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In cluster analysis, a common first step is to scale the data aiming to better partition them into clusters. Even though many different techniques have throughout many years been introduced to this end, it is probably fair to say that the…

Machine Learning · Computer Science 2023-05-30 Eduardo J. Aguilar , Valmir C. Barbosa

Classification of cluster variables in cluster algebras (in particular, Grassmannian cluster algebras) is an important problem, which has direct application to computations of scattering amplitudes in physics. In this paper, we apply the…

High Energy Physics - Theory · Physics 2026-02-16 Man-Wai Cheung , Pierre-Philippe Dechant , Yang-Hui He , Elli Heyes , Edward Hirst , Jian-Rong Li

We present a detailed study of the morphological features of 22 rich galaxy clusters. Our sample is constructed from a cross-correlation of optical (Abell+APM) data with X-ray (0.1 - 2.4) keV ROSAT pointed observations. We systematically…

In the framework of the hierarchical model the intra-cluster medium properties of galaxy clusters are tightly linked to structure formation, which makes X-ray surveys well suited for cosmological studies. To constrain cosmological…

Cosmology and Nongalactic Astrophysics · Physics 2019-08-07 Florian Käfer , Alexis Finoguenov , Dominique Eckert , Jeremy S. Sanders , Thomas H. Reiprich , Kirpal Nandra

In cluster tomography, we propose measuring the number of clusters $N$ intersected by a line segment of length $\ell$ across a finite sample. As expected, the leading order of $N(\ell)$ scales as $a\ell$, where $a$ depends on microscopic…

Disordered Systems and Neural Networks · Physics 2024-02-13 Helen S. Ansell , Samuel J. Frank , István A. Kovács

We study the implications and limitations of galaxy cluster surveys for constraining models of particle physics and gravity beyond the Standard Model. Flux limited cluster counts probe the history of large scale structure formation in the…

High Energy Physics - Phenomenology · Physics 2008-11-26 Joshua Erlich , Brian Glover , Neal Weiner

In O($N$) non-linear $\sigma$-models on the lattice, the Wolff cluster algorithm is based on rewriting the functional integral in terms of mutually independent clusters. Through improved estimators, the clusters are directly related to…

High Energy Physics - Lattice · Physics 2019-12-23 Wolfgang Bietenholz , João C. Pinto Barros , Stephan Caspar , Manes Hornung , Uwe-Jens Wiese

Macroscopic spherical particles spontaneously form rich patterns on a standing Faraday wave. These patterns are found to follow a very systematic trend depending on the floater concentration $\phi$: The same floaters that accumulate at…

Fluid Dynamics · Physics 2014-05-09 Ceyda Sanlı , Detlef Lohse , Devaraj van der Meer

Critical phase transitions have proven to be a powerful concept to capture the phenomenology of many systems, including deeply non-equilibrium ones like living systems. The study of these phase transitions has overwhelmingly relied on…

Statistical Mechanics · Physics 2025-12-12 Leone V. Luzzatto , Mathias Casiulis , Stefano Martiniani , István A. Kovács

The analysis of the spatial distribution and kinematics of galaxies in clusters allows one to determine the cluster internal dynamics. In this paper, I review the state of the art of this topic. In particular, I summarize what we have…

Astrophysics · Physics 2007-05-23 Andrea Biviano

The generalization of Kasteleyn and Fortuin clusters formalism is introduced in XY (or more generally O(n)) models. Clusters geometrical structure may be linked to spin physical properties as correlation functions. To investigate…

Condensed Matter · Physics 2015-06-25 Mario Nicodemi

Observed clusters should be modelled by considering the distribution function to be a random variable that quantifies the degree of excitation of the system's normal modes. A system of canonical coordinates for the space of DFs is…

Astrophysics of Galaxies · Physics 2021-08-11 Jun Yan Lau , James Binney

Internal cluster validity measures (such as the Calinski-Harabasz, Dunn, or Davies-Bouldin indices) are frequently used for selecting the appropriate number of partitions a dataset should be split into. In this paper we consider what…

Machine Learning · Statistics 2022-08-31 Marek Gagolewski , Maciej Bartoszuk , Anna Cena

Galaxy superclusters, the largest galaxy structures in the cosmic web, are formed due to the gravitational collapse (although they are not usually gravitationally bound). Their geometrical properties can shed light on the structure…

Cosmology and Nongalactic Astrophysics · Physics 2023-04-20 Satadru Bag , Lauri Juhan Liivamägi , Maret Einasto

In this review I focus on the galactic properties in clusters at $z>0.1-02$. The most salient results regarding the evolution in galaxy colors, spectral features and morphologies are discussed.

Astrophysics · Physics 2009-11-07 Bianca M. Poggianti

We introduce surface Minkowski tensors to characterize rotational symmetries of shapes embedded in curved surfaces. The definition is based on a modified vector transport of the shapes boundary co-normal into a reference point which…

Numerical Analysis · Mathematics 2026-02-10 Lea Happel , Hanne Hardering , Simon Praetorius , Axel Voigt

Using the apparatus of correlation Gamma-function (``conditional density''), we have analyzed spatial clustering of objects from several different samples of galaxies, clusters and superclusters. On small scales the distribution of objects…

Astrophysics · Physics 2007-05-23 A. V. Tikhonov , D. I. Makarov , A. I. Kopylov

An algebraic characterization of vacuum states in Minkowski space is given which relies on recently proposed conditions of geometric modular action and modular stability for algebras of observables associated with wedge-shaped regions. In…

Mathematical Physics · Physics 2007-05-23 Detlev Buchholz , Martin Florig , Stephen J. Summers

The main ingredients of recent semi-analytic models of galaxy formation are summarised. We present predictions for the galaxy clustering properties of a well specified LCDM model whose parameters are constrained by observed local galaxy…

Astrophysics · Physics 2007-05-23 Shaun Cole , Andrew Benson , Carlton Baugh , Cedric Lacey , Carlos Frenk

Usual formulations of the clustering coefficient can be shown to be insufficient in the task of describing the local topology of very simple networks. Motivated by this, we review some alternatives in order to present an extension, the…

Data Analysis, Statistics and Probability · Physics 2007-05-23 Alexandre H. Abdo , A. P. S. de Moura