J/A+A/699/A212ivo://CDS.VizieR/J/A+A/699/A212doi:10.26093/cds/vizier/bc-nv/lcbcCDSJiang Z.Yuan H.Bai Z.Yang M.Yang X.Liu Q.He Y.Li G.Dong Y.,Wang M.Zhou M.Zhang H.2026-08-03T06:55:35Z2025-07-08T10:49:57ZCDS support team

CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France

cds-question@unistra.frspectroscopic-binary-starswhite-dwarf-starsradial-velocityvisible-astronomyMergers of double white dwarfs (DWDs) are considered significant potential progenitors of type Ia supernovae (SNe Ia), which serve as "standard candles" in cosmology to measure the expansion rate of the Universe and explore the nature of dark energy. Although there is no direct observational evidence to definitively determine the formation pathways of SNe Ia, studying the physical properties of DWDs provides valuable insights into their evolutionary processes, interaction modes, and merger mechanisms, which are essential for understanding the explosion mechanisms of SNe Ia. This study aims to identify DWD candidates through spectroscopic radial velocity (RV) measurements and analyze their physical properties based on DESI EDR. We crossmatched DESI EDR with Gaia EDR3 WD catalog to select DA spectra. Spectroscopic RV was measured using the cross-correlation function (CCF), with RV variability assessed via a chi-squared method. We derived spectroscopic Teff and log g by fitting hydrogen Balmer lines, applying 3D convection corrections. Orbital periods and semi-amplitudes came from Lomb-Scargle analysis of RV time series. WD cooling models and Monte Carlo simulations were used to calculate masses, cooling ages, radii, and uncertainties. We also analyzed photometric and SED properties to derive temperatures and radii, comparing them with spectroscopic parameters. We identified 33 DA DWD candidates with significant RV variability, including 28 new discoveries. Among them, an extremely low mass (ELM) DWD candidate and a potential triple system were found. We measured key parameters like Teff, logg, mass, and radius for these candidates and estimated their orbital periods from the data. Of these, 17 showed clear periodic RV variability, and we reported their best-fitting periods and RV semi-amplitudes.2025A&A...699A.212Jhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/699/A212CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toI/350 : Gaia EDR3 (Gaia Collaboration, 2020)J/MNRAS/508/3877 : Catalogue of white dwarfs in Gaia EDR3 (Gentile+, 2021)J/ApJ/970/181 : Categorizing WDs with Gaia XP spectra and UMAP (Kao+, 2024)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/699/A212https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/699/A212http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/699/A212https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/699/A212https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/699/A212http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/699/A212GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/699/A212/tableb2 (Parameters for 33 DWD candidates)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/699/A212/tableb2?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/699/A212/tableb2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/699/A212/tableb2?GETtext/xml+votable180.050000true110.5501125241.4302520.0055555555555555566/4726-4727 5050 5613 5634 5643 5943 6742 7585 7588 8769 9420 9830 9923 10150 10183 10199 10404 10497 11163 11326 11402 11424-11425 21863 26251 26282 26959 27257 27259 285401.9867573869263685e-19 3.916500758235022e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/699/A212?format=asciiOpticaldefaultJ/A+A/699/A212/tableb2Parameters for 33 DWD candidatesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintVCShow the Radial Velocity curvesmeta.ref.urlcharWDJnameWDJ name (WDJHHMMSS.ssDDMMSS.ss, equinox and epoch 2000)meta.id;meta.maincharRAJ2000Right ascension (J2000)degpos.eq.ra;meta.mainSimbadNameSimbad column added by the CDSmeta.idcharnullableDEJ2000Declination (J2000)degpos.eq.dec;meta.mainGmagGaia EDR3 G-band mean magnitudemagphot.mag;em.optfloatplxGaia EDR3 Absolute stellar parallax at Ep=2016.0maspos.parallax.trigfloatBP-RPGaia EDR3 BP-RP colourmagphot.color;em.opt.B;em.opt.RdoubleGMAGGaia EDR3 Absolute G magnitudemagphys.magAbsfloatE(B-V)3D extinction obtained from dustmaps (1)magphot.color.excessdoubleNNumber of observationsmeta.numberinteta? RV Variability parameter {eta}src.var.indexfloatnullablen_eta[I] i means a very large etameta.notechardeltaRVMaximum difference in RVkm/sphys.veloc;arith.diffintTeff1dEffective temperature obtained from wd-tools (2)Kphys.temperature.effectiveinte_Teff1dError of effective temperature obtained from wdtools (2)Kstat.errorintlogg1dSurface gravity obtained from wdtoolslog(cm.s**-2)phys.gravityfloate_logg1dError of surface gravity obtained from wdtools (2)log(cm.s**-2)stat.errorfloatTeffEffective temperature after 3D corrections (3)Kphys.temperature.effectiveintloggSurface gravity after 3D corrections (3)log(cm.s**-2)phys.gravityfloate_TeffError of TeffKstat.error;phys.temperature.effectiveinte_loggError of logglog(cm.s**-2)stat.errorfloatMassMass obtained by interpolating Teff and logg into WD evolutionary modelssolMassphys.mass;meta.modelledfloate_Mass? Error of masssolMassstat.error;phys.massfloatnullableAgecool? Cooling age obtained by interpolating Teff and logg into WD evolutionary modelsGyrtime.age;meta.modelledfloatnullablee_Agecool? Error of AgecoolGyrstat.errorfloatnullableRadspRadius obtained by interpolating Teff and logg into WD evolutionary modelssolRadphys.size.radius;meta.modelledfloate_RadspError of RadspsolRadstat.errorfloatTeffsed? Effective temperature obtained from the single-DA SED fittingKphys.temperature.effectiveintnullableRadsed? Radius obtained from the single-DA SED fittingsolRadphys.size.radiusfloatnullableTeffDESIsp1d? Effective temperature from DESI spectroscopic fitting (4)Kphys.temperature.effectiveintnullableloggDESIsp1d? Surface gravity from DESI spectroscopic fitting (4)log(cm.s**-2)phys.gravityfloatnullableTeffDESIsp3d? Effective temperature after 3D corrections from DESI spectroscopic fitting (4)Kphys.temperature.effectiveintnullableloggDESIsp3d? Surface gravity after 3D corrections from DESI spectroscopic fitting (4)log(cm.s**-2)phys.gravityfloatnullableRadDESI? Radius obtained by interpolating TeffDESIsp3d and loggDESIsp3d into WD evolutionary modelssolRadphys.size.radius;meta.modelledfloatnullableJ/A+A/699/A212/tableb1Radial velocities of single-exposure spectraMedS/NMedian S/N for a unique DESI spectrumstat.snrfloatRVRV obtained from CCF of template-matchingkm/sphys.veloc;pos.heliocentricfloate_RVError of RV obtained from Equation 2 of the paperkm/sstat.errorfloatrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintWDJnameWDJ name (WDJHHMMSS.ss+DDMMSS.ss)meta.id;meta.maincharMJDMJD identifier for a unique DESI spectrumdmeta.id;time.epochdoubleJ/A+A/699/A212/tableb3Orbital parameters for 33 DWD candidatesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintWDJnameWDJ name (WDJHHMMSS.ss+DDMMSS.ss)meta.id;meta.maincharPerPeriod obtained from the Lomb-Scargle methoddtime.perioddoubleRankPower spectrum rank of the periodmeta.code.qualintKSemi-amplitude corresponding to the periodkm/ssrc.var.amplitudedoubleR2R^2^ of the fitting curvestat.fit.paramfloat