Alert Classification for the ALeRCE Broker System: The Anomaly Detector
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Fecha
2023-10-01
Profesor/a Guía
Facultad/escuela
Idioma
en
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Título del volumen
Editor
American Astronomical Society
Nombre de Curso
Licencia CC
CC BY 4.0 DEED
Attribution 4.0 International
Licencia CC
https://creativecommons.org/licenses/by/4.0/
Resumen
Astronomical broker systems, such as Automatic Learning for the Rapid Classification of Events (ALeRCE), are currently analyzing hundreds of thousands of alerts per night, opening up an opportunity to automatically detect anomalous unknown sources. In this work, we present the ALeRCE anomaly detector, composed of three outlier detection algorithms that aim to find transient, periodic, and stochastic anomalous sources within the Zwicky Transient Facility data stream. Our experimental framework consists of cross-validating six anomaly detection algorithms for each of these three classes using the ALeRCE light-curve features. Following the ALeRCE taxonomy, we consider four transient subclasses, five stochastic subclasses, and six periodic subclasses. We evaluate each algorithm by considering each subclass as the anomaly class. For transient and periodic sources the best performance is obtained by a modified version of the deep support vector data description neural network, while for stochastic sources the best results are obtained by calculating the reconstruction error of an autoencoder neural network. Including a visual inspection step for the 10 most promising candidates for each of the 15 ALeRCE subclasses, we detect 31 bogus candidates (i.e., those with photometry or processing issues) and seven potential astrophysical outliers that require follow-up observations for further analysis. © 2023. The Author(s). Published by the American Astronomical Society.
Notas
INDEXACIÓN: SCOPUS.
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Citación
Astronomical Journal, Volume 166, Issue 4, 1 October 2023, Article number 151
DOI
10.3847/1538-3881/ace0c1