ACDS V10.0 - Detailed Description of J/MNRAS/482/4570

ACDS V10.0 - Wed Dec 18 03:33:15 CET 2024

| # Detailed Description of J/MNRAS/482/4570 : Gaia DR2 white dwarf candidates (Gentile Fusillo+, 2019) |

Note : this is the description file of the original catalog. This HTML page corresponds well to the original description, but some minor changes in the format may have been introduced in the FITS output files in order to allow for arithmetic operations on quantities such as coordinates and times. h:m:s and d:m:s units are normally converted into degrees, and YYYY-MM-DD into julian days.
Similarly, some slight changes may have been introduced in the units; the value given in the HTML files supersedes the value indicated in the ReadMe file for this catalogue.

    J/MNRAS/482/4570   Gaia DR2 white dwarf candidates      (Gentile Fusillo+, 2019)
    ================================================================================
    A Gaia Data Release 2 catalogue of white dwarfs and a comparison with SDSS.
        Gentile Fusillo N.P., Tremblay P-E,  Gaensicke B.T., Manser C.J.,
        Cunningham T., Cukanovaite E., Hollands M., Marsh T., Raddi R.,
        Jordan S., Toonen S., Geier S., Barstow M., Cummings J.D.
        <Mon. Not. R. Astron. Soc. 482, 4570-4591 (2019)>
        =2019MNRAS.482.4570G        (SIMBAD/NED BibCode)
    ================================================================================
    ADC_Keywords: Surveys ; Stars, white dwarf ; Parallaxes, trigonometric;
                  Photometry
    Keywords: catalogues - surveys - white dwarfs

    Abstract:
        We present a catalogue of white dwarf candidates selected from the
        second data release of Gaia (DR2). We used a sample of
        spectroscopically confirmed white dwarfs from the Sloan Digital Sky
        Survey (SDSS) to map the entire space spanned by these objects in the
        Gaia Hertzsprung-Russell diagram.

        We then defined a set of cuts in absolute magnitude, colour, and a
        number of Gaia quality flags to remove the majority of contaminating
        objects. Finally, we adopt a method analogous to the one presented in
        our earlier SDSS photometric catalogues to calculate a probability of
        being a white dwarf (PWD) for all Gaia sources which passed the
        initial selection. The final catalogue is composed of 486641 stars
        with calculated PWD from which it is possible to select a sample
        of~260000 high-confidence white dwarf candidates in the magnitude
        range 8<G<21. By comparing this catalogue with a sample of SDSS white
        dwarf candidates we estimate an upper limit in completeness of 85 per
        cent for white dwarfs with G<=20mag and Teff>7000K, at high
        Galactic latitudes (|b|>20deg). However, the completeness drops at
        low Galactic latitudes, and the magnitude limit of the catalogue
        varies significantly across the sky as a function of Gaia's scanning
        law. We also provide the list of objects within our sample with
        available SDSS spectroscopy.

    Description:
        The main catalogue provides 486,641 stars selected from Gaia DR2 with
        calculated probabilities of being a white dwarf (PWD). The PWD values
        can used to reliably select high-confidence white dwarf candidates
        with a flexible compromise between completeness and level of potential
        contamination. As a generic guideline selecting objects with PWD>0.75
        recovers 96 per cent of the spectroscopically confirmed white dwarfs
        from SDSS and only 1 per cent of the contaminant (non white dwarfs)
        objects.

        All Gaia sources in the catalogue have also been cross matched with
        SDSS DR14 taking into account the difference in epoch of observation
        and proper motions. Whether available we include SDSS ugriz
        photometry. In a separate table we provide informations on all the
        available SDSS spectra for the Gaia sources in the main catalogue.

    File Summary:

           FileName      Lrecl  Records   Explanations

    ×                   80        .   This file
    × ReadMe            80        .   This file
    × gaia2wd.dat     1008   486641   DR2 white dwarf candidates, corrected version
                                     (gaiadr2whitedwarfcandidates.dat)
    × gaiasdss.dat     344    37259   Available SDSS spectra of candidates, corrected
                                     version (gaia-sdsswhitedwarf_catalogue.dat)

    See also:
                B/wd  : Spectroscopically identified white dwarfs (McCook+, 2014)
                I/345 : Gaia DR2 (Gaia Collaboration, 2018)
                V/147 : The SDSS Photometric Catalogue, Release 12 (Alam+, 2015)
     J/MNRAS/465/2849 : Gaia DR1 mass-radius relation of WD (Tremblay+ 2017)

    Byte-by-byte Description of file:  gaia2wd.dat

       Bytes Format Units    Label    Explanations

       1- 23  A23   ---      WD       WD name (WDJHHMMSS.ss+DDMMSS.ss, J2000)
                                         (whitedwarfname)
      25- 52  A28   ---      DR2Name  Unique Gaia source designation (designation)
      54- 72  I19   ---      Source   Unique Gaia source identifier (source_id)
      74- 96 F23.19 deg      RAdeg    Gaia DR2 barycentric right ascension (ICRS)
                                          at epoch J2015.5 (ra)
      98-117 F20.18 mas      e_RAdeg  Standard error of right ascension (ra_error)
     119-140 E22.18 deg      DEdeg    Gaia DR2 barycentric declination (ICRS)
                                         at epoch J2015.5 (dec)
     142-161 F20.18 mas      e_DEdeg  Standard error of declination (dec_error)
     163-183 F21.17 mas      Plx      Absolute stellar parallax of the source
                                          at J2015.5 (parallax)
     185-204 F20.18 mas      e_Plx    Standard error of parallax (parallax_error)
     206-227 E22.19 mas/yr   pmRA     Proper motion in right ascension
                                          (pmRAxcosDE) (pmra)
     229-248 F20.18 mas/yr   e_pmRA   Standard error of proper motion in
                                          right ascension (pmra_error)
     250-271 E22.19 mas/yr   pmDE     Proper motion in declination (pmdec)
     273-292 F20.18 mas/yr   e_pmDE   Standard error of proper motion
                                          in declination (pmdec_error)
     294-315 F22.19 mas      epsi     Measure of the residuals in the astrometric
                                          solution for the source
                                          (astrometricexcessnoise)
     317-327  F11.9 mas      amax     Five-dimensional equivalent to the
                                          semi-major axis of the Gaia position error
                                          ellipse (astrometricsigma5dmax)
     329-350 F22.14 e-/s     FG       Gaia G-band mean flux (photgmean_flux)
     352-374 F23.17 e-/s     e_FG     Error on G-band mean flux
                                          (photgmeanfluxerror)
     376-385  F10.7 mag      Gmag     Gaia G-band mean magnitude (Vega scale)
                                          (photgmean_mag)
     387-409 F23.15 e-/s     FBP      Integrated GBP mean flux (photbpmean_flux)
     411-435 F25.18 e-/s     e_FBP    Error on GBP-band mean flux
                                          (photbpmeanfluxerror)
     437-446  F10.7 mag      BPmag    Gaia GBP-band mean magnitude (Vega scale)
                                          (photbpmean_mag)
     448-470 F23.15 e-/s     FRP      Integrated GRP mean flux (photrpmean_flux)
     472-497 F26.19 e-/s     e_FRP    Error on GRP-band mean flux
                                          (photrpmeanfluxerror)
     499-508  F10.7 mag      RPmag    Gaia GRP-band mean magnitude (Vega scale)
                                         (photrpmean_mag)
     510-520  F11.9 ---     E(BR/RP)  GBP/GRP excess factor estimated from the
                                         comparison of the sum of integrated GBP and
                                         GRP fluxes with respect to the flux in the
                                         G-band (photbprpexcessfactor)
     522-542 E21.19 deg      GLON     Galactic longitude (l)
     544-565 E22.19 deg      GLAT     Galactic latitude (b)
     567-578  F12.4 ---      Density  The number of Gaia sources per square degree
                                         around this object (density)
     580-602 F23.19 mag      AG       Extinction  in the Gaia G-band band derived
                                         from E(B-V) values from Schlafly and
                                         Finkbeiner (2011ApJ...737..103S) (AG)
     604-622  A19   ---      SDSS     SDSS object name if available
                                         (JHHMMSS,.ss+DDMMSS.s, J2000) (SDSS_name)
     624-641 F18.15 mag      umag     ? SDSS u band magnitude (umag)
     643-664 F22.18 mag      e_umag   ? SDSS u band magnitude uncertainty (e_umag)
     666-683 F18.15 mag      gmag     ? SDSS g band magnitude (gmag)
     685-706 F22.19 mag      e_gmag   ? SDSS g band magnitude uncertainty (e_gmag)
     708-725 F18.15 mag      rmag     ? SDSS r band magnitude (rmag)
     727-747 F21.18 mag      e_rmag   ? SDSS r band magnitude uncertainty (e_rmag)
     749-766 F18.15 mag      imag     ? SDSS i band magnitude (imag)
     768-789 F22.19 mag      e_imag   ? SDSS i band magnitude uncertainty (e_imag)
     791-808 F18.15 mag      zmag     ? SDSS z band magnitude (zmag)
     810-830 F21.18 mag      e_zmag   ? SDSS z band magnitude uncertainty (e_zmag)
     832-852 E21.19 ---      Pwd      [0/1]? The probability of being a white
                                           dwarf (Pwd)
         854  I1    ---      f_Pwd    [0/1] If 1 it indicates the PWD value
                                            could be unreliable (Pwd_flag)
     856-868  F13.6 K        TeffH    ? Effective temperature from fitting the
                                          dereddened G,GBP, and GRP absolute fluxes
                                          with pure-H model atmospheres (Teff_H)
     870-882  F13.6 K        e_TeffH  ? Uncertainty on Teff_H (eTeff_H)
     884-891  F8.6  ---      loggH    ? Surface gravity from fitting the
                                          dereddened G,GBP,and GRP absolute fluxes
                                          with pure-H model atmospheres (loggH)
     893-900  E8.6  ---      e_loggH  ? Uncertainty on loggH (eloggH)
     902-909  F8.6  Msun     MassH    ? Stellar mass resulting from the adopted
                                          mass-radius relation (mass_H)
     911-919  E9.6  Msun     e_MassH  ? Uncertainty on the mass (emass_H)
     921-931  E11.6 ---      chi2H    ? chi2 value of the fit (pure-H) (chi2_H)
     933-944  F12.6 K        TeffHe   ? Effective temperature from fitting the
                                          dereddened G,GBP, and GRP absolute fluxes
                                          with pure-He model atmospheres (Teff_He)
     946-959  F14.6 K       e_TeffHe  ? Uncertainty on Teff_He (eTeff_He)
     961-968  F8.6  ---      loggHe   ? Surface gravity from fitting the
                                          dereddened G,GBP,and GRP absolute fluxes
                                          with pure-He model atmospheres (loggHe)
     970-977  E8.6  ---     e_loggHe  ? Uncertainty on loggHe (eloggHe)
     979-986  F8.6  Msun     MassHe   ? Stellar mass resulting from the adopted
                                          mass-radius relation (mass_He)
     988-996  E9.6  Msun    e_MassHe  ? Uncertainty on the mass (emass_He)
     998-1008  E11.6 ---      chisqHe  ? chi2 value of the fit (pure-H) (chisq_He)

    Byte-by-byte Description of file:  gaiasdss.dat

       Bytes Format Units   Label     Explanations

       1- 22  A22   ---     WD        WD name (WDJHHMMSS.ss+DDMMSS.ss, J2000)
                                       (whitedwarfname)
          23  A1    ---     n_WD      [a] Multiplicity index on WD
      24- 42  I19   ---     Source    Unique Gaia source identifier (source_id)
      44- 62  A19   ---     SDSS      SDSS object name (JHHMMSS,.ss+DDMMSS.s, J2000)
                                       (SDSS_name)
      64- 83 F20.16 deg     RAdeg     Right ascension (J2000) of the spectrum source
                                       from SDSS DR14 (SDSS_ra)
      85- 98 E14.10 deg     DEdeg     Declination (J2000) of the spectrum source
                                       from SDSS DR14 (SDSS_dec)
     100-117 F18.15 mag     umag      ? SDSS u band magnitude (umag)
     119-139 F21.18 mag     e_umag    ? SDSS u band magnitude uncertainty (e_umag)
     141-158 F18.15 mag     gmag      ? SDSS g band magnitude (gmag)
     160-179 F20.18 mag     e_gmag    ? SDSS g band magnitude uncertainty (e_gmag)
     181-198 F18.15 mag     rmag      ? SDSS r band magnitude (rmag)
     200-219 F20.18 mag     e_rmag    ? SDSS r band magnitude uncertainty (e_rmag)
     221-238 F18.15 mag     imag      ? SDSS i band magnitude (imag)
     240-260 F21.18 mag     e_imag    ? SDSS i band magnitude uncertainty (e_imag)
     262-279 F18.15 mag     zmag      ? SDSS z band magnitude (zmag)
     281-301 F21.18 mag     e_zmag    ? SDSS z band magnitude uncertainty (e_zmag)
     303-306  I4    ---     Plate     Identifier of the plate used in the
                                       observation of the spectrum (Plate)
     308-312  I5    ---     MJD       Modified Julian date of the observation of
                                       the spectrum (mjd)
     314-317  I4    ---     Fiber     Identifier of the fiber used in the
                                       observation of the spectrum (fiberID)
     319-333 F15.11 ---     S/N       Signal-to-noise ratio of the spectrum
                                       calculated in the range 4500-5500 A (S/N)
     335-344  A10   ---     SpClass   Classification of the object based on a visual
                                       inspection of the SDSS spectrum
                                       (spectral_class) (1)

    Note (1): spectral classes are as follows:
                       CV = Cataclysmic Variable star
                       DA = white dwarfs with H lines only
                  DAB/DAB = white dwarfs with H lines and neutral He lines
      DABZ/DBAZ/DZAB/DZBA = white dwarfs with H lines, neutral He lines and
                             Ca H & K lines
                   DAO/DO = white dwarfs with H lines and He II lines
                  DAZ/DZA = white dwarfs with H lines and Ca H & K lines
                       DB = white dwarfs with neutral He lines only
                  DBZ/DZB = white dwarfs with neutral He lines and Ca H & K lines
                       DC = white dwarfs with feature-less spectra
                       DQ = white dwarfs with molecular C absorptions
                    hotDQ = white dwarfs with atomic C absorption
                    DQpec = Peculiar white dwarfs with molecular C absorptions
                       DZ = white dwarfs with Ca H & K lines
                      DAH = white dwarfs with Zeeman split  H lines
                      DBH = white dwarfs with Zeeman split  He lines
                      DZH = white dwarfs with Zeeman split Ca H & K lines
                      MWD = Magnetic white dwarfs with unidentified absorption lines
                    WDPec = Peculiar magnetic white dwarf
                   PG1159 = Pre-white dwarf star
         DB+MS/DA+MS/DC+M = White Dwarf - Main Sequence binary
                     STAR = non white dwarf stellar object
                      QSO = Quasar
                      UNK = Spectra which we were unable to classify
               Unreliable = Unreliable spectra

    Acknowledgements:
        Nicola Gentile Fusillo, n.gentile-fusillo(at)warwick.ac.uk

    History:
        * 01-Feb-2019: on-line version
        * 01-Apr-2019: corrected version (from author)
    ================================================================================
    (End)                                      Patricia Vannier [CDS]    31-Jan-2019