J/ApJS/267/7ivo://CDS.VizieR/J/ApJS/267/7CDSZhang J.Zhang Y.Kang Z.Li C.Zhao Y.2024-08-13T12:57:57Z2023-10-31T15:15:06ZCDS support team

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

cds-question@unistra.fryoung-stellar-objectsphotometryvisible-astronomyspectroscopystellar-spectral-typesAs astronomical data sets become too large for traditional analysis approaches, more machine-learning algorithms are employed in astronomy. A wealth of light variation data have been accumulated, which provide rich samples for astronomers to study variable stars. Facing the challenge of big data, this article takes the classification of variable and transient objects observed by the Zwicky Transient Facility (ZTF) as the main goal, and a self-paced ensemble (SPE) imbalanced-learning classifier is constructed to separate different classes. The performance of the classifier reveals that SPE is better than a traditional imbalanced-learning algorithm for the minority classes. In our work, the SPE classifier is satisfactory for young stellar objects (YSOs), and the completeness (recall) of YSOs is enhanced to 91%. As a result, 868,371 ZTF sources are classified into 15 classes by this classifier, which contains 8210 YSO candidates (YSO_prob>=0.70). In order to further identify YSO candidates, these candidates are crossmatched with LAMOST DR9. Finally, 833 candidates are observed by LAMOST, among them 379 objects that are known YSOs in SIMBAD. For the remaining objects with good-quality LAMOST spectra, we visually check their spectral characteristics, and 238 objects are newly confirmed YSOs. These newfound YSOs supplement the present YSO sample, and other YSO candidates may be used for follow-up observation, which is useful for characterizing YSOs, finding more YSOs, and then giving a better stellar evolution model in the future. The classified ZTF sources by SPE provide reference to the study of variables and transients.2023ApJS..267....7Zhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJS/267/7CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toV/156 : LAMOST DR7 catalogs (Luo+, 2019)J/ApJS/246/8 : RR Lyrae star candidates from SDSS-DR15 (Zhang+, 2020)J/ApJS/259/11 : LAMOST variable sources based on ZTF phot. (Xu+, 2022)J/AJ/163/263 : 323 YSOs properties with ZTF (Hillenbrand+, 2022)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJS/267/7https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJS/267/7http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJS/267/7https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJS/267/7https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJS/267/7http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJS/267/7GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJS/267/7/table3 (YSO candidates from the ZTF and LAMOST DR9 surveys by self-paced ensemble (SPE))https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJS/267/7/table3?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJS/267/7/table3?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJS/267/7/table3?GETtext/xml+votable180.050000true67.62341424.4458170.0055555555555555565/292 5714-5715 5934 5992 5998 6106 6/342 349 501 511 857 859-860 862 881 1029 1031 1037 1039-1040 1042-1043 1047 1049-1054 1061 1068 1075 1080-1082 1104 1109 1115 1124 1126 1136 1149 1156-1157 1159 1176 1192 1201 1204 1208 1211 1230-1231 1240 1242-1243 1274 1285 1289 1297-1299 1302 1309 1337 1344 1346 1376-1377 1412 1417 1421 1436 1446 1458 1465 1470 1538-1539 1542 1551 1554-1555 1561 1563 1590 1596 1606 1622 1630 1635 1730-1731 1781-1783 1788-1790 1792 1795 1807 1836 1923 1930-1931 1940 1952 1954 1962-1963 2747 2794 2812 2909 3003-3005 3029 3031 3156 3158 3161 3164 3168-3169 3181 3184-3185 3195-3196 3198-3199 3223 3229 3251 3260-3261 3271 3281-3283 3285-3286 3290 3301 3312 3325 3336 3355 3375 3384 3459 3466 3594 3602 3628 3630 3720 13786 14147 14199 14281 14622 14645 14670 14676 14678 14682 14685-14686 14688-14689 14716 14773 15362-15363 15368-15370 21371 21435 21437-21439 21456-21458 21464 21486 21622 22034 22040 22127 22196 22199 22218 22240 22243 22249 22252-22253 22331 22442 22481 22740 22800 22804-22805 22807 22848 22850-22852 22854-22855 22866 22872-22874 22876 22880-22881 22884 22892 22894-22895 22905 22907 22994 23030-23031 23038 23509 23543 23548-23549 23551 23557 23560 23562 23566 23584 23590 23597-23598 23600 23627 23637-23639 23641 23644 23646 23669 23690-23691 23695 23697-23698 23704 23706 23711 23717 23719 23727-23728 23730 23760 23762-23763 23768 23773 23782 23795 23797-23798 23801-23802 23850 23938 23950 23974-23975 23977-23978 23980-23982 23996-23997 24080-24081 24086 24099 24119 24158 24162-24163 24169 24181 24183 24185 24188 24190-24191 24224 24269 24274 24284-24286 24289 24294-24295 24300 24320 24324 24340 24345-24347 24353 24355 24357 24363 24365-24367 24371 24378 24400 24448 24450 24454 24457 24460 24464 24467 24474 24485 24487 24493 24496-24497 24499-24500 24507 24509 24511-24513 24515 24547 24554 30360 30363 30366-30367 30389 30452 30462 31050https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJS/267/7?format=asciiOpticaldefaultJ/ApJS/267/7/table3YSO candidates from the ZTF and LAMOST DR9 surveys by self-paced ensemble (SPE)RAICRSICRS Right Ascension (J2000)degpos.eq.ra;meta.mainProb[0.7/0.98] YSO probabilitystat.probabilityfloatDEICRS[-7/64.6] ICRS Declination (J2000)degpos.eq.dec;meta.maingmag[12.6/22]? g band mean magnitude over ZTF time seriesmagphot.mag;em.opt.Bfloatnullablermag[12.3/20.2]? r band mean magnitude over ZTF time seriesmagphot.mag;em.opt.RfloatnullableSpTSpectral Type from LAMOST low resolution spectrasrc.spTypecharDR7Display data from LAMOST DR7 within 0.5"meta.ref.urlintnullableSimbadSimbad column added by the CDSmeta.ref.urlcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintZTFZTF identifier (YYaaaaaaa)meta.id;meta.mainchar