SELDON: Supernova Explosions Learned by Deep ODE Networks
Professional Abstract
"The paper introduces SELDON, a novel continuous-time variational autoencoder designed to handle the challenges posed by the anticipated influx of optical transient alerts from the Vera C. Rubin Observatory's Legacy Survey of Space and Time (LSST). With projections estimating up to 10 million public alerts per night, traditional physics-based inference methods are at risk of being overwhelmed due to their slow processing times, often requiring hours for each object. SELDON aims to address this issue by providing millisecond-scale inference capabilities for thousands of astronomical objects daily. The core of SELDON's architecture is a masked GRU-ODE (Gated Recurrent Unit - Ordinary Differential Equation) encoder, which is adept at summarizing panels of sparse and irregularly sampled astrophysical light curves. These light curves are characterized by their nonstationary, heteroscedastic, and dependent nature, complicating traditional analysis methods. The encoder is designed to effectively learn from imbalanced and correlated data, even when only a limited number of observations are available. Following the encoding process, SELDON employs a neural ODE to propagate the learned hidden state forward in continuous time, allowing for the extrapolation of future observations that have not yet been recorded. This capability is crucial for timely decision-making in astrophysical surveys, where rapid follow-up observations can significantly enhance the understanding of transient phenomena. The extrapolated time series is subsequently encoded using deep sets, leading to a latent distribution that is decoded into a weighted sum of Gaussian basis functions. The parameters derived from this decoding process—such as rise time, decay rate, and peak flux—are not only interpretable but also physically meaningful, providing valuable insights for downstream tasks like prioritizing spectroscopic follow-ups. The implications of SELDON extend beyond astronomy, as its architecture offers a versatile framework for continuous-time sequence modeling applicable in various fields where data is multivariate, sparse, heteroscedastic, and irregularly spaced. This adaptability positions SELDON as a significant advancement in the field of machine learning and data analysis, promising to enhance the efficiency and effectiveness of data-driven decision-making in a range of scientific domains."