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The possibility to constrain cosmological parameters from galaxy surveys using field-level machine learning methods that bypass traditional summary statistics analyses, depends crucially on our ability to generate simulated training sets.…

Cosmology and Nongalactic Astrophysics · Physics 2026-02-11 Iñigo Sáez-Casares , Matteo Calabrese , Davide Bianchi , Marina S. Cagliari , Marco Chiarenza , Jean-Marc Christille , Luigi Guzzo

With the advent of future big-data surveys, automated tools for unsupervised discovery are becoming ever more necessary. In this work, we explore the ability of deep generative networks for detecting outliers in astronomical imaging…

Galaxy clusters are usually detected in blind optical surveys via suitable filtering methods. We present an optimal matched filter which maximizes their signal-to-noise ratio by taking advantage of the knowledge we have of their intrinsic…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-19 Fabio Bellagamba , Matteo Maturi , Takashi Hamana , Massimo Meneghetti , Satoshi Miyazaki , Lauro Moscardini

Strong lensing in galaxy clusters probes properties of dense cores of dark matter halos in mass, studies the distant universe at flux levels and spatial resolutions otherwise unavailable, and constrains cosmological models independently.…

Instrumentation and Methods for Astrophysics · Physics 2023-01-04 Peng Jia , Ruiqi Sun , Nan Li , Yu Song , Runyu Ning , Hongyan Wei , Rui Luo

We present a modified adaptive matched filter algorithm designed to identify clusters of galaxies in wide-field imaging surveys such as the Sloan Digital Sky Survey. The cluster-finding technique is fully adaptive to imaging surveys with…

Astrophysics · Physics 2009-11-13 Feng Dong , Elena Pierpaoli , James E. Gunn , Risa H. Wechsler

We present a novel approach to reconstruct gas and dark matter projected density maps of galaxy clusters using score-based generative modeling. Our diffusion model takes in mock SZ and X-ray images as conditional inputs, and generates…

Cosmology and Nongalactic Astrophysics · Physics 2025-07-16 Alan Hsu , Matthew Ho , Joyce Lin , Carleen Markey , Michelle Ntampaka , Hy Trac , Barnabás Póczos

We train three convolutional neural networks (CNNs) to classify galaxies with Galaxy Zoo 2 dataset and extract the activations from the last fully connected layer or the last average pooling layer of CNNs to study the high-dimensional…

Astrophysics of Galaxies · Physics 2018-07-17 Jia-Ming Dai , Jizhou Tong

We consider the problem of clustering data points in high dimensions, i.e. when the number of data points may be much smaller than the number of dimensions. Specifically, we consider a Gaussian mixture model (GMM) with non-spherical…

Statistics Theory · Mathematics 2014-06-10 Martin Azizyan , Aarti Singh , Larry Wasserman

We explore how diffuse stellar light and globular clusters (GCs) can be used to trace the matter distribution of their host halo using an observational methodology. For this, we use 117 simulated dark matter (DM) haloes from the $(34.4~\rm…

An approach to utilize recent advances in deep generative models for anomaly detection in a granular (continuous) sense on a real-world image dataset with quality issues is detailed using recent normalizing flow models, with implications in…

Machine Learning · Computer Science 2020-01-14 John Just

Hubble Space Telescope allows us to study the central surface brightness profiles for globular clusters at unprecedented detail. We have mined the HST archives to obtain 38 WFPC2 images of galactic globular clusters with adequate exposure…

Astrophysics · Physics 2008-11-26 E. Noyola , K. Gebhardt

We present a machine-learning framework to accurately characterize morphologies of Active Galactic Nucleus (AGN) host galaxies within $z<1$. We first use PSFGAN to decouple host galaxy light from the central point source, then we invoke the…

A significant fraction of observed galaxies in the Rubin Observatory Legacy Survey of Space and Time (LSST) will overlap at least one other galaxy along the same line of sight, in a so-called "blend." The current standard method of…

Instrumentation and Methods for Astrophysics · Physics 2022-01-20 James J. Buchanan , Michael D. Schneider , Robert E. Armstrong , Amanda L. Muyskens , Benjamin W. Priest , Ryan J. Dana

We consider the problem of clustering datasets in the presence of arbitrary outliers. Traditional clustering algorithms such as k-means and spectral clustering are known to perform poorly for datasets contaminated with even a small number…

Machine Learning · Statistics 2021-02-02 Prateek R. Srivastava , Purnamrita Sarkar , Grani A. Hanasusanto

We employ self-supervised representation learning to distill information from 76 million galaxy images from the Dark Energy Spectroscopic Instrument Legacy Imaging Surveys' Data Release 9. Targeting the identification of new strong…

Instrumentation and Methods for Astrophysics · Physics 2022-06-23 George Stein , Jacqueline Blaum , Peter Harrington , Tomislav Medan , Zarija Lukic

We present the first results from our HST Brightest Cluster Galaxy (BCG) survey of seven central supergiant cluster galaxies and their globular cluster (GC) systems. We measure a total of 48000 GCs in all seven galaxies, representing the…

We present recent results from the LCDM (Laboratory for Cosmological Data Mining; http://lcdm.astro.uiuc.edu) collaboration between UIUC Astronomy and NCSA to deploy supercomputing cluster resources and machine learning algorithms for the…

Astrophysics · Physics 2008-04-29 Nicholas M. Ball , Robert J. Brunner , Adam D. Myers

We present a convolutional neural network to classify distinct cosmological scenarios based on the statistically similar weak-lensing maps they generate. Modified gravity (MG) models that include massive neutrinos can mimic the standard…

Cosmology and Nongalactic Astrophysics · Physics 2019-07-17 Austin Peel , Florian Lalande , Jean-Luc Starck , Valeria Pettorino , Julian Merten , Carlo Giocoli , Massimo Meneghetti , Marco Baldi

Machine-learning (ML) algorithms will play a crucial role in studying the large datasets delivered by new facilities over the next decade and beyond. Here, we investigate the capabilities and limits of such methods in finding galaxies with…

Instrumentation and Methods for Astrophysics · Physics 2019-08-22 Andreas L. Faisst , Abhishek Prakash , Peter L. Capak , Bomee Lee

We present a systematic search for wide-separation (Einstein radius >1.5"), galaxy-scale strong lenses in the 30 000 sq.deg of the Pan-STARRS 3pi survey on the Northern sky. With long time delays of a few days to weeks, such systems are…

Astrophysics of Galaxies · Physics 2021-04-08 R. Canameras , S. Schuldt , S. H. Suyu , S. Taubenberger , T. Meinhardt , L. Leal-Taixe , C. Lemon , K. Rojas , E. Savary
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