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Machine-learning applications for cataclysmic variable discovery in the ZTF alert stream

Mistry, D, Copperwheat, CM, Darnley, MJ and Olier, I (2023) Machine-learning applications for cataclysmic variable discovery in the ZTF alert stream. Monthly Notices of the Royal Astronomical Society, 527. pp. 8633-8658. ISSN 0035-8711

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Cataclysmic variables (CV) encompass a diverse array of accreting white dwarf binary systems. Each class of CV represents a snapshot along an evolutionary journey, one with the potential to trigger a type Ia supernova event. The study of CVs offers valuable insights into binary evolution and accretion physics, with the rarest examples potentially providing the deepest insights. However, the escalating number of detected transients, coupled with our limited capacity to investigate them all, poses challenges in identifying such rarities. Machine Learning (ML) plays a pivotal role in addressing this issue by facilitating the categorisation of each detected transient into its respective transient class. Leveraging these techniques, we have developed a two-stage pipeline tailored to the ZTF transient alert stream. The first stage is an alerts filter aimed at removing non-CVs, while the latter is an ML classifier produced using XGBoost, achieving a macro average AUC score of 0.92 for distinguishing between CV classes. By utilising the Generative Topographic Mapping algorithm with classifier posterior probabilities as input, we obtain representations indicating that CV evolutionary factors play a role in classifier performance, while the associated feature maps present a potent tool for identifying the features deemed most relevant for distinguishing between classes. Implementation of the pipeline in June 2023 yielded 51 intriguing candidates that are yet to be reported as CVs or classified with further granularity. Our classifier represents a significant step in the discovery and classification of different CV classes, a domain of research still in its infancy.

Item Type: Article
Uncontrolled Keywords: astro-ph.SR; astro-ph.SR; astro-ph.HE; astro-ph.IM
Subjects: Q Science > QA Mathematics > QA76 Computer software
Q Science > QB Astronomy
Divisions: Astrophysics Research Institute
Computer Science & Mathematics
Publisher: Oxford University Press
Related URLs:
SWORD Depositor: A Symplectic
Date Deposited: 13 Dec 2023 10:38
Last Modified: 11 Jan 2024 15:30
DOI or ID number: 10.1093/mnras/stad3768
URI: https://researchonline.ljmu.ac.uk/id/eprint/22094
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