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Dark Matter (DM) direct detection experiments usually assume the simplest possible 'Standard Halo Model' for the Milky Way (MW) halo in which the velocity distribution is Maxwellian. This model assumes that the MW halo is an isotropic,…

宇宙学与河外天体物理 · 物理学 2014-04-02 Mattia Fornasa , Anne M. Green

Using a set of 73 numerically simulated galaxy clusters, we have characterised the statistical and physical biases for three velocity dispersion and mass estimators, namely biweight, gapper and standard deviation, in the small number of…

Gas motions in the hot intracluster medium of galaxy clusters have an important effect on the mass determination of the clusters through X-ray observations. The corresponding dynamical pressure has to be accounted for in addition to the…

宇宙学与河外天体物理 · 物理学 2015-05-20 Veronica Biffi , Klaus Dolag , Hans Boehringer

Dark matter N-body simulations suggest that the velocity distribution of dark matter is anisotropic. In this work we employ a mass model for the Milky Way whose parameters are determined from a fit to kinematical data. Then we adopt an…

宇宙学与河外天体物理 · 物理学 2015-06-17 Nassim Bozorgnia , Riccardo Catena , Thomas Schwetz

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

The structural and dynamical properties of star clusters are generally derived by means of the comparison between steady-state analytic models and the available observables. With the aim of studying the biases of this approach, we fitted…

太阳与恒星天体物理 · 物理学 2015-05-12 A. Sollima , H. Baumgardt , A. Zocchi , E. Balbinot , M. Gieles , V. Henault-Brunet , A. L. Varri

The velocity anisotropy profiles, $\beta(r)$, of galaxy clusters are directly related to the shape of the orbits of their member galaxies. Knowledge of $\beta(r)$ is important to understand the assembly process of clusters and the…

We derive the escape velocity profile for an Einasto density field in an accelerating universe and demonstrate its physical viability by comparing theoretical expectations to both light-cone data generated from N-body simulations and…

宇宙学与河外天体物理 · 物理学 2016-11-18 Alejo Stark , Christopher J. Miller , Daniel Gifford

Joint lensing and dynamical mass profile determinations of galaxy clusters are an excellent tool to constrain modification of gravity at cosmological scales. However, search for tiny departures from General Relativity calls for an accurate…

宇宙学与河外天体物理 · 物理学 2020-04-29 L. Pizzuti , B. Sartoris , S. Borgani , A. Biviano

The virial theorem prescribes the ratio of the globally-averaged equatorial to vertical velocity dispersion of a tracer population in spherical and flattened dark haloes. This gives sequences of physical models in the plane of global…

星系天体物理 · 物理学 2015-06-03 A. Agnello , N. W. Evans

Dark matter haloes in cosmological N-body simulations are affected by processes such as mergers, accretion and the gravitational interaction with baryonic matter. Typically the analysis of dark matter haloes is performed in spherical or…

宇宙学与河外天体物理 · 物理学 2012-07-26 Martin Sparre , Steen H. Hansen

The properties of clusters of galaxies offer key insights into the assembly process of structure in the universe. Numerical simulations of cosmic structure formation in a hierarchical, dark matter dominated universe suggest that galaxy…

天体物理学 · 物理学 2008-11-26 Julia M. Comerford , Priyamvada Natarajan

We present a framework for inferring the dark matter halo masses of quasars and [O III]-emitting galaxies from JWST/NIRCam Wide Field Slitless Spectroscopy (WFSS) clustering measurements at z approximately 6. Using the FLAMINGO-10k N-body…

宇宙学与河外天体物理 · 物理学 2026-05-13 Jiamu Huang , Elia Pizzati , Joseph F. Hennawi , Joop Schaye , Matthieu Schaller , Benjamin Snyder , Yi Kang

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

We study the implications of a pseudo-phase-space density power-law for the anisotropy profile of a Milky Way-like dark matter halo. Requiring that the anisotropy parameter does not take non-physical values within the virial radius places a…

宇宙学与河外天体物理 · 物理学 2014-02-18 Daniel R. Hunter

We present new measurements of dark matter distributions in 25 X-ray luminous clusters by making a full use of the two-dimensional (2D) weak lensing signals obtained from high-quality Subaru/Suprime-Cam imaging data. Our approach to…

宇宙学与河外天体物理 · 物理学 2015-05-18 Masamune Oguri , Masahiro Takada , Nobuhiro Okabe , Graham P. Smith

Dark matter dominates the properties of large cosmological structures such as galaxy clusters, and the mass profiles of the dark matter have been measured for these equilibrated structures for years using X-rays, lensing or galaxy…

宇宙学与河外天体物理 · 物理学 2020-10-28 Jacob Svensmark , Steen H. Hansen , Davide Martizzi , Ben Moore , Romain Teyssier

The use of galaxy clusters as cosmological probes hinges on our ability to measure their masses accurately and with high precision. Hydrostatic mass is one of the most common methods for estimating the masses of individual galaxy clusters,…

宇宙学与河外天体物理 · 物理学 2014-02-12 Kaylea Nelson , Erwin T. Lau , Daisuke Nagai , Douglas H. Rudd , Liang Yu

We probe the dynamical mass profiles of 10 galaxy clusters from the HIghest X-ray FLUx Galaxy Cluster Sample (HIFLUGCS) using galaxy kinematics. We numerically solve the spherical Jeans equation, and parameterize the dynamical mass profile…

The evolution of galaxy cluster counts is a powerful probe of several fundamental cosmological parameters. A number of recent studies using this probe have claimed tension with the cosmology preferred by the analysis of the Planck primary…

宇宙学与河外天体物理 · 物理学 2016-09-21 C. E. Caldwell , I. G. McCarthy , I. K. Baldry , C. A. Collins , J. Schaye , S. Bird