Related papers: Direct X-ray Spectral Deprojection of Galaxy Clust…
We have used the ROSAT PSPC to study the properties of a sample of 24 X-ray bright galaxy groups, representing the largest sample examined in detail to date. Hot plasma models are fitted to the spectral data to derive temperatures, and…
Mahdavi et al. find that the degree of agreement between weak lensing and X-ray mass measurements is a function of cluster radius. Numerical simulations also point out that X-ray mass proxies do not work equally well at all radii. The…
In order to study the internal dynamics of actual galaxy pairs, we need to derive the probability distribution function (PDF) of true 3D (orbital) intervelocities and interdistances between pair members from their observed (projected)…
The failure of purely gravitational models of X-ray cluster formation to reproduce basic observed properties of the local cluster population suggests the need for one or more additional physical processes operating on the intracluster…
Using the PV observation of A1795, we illustrate the capability of XMM-EPIC to measure cluster temperature profiles, a key ingredient for the determination of cluster mass profiles through the equation of hydrostatic equilibrium. We develop…
We present an X-ray image deprojection analysis of Einstein Observatory imaging data on 207, clusters of galaxies. The resulting radial profiles for luminosity, temperature, and electron density variations are determined from the cluster…
In a previous paper we have described a technique to derive constraints on the differential emission measure (DEM) distribution, a measure of the temperature distribution, of collisionally ionized hot plasmas from their X-ray emission line…
Cold Dark Matter (CDM) models of galaxy formation had been remarkably successful to explain a number of observations in the past decade. However, with both the theoretical modeling and the observations being improved, CDM models have been…
We show that a Denoising Diffusion Probabalistic Model (DDPM), a class of score-based generative model, can be used to produce realistic mock images that mimic observations of galaxies. Our method is tested with Dark Energy Spectroscopic…
Similar to the case of solar system planets, reflected starlight from exoplanets is expected to be polarized due to atmospheric scattering and the net disk integrated polarization should be non-zero owing to the asymmetrical illumination of…
In collisional ionization equilibrium (CIE), the X-ray spectrum from a plasma depends on the distribution of emission measure over temperature (DEM). Due to the well-known ill conditioning problem, no precisely resolved DEM can be inverted…
We calculate temperature profiles and X-ray spectra of accretion disks around rapidly rotating neutron stars considering the full effect of general relativity. Computed disk temperatures and luminosities are compared with the EXOSAT data to…
Thermodynamic profiles from X-ray and millimetre observations of galaxy clusters are often compared under the simplifying assumptions of smooth, spherically symmetric intracluster medium. These approximations lead to expected discrepancies…
The cooling cores of clusters of galaxies are among the brightest thermal X-ray line sources in the universe. High resolution X-ray spectra would allow individual line fluxes to be measured. The fluxes of low ionization X-ray lines in…
Numerical hydro-N-body simulations are very important tools for making theoretical predictions for the formation of galaxy clusters. They show that the atmospheres of clusters of galaxies have quite complex angular and thermal structures.…
Recent advances in machine learning algorithms have unlocked new insights in observational astronomy by allowing astronomers to probe new frontiers. In this article, we present a methodology to disentangle the intrinsic X-ray spectrum of…
Dual-energy X-ray Computed Tomography (DECT) constitutes an advanced technology which enables automatic decomposition of materials in clinical images without manual segmentation using the dependency of the X-ray linear attenuation with…
We show that galaxy clusters conform to a tight relation between X-ray isophotal size R_I and emission weighted intracluster medium (ICM) temperature T_X. The best fit relation for 41 members of an X-ray flux limited cluster sample is:…
X-ray observations of galaxy cluster merger shocks can be used to constrain nonthermal processes in the intracluster medium (ICM). The presence of nonthermal pressure components in the ICM, as well as the shock acceleration of particles and…
Using a large and well-controlled sample of clusters of galaxies, we investigate the relation between cluster velocity dispersions and X-ray temperatures of intra-cluster gas. In order to obtain a reliable estimate of the total velocity…