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Turbulent gas motion inside galaxy clusters provides a non-negligible non-thermal pressure support to the intracluster gas. If not corrected, it leads to a systematic bias in the estimation of cluster masses from X-ray and…

Cosmology and Nongalactic Astrophysics · Physics 2015-02-17 Xun Shi , Eiichiro Komatsu , Kaylea Nelson , Daisuke Nagai

The principles of measuring the shapes of galaxies by a model-fitting approach are discussed in the context of shape-measurement for surveys of weak gravitational lensing. It is argued that such an approach should be optimal, allowing…

Astrophysics · Physics 2009-11-13 L. Miller , T. D. Kitching , C. Heymans , A. F. Heavens , L. Van Waerbeke

In order to obtain morphological information of unlabeled galaxies, we present an unsupervised machine-learning (UML) method for morphological classification of galaxies, which can be summarized as two aspects: (1) the methodology of…

Astrophysics of Galaxies · Physics 2022-02-02 C. C. Zhou , Y. Z. Gu , G. W. Fang , Z. S. Lin

In metallic nanoparticles, the cluster geometric structures control the particle's electronic band structure, polarizability, and catalytic properties. Analyzing the structural properties is a complex problem; the structure of an assembled…

Materials Science · Physics 2022-10-12 Jiale Shi , Shanghui Huang , François Gygi , Jonathan K. Whitmer

This paper introduces a new approach to analyzing spatial point data clustered along or around a system of curves or "fibres." Such data arise in catalogues of galaxy locations, recorded locations of earthquakes, aerial images of minefields…

Methodology · Statistics 2012-10-01 Bryony J. Hill , Wilfrid S. Kendall , Elke Thönnes

We present observations and analysis of a sample of 123 galaxy clusters from the 2013 Planck catalogue of Sunyaev-Zel'dovich sources with the Arcminute Microkelvin Imager (AMI), a ground-based radio interferometer. AMI provides an…

We build a simple, {\it top-down} model for the gas density and temperature profiles for galaxy clusters. The gas is assumed to be in hydrostatic equilibrium along with a component of non-thermal pressure taken from simulations and the gas…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 Anya Chaudhuri , Subhabrata Majumdar

If properly calibrated, the shapes of galaxy clusters can be used to investigate many physical processes: from feedback and quenching of star formation, to the nature of dark matter. Theorists frequently measure shapes using moments of…

Cosmology and Nongalactic Astrophysics · Physics 2020-11-11 David Harvey , Andrew Robertson , Sut-Ieng Tam , Mathilde Jauzac , Richard Massey , Jason Rhodes , Ian G. McCarthy

We present a quantitative study of the X-ray morphology of galaxy clusters, as a function of their detection method and redshift. We analyze two separate samples of galaxy clusters: a sample of 36 clusters at 0.35 < z < 0.9 selected in the…

Context: The huge and still rapidly growing amount of galaxies in modern sky surveys raises the need of an automated and objective classification method. Unsupervised learning algorithms are of particular interest, since they discover…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 Rene Andrae , Peter Melchior , Matthias Bartelmann

Many simple natural phenomena are characterized by complex motion that appears random at first glance, but that often displays underlying patterns and behavior that can be clustered in groups. The movement of small pieces of paper falling…

Data Analysis, Statistics and Probability · Physics 2022-10-10 Arthur A. B. Pessa , Matjaz Perc , Haroldo V. Ribeiro

While clusters of galaxies are considered one of the most important cosmological probes, the standard spherical modelling of the dark matter and the intracluster medium is only a rough approximation. Indeed, it is well established both…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-11 Marceau Limousin , Andrea Morandi , Mauro Sereno , Massimo Meneghetti , Stefano Ettori , Matthias Bartelmann , Tomas Verdugo

Galaxy clusters, the most massive collapsed structures, have been routinely used to determine cosmological parameters. When using clusters for cosmology, the crucial assumption is that they are relaxed. However, subarcminute resolution…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 Sandor M. Molnar , Nathan C. Hearn , Joachim G. Stadel

This study focuses on modelling galaxy cluster gas profiles via a semi-parametric nodal approach. While traditional methods like the generalised Navarro-Frenk-White (gNFW) often encounter parameter degeneracy, our flexible node-based method…

Cosmology and Nongalactic Astrophysics · Physics 2024-04-05 Kang Wang , Yvette Perrott , Richard Arnold , David Huijser

Researchers are often interested in predicting outcomes, conducting clustering analysis to detect distinct subgroups of their data, or computing causal treatment effects. Pathological data distributions that exhibit skewness and…

Methodology · Statistics 2020-08-24 Arman Oganisian , Nandita Mitra , Jason Roy

In this work, we performed an analysis of the X-ray morphology of the 118 CHEX-MATE (Cluster HEritage project with XMM-Newton - Mass Assembly and Thermodynamics at the Endpoint of structure formation) galaxy clusters, with the aim to…

The projected gravitational potential of galaxy clusters is reflected in both their X-ray emission and their imprint on the images of background sources due to their gravitational lensing effects. Since these projections of the potential…

Astrophysics · Physics 2007-05-23 Matthias Bartelmann , Tsafrir S. Kolatt

This paper is the first in a series in which we perform an extensive comparison of various galaxy-based cluster mass estimation techniques that utilise the positions, velocities and colours of galaxies. Our primary aim is to test the…

Likelihood fitting to two-point clustering statistics made from galaxy surveys usually assumes a multivariate normal distribution for the measurements, with justification based on the central limit theorem given the large number of…

Cosmology and Nongalactic Astrophysics · Physics 2019-04-23 Mike Shengbo Wang , Will J. Percival , Santiago Avila , Robert Crittenden , Davide Bianchi
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