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Descripción
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The High Cadence Transient Survey (HiTS) aims to discover and study transient objects with characteristic timescales between hours and days, such as pulsating, eclipsing and exploding stars. This survey represents a unique laboratory to explore large etendue observations from cadences of about 0.1 days and to test new computational tools for the analysis of large data. This work follows a fully Data Science approach: from the raw data to the analysis and classification of variable sources. We compile a catalog of ~15 million object detections and a catalog of ~2.5 million light-curves classified by variability. The typical depth of the survey is 24.2, 24.3, 24.1 and 23.8 in u, g, r, and i bands, respectively. We classified all point-like non-moving sources by first extracting features from their light--curves and then applying a Random Forest classifier. For the classification, we used a training set constructed using a combination of cross-matched catalogs, visual inspection, transfer/active learning, and data augmentation. The classification model consists of several Random Forest classifiers organized in a hierarchical scheme. The classifier accuracy estimated on a test set is approximately 97%. In the unlabeled data, 3,485 sources were classified as variables, of which 1,321 were classified as periodic. Among the periodic classes we discovered with high confidence, 1 δ scuti, 39 eclipsing binaries, 48 rotational variables, and 90 RR-Lyrae. For the non-periodic classes we discovered 1 cataclysmic variables, 630 QSO, and 1 supernova candidate. (2018-11-06)
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