - white dwarfs
Abstract:
We investigate the use of a narrowband DDO51 filter for photometric
identification of cool white dwarfs. We report photometric
observations of 30 known cool white dwarfs with temperatures ranging
from 10,000K down to very cool temperatures (≤3500K). Follow-up
spectroscopic observations of a sample of objects selected using this
filter and our photometric observations show that DDO51 filter
photometry can help select cool white dwarf candidates for follow-up
multiobject spectroscopy by rejecting 65% of main-sequence stars with
the same broadband colors as the cool white dwarfs. This technique is
not selective enough to efficiently feed single-object spectrographs.
We present the white dwarf cooling sequence using this filter. Our
observations show that very cool white dwarfs form a sequence in the
r-DDO versus r-z color-color diagram and demonstrate that significant
improvements are needed in white dwarf model atmospheres.
Description:
Follow-up spectroscopy of nine white dwarf candidates in the Spaghetti
Survey field was obtained in 2002 April and May using the HET
(Hobby-Eberly Telescope) and in 2003 February using the McDonald 2.7m
Harlan-Smith Telescope.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 125 40 Objects with SDSS Spectroscopy
table2.dat 105 9 Objects with HET+McDonald 2.7Meter Spectroscopy
table3.dat 67 30 DDO51 Photometry for Previously Identified
White Dwarfs
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See also:
III/70 : Luyten's White Dwarf Catalogues (Luyten, 1970-77)
III/235 : Spectroscopically Identified White Dwarfs (McCook+, 2003)
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/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- 4 A4 --- --- [SDSS]
6- 24 A19 --- SDSS SDSS designation (JHHMMSS.ss+DDMMSS.s)
27- 29 I3 --- Plate Plate
31- 37 I7 d Date Julian date of observation
39- 41 I3 --- Fiber Fiber
44- 48 F5.2 mag DDOmag Magnesium absorption line centered filter DDO51
51- 55 F5.2 mag umag u SDSS magnitude
58- 62 F5.2 mag gmag g SDSS magnitude
65- 69 F5.2 mag rmag r SDSS magnitude
72- 76 F5.2 mag imag i SDSS magnitude
79- 83 F5.2 mag zmag z SDSS magnitude
86- 89 F4.2 mag e_DDOmag Error in DDOmag
92- 95 F4.2 mag e_umag Error in umag
98-101 F4.2 mag e_gmag Error in gmag
104-107 F4.2 mag e_rmag Error in rmag
110-113 F4.2 mag e_imag Error in imag
116-119 F4.2 mag e_zmag Error in zmag
122-125 A4 --- Type Object type
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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 I1 --- Seq Sequential number
4- 7 A4 --- --- [SDSS]
9- 27 A19 --- SDSS SDSS designation (JHHMMSS.ss+DDMMSS.s)
30- 34 F5.2 mag DDOmag Magnesium absorption line centered filter DDO51
37- 41 F5.2 mag umag u SDSS magnitude
44- 48 F5.2 mag gmag g SDSS magnitude
51- 55 F5.2 mag rmag r SDSS magnitude
58- 62 F5.2 mag imag i SDSS magnitude
65- 69 F5.2 mag zmag z SDSS magnitude
72- 75 F4.2 mag e_DDOmag Error in DDOmag
78- 81 F4.2 mag e_umag Error in umag
84- 87 F4.2 mag e_gmag Error in gmag
90- 93 F4.2 mag e_rmag Error in rmag
96- 99 F4.2 mag e_imag Error in imag
102-105 F4.2 mag e_zmag Error in zmag
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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- 24 A24 --- Name Object name
27- 31 F5.2 mag Rmag Cousins R magnitude
34- 38 F5.2 mag r-z SDSS r-z colour index
41- 44 F4.2 mag e_r-z Error in r-z
47- 51 F5.2 mag r-DDO r-DDO51 colour index
54- 57 F4.2 mag e_r-DDO Error in r-DDO
60- 64 I5 K Teff ? Effective temperature
65 A1 --- f_Teff [:] Flag on Teff
67 I1 --- Note Individual Note (1)
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Note (1): Note is defined as follows:
1 = R magnitude and Teff from Bergeron et al. (1997ApJS..108..339B 1997ApJS..108..339B)
2 = Spectral type DBQA5 (Wesemeal et al. 1993PASP..105..761W 1993PASP..105..761W)
3 = R magnitude and Teff from Ruiz & Bergeron (2001ApJ...558..761R 2001ApJ...558..761R)
4 = R magnitude and Teff from Bergeron et al. 2001, Cat. J/ApJS/133/413
5 = R59F magnitude and/or Teff from Oppenheimer et al.
(2001Sci...292..698O 2001Sci...292..698O)
6 = SDSS (Cat.J/AJ/126/2579) r magnitude
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History:
From electronic version of the journal
(End) Marianne Brouty [CDS] 13-Apr-2005