Exploring the spectroscopic diversity of Type Ia supernovae with DRACULA: a machine learning approach

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Sasdelli, M. ; Ishida, E. E. O. ; Vilalta, R. ; Aguena, M. ; Busti, V. C. ; Camacho, H. ; Trindade, A. M. M. ; Gieseke, F. ; de Souza, R. S. ; Fantaye, Y. T. ; Mazzali, P. A. ; Collaboration, COIN

• Tipo de documento: Artigo Científico
• Fonte: Monthly Notices of the Royal Astronomical Society; v. 461, n. 2, p. 2044-2059, SEP 11 2016.
• Citações Web of Science: 6

Resumo

The existence of multiple subclasses of Type Ia supernovae (SNe Ia) has been the subject of great debate in the last decade. One major challenge inevitably met when trying to infer the existence of one or more subclasses is the time consuming, and subjective, process of subclass definition. In this work, we show how machine learning tools facilitate identification of subtypes of SNe Ia through the establishment of a hierarchical group structure in the continuous space of spectral diversity formed by these objects. Using deep learning, we were capable of performing such identification in a four-dimensional feature space (+1 for time evolution), while the standard principal component analysis barely achieves similar results using 15 principal components. This is evidence that the progenitor system and the explosion mechanism can be described by a small number of initial physical parameters. As a proof of concept, we show that our results are in close agreement with a previously suggested classification scheme and that our proposed method can grasp the main spectral features behind the definition of such subtypes. This allows the confirmation of the velocity of lines as a first-order effect in the determination of SN Ia subtypes, followed by 91bg-like events. Given the expected data deluge in the forthcoming years, our proposed approach is essential to allow a quick and statistically coherent identification of SNe Ia subtypes (and outliers). All tools used in this work were made publicly available in the PYTHON package Dimensionality Reduction And Clustering for Unsupervised Learning in Astronomy (DRACULA) and can be found within COINtoolbox (https://github.com/COINtoolbox/DRACULA). (AU)

• Processo FAPESP: 13/26612-2 - Cosmologia com aglomerados de galáxias no Dark Energy Survey
• Beneficiário: Michel Aguena da Silva
• Modalidade de apoio: Bolsas no Brasil - Doutorado
• Processo FAPESP: 14/21098-1 - Cosmologia de precisão com o Dark Energy Survey
• Beneficiário: Vinicius Consolini Busti
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado