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We present a novel graph-based machine learning classifier for identifying the dark matter cosmic web environments of galaxies. Large galaxy surveys offer comprehensive statistical views of how galaxy properties are shaped by large-scale…

Astrophysics of Galaxies · Physics 2026-04-02 Dakshesh Kololgi , Krishna Naidoo , Amelie Saintonge , Ofer Lahav

We propose to use a simple observable, the fractional area of "hot spots" in weak gravitational lensing mass maps which are detected with high significance, to determine background cosmological parameters. Because these high-convergence…

Astrophysics · Physics 2011-02-11 Sheng Wang , Zoltán Haiman , Morgan May

We study the geometry and topology of the large-scale structure traced by galaxy clusters in numerical simulations of a box of side 320 $h^{-1}$ Mpc, and compare them with available data on real clusters. The simulations we use are…

Astrophysics · Physics 2020-11-25 P. Coles , R. C. Pearson , S. Borgani , M. Plionis , L. Moscardini

We propose and investigate a new algorithm for quantifying the topological properties of cosmological density fluctuations. We first motivate this algorithm by drawing a formal distinction between two definitions of relevant topological…

Astrophysics · Physics 2015-06-24 Peter Coles , Andrew G. Davies , Russell C. Pearson

We impose constraints on the topology of the Universe determined from a search for matched circles in the temperature anisotropy patterns of the 7-year WMAP data. We pay special attention to the sensitivity of the method to residual…

Cosmology and Nongalactic Astrophysics · Physics 2018-02-07 P. Bielewicz , A. J. Banday

The abundance of peaks in weak gravitational lensing maps is a potentially powerful cosmological tool, complementary to measurements of the shear power spectrum. We study peaks detected directly in shear maps, rather than convergence maps,…

Cosmology and Nongalactic Astrophysics · Physics 2015-09-16 Nicolas Martinet , James G. Bartlett , Alina Kiessling , Barbara Sartoris

The recent measurement of the gravitational redshifts of galaxies in galaxy clusters by Wojtak et al. has opened a new observational window on dark matter and modified gravity. By stacking clusters this determination effectively used the…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-15 Rupert A. C. Croft

The galaxy cluster power spectrum and mass/temperature functions are currently the most precise observational tools for constraining the theory of the formation of large scale structure (LSS) in the Universe. Complementing these tests by…

Astrophysics · Physics 2007-05-23 V. N. Lukash

The standard cosmological model, now strongly constrained by direct observation at early epochs, is very successful in describing the structure of the evolved universe on large and intermediate scales. Unfortunately, serious contradictions…

Astrophysics · Physics 2009-11-11 Sergey Mashchenko , H. M. P. Couchman , James Wadsley

The large-scale structure is a major source of cosmological information. However, next-generation photometric galaxy surveys will only provide a distorted view of cosmic structures due to large redshift uncertainties. To address the need…

Cosmology and Nongalactic Astrophysics · Physics 2023-01-10 Eleni Tsaprazi , Jens Jasche , Guilhem Lavaux , Florent Leclercq

Numerical simulations and observations show that galaxies are not uniformly distributed. In cosmology, the largest known structures in the universe are galaxy filaments formed from the hierarchical clustering of galaxies due to…

Astrophysics of Galaxies · Physics 2024-04-12 Sophia-Gisela Strey , Alexander Castronovo , Kailash Elumalai

Comparison of graph structure is a ubiquitous task in data analysis and machine learning, with diverse applications in fields such as neuroscience, cyber security, social network analysis, and bioinformatics, among others. Discovery and…

Applications · Statistics 2023-01-11 Peter Wills , Francois G. Meyer

We train deep learning models on thousands of galaxy catalogues from the state-of-the-art hydrodynamic simulations of the CAMELS project to perform regression and inference. We employ Graph Neural Networks (GNNs), architectures designed to…

Cosmology and Nongalactic Astrophysics · Physics 2023-02-10 Pablo Villanueva-Domingo , Francisco Villaescusa-Navarro

In this paper we develop the theory of clusterization of peaks in a Gaussian random field. We have obtained new mathematical results from this theory and the theory of percolation and have proposed a topological method of analysis of sky…

Astrophysics · Physics 2009-10-28 D. I. Novikov , H. E. Jorgensen

Future microwave sky surveys will have the sensitivity to detect the kinematic Sunyaev-Zeldovich signal from moving galaxy clusters, thus providing a direct measurement of their line-of-sight peculiar velocity. We show that cluster peculiar…

Astrophysics · Physics 2009-11-11 Suman Bhattacharya , Arthur Kosowsky

We investigate how observations of strong lensing can be used to infer cosmological parameters, in particular the equation of state of dark energy. We focus on the growth of the critical lines of lensing clusters with the source redshift as…

Cosmology and Nongalactic Astrophysics · Physics 2012-04-03 Britta Zieser , Matthias Bartelmann

In recent years, deep learning approaches have achieved state-of-the-art results in the analysis of point cloud data. In cosmology, galaxy redshift surveys resemble such a permutation invariant collection of positions in space. These…

Cosmology and Nongalactic Astrophysics · Physics 2022-11-23 Sotiris Anagnostidis , Arne Thomsen , Tomasz Kacprzak , Tilman Tröster , Luca Biggio , Alexandre Refregier , Thomas Hofmann

We perform an analysis of the Cosmic Web as a complex network, which is built on a $\Lambda$CDM cosmological simulation. For each of nodes, which are in this case dark matter halos formed in the simulation, we compute 10 network metrics,…

Cosmology and Nongalactic Astrophysics · Physics 2020-08-04 Maksym Tsizh , Bohdan Novosyadlyj , Yurij Holovatch , Noam I Libeskind

We analyse the clustering of cosmic large scale structure using a consistent modified gravity perturbation theory, accounting for anisotropic effects along and transverse to the line of sight. The growth factor has a particular scale…

A fundamental assumption in cosmology is that of statistical isotropy - that the universe, on average, looks the same in every direction in the sky. Statistical isotropy has recently been tested stringently using Cosmic Microwave Background…

Cosmology and Nongalactic Astrophysics · Physics 2011-09-14 Caroline Zunckel , Dragan Huterer , Glenn D. Starkman