Related papers: Constraining gas motions in the Centaurus cluster …
We present the power spectrum analysis of clustering in the Durham/UKST Galaxy Redshift Survey, which covers 1450 square degrees and consists of 2501 galaxy redshifts sampled at a rate of 1 in 3 to b_J = 17. The fluctuations that we measure…
The recent detection of Doppler shifts of X-ray spectral lines in the intracluster gas of the Centaurus and Perseus clusters of galaxies with ASCA has raised the question of the frequency of such velocity gradients and their relation to…
Accurate estimation of galaxy cluster masses is a central problem in cosmology. Turbulence is believed to introduce significant deviations from the hydrostatic mass estimates. Estimation of turbulence properties is complicated by projection…
The distribution of atomic hydrogen in the Galactic plane is usually mapped using the Doppler shift of 21cm emission line. We calculate the emission spectrum in velocity slices of data (channel maps) and derive its dependence on the…
Small-scale fluctuations of different tracers of the interstellar the medium can be used to study the nature of turbulence in astrophysical scales. Of these, the `continuum' emission traces the fluctuations integrated along the line of…
The precision of intensity measurements of the extragalactic X-ray Background (XRB) on an angular scale of about a degree is dominated by spatial fluctuations caused by source confusion noise. X-ray source counts at the flux level…
We investigate the properties of clusters of galaxies in two cosmological models using N-body simulations and the Press-Schecter (PS) theory. In the first model, the initial power spectrum of density fluctuations is in the form P(k) \propto…
A new method for determining the nature of the orbital motion (chaotic or regular) of globular clusters in the central region of the Galaxy with a radius of 3.5 kpc, which are most affected by the bar, is proposed. The method is based on…
(Abridged) We study the impact of cluster environment on the evolution of spiral galaxies by examining their structure and kinematics. Rather than two-dimensional rotation curves, we observe complete velocity fields by placing three…
Fluctuations in the 21cm brightness from cosmic hydrogen at redshifts z > 6 were sourced by the primordial density perturbations from inflation as well as by the radiation from galaxies. We propose a method to separate these components…
We explore the detectability of bulk motions in the X-ray emitting intracluster medium (ICM) using a catalog of 1,836 mock Astro-E2 observations of simulated clusters of galaxies. We generate high resolution mock spectra for two observing…
We present a detailed analysis of the velocity structure of the Virgo cluster using {\it XMM-Newton} observations. Using a novel technique which uses uses the Cu K$\alpha$ instrumental line to calibrate the EPIC-pn energy scale, we are able…
Galaxy clusters, the largest gravitationally bound structures in the Universe, contain vast amounts of dark matter, galaxies, and hot ionised gas known as the intracluster medium (ICM). In relaxed cluster cores, the ICM appears to cool…
We study the surface brightness fluctuations of the cosmic X-ray background (CXB) using Chandra data of XBOOTES. After masking out resolved sources we compute the power spectrum of fluctuations of the unresolved CXB for angular scales from…
We present I-band Surface Brightness Fluctuations (SBF) measurements for 15 early type galaxies (3 giants, 12 dwarfs) in the central region of the Centaurus cluster, based on VLT FORS1 imaging data. From the SBF-distances to our sample…
We show that Compton scattering by electrons of the hot intergalactic gas in galaxy clusters should lead to peculiar distortions of the cosmic background X-ray and soft gamma-ray radiation - an increase in its brightness at E<60-100 keV and…
We study the late-time evolution of the central regions of two Milky Way-like simulations of galaxies formed in a cosmological context, one hosting a fast bar and the other a slow one. We find that bar length, R_b, measurements fluctuate on…
(Abridged version) We study the properties of the X-ray surface brightness profiles in a sample of galaxy clusters that were observed with Chandra and have emission detectable with a signal-to-noise ratio higher than 2 at a radius beyond…
We investigate the kinematics of stars in the mid-plane of the Milky Way on scales between 25 pc and 10 kpc with data from the Apache Point Observatory Galactic Evolution Experiment (APOGEE), the Radial Velocity Experiment (RAVE), and the…
We present here a new parameterization for the bulk motions of galaxies and clusters (in the linear regime) that can be measured statistically from the shape and amplitude of the two-dimensional two-point correlation function. We further…