A Machine-Readable Value-Added Catalog for Uncertain-Type Blazars in the Fifth Roma-BZCAT
The fifth edition of the Roma-BZCAT catalog (5BZCAT) contains 227 blazars of the uncertain type (BZU), whose available data do not support an unambiguous assignment to the BL Lacertae object (BZB), flat-spectrum radio quasar (BZQ), or host-galaxy-dominated blazar-like source (BZG) categories. We construct a machine-readable value-added catalog for these sources using 1151 BZB, 1909 BZQ, and 274 BZG catalog entries as the supervised reference sample. The compact input set contains redshift, optical magnitude, radio, X-ray, and gamma-ray measurements; missingness indicators; and spectral slopes connecting the radio, optical, and X-ray bands. Redshift and its availability are explicitly treated as optical-spectroscopy-related label proxies. Cross-validation shows that the Light Gradient Boosting Machine (LightGBM) provides the most reliable probability scores among the tested models, although the stacking ensemble gives a slightly higher balanced accuracy. The final catalog reports LightGBM probabilities and contains 61 BZB-like, 120 BZQ-like, and 46 BZG-like sources; 17 are flagged for low probability separation. These probabilities quantify similarity to existing 5BZCAT labels conditional on catalog measurements, rather than an independent physical taxonomy.
Authors
- Hubing Xiao (ORCID: https://orcid.org/0000-0001-8244-1229)
- Jingtian Zhu (ORCID: https://orcid.org/0000-0002-8206-5080)
- J. H. Fan (ORCID: https://orcid.org/0000-0002-5929-0968)
- D. Bastieri (ORCID: https://orcid.org/0000-0002-6954-8862)
- Xinwen Shu (ORCID: https://orcid.org/0000-0002-7020-4290)
- Tianbo Xu (ORCID: https://orcid.org/0000-0002-7953-3736)
- Qian Wang (ORCID: https://orcid.org/0000-0002-1608-163X)
- Haitao Cao (ORCID: https://orcid.org/0000-0002-8626-8686)
- Wen Yang (ORCID: https://orcid.org/0009-0002-2523-2636)
- Guo Li
- Jun Zhang (ORCID: https://orcid.org/0009-0002-3402-5858)
- Fengchun Tao
- Xianyao Zhang
- Aibo Liu (ORCID: https://orcid.org/0009-0003-1029-9851)
- Kun Ou (ORCID: https://orcid.org/0009-0004-2832-4549)
- Yuhui Song (ORCID: https://orcid.org/0009-0007-6883-4473)
Institutions
- University of Padua (IT)
- Shanghai Normal University (CN)
- Guangzhou University (CN)
- Guangzhou Panyu Polytechnic (CN)
- Istituto Nazionale di Fisica Nucleare, Sezione di Padova (IT)
- Guangdong Polytechnic Normal University (CN)
- Anhui Institute of Information Technology (CN)
- Wuhu Institute of Technology (CN)
- Osservatorio Astronomico di Padova (IT)
- Anhui Normal University (CN)
Publication Details
- Journal
- Universe
- Published
- 2026-08-17
- DOI
- https://doi.org/10.3390/universe12080250
- Primary Topic
- Astrophysics and Cosmic Phenomena
- Type
- article
- Field-Weighted Citation Impact
- 0.00
Funders
- National Natural Science Foundation of China
- Anhui Provincial Department of Education