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Multi-connected universe models with space identification scales smaller than the size of the observable universe produce topological images of cosmic sources. We generalise to locally hyperbolic spaces the crystallographic method, aimed to…

Astrophysics · Physics 2011-05-23 Jean-Philippe Uzan , Roland Lehoucq , Jean-Pierre Luminet

Cosmic crystallography is based on the principle that peaks in the pair separation histogram (PSH) of objects in a catalogue should be induced by the high number of topologically lensed pairs that are separated by Clifford translations, in…

Astrophysics · Physics 2011-07-19 Andrzej Marecki , Boudewijn F. Roukema , Stanislaw Bajtlik

We present a method to constrain cosmic topology from the distribution of astronomical objects projected on the celestial sphere. This is an extension of the 3D method introduced in Fujii & Yoshii (2011) that is to search for a pair of…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 Hirokazu Fujii , Yuzuru Yoshii

When the density parameter is close to unity, the universe has a large curvature radius independently of its being hyperbolic, flat, or spherical. Whatever the curvature, the universe may have either a simply connected or a multiply…

Astrophysics · Physics 2017-08-23 Jeffrey Weeks , Roland Lehoucq , Jean-Philippe Uzan

(abridged) We present the Significant Cosmic Holes in Universe (SCHU) method for identifying cosmic voids and loops of filaments in cosmological datasets and assigning their statistical significance using techniques from topological data…

Cosmology and Nongalactic Astrophysics · Physics 2019-03-19 Xin Xu , Jessi Cisewski-Kehe , Sheridan B. Green , Daisuke Nagai

Star formation is a multi-scale problem, and only global simulations that account for the connection from the molecular cloud scale gas flow to the accreting protostar can reflect the observed complexity of protostellar systems.…

Astrophysics of Galaxies · Physics 2023-07-28 Rami Al-Belmpeisi , Vito Tuhtan , Mikkel Bregning Christensen , Rajika L Kuruwita , Troels Haugbølle

This paper describes the systematic application of local topological methods for detecting interfaces and related anomalies in complicated high-dimensional data. By examining the topology of small regions around each point, one can…

Algebraic Topology · Mathematics 2022-05-25 Bernadette J Stolz , Jared Tanner , Heather A Harrington , Vidit Nanda

A flat Universe model supported by recent observations has 18 possible choices for its overall topology. To detect or exclude these possibilities is one of the most important tasks in modern cosmology, but it has been very difficult for…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-30 Hirokazu Fujii

Multi-connected Universe models with space idenfication scales smaller than the size of the observable universe produce topological images in the catalogs of cosmic sources. In this review, we present the recent developments for the search…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Jean-Philippe Uzan , Roland Lehoucq , Jean-Pierre Luminet

We present a new technique for constraining the topology of the universe. The method exploits the existence of correlations in the phases of the spherical harmonic coefficients of the CMB temperature pattern associated with matched pairs of…

Astrophysics · Physics 2009-11-10 Patrick Dineen , Graca Rocha , Peter Coles

We study the topological signature of euclidean isometries in pair separations histograms (PSH) and elucidate some unsettled issues regarding distance correlations between cosmic sources in cosmic crystallography. Reducing the noise of…

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

In recent years, cosmic shear has emerged as a powerful tool to study the statistical distribution of matter in our Universe. Apart from the standard two-point correlation functions, several alternative methods like peak count statistics…

Cosmology and Nongalactic Astrophysics · Physics 2021-04-21 Sven Heydenreich , Benjamin Brück , Joachim Harnois-Déraps

We investigate to what extent the cosmic crystallographic methods aimed to detect the topology of the universe using catalogues of cosmic objects would be damaged by various observational uncertainties. We find that the topological…

Astrophysics · Physics 2011-05-23 Roland Lehoucq , Jean-Philippe Uzan , Jean-Pierre Luminet

We present a new method to identify large scale filaments and apply it to a cosmological simulation. Using positions of haloes above a given mass as node tracers, we look for filaments between them using the positions and masses of all the…

Cosmology and Nongalactic Astrophysics · Physics 2011-02-22 Roberto E. Gonzalez , Nelson E. Padilla

This paper presents a systematic literature review focusing on the application of machine learning techniques for deriving observational constraints in cosmology. The goal is to evaluate and synthesize existing research to identify…

Cosmology and Nongalactic Astrophysics · Physics 2025-10-14 Luis Rojas , Sebastián Espinoza , Esteban González , Carlos Maldonado , Fei Luo

This article gives the construction and complete classification of all three-dimensional spherical manifolds, and orders them by decreasing volume, in the context of multiconnected universe models with positive spatial curvature. It…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Evelise Gausmann , Roland Lehoucq , Jean-Pierre Luminet , Jean-Philippe Uzan , Jeffrey Weeks

We review recent advancements in cosmology with galaxy clusters. Galaxy clusters are the most massive objects in the Universe. Consequently the cluster number density as a function of cluster mass, or cluster abundance, is sensitive to…

Cosmology and Nongalactic Astrophysics · Physics 2025-05-13 Hironao Miyatake

The identification of substructures within halos in cosmological hydrodynamical simulations is a fundamental step to identify the simulated counterparts of real objects, namely galaxies. For this reason, substructure finders play a crucial…

Cosmology and Nongalactic Astrophysics · Physics 2024-09-04 Michela Esposito , Stefano Borgani , Giuseppe Murante

Numerical simulations are a key tool to decipher the dynamics of gravitation. Yet, they fail to spatially reproduce the Universe we observe, limiting comparison between observations and simulations to a statistical level. This is highly…

Cosmology and Nongalactic Astrophysics · Physics 2026-02-04 Aurélien Valade , Noam Libeskind , Daniel Pomarède , Richard Stiskalek , Yehuda Hoffman , Stefan Gottlöber , R. Brent Tully

In this paper we present a novel method to identify and characterize stellar clusters deeply embedded in a dark molecular cloud. The method is based on measuring stellar surface density in wide-field infrared images using star counting…

Instrumentation and Methods for Astrophysics · Physics 2017-11-29 Marco Lombardi , Charles J. Lada , Joao Alves
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