Alert classification for the ALeRCE broker system: The light curve classifier

作     者：Sánchez-Sáez, Paula Reyes, I. Valenzuela, C. Förster, F. Eyheramendy, S. Elorrieta, F. Bauer, F.E. Cabrera-Vives, G. Estévez, P.A. Catelan, M. Pignata, G. Huijse, P. de Cicco, D. Arévalo, P. Carrasco-Davis, R. Abril, J. Kurtev, R. Borissova, J. Arredondo, J. Castillo-Navarrete, E. Rodriguez, D. Ruz-Mieres, D. Moya, A. Sabatini-Gacitúa, L. Sepúlveda-Cobo, C. Camacho-Iñiguez, E. 

作者机构： Nuncio Monseñor Sótero Sanz 100 Providencia Santiago Chile Instituto de Astrofísica Facultad de Física Pontificia Universidad Católica de Chile Casilla 306 Santiago 22 Chile Faculty of Engineering and Sciences Universidad Adolfo Ibañez Diagonal Las Torres 2700 Peñalolén Santiago Chile Center for Mathematical Modeling Universidad de Chile Beauchef 851 North building 7th floor Santiago8320000 Chile Department of Electrical Engineering Universidad de Chile Av. Tupper 2007 Santiago8320000 Chile Data Observatory Diagonal Las Torres 2640 Peñalolén Santiago Chile Departmento de Matemáticas Facultad de Ciencia Universidad de Santiago de Chile Estación Central Av. Libertador Bernardo O'Higgins 3663 Santiago Chile Departamento de Astronomía Universidad de Chile Casilla 36D Santiago Chile Centro de Astroingeniería Pontificia Universidad Católica de Chile Av. Vicuña Mackenna 4860 Macul Santiago7820436 Chile Space Science Institute 4750 Walnut Street Suite 205 BoulderCO80301 United States Department of Computer Science University of Concepcón Edmundo Larenas 219 Concepción Chile Departamento de Ciencias Fisícas Universidad Andres Bello Avda. Republica 252 Santiago Chile Informatics Institute Universidad Austral de Chile General Lagos 2086 Valdivia Chile Instituto de Física y Astronomía Facultad de Ciencias Universidad de Valparaíso Gran Bretana No. 1111 Playa Ancha Valparaíso Chile  Alonso de Córdova 3107 Vitacura Santiago Chile - Unidad Asociada al CSIC Plaza San Juan 1 TeruelE-44001 Spain 

出 版 物：《arXiv》 (arXiv)

年 卷 期：2020年

核心收录：

主　　题：Surveys 

摘      要：We present the first version of the ALeRCE (Automatic Learning for the Rapid Classification of Events) broker light curve classifier. ALeRCE is currently processing the Zwicky Transient Facility (ZTF) alert stream, in preparation for the Vera C. Rubin Observatory. The ALeRCE light curve classifier uses variability features computed from the ZTF alert stream, and colors obtained from AllWISE and ZTF photometry. We apply a Balanced Random Forest algorithm with a two-level scheme, where the top level classifies each source as periodic, stochastic, or transient, and the bottom level further resolves each of these hierarchical classes, amongst 15 total classes. This classifier corresponds to the first attempt to classify multiple classes of stochastic variables (including core- and host-dominated active galactic nuclei, blazars, young stellar objects, and cataclysmic variables) in addition to different classes of periodic and transient sources, using real data. We created a labeled set using various public catalogs (such as the Catalina Surveys and Gaia DR2 variable stars catalogs, and the Million Quasars catalog), and we classify all objects with ≥ 6 g-band or ≥ 6 r-band detections in ZTF (868,371 sources as of 2020/06/09), providing updated classifications for sources with new alerts every day. For the top level we obtain macro-averaged precision and recall scores of 0.96 and 0.99, respectively, and for the bottom level we obtain macro-averaged precision and recall scores of 0.57 and 0.76, respectively. Updated classifications from the light curve classifier can be found at the ALeRCE Explorer website. Copyright © 2020, The Authors. All rights reserved.