The classification of variable objects provides insight into a wide variety of astrophysics ranging from stellar interiors to galactic nuclei. The Zwicky Transient Facility (ZTF) provides time-series observations that record the variability of more than a billion sources. The scale of these data necessitates automated approaches to make a thorough analysis. Building on previous work, this paper reports the results of the ZTF Source Classification Project (SCoPe), which trains neural network and XGBoost (XGB) machine-learning (ML) algorithms to perform dichotomous classification of variable ZTF sources using a manually constructed training set containing 170,632 light curves. We find that several classifiers achieve high precision and recall scores, suggesting the reliability of their predictions for 209,991,147 light curves across 77 ZTF fields. We also identify the most important features for XGB classification and compare the performance of the two ML algorithms, finding a pattern of higher precision among XGB classifiers. The resulting classification catalog is available to the public, and the software developed for SCoPe is open source and adaptable to future time-domain surveys.
The ZTF Source Classification Project. III. A Catalog of Variable Sources
- Creators
- Healy, Brian F.
- Coughlin, Michael W.
- Mahabal, Ashish A.1
- Jegou du Laz, Theophile
- Drake, Andrew
- Graham, Matthew J.1
- Hillenbrand, Lynne A.
- van Roestel, Jan
- Szkody, Paula
- Zielske, LeighAnna
- Guiga, Mohammed
- Hassan, Muhammad Yusuf
- Hughes, Jill L.
- Nir, Guy
- Parikh, Saagar
- Park, Sungmin
- Purohit, Palak
- Rebbapragada, Umaa
- Reed, Draco
- Warshofsky, Daniel
- Wold, Avery
- Bloom, Joshua S.
- Masci, Frank J.
- Riddle, Reed
- Smith, Roger1
Abstract
Copyright and License
© 2024. The Author(s). Published by the American Astronomical Society. Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.
Acknowledgement
We are grateful to the referee for providing helpful comments that strengthened the paper. B.F.H. and M.W.C. acknowledge support from the National Science Foundation with grant Nos. PHY-2308862 and PHY-2117997. This work used Expanse at the San Diego Supercomputer Cluster through allocation AST200029, "Towards a complete catalog of variable sources to support efficient searches for compact binary mergers and their products," from the Advanced Cyberinfrastructure Coordination Ecosystem: Services & Support (ACCESS) program, which is supported by National Science Foundation grant Nos. 2138259, 2138286, 2138307, 2137603, and 2138296.
Based on observations obtained with the Samuel Oschin 48 inch telescope and the 60 inch telescope at the Palomar Observatory as part of the Zwicky Transient Facility project. ZTF is supported by the National Science Foundation under grant Nos. AST-1440341 and AST-2034437 and a collaboration including current partners Caltech, IPAC, the Weizmann Institute of Science, the Oskar Klein Center at Stockholm University, the University of Maryland, Deutsches Elektronen-Synchrotron and Humboldt University, the TANGO Consortium of Taiwan, the University of Wisconsin at Milwaukee, Trinity College Dublin, Lawrence Livermore National Laboratories, IN2P3, University of Warwick, Ruhr University Bochum, and Northwestern University and former partners the University of Washington, Los Alamos National Laboratories, and Lawrence Berkeley National Laboratories. Operations are conducted by COO, IPAC, and UW.
The Gordon and Betty Moore Foundation, through both the Data-Driven Investigator Program and a dedicated grant, provided critical funding for SkyPortal.
Data Availability
The data are available on Zenodo under an open-source Creative Commons Attribution license at doi:10.5281/zenodo.8410825.
Facilities
PO:1.2m - , Gaia - , WISE - Wide-field Infrared Survey Explorer, PS1 - Panoramic Survey Telescope and Rapid Response System Telescope #1 (Pan-STARRS)
Software References
scope-ml (https://github.com/ZwickyTransientFacility/scope-ml), cesium (Brettet al. 2016), jupyter (Granger & Pérez 2021), kowalski (Duev et al. 2019), matplotlib (Hunter 2007), numpy (Oliphant 2006; van der Walt et al. 2011), pandas (McKinney 2010), penquins (https://github.com/dmitryduev/penquins), periodfind (https://github.com/ZwickyTransientFacility/periodfind), scikit-learn (Pedregosa et al. 2011), SkyPortal (van der Walt et al. 2019; Coughlin et al. 2023), tdtax (https://github.com/profjsb/timedomain-taxonomy), tensorflow (Abadi et al. 2016), wandb (https://wandb.ai/site), XGBoost (Chen & Guestrin 2016)
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Additional details
- ISSN
- 1538-4365
- National Science Foundation
- PHY-2308862
- National Science Foundation
- PHY-2117997
- National Science Foundation
- AST200029
- National Science Foundation
- OAC-2138259
- National Science Foundation
- OAC-2138286
- National Science Foundation
- OAC-2138307
- National Science Foundation
- OAC-2137603
- National Science Foundation
- OAC-2138296
- National Science Foundation
- AST-1440341
- National Science Foundation
- AST-2034437
- Gordon and Betty Moore Foundation
- Caltech groups
- Astronomy Department, Infrared Processing and Analysis Center (IPAC), Zwicky Transient Facility