J/AJ/161/80ivo://CDS.VizieR/J/AJ/161/80doi:10.26093/cds/vizier.51610080CDSZhao L.L.Hogg D.W.Bedell M.Fischer D.A.2022-09-30T21:39:21Z2021-04-23T07:35:47ZCDS support team

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

cds-question@unistra.frg-starsexoplanetsvisible-astronomyspectroscopyradial-velocityExcalibur is a nonparametric, hierarchical framework for precision wavelength calibration of spectrographs. It is designed with the needs of extreme-precision radial-velocity (EPRV) instruments in mind, which require calibration or stabilization to better than 10^-4^pixels. Instruments vary along only a few dominant degrees of freedom, especially EPRV instruments that feature highly stabilized optical systems and detectors. Excalibur takes advantage of this property by using all calibration data to construct a low-dimensional representation of all accessible calibration states for an instrument. Excalibur also takes advantage of laser-frequency combs or etalons, which generate a dense set of stable calibration points. This density permits the use of a nonparametric wavelength solution that can adapt to any instrument or detector oddities better than parametric models, such as a polynomial. We demonstrate the success of this method with data from the Extreme Precision Spectrograph (EXPRES), which uses a laser-frequency comb. When wavelengths are assigned to laser comb lines using excalibur, the rms of the residuals is about one-fifth that of wavelengths assigned using polynomial fits to individual exposures. Radial-velocity measurements of HD34411 show a reduction in rms scatter over a 10 month time baseline from 1.17 to 1.05m/s.2021AJ....161...80Zhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/161/80CatalogResearchIsServedByTAP VizieR generic servicerelated-toJ/A+A/468/1115 : Thorium and argon lines in the visible (Lovis+, 2007)J/A+A/549/A109 : HARPS XXXI. The M-dwarf sample (Bonfils+, 2013)J/A+A/560/A61 : A frequency Comb calibrated solar atlas (Molaro+, 2013)J/ApJS/225/32 : Extended abundance analysis of cool stars (Brewer+, 2016)J/AJ/153/208 : LCES HIRES/Keck RVel Exoplanet Survey (Butler+, 2017)J/AJ/156/18 : APOGEE DR14:Binary comp. of evolved stars (Price-Whelan+,2018)J/AJ/159/187 : First RVs with EXPRES spectrograph: 51Peg (Petersburg+, 2020)J/A+A/639/A77 : Proxima Cen RV, FWHM and fluxes (Suarez Mascareno+, 2020)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/161/80https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/AJ/161/80http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/AJ/161/80https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/AJ/161/80https://vizier.iucaa.in/viz-bin/votable?-source=J/AJ/161/80http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/AJ/161/80GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticaldefaultJ/AJ/161/80/table1EXPRES radial velocities using excalibur WavelengthsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintHJD[18764/19075] Heliocentric Julian Date; JD-2440000dtime.epochdoubleRVel[-3.42/3.66] Radial velocitym/sphys.veloc;pos.heliocentricdoublee_RVel[0.27/0.59] Uncertainty in RVelm/sstat.error;phys.velocdouble