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Fields in cosmology, such as the matter distribution, are observed by experiments up to experimental noise. The first step in cosmological data analysis is usually to de-noise the observed field using an analytic or simulation driven prior.…

Cosmology and Nongalactic Astrophysics · Physics 2022-11-29 Adam Rouhiainen , Moritz Münchmeyer

We demonstrate an algorithm for learning a flexible color-magnitude diagram from noisy parallax and photometry measurements using a normalizing flow, a deep neural network capable of learning an arbitrary multi-dimensional probability…

Instrumentation and Methods for Astrophysics · Physics 2019-08-23 Miles D. Cranmer , Richard Galvez , Lauren Anderson , David N. Spergel , Shirley Ho

The hierarchical model of galaxy formation predicts that the Milky Way halo is populated by tidal debris of dwarf galaxies and globular clusters. Due to long dynamical times, debris from the lowest mass objects remains coherent as thin and…

Astrophysics of Galaxies · Physics 2024-05-31 Ana Bonaca , Adrian M. Price-Whelan

We present a novel, data-driven analysis of Galactic dynamics, using unsupervised machine learning -- in the form of density estimation with normalizing flows -- to learn the underlying phase space distribution of 6 million nearby stars…

Astrophysics of Galaxies · Physics 2025-12-05 Sung Hak Lim , Eric Putney , Matthew R. Buckley , David Shih

Spectrum denoising is an important procedure for large-scale spectroscopical surveys. This work proposes a novel stellar spectrum denoising method based on deep Bayesian modeling. The construction of our model includes a prior distribution…

Instrumentation and Methods for Astrophysics · Physics 2021-09-08 Xin Kang , Shiyuan He , Yanxia Zhang

The observation of our home galaxy, the Milky Way (MW), is made difficult by our internal viewpoint. The Gaia survey that contains around 1.6 billion star distances is the new flagship of MW structure and can be combined with other…

Astrophysics of Galaxies · Physics 2020-12-15 David Cornu

Point cloud denoising aims to restore clean point clouds from raw observations corrupted by noise and outliers while preserving the fine-grained details. We present a novel deep learning-based denoising model, that incorporates normalizing…

Computer Vision and Pattern Recognition · Computer Science 2022-07-26 Aihua Mao , Zihui Du , Yu-Hui Wen , Jun Xuan , Yong-Jin Liu

We review the implications of the Gaia Data Release 2 catalogue for studying the dynamics of Milky Way globular clusters, focusing on two separate topics. The first one is the analysis of the full 6-dimensional phase-space distribution of…

Astrophysics of Galaxies · Physics 2020-03-18 Eugene Vasiliev

Density deconvolution is the task of estimating a probability density function given only noise-corrupted samples. We can fit a Gaussian mixture model to the underlying density by maximum likelihood if the noise is normally distributed, but…

Machine Learning · Statistics 2020-07-14 Tim Dockhorn , James A. Ritchie , Yaoliang Yu , Iain Murray

Normalizing flows are a powerful tool to create flexible probability distributions with a wide range of potential applications in cosmology. Here we are studying normalizing flows which represent cosmological observables at field level,…

Cosmology and Nongalactic Astrophysics · Physics 2021-05-26 Adam Rouhiainen , Utkarsh Giri , Moritz Münchmeyer

We construct the first comprehensive dynamical model for the high-quality subset of stellar kinematics of the Milky Way disc, with full 6D phase-space coordinates, provided by the Gaia Data Release 2. We adopt an axisymmetric approximation…

Astrophysics of Galaxies · Physics 2020-04-24 Maria Selina Nitschai , Michele Cappellari , Nadine Neumayer

The Gaia satellite will observe the positions and velocities of over a billion Milky Way stars. In the early data releases, the majority of observed stars do not have complete 6D phase-space information. In this Letter, we demonstrate the…

Astrophysics of Galaxies · Physics 2021-07-08 Adriana Dropulic , Bryan Ostdiek , Laura J. Chang , Hongwan Liu , Timothy Cohen , Mariangela Lisanti

Stellar streams provide one of the most promising avenues for constraining the global mass distribution of the Milky Way and the nature of dark matter (DM). The stream stars' kinematic "track" enables inference of large-scale properties of…

Astrophysics of Galaxies · Physics 2025-10-02 Kiyan Tavangar , Adrian M. Price-Whelan

A suite of vast stellar surveys mapping the Milky Way, culminating in the Gaia mission, is revolutionizing the empirical information about the distribution and properties of stars in the Galactic stellar disk. We review and lay out what…

Astrophysics of Galaxies · Physics 2013-12-04 Hans-Walter Rix , Jo Bovy

We have mapped the number density and mean vertical velocity of the Milky Way's stellar disk out to roughly two kiloparsecs from the Sun using Gaia Data Release 3 (DR3) and complementary photo-astrometric distance information from…

Astrophysics of Galaxies · Physics 2022-12-14 Axel Widmark , Lawrence M. Widrow , Aneesh Naik

The gravitational potential of the Milky Way encodes information about the distribution of all matter -- including dark matter -- throughout the Galaxy. Gaia data release 3 has revealed a complex structure that necessitates flexible models…

Astrophysics of Galaxies · Physics 2025-08-05 Taavet Kalda , Gregory M. Green

The abundance of dark matter (DM) subhalos orbiting a host galaxy is a generic prediction of the cosmological framework, and is a promising way to constrain the nature of DM. In this paper, we investigate the use of machine learning-based…

Astrophysics of Galaxies · Physics 2023-01-02 Abdullah Bazarov , María Benito , Gert Hütsi , Rain Kipper , Joosep Pata , Sven Põder

We introduce a method to infer the vertical distribution of stars in the Milky Way using a Poisson likelihood function, with a view to applying our method to the Gaia catalogue. We show how to account for the sample selection function and…

Astrophysics of Galaxies · Physics 2021-12-08 Andrew Everall , N. Wyn Evans , Vasily Belokurov , Douglas Boubert , Robert J. J. Grand

GAIA has been approved to provide the data needed to quantify the formation and evolution of the Milky Way Galaxy, and its near neighbours. That requires study of all four key Galactic stellar populations: Bulge, Halo, Thick Disk, Thin…

Astrophysics · Physics 2007-05-23 Gerry Gilmore

The advent of Gaia's 2nd data release in combination with large spectroscopic surveys are revolutionizing our understanding of the Galaxy. Thanks to these and the knowledge accumulated thus far, a more mature picture of the evolution of the…

Astrophysics of Galaxies · Physics 2020-08-18 Amina Helmi
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