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We study the mass distribution of a sample of 24 X-ray bright Abell clusters through weak gravitational lensing. This method is independent of the dynamical state of the galaxy cluster. Hence, by comparing dynamical and lensing mass…

Astrophysics · Physics 2007-05-23 E. S. Cypriano , L. Sodre , J. -P. Kneib , L. E. Campusano

We use numerical simulations to explore biases that arise in dynamical estimates of the mean mass profile for a collection of galaxy clusters that have been stacked to make a composite. There are three types of bias. One arises from…

Cosmology and Nongalactic Astrophysics · Physics 2025-06-16 Yan-Chuan Cai , Nick Kaiser , Shaun Cole , Carlos Frenk

We discuss how to use the Rees-Sciama (RS) effect associated with merging clusters of galaxies to measure their kinematic properties. In a previous work (Rubino-Martin et al. 2004), the morphology and symmetries of the effect were examined…

With the recent growth in data availability and complexity, and the associated outburst of elaborate modelling approaches, model selection tools have become a lifeline, providing objective criteria to deal with this increasingly challenging…

Methodology · Statistics 2020-10-08 Alessandro Casa , Luca Scrucca , Giovanna Menardi

The paper presents the algorithm for clustering a dataset by grouping the optimal, from the point of view of the BIC criterion, number of Gaussian clusters into the optimal, from the point of view of their statistical separability,…

Machine Learning · Computer Science 2023-10-31 Oleg I. Berngardt

Using a large N-body cosmological simulation combined with a subgrid treatment of galaxy formation, we study the formation and evolution of the galaxy and cluster population in a comoving volume (100 Mpc)^3 in a LCDM universe. At z = 0, our…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-19 Hugo Martel , Fidèle Robichaud , Paramita Barai

The large-scale structure of the Universe is thought to evolve by a process of gravitational amplification from low-amplitude Gaussian noise generated in the early Universe. The later, non-linear stages of gravitation-induced clustering…

Astrophysics · Physics 2009-11-07 Peter Watts , Peter Coles , Adrian Melott

In model-based clustering, the Galaxy data set is often used as a benchmark data set to study the performance of different modeling approaches. Aitkin (2001) compares maximum likelihood and Bayesian analyses of the Galaxy data set and…

Applications · Statistics 2021-08-17 Bettina Grün , Gertraud Malsiner-Walli , Sylvia Frühwirth-Schnatter

Galaxy mergers are crucial to understanding galaxy evolution, therefore we must determine their observational signatures to select them from large IFU galaxy samples such as MUSE and SAMI. We employ 24 high-resolution idealised…

We study an SDSS sample of galaxies within 50 Mpc of the nominal center of the Ursa Major supercluster. Our aim is to study galaxy distribution around groups in the supercluster and the link between the distribution of relaxed and…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-15 Marcelo Krause , Andre Ribeiro , Paulo Lopes

Many astrophysical and galaxy-scale cosmological problems require a well determined gravitational potential which is often modeled by observers under strong assumptions. Globular clusters (GCs) surrounding galaxies can be used as dynamical…

Astrophysics of Galaxies · Physics 2020-05-20 Sophia Lilleengen , Wilma H. Trick , Glenn van de Ven

A sample of hundreds of simulated galaxy clusters is used to study the statistical properties of galaxy cluster formation. Individual assembly histories are discussed, the degree of virialization is demonstrated and various commonly used…

Astrophysics · Physics 2008-11-26 J. D. Cohn , Martin White

The degree of complexity and, to a somewhat lesser degree, realism in simulations has advanced rapidly in the past few years. The simplest approach - modeling a cluster as collisionless dark matter and collisonal, non--radiative gas is now…

Astrophysics · Physics 2007-05-23 August E. Evrard

In this paper we test the performance of explicit simulations of groups of galaxies, (i.e. simulations in which each galaxy is treated as a mass point and the physics of the interactions is modelled by specific analand the physics of the…

Astrophysics · Physics 2007-05-23 C. Garcia-Gomez , E. Athanassoula , A. Garijo

Analytical estimates of the mass and radial dependence of the rates of galaxy mergers and of tidal interactions are derived for clusters and groups of galaxies, taking into account the tides from the system potential that limit the sizes of…

Astrophysics · Physics 2007-05-23 Gary A. Mamon

Simulation based inference has seen increasing interest in the past few years as a promising approach to model the non linear scales of galaxy clustering. The common approach using Gaussian process is to train an emulator over the…

Cosmology and Nongalactic Astrophysics · Physics 2023-11-20 Tyann Dumerchat , Julian Bautista

The process of galaxy cluster formation likely leaves an imprint on the properties of its individual member galaxies. Understanding this process is essential for uncovering the evolutionary connections between galaxies and cosmic…

We use updated gas mass fraction measurements of 44 massive dynamically relaxed galaxy clusters collated in arXiv:2111.09343 to distinguish between the standard $\Lambda$CDM model and $R_h=ct$ universe. For this purpose, we use Bayesian…

Cosmology and Nongalactic Astrophysics · Physics 2024-06-10 Kunj Panchal , Shantanu Desai

We study the formation and the evolution of galaxy groups in a critical universe, showing the importance of secondary infall for their dynamical evolution. Merging is only slightly accelerated if galaxies have massive halos, because the…

Astrophysics · Physics 2009-10-28 Fabio Governato , Paolo Tozzi , Alfonso Cavaliere

Galaxies and clusters embedded in the large-scale structure of the Universe are observed to align in preferential directions. Galaxy alignment has been established as a potential probe for cosmological information, but the application of…

Cosmology and Nongalactic Astrophysics · Physics 2020-12-02 Casper J. G. Vedder , Nora Elisa Chisari