J/ApJS/267/7 YSO candidates from LAMOST LRS DR9 & ZTF (Zhang+, 2023)
A catalog of young stellar objects from the LAMOST and ZTF surveys.
Zhang J., Zhang Y., Kang Z., Li C., Zhao Y.
<Astrophys. J. Suppl. Ser., 267, 7 (2023)>
=2023ApJS..267....7Z 2023ApJS..267....7Z
ADC_Keywords: YSOs; Photometry; Spectra, optical; Spectral types
Keywords: Astronomy data analysis ; Astrostatistics techniques ;
Time series analysis ; Light curve classification ;
Pre-main sequence stars
Abstract:
As 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.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 63 833 YSO candidates from the ZTF and LAMOST DR9 surveys
by self-paced ensemble (SPE)
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See also:
V/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)
Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 3 A3 --- --- [ZTF]
4- 12 A9 --- ZTF ZTF identifier (YYaaaaaaa)
14- 24 F11.7 deg RAdeg ICRS Right Ascension (J2000)
26- 35 F10.7 deg DEdeg [-7/64.6] ICRS Declination (J2000)
37- 40 F4.2 --- Prob [0.7/0.98] YSO probability
42- 46 F5.2 mag gmag [12.6/22]? g band mean magnitude over
ZTF time series
48- 52 F5.2 mag rmag [12.3/20.2]? r band mean magnitude over
ZTF time series
54- 63 A10 --- SpT Spectral Type from LAMOST low resolution spectra
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 17-Aug-2023