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SDSSWDSD - Sloan Digital Sky Survey DR4 White Dwarf & Hot Subdwarf Catalog |
HEASARC Archive |
The SDSS DR4 (Adelman-McCarthy et al. 2006, ApJS, 162, 38; see also http://www.sdss.org/dr4/ ) contains 800,000 spectra from 4783 square degrees. The authors have used automated techniques supplemented by visual classification to select 13,000 candidates. An extensive analysis of these objects has yielded 9316 white dwarfs, including 8000 DA, 713 DB, 41 DO or PG1159, 289 DC, 104 DQ, and 133 DZ types, as well as 928 hot subdwarf stars. As well as the 10,244 primary spectra, the authors have also presented 774 duplicate spectra of WD stars and 60 duplicate spectra of SD stars. Thus, the present table has 11,078 (=10,244 + 774 + 60) entries.
Much more information on the SDSS is available at the project's web site at http://www.sdss.org/.
A Catalog of Spectroscopically Confirmed White Dwarfs from the Sloan Digital Sky Survey Data Release 4 Eisenstein D.J., Liebert J., Harris H.C., Kleinman S.J., Nitta A., Silvestri N., Anderson S.A., Barentine J.C., Brewington H.J., Brinkmann J., Harvanek M., Krzesinski J., Neilsen E.H., Long D., Schneider D.P., Snedden S.A. <Astrophys. J. Suppl., 167, 40-58 (2006)> =2006ApJS..167...40E
Spect_Type
The spectral classification of the white dwarf or subdwarf,
mostly using the usual spectral typing scheme. Automatic classifications
(limited to the typing DA, DB, SD or other) for which a human has not
confirmed the classification are indicated by the addition of "auto" to
the spectral type. See Section 4 and Tables 2, 3 and 4 in the published paper
for more details on the classification procedure and the breakdown of the
catalog by WD and SD spectral types
Wd_Name
The name of the object in the McCook & Sion (1999, ApJS, 121, 1)
White Dwarf Catalog (as of 2005 August).
Ref_Spect_Type
The provenance of the SDSS classification. Notice that this
is merely to track the provenance of the quoted spectral classification; it
does not indicate discovery or literature classifications, which can be
tracked through the McCook & Sion (1999) catalog. 'Kle04' stands for Kleinman
et al. (2004, ApJ, 607, 426), 'Sil05' for Silvestri et al. (2006, AJ, 131,
1674), and 'DR4' for spectral types from this paper itself.
Primary_Flag
This parameter flags whether the entry refers to a primary
spectrum (set to 1), or to a duplicate spectrum (set to 0).
Name
The SDSS IAU-style name for the object, using the 'SDSS J' prefix
and the J2000 coordinates (HHMMSS.ssdDDMMSS.s). This is the name from the
SDSS DR4. Because of tiny astrometry shifts, it is possible that this name
may differ from the name in previous SDSS releases. This breaks the IAU
convention that published names never change. The authors strongly recommend
that associations be performed on the astrometric coordinates rather than on
the name.
RA
The Right Ascension of the object in the selected equinox (given in
J2000 decimal degree coordinates and to a precision of 10-6 degrees in the
original table). The epoch of the coordinates is given by the time of the
SDSS imaging observation as specified in the value of the imaging_date
parameter.
Dec
The Declination of the object in the selected equinox (given in
J2000 decimal degree coordinates and to a precision of 10-6 degrees in the
original table). The epoch of the coordinates is given by the time of the
SDSS imaging observation as specified in the value of the imaging_date
parameter.
LII
The Galactic Longitude of the object.
BII
The Galactic Latitude of the object.
PM_Tot
The total proper motion of the object, in mas/yr. This was
converted from the units of arcseconds per century used in the original
reference.
PM_PA
The proper-motion position angle, in degrees, where 0 means
North, 90 degrees means East, etc.
PM_RA
The proper motion of the object in Right Ascension, in mas/yr. This
was converted from the units of arcseconds per century used in the original
reference.
PM_Dec
The proper motion of the object in Declination, in mas/yr. This was
converted from the units of arcseconds per century used in the original
reference.
Imaging_Date
The date and time of the imaging observation for the
object. This was given in Modified Julian Date (MJD) and to a precision
of 0.01 days (~14 minutes) in the original table.
SDSS_Run_Number
The SDSS run number.
SDSS_Rerun_Number
The SDSS rerun number.
SDSS_Camera_Column
The SDSS camera column.
SDSS_Field_Number
The SDSS field number.
SDSS_Id_Number
The SDSS identification (ID) number within the field. This
is not the objID parameter referred to in the SDSS Catalog Archive Server.
Umag
The point-spread function PSF, as observed, SDSS u-band magnitude.
Gmag
The point-spread function PSF, as observed, SDSS g-band magnitude.
Rmag
The point-spread function PSF, as observed, SDSS r-band magnitude.
Imag
The point-spread function PSF, as observed, SDSS i-band magnitude.
Zmag
The point-spread function PSF, as observed, SDSS z-band magnitude.
Umag_Error
The error in the u magnitude.
Gmag_Error
The error in the g magnitude.
Rmag_Error
The error in the r magnitude.
Imag_Error
The error in the i magnitude.
Zmag_Error
The error in the z magnitude.
Umag_Flag
The photometry flag for the u magnitude, where 1 means bad and
0 means good.
Gmag_Flag
The photometry flag for the g magnitude, where 1 means bad and
0 means good.
Rmag_Flag
The photometry flag for the r magnitude, where 1 means bad and
0 means good.
Imag_Flag
The photometry flag for the i magnitude, where 1 means bad and
0 means good.
Zmag_Flag
The photometry flag for the z magnitude, where 1 means bad and
0 means good.
Gmag_Extinction
The extinction in the g band, A_g, in magnitudes.
The canonical SDSS extinction curve implies relative extinctions in the u, g,
r, i and z bands of 1.36, 1.00, 0.73, 0.55, and 0.39 times A_g.
Plate_Number
The plate number of the spectroscopic observation.
Fiber_Number
The fiber number of the object for the spectroscopic
observation.
Spectrum_Date
The date and time of the spectroscopic observation for the
object. This was given in Modified Julian Date (MJD) and to a precision
of 1 day in the original table.
Spectrum_Gmag_SNR
The signal-to-noise ratio (SNR) of the spectrum in the
g band, per spectroscopic pixel.
Deblend_Flag
This flag indicates whether or not the object was deblended:
1 means that the object was isolated, 0 that it had to be deblended. Most of
the relevant target selection catagories require that the object be
sufficiently isolated on the sky that it was not blended with any other
object. Blended stars have much lower completeness; see Section 5.6 of
the published paper for more details.
Dec_Prim_Target_Flag
The decimal PrimTarget flag. This flag is one of the
flags which records the decisions from the various spectroscopic targeting
algorithms. See Stoughton et al. (2002, AJ, 123, 485) and Adelman-McCarthy
et al. (2006, ApJS, 162, 38) or the SDSS online documentation for more
details. The southern survey bit (0x80000000) has been suppressed
in the secTarget flag for brevity but retained in the primTarget flag
(Adelman-McCarthy et al. 2006).
Hex_Prim_Target_Flag
The hexadecimal PrimTarget flag. This flag is one of
the flags which records the decisions from the various spectroscopic targeting
algorithms. See Stoughton et al. (2002, AJ, 123, 485) and Adelman-McCarthy
et al. (2006, ApJS, 162, 38) or the SDSS online documentation for more
details. The southern survey bit (0x80000000) has been suppressed
in the secTarget flag for brevity but retained in the primTarget flag
(Adelman-McCarthy et al. 2006).
Dec_Sec_Target_Flag
The decimal SecTarget flag. This flag is one of the
flags which records the decisions from the various spectroscopic targeting
algorithms. See Stoughton et al. (2002, AJ, 123, 485) and Adelman-McCarthy
et al. (2006, ApJS, 162, 38) or the SDSS online documentation for more
details. The southern survey bit (0x80000000) has been suppressed
in the secTarget flag for brevity but retained in the primTarget flag
(Adelman-McCarthy et al. 2006).
Hex_Sec_Target_Flag
The hexadecimal SecTarget flag. This flag is one of the
flags which records the decisions from the various spectroscopic targeting
algorithms. See Stoughton et al. (2002, AJ, 123, 485) and Adelman-McCarthy
et al. (2006, ApJS, 162, 38) or the SDSS online documentation for more
details. The southern survey bit (0x80000000) has been suppressed
in the secTarget flag for brevity but retained in the primTarget flag
(Adelman-McCarthy et al. 2006).
Autofit_Quality_Flag
The autofit quality flag, where 1 means good and
0 means do not use the autofit numbers for anything but diagnostic searching.
Autofit is the name of the method used to fit the spectra and the photometry
of the candidate objects relative to a model astmosphere grid by a
chi-squared miniminzation procedure, thereby yielding a temperature and
surface gravity estimate, as well as a classification of helium or hydrogen
atmosphere. This enabled the authors to separate the white dwarfs from lower
gravity objects. Autofit is described in full by Kleinman et al. (2004, ApJ,
607, 426).
Autofit_Element_Flag
The autofit atmosphere element flag, being 1 for
hydrogen, 2 for helium atmospheres.
Autofit_Eff_Temp
The autofit effective temperature estimate, in K.
Autofit_Eff_Temp_Error
The error in the autofit effective temperature, in K.
Autofit_Log_G
The autofit logarithmic surface gravity, log g, in units
of dex(cm/s2)
Autofit_Log_G_Error
The error in log g, in dex(cm/s2).
Autofit_Red_Chisquared
The autofit chi-squared value per degrees of freedom,
i.e., the reduced chi-squared, of the fit to the object.
Broad_Class
The broad classification of the object: 'WD' means white
dwarf, while 'SD' means hot subdwarf. The HEASARC created this parameter
to differentiate entries from the two original tables which were
merged to create this Browse table: white dwarfs from the original Table 1B
have been given a broad_class value of 'WD', while the hot subdwarfs listed
in Table 1C have been assigned a broad_class of 'SD'.
Class
The HEASARC Browse object classification, based on the value of
the spect_type parameter.