Related papers: Constraining gas motions in the Centaurus cluster …
We present new deep Chandra observations of the Centaurus A jet, with a combined on-source exposure time of 719 ks. These data allow detailed X-ray spectral measurements to be made along the jet out to its disappearance at 4.5 kpc from the…
Line-of-sight velocities of gas and stars can constrain dark matter (DM) within rotationally supported galaxies if they trace circular orbits extensively. Photometric asymmetries may signify non-circular motions, requiring spectra with…
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…
We discuss various possibilities to constrain ICM turbulence in galaxy clusters using bright X-ray lines. Numerical simulations are used to find the most appropriate description of the 3D velocity field power spectrum (PDS) and to calibrate…
We demonstrate a novel technique for calibrating the energy scale of the XMM EPIC-pn detector, which allows us to measure bulk flows in the intracluster medium (ICM) of the Perseus and Coma clusters. The procedure uses the instrumental…
The increasing sensitivity of current experiments, which nowadays routinely measure the thermal SZ effect within galaxy clusters, provide the hope that peculiar velocities of individual clusters of galaxies will be measured rather soon…
Velocity distributions in a vibrated granular monolayer are investigated experimentally. Non-Gaussian velocity distributions are observed at low vibration amplitudes but cross over smoothly to Gaussian distributions as the amplitude is…
The peculiar velocity of the Local Group of galaxies manifested in the Cosmic Microwave Background dipole is found to decompose into three dominant components. The three components are clearly separated because they arise on distinct…
We present the high-resolution X-rayspectroscopic observations of the Ophiuchus galaxy cluster core using the XRISM satellite. Despite previous observations revealing multiple cold fronts and dynamical disturbances in the cluster core, our…
The number density of galaxy clusters provides tight statistical constraints on the matter fluctuation power spectrum normalization, traditionally phrased in terms of sigma_8, the root mean square mass fluctuation in spheres with radius 8…
The fluctuations in the Cosmic Microwave Background (CMB) intensity due to the Sunyaev-Zeldovich (SZ) effect are the sum of a thermal and a kinetic contribution. Separating the two components to measure the peculiar velocity of galaxy…
We investigate peculiar velocities predicted for clusters in Lambda cold dark matter ($\Lambda$CDM) models assuming that the initial density fluctuation field is Gaussian. To study the non-linear regime, we use N-body simulations. We…
We show how the virial theorem can be applied to the hot gas in clusters of galaxies to obtain a yardstick, which could then be used to determine cosmological parameters. This yardstick relies on the assumptions of hydrostatic equilibrium…
We present an analysis of the temperature structure of the Perseus cluster atmosphere using XRISM Resolve observations. The average temperature rises from 3.3 keV near the nucleus of NGC 1275 to 8 keV at 10 arcmin (210 kpc), which is…
The potential of the Surface Brightness Fluctuation (SBF) method to determine distances to dwarf ellipticals in nearby clusters is investigated. We find that for the Fornax cluster, the SBF method yields reliable results down to very faint…
A driven granular material, e.g. a vibrated box full of sand, is a stationary system which may be very far from equilibrium. The standard equilibrium statistical mechanics is therefore inadequate to describe fluctuations in such a system.…
We discuss, using simple analytical models and MHD simulations, the origin and parameters of turbulence and magnetic fields in galaxy clusters. Three physically distinct regimes can be identified in the evolution of cluster turbulence and…
We study statistical properties of galaxy structures in several samples extracted from the 2dF Galaxy Redshift Survey. In particular, we measured conditional fluctuations by means of the scale-length method and determined their probability…
Gas motions in galaxy clusters play important roles in determining the properties of the intracluster medium (ICM) and in the constraint of cosmological parameters via X-ray and Sunyaev-Zel'dovich effect observations of galaxy clusters. The…
We present Chandra data from a 31.7 ks observation of the Centaurus cluster, using the ACIS-S detector. Images of the X-ray emission show a plume-like feature at the centre of the cluster, of extent 60 arcsec (20 kpc in projection). The…