J/AJ/159/84ivo://CDS.VizieR/J/AJ/159/84doi:10.26093/cds/vizier.51590084CDSBai YuLiu J.Wang Y.Wang S.2024-01-09T13:07:16Z2020-11-04T09:45:13ZCDS support team

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

cds-question@unistra.frsurveysextinctionvisible-astronomyMachine learning has become a popular tool to help us make better decisions and predictions, based on experiences, observations, and analyzing patterns, within a given data set without explicit functions. In this paper, we describe an application of the supervised machine-learning algorithm to the extinction regression for the second Gaia data release, based on the combination of the Large Sky Area Multi-Object Fiber Spectroscopic Telescope, Sloan Extension for Galactic Understanding and Exploration, and the Apache Point Observatory Galactic Evolution Experiment. The derived extinction in our training sample is consistent with other spectrum-based estimates, and its standard deviation of the cross-validations is 0.0127mag. A blind test is carried out using the RAdial Velocity Experiment catalog, and the standard deviation is 0.0372mag. Such a precise training sample enables us to regress the extinction, E(BP-RP), for 133 million stars in the second Gaia data release. Of these, 106 million stars have the uncertainties less than 0.1mag, which suffer less bias from the external regression. We also find that there are high deviations between the extinctions from photometry-based methods, and between spectrum- and photometry-based methods. This implies that the spectrum-based method could bring more signal to a regressing model than multiband photometry, and a higher signal-to-noise ratio would acquire a more reliable result.2020AJ....159...84Bhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/159/84CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toIII/279 : RAVE 5th data release (Kunder+, 2017)I/345 : Gaia DR2 (Gaia Collaboration, 2018)I/349 : StarHorse, Gaia DR2 photo-astrometric distances (Anders+, 2019)V/146 : LAMOST DR1 catalogs (Luo+, 2015)J/AJ/136/2070 : SEGUE stellar parameter pipeline. III (Allende Prieto+,2008)J/AJ/136/2050 : SEGUE stellar parameter pipeline. II. (Lee+, 2008)J/AJ/137/4377 : List of SEGUE plate pairs (Yanny+, 2009)J/AJ/141/89 : SEGUE stellar parameter pipeline. IV. (Smolinski+, 2011)J/AJ/146/133 : Stellar parameters SDSS-III APOGEE DR10 (Meszaros+, 2013)J/ApJ/798/122 : Abundances SEGUE Stellar Parameters Pipeline (Miller+, 2015)J/AJ/151/144 : ASPCAP weights 15 APOGEE chemical elements (Garcia+, 2016)J/MNRAS/460/3179 : APOGEE stars distance and extinction (Wang+, 2016)J/ApJS/229/30 : Revised stellar properties of Q1-17 Kepler (Mathur+, 2017)J/A+A/619/A180 : Gaia DR2 photo. sensitivity curves (Maiz Apellaniz+, 2018)J/AJ/158/93 : Regression of stellar temperatures in GaiaDR2 (Bai+, 2019)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/159/84https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/AJ/159/84http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/AJ/159/84https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/AJ/159/84https://vizier.iucaa.in/viz-bin/votable?-source=J/AJ/159/84http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/AJ/159/84GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/AJ/159/84/table2 (Results of our regression for Gaia DR2 (Cat. I/345) (1000 sources among 132,739,322))https://vizier.cds.unistra.fr/viz-bin/conesearch/J/AJ/159/84/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/AJ/159/84/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/AJ/159/84/table2?GETtext/xml+votable180.050000true45.004974244980.019877000370.0055555555555555560/0-11 6/https://cdsarc.cds.unistra.fr/viz-bin/moc/J/AJ/159/84?format=asciiOpticaldefaultJ/AJ/159/84/table2Results of our regression for Gaia DR2 (Cat. I/345) (1000 sources among 132,739,322)SourceSource identifier in Gaia DR2meta.id;meta.mainindexedRA_ICRSGaia DR2 Right Ascension (ICRS) at Ep=2015.5 (column added by the CDS)degpos.eq.ra;meta.mainDE_ICRSGaia DR2 Declination (ICRS) at Ep=2015.5 (column added by the CDS)degpos.eq.dec;meta.mainE(BP-RP)[-0.46/2.91] Regressed redenning E(BP-RP)magphot.color.excessdoublee_E(BP-RP)[0.0024/0.87] Uncertainty in E(BP-RP)magstat.errordouble