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We present a deep-learning-based approach for identifying dark matter haloes in cosmological N-body simulations. Our framework consists of a volumetric Convolutional Neural Network to classify individual simulation particles as either halo…

Cosmology and Nongalactic Astrophysics · Physics 2026-02-26 Soumadeep Maiti , Carlos M. Correa , Andrea Fiorilli , Andrés N. Ruiz , Dante J. Paz , Alejandro Pérez Fernández , Ariel G. Sánchez

We use measurements from the South Pole Telescope (SPT) Sunyaev Zel'dovich (SZ) cluster survey in combination with X-ray measurements to constrain cosmological parameters. We present a statistical method that fits for the scaling relations…

Digital co-addition of astronomical images is a common technique for increasing signal-to-noise and image depth. A modification of this simple technique has been applied to the detection of minor bodies in the Solar System: first stationary…

Earth and Planetary Astrophysics · Physics 2015-05-18 Alex H. Parker , JJ. Kavelaars

We develop an analysis pipeline for characterizing the topology of large scale structure and extracting cosmological constraints based on persistent homology. Persistent homology is a technique from topological data analysis that quantifies…

Cosmology and Nongalactic Astrophysics · Physics 2021-06-14 Matteo Biagetti , Alex Cole , Gary Shiu

A novel method, termed Reduced Dimensionality Cluster Identification, RDCI, is presented, for the identification and quantitative description of clusters formed by N objects in three dimensional space. The method consists of finding a path,…

Other Condensed Matter · Physics 2013-06-17 Theophanes Raptis , Vasilios Raptis

Small- and intermediate-scale galaxy clustering can be used to establish the galaxy-halo connection to study galaxy formation and evolution and to tighten constraints on cosmological parameters. With the increasing precision of galaxy…

Cosmology and Nongalactic Astrophysics · Physics 2016-03-23 Zheng Zheng , Hong Guo

The topology of the observable Universe is not yet known. The most significant observational sign of a non-trivial topology would be multiple images (``ghosts'') of a single object at (in general) different sky positions and redshifts. It…

Astrophysics · Physics 2015-06-24 Boudewijn F. Roukema , Alastair C. Edge

Convolutional neural network (CNN) has led to significant progress in object detection. In order to detect the objects in various sizes, the object detectors often exploit the hierarchy of the multi-scale feature maps called feature…

Computer Vision and Pattern Recognition · Computer Science 2020-01-22 Jin Hyeok Yoo , Dongsuk Kum , Jun Won Choi

If the universe is multiply connected and small the sky shows multiple images of cosmic objects, correlated by the covering group of the 3-manifold used to model it. These correlations were originally thought to manifest as spikes in pair…

General Relativity and Quantum Cosmology · Physics 2009-10-31 G. I. Gomero , A. F. F. Teixeira , M. J. Reboucas , A. Bernui

Clustering aims to group unlabelled samples based on their similarities. It has become a significant tool for the analysis of high-dimensional data. However, most of the clustering methods merely generate pseudo labels and thus are unable…

Artificial Intelligence · Computer Science 2023-06-21 Tianyi Huang , Shenghui Cheng , Stan Z. Li , Zhengjun Zhang

In deep, ground-based imaging, about 15%-30% of object detections are expected to correspond to two or more true objects - these are called ``unrecognized blends''. We use Machine Learning algorithms to detect unrecognized blends in deep…

Cosmology and Nongalactic Astrophysics · Physics 2026-05-25 Shuang Liang , Prakruth Adari , Anja von der Linden , The LSST Dark Energy Science Collaboration

Flat space models with multiply connected topology, which have compact dimensions, are tested against the distribution of high-redshift ($z \geq 4$) quasars of the Sloan Digital Sky Survey (SDSS). When the compact dimensions are smaller in…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-16 Hirokazu Fujii , Yuzuru Yoshii

We present a novel method of robust probabilistic cosmic web particle classification in three dimensions using a supervised machine learning algorithm. Training data was generated using a simplified $\Lambda$CDM toy model with…

Cosmology and Nongalactic Astrophysics · Physics 2020-09-10 Brandon Buncher , Matias Carrasco Kind

The clustering of galaxy clusters is a powerful cosmological tool, which can help to break degeneracies between parameters when combined with other cosmological observables. We aim to demonstrate its potential in constraining cosmological…

Cosmology and Nongalactic Astrophysics · Physics 2024-02-16 Alessandra Fumagalli , Matteo Costanzi , Alexandro Saro , Tiago Castro , Stefano Borgani

Star clusters are often hard to find, as they may lie in a dense field of background objects or, because in the case of embedded clusters, they are surrounded by a more dispersed population of young stars. This paper discusses four…

Astrophysics of Galaxies · Physics 2011-02-16 S. Schmeja

Subspace clustering is the problem of clustering data that lie close to a union of linear subspaces. In the abstract form of the problem, where no noise or other corruptions are present, the data are assumed to lie in general position…

Computer Vision and Pattern Recognition · Computer Science 2020-02-13 Manolis C. Tsakiris , Rene Vidal

A methodology is developed to identify clusters in a bulk phase which are topologically equivalent to certain reference clusters. The selected reference clusters are the Morse clusters with 13 or less atoms and the 13 atom clusters found in…

Soft Condensed Matter · Physics 2007-05-23 Stephen R. Williams

The robust and automated determination of crystal symmetry is of utmost importance in material characterization and analysis. Recent studies have shown that deep learning (DL) methods can effectively reveal the correlations between X-ray or…

Computational Physics · Physics 2020-05-27 Leslie Ching Ow Tiong , Jeongrae Kim , Sang Soo Han , Donghun Kim

Non-trivial spatial topology of the Universe may give rise to potentially measurable signatures in the cosmic microwave background. We explore different machine learning approaches to classify harmonic-space realizations of the microwave…

We construct entangled microstates of a pair of holographic CFTs whose dual semiclassical description includes big bang-big crunch AdS cosmologies in spaces without boundaries. The cosmology is supported by inhomogeneous heavy matter and it…

High Energy Physics - Theory · Physics 2025-07-15 Stefano Antonini , Martin Sasieta , Brian Swingle