Search Results for author: Joshua S. Bloom

Found 9 papers, 6 papers with code

Stellar Spectra Fitting with Amortized Neural Posterior Estimation and nbi

1 code implementation9 Dec 2023 Keming Zhang, Tharindu Jayasinghe, Joshua S. Bloom

Given the association of spectral data properties with the observing instrument, we discuss the utility of an ANPE "model zoo," where models are trained for specific instruments and distributed under the nbi framework to facilitate real-time stellar parameter inference.

nbi: the Astronomer's Package for Neural Posterior Estimation

1 code implementation6 Dec 2023 Keming Zhang, Joshua S. Bloom, Stéfan van der Walt, Nina Hernitschek

We identify three critical issues: the need for custom featurizer networks tailored to the observed data, the inference inexactness, and the under-specification of physical forward models.

Astronomy Bayesian Inference

A Ubiquitous Unifying Degeneracy in Two-Body Microlensing Systems

no code implementations26 Nov 2021 Keming Zhang, B. Scott Gaudi, Joshua S. Bloom

While gravitational microlensing by planetary systems provides unique vistas on the properties of exoplanets, observations of a given 2-body microlensing event can often be interpreted with multiple distinct physical configurations.

Vocal Bursts Valence Prediction

Real-Time Likelihood-Free Inference of Roman Binary Microlensing Events with Amortized Neural Posterior Estimation

no code implementations10 Feb 2021 Keming Zhang, Joshua S. Bloom, B. Scott Gaudi, Francois Lanusse, Casey Lam, Jessica R. Lu

Fast and automated inference of binary-lens, single-source (2L1S) microlensing events with sampling-based Bayesian algorithms (e. g., Markov Chain Monte Carlo; MCMC) is challenged on two fronts: high computational cost of likelihood evaluations with microlensing simulation codes, and a pathological parameter space where the negative-log-likelihood surface can contain a multitude of local minima that are narrow and deep.

Classification of Periodic Variable Stars with Novel Cyclic-Permutation Invariant Neural Networks

1 code implementation2 Nov 2020 Keming Zhang, Joshua S. Bloom

Neural networks (NNs) have been shown to be competitive against state-of-the-art feature engineering and random forest (RF) classification of periodic variable stars.

Astronomy Feature Engineering +2

Automating Inference of Binary Microlensing Events with Neural Density Estimation

no code implementations8 Oct 2020 Keming Zhang, Joshua S. Bloom, B. Scott Gaudi, Francois Lanusse, Casey Lam, Jessica Lu

Automated inference of binary microlensing events with traditional sampling-based algorithms such as MCMC has been hampered by the slowness of the physical forward model and the pathological likelihood surface.

Density Estimation

On Neural Architectures for Astronomical Time-series Classification with Application to Variable Stars

1 code implementation19 Mar 2020 Sara Jamal, Joshua S. Bloom

Despite the utility of neural networks (NNs) for astronomical time-series classification, the proliferation of learning architectures applied to diverse datasets has thus far hampered a direct intercomparison of different approaches.

Instrumentation and Methods for Astrophysics

deepCR: Cosmic Ray Rejection with Deep Learning

2 code implementations22 Jul 2019 Keming Zhang, Joshua S. Bloom

We demonstrate that at a false positive rate of 0. 5%, deepCR achieves close to 100% detection rates in both extragalactic and globular cluster fields, and 91% in resolved galaxy fields, which is a significant improvement over the current state-of-the-art method LACosmic.

Benchmarking Image Inpainting

A recurrent neural network for classification of unevenly sampled variable stars

2 code implementations28 Nov 2017 Brett Naul, Joshua S. Bloom, Fernando Pérez, Stéfan van der Walt

These networks can continue to learn from new unlabeled observations and may be used in other unsupervised tasks such as forecasting and anomaly detection.

Instrumentation and Methods for Astrophysics Solar and Stellar Astrophysics Data Analysis, Statistics and Probability

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