J/ApJ/940/19ivo://CDS.VizieR/J/ApJ/940/19doi:10.26093/cds/vizier.19400019CDSCalamida A.Matheson T.Olszewski E.W.Saha A.Axelrod T.,Shanahan C.Holberg J.Points S.Narayan G.Malanchev K.,Ridden-Harper R.Gentile-Fusillo N.Raddi R.Bohlin R.Rest A.,Hubeny I.Deustua S.Mackenty J.Sabbi E.Stubbs C.W.2025-02-13T20:11:44Z2024-11-22T16:29:13ZCDS support team

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

cds-question@unistra.frwhite-dwarf-starsvisible-astronomyspectroscopyhst-photometryWe verified for photometric stability a set of DA white dwarfs with Hubble Space Telescope magnitudes from the near-ultraviolet to the near-infrared and ground-based spectroscopy by using time-spaced observations from the Las Cumbres Observatory network of telescopes. The initial list of 38 stars was whittled to 32 final ones, which comprise a high-quality set of spectrophotometric standards. These stars are homogeneously distributed around the sky and are all fainter than r~16.5mag. Their distribution is such that at least two of them would be available to be observed from any observatory on the ground at any time at airmass less than 2. Light curves and different variability indices from the Las Cumbres Observatory data were used to determine the stability of the candidate standards. When available, Pan-STARRS1, Zwicky Transient Facility, and TESS data were also used to confirm the star classification. Our analysis showed that four DA white dwarfs may exhibit evidence of photometric variability, while a fifth is cooler than our established lower temperature limit, and a sixth star might be a binary. In some instances, due to the presence of faint nearby red sources, care should be used when observing a few of the spectrophotometric standards with ground- based telescopes. Light curves and finding charts for all the stars are provided.2022ApJ...940...19Chttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/940/19CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toIII/210 : Spectroscopically Identified White Dwarfs (McCook+, 1999)II/282 : The SDSS Photometric Catalog, Release 6 (Adelman-McCarthy+, 2007)III/235 : Spectroscopically Identified White Dwarfs (McCook+, 2008)I/331 : Absolute Proper motions Outside the Plane (APOP) (Qi+, 2015)J/AJ/127/477 : Hard X-ray emissions of white dwarfs (Chu+, 2004)J/A+A/492/277 : Analysis of Collinder 69 stars with VOSA (Bayo+, 2008)J/ApJS/204/5 : SDSS DR7 white dwarf catalog (Kleinman+, 2013)J/A+A/568/A22 : Joint analysis of the SDSS-II & SNLS SNe Ia (Betoule+, 2014)J/MNRAS/457/1988 : White dwarfs in Galactic plane (Raddi+, 2016)J/MNRAS/469/621 : VST ATLAS white dwarf cand. cat. (Gentile Fusillo+, 2017)J/MNRAS/472/4173 : Bright white dwarfs for high-speed photometry (Raddi+, 2017)J/AJ/156/241 : Variable stars measured by ATLAS (Heinze+, 2018)J/ApJ/872/199 : Cand. spectrophotometric standard DA WDs (Calamida+, 2019)J/ApJ/874/30 : RRab stars toward Baade's window with DECam (Saha+, 2019)J/MNRAS/502/5147 : Anomaly detection in the ZTF DR3 (Malanchev+, 2021)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/940/19https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/940/19http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/940/19https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/940/19https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/940/19http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/940/19GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/940/19/dawds (Gaia DR3 astrometry and photometry for the candidate spectrophotometric standard DA white dwarfs (Table 1) and spectroscopic and photometric parameters (Table 4))https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/940/19/dawds?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/940/19/dawds?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/940/19/dawds?GETtext/xml+votable180.050000true15.84250417-0.346611110.005555555555555556Cone search capability for table J/ApJ/940/19/table2 (Log of the observations collected with the Goodman spectrograph on the 4m-SOAR telescope NOAO programs 2017A-0052 (PI: Olszewski))https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/940/19/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/940/19/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/940/19/table2?GETtext/xml+votable180.050000true20.50302083-30.867763890.005555555555555556Cone search capability for table J/ApJ/940/19/table3 (Log of the observations collected with LCO during programs LCO2016B-007, LCO2017AB-002, LCO2018A-002, LCO2018B-001, and LCO2019-B004 (PI: T. Matheson).)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/940/19/table3?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/940/19/table3?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/940/19/table3?GETtext/xml+votable180.050000true15.84249167-0.346613890.0055555555555555566/992 5438 6339 10935 11522 16299 16497 16555 16656 16897 18020 18790 20472 21082 21257 22012 22711 24722 24772 25289 26180 26535 27220 27238 27652 28912 31150 31405 32680 32888 33486 33492 33851 33959 34197 34302 34674 35199 35729 35931 36035 36058 36110 36383 36781 36888 36960 37027 37592 37933 37944 38161 38371 38378 38522 38970 41068 43693 44210 45700 46315 46455 46841 46956 47001 47224 47470 47972 49087 491011.9867573869263685e-19 4.621782916333392e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/940/19?format=asciiOpticaldefaultJ/ApJ/940/19/dawdsGaia DR3 astrometry and photometry for the candidate spectrophotometric standard DA white dwarfs (Table 1) and spectroscopic and photometric parameters (Table 4)NlcoNumber of LCO observation logs for this WD (link to Table 3)meta.numberintnullableNspNumber of SOAR observations for this WD (link to Table 2)meta.numberintnullablef_ID[*] Flag excluding star from final network of spectrophotometric standard DAWDsmeta.codecharSimbadSimbad column added by the CDSmeta.ref.urlcharsigmaLCO[0.01/0.04] Dispersion in LCO timeseriesmagstat.variance;phot.magfloatchi2[0.7/16.4] Variable reduced {chi}^2^, Equation 1stat.fit.chi2floatIQR[0/0.12] Interquartile range, LCO time-series (2)src.var.indexfloat1/eta[0/33] Von Neumann ratio {eta}, LCO time-series, Equation 2src.var.indexfloatIQR-ATLAS[0.05/0.91]? Interquartile range, ATLAS time-seriessrc.var.indexfloatnullable1/eta-ATLAS[0.07/77.25]? Von Neumann ratio {eta}, ATLAS time-seriessrc.var.indexfloatnullableNoteNote on IR excessmeta.notecharpmRA[-48.6/143.6] Gaia DR3 proper motion in RAmas/yrpos.pm;pos.eq.rafloate_pmRA[0.04/0.9] Uncertainty in pmRAmas/yrstat.error;pos.pm;pos.eq.rafloatpmDE[-76/66.5] Gaia DR3 proper motion in Decmas/yrpos.pm;pos.eq.decfloatrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintStarPosition-based Star Name (JHHMM+DDMM) (G2)meta.idcharWDFSWhite Dwarf Flux Standard designation (WDFS HHMM+DD; J2000)meta.idcharONameAlternative Name (G3)meta.idcharFlagFlag (1)meta.code.errorcharSetHemisphere sample (G1)src.samplecharGaiaGaia DR3 identifiermeta.id;meta.mainRAJ2000Hour of Right Ascension (J2000) (G2)pos.eq.ra;meta.mainDEJ2000Degree of Declination (J2000) (G2)pos.eq.dec;meta.maine_pmDE[0.05/0.8] Uncertainty in pmDEmas/yrstat.error;pos.pm;pos.eq.decfloatGmag[15.88/19.97] Gaia DR3 G-band magnitudemagphot.mag;em.optfloatRPmag[16.11/20.25] Gaia DR3 RP band magnitudemagphot.mag;em.opt.RfloatBPmag[15.77/19.82] Gaia DR3 BP band magnitudemagphot.mag;em.opt.BfloatIDIdentifier as given in Tables 3 and 4; column added by CDSmeta.idcharprimaryNexp[6/45] Number of exposuresmeta.numberintGmagEDR3[15.88/20] Gaia EDR3 G band magnitudemagphot.mag;em.optfloate_GmagEDR3[0.001/0.006] Uncertainty in Gmagmagstat.error;phot.mag;em.optfloatJ/ApJ/940/19/table2Log of the observations collected with the Goodman spectrograph on the 4m-SOAR telescope NOAO programs 2017A-0052 (PI: Olszewski)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintCDisplay the WD parameters (link to Tables 1+4)meta.ref.urlintnullableStarPosition-based Star Name (G2)meta.idcharSimbadSimbad column added by the CDSmeta.ref.urlcharONameAlternative Name (G3)meta.idcharGaiaGaia DR3 identifiermeta.id;meta.mainRAJ2000Hour of Right Ascension (J2000) (G2)pos.eq.ra;meta.mainDEJ2000Degree of Declination (J2000) (G2)pos.eq.dec;meta.mainObs[2016/2017] Observation date, UTC, yeartime.epoch;obslam1[3850/3870] Wavelength min, Angstroms0.1nmem.wl;stat.minintlam2[7100/7150] Wavelength max, Angstroms0.1nmem.wl;stat.maxintPA[5/348] Position angle of spectrum, E of Ndegpos.posAngfloatAirmass[1/1.7] Air massobs.airMassfloatStdFlux Standard ("Feige110", "Feige67" or "GD71")meta.notecharExpTimeExposure time, Seconds or CoaddxSecondstime.duration;obs.exposurecharJ/ApJ/940/19/table3Log of the observations collected with LCO during programs LCO2016B-007, LCO2017AB-002, LCO2018A-002, LCO2018B-001, and LCO2019-B004 (PI: T. Matheson).IDWhite Dwarf Flux Standard designation or ONamemeta.id;meta.maincharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSetHemisphere sample (G1)src.samplecharTelLCO Telescope codemeta.id;instr.telcharRAJ2000Hour of Right Ascension (J2000) (G2)pos.eq.ra;meta.mainDEJ2000Degree of Declination (J2000) (G2)pos.eq.dec;meta.mainMJD[57696.9/58817.1] Modified Julian Date of Observation (JD-2400000.5)dtime.epochdoubleExpTime[39/579] Exposure timestime.duration;obs.exposureint