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Modified gravity theories have richer observational consequences for large-scale structure than conventional dark energy models, in that different observables are not described by a single growth factor even in the linear regime. We examine…

天体物理学 · 物理学 2009-02-20 Bhuvnesh Jain , Pengjie Zhang

With the advent of wide-field cosmological surveys, we are approaching samples of hundreds of thousands of galaxy clusters. While such large numbers will help reduce statistical uncertainties, the control of systematics in cluster masses…

Cosmological inference from cluster number counts is systematically limited by the accuracy of the mass calibration, i.e. the empirical determination of the mapping between cluster selection observables and halo mass. In this work we…

宇宙学与河外天体物理 · 物理学 2021-09-21 Sebastian Grandis , Sebastian Bocquet , Joseph J. Mohr , Matthias Klein , Klaus Dolag

We propose a new cosmological test of gravity, by using the observed mass fraction of X-ray emitting gas in massive galaxy clusters. The cluster gas fraction, believed to be a fair sample of the average baryon fraction in the Universe, is a…

宇宙学与河外天体物理 · 物理学 2015-12-23 Baojiu Li , Jian-hua He , Liang Gao

We use the Millennium Simulation to quantify the statistical accuracy and precision of the escape velocity technique for measuring cluster-sized halo masses at z~0.1. We show that in 3D, one can measure nearly unbiased (<4%) halo masses…

宇宙学与河外天体物理 · 物理学 2013-07-02 Daniel Gifford , Christopher J. Miller

We show how hydrostatic equilibrium in galaxy clusters can be quantitatively probed combining X-ray, SZ, and gravitational-lensing data. Our previously published method for recovering three-dimensional cluster gas distributions avoids the…

天体物理学 · 物理学 2009-11-13 Ewald Puchwein , Matthias Bartelmann

The masses of galaxy clusters are commonly measured from X-ray observations under the assumption of hydrostatic equilibrium (HSE). This technique is known to underestimate the true mass systematically. The fiducial FLAMINGO cosmological…

宇宙学与河外天体物理 · 物理学 2024-12-19 Joey Braspenning , Joop Schaye , Matthieu Schaller , Roi Kugel , Scott T. Kay

This is the fourth in a series of papers studying the astrophysics and cosmology of massive, dynamically relaxed galaxy clusters. Here, we use measurements of weak gravitational lensing from the Weighing the Giants project to calibrate…

We aim at investigating potential biases in lensing and X-ray methods to measure the cluster mass profiles. We do so by performing realistic simulations of lensing and X-ray observations that are subsequently analyzed using observational…

宇宙学与河外天体物理 · 物理学 2015-05-14 M. Meneghetti , E. Rasia , J. Merten , F. Bellagamba , S. Ettori , P. Mazzotta , K. Dolag

We use cosmological gas dynamic simulations to investigate the accuracy of galaxy cluster mass estimates based on X-ray observations. The experiments follow the formation of clusters in different cosmological models and include the effects…

天体物理学 · 物理学 2009-10-28 August E. Evrard , Christopher A. Metzler , Julio F. Navarro

We investigate the power of the caustic technique for identifying substructures of galaxy clusters from optical redshift data alone. The caustic technique is designed to estimate the mass profile of galaxy clusters to radii well beyond the…

宇宙学与河外天体物理 · 物理学 2015-09-09 Heng Yu , Ana Laura Serra , Antonaldo Diaferio , Marco Baldi

We present \textsc{MG-MAMPOSSt}, a license-free code to constrain modified gravity models by reconstructing the mass profile of galaxy clusters with the kinematics of the cluster's member galaxies. We describe the main features of the code…

宇宙学与河外天体物理 · 物理学 2022-04-12 Lorenzo Pizzuti

The main goal of this work is to compare the results of three dynamical mass estimators to the X-ray hydrostatic values, focussing on massive galaxy clusters at intermediate redshifts $z\sim0.3$. We estimated dynamical masses with the…

宇宙学与河外天体物理 · 物理学 2017-10-25 G. Foëx , H. Böhringer , G. Chon

Accurate mass determination of clusters of galaxies is crucial if they are to be used as cosmological probes. However, there are some discrepancies between cluster masses determined based on gravitational lensing, and X-ray observations…

宇宙学与河外天体物理 · 物理学 2015-05-18 S. M. Molnar , I. -N. Chiu , K. Umetsu , P. Chen , N. Hearn , T. Broadhurst , G. Bryan , C. Shang

The relation between mass and concentration of galaxy clusters traces their formation and evolution. Massive lensing clusters were observed to be over-concentrated and following a steep scaling in tension with predictions from the…

宇宙学与河外天体物理 · 物理学 2015-06-23 Mauro Sereno , Carlo Giocoli , Stefano Ettori , Lauro Moscardini

Machine learning (ML) techniques, in particular supervised regression algorithms, are a promising new way to use multiple observables to predict a cluster's mass or other key features. To investigate this approach we use the \textsc{MACSIS}…

宇宙学与河外天体物理 · 物理学 2019-01-16 Thomas J. Armitage , Scott T. Kay , David J. Barnes

We present a statistical comparison of three different estimates of cluster mass, namely, the dynamical masses obtained from the velocity dispersion of optical galaxies, the X-ray masses measured from the temperature of X-ray emitting gas…

天体物理学 · 物理学 2009-10-30 Xiang-Ping Wu , Li-Zhi Fang

We present a new test of the modified gravity endowed with the Vainshtein mechanism with the density profile of a galaxy cluster halo observed through gravitational lensing. A scalar degree of freedom in the galileon modified gravity is…

宇宙学与河外天体物理 · 物理学 2012-05-16 Tatsuya Narikawa , Kazuhiro Yamamoto

The location of a galaxy cluster's centroid is typically derived from observations of the galactic and/or gas component of the cluster, but these typically deviate from the true centre. This can produce bias when observations are combined…

宇宙学与河外天体物理 · 物理学 2020-02-05 Z. Yan , N. Raza , L. Van Waerbeke , A. J. Mead , I. G. McCarthy , T. Troester , G. Hinshaw

Measurements of the shear induced by weak gravitational lensing around galaxy cluster lines of sight are the gold standard for calibrating cluster observable-mass relations, thereby enabling a robust and precise inference of cosmological…

宇宙学与河外天体物理 · 物理学 2026-03-26 S. Bocquet , A. Fumagalli , C. T. Davies , K. Dolag , S. Grandis , J. J. Mohr