Related papers: Galaxy Clusters: Oblate or Prolate?
For the quadruple gravitational lens PG 1115+080, we combine recent measurements of the time delays with new lens models to determine the Hubble constant H_0. We explore the effects of systematic uncertainties in the lens models on the…
We investigated the influence of environment on cluster galaxies by examining the alignment of the brightest cluster galaxy (BCG) position angle with respect to the host cluster X-ray position angle. The cluster position angles were…
We present thermal Sunyaev-Zel'dovich effect (SZE) measurements for 42 galaxy clusters observed at 150 GHz with the APEX-SZ experiment. For each cluster, we model the pressure profile and calculate the integrated Comptonization $Y$ to…
I review the current state of determinations of the Hubble constant, which gives the length scale of the Universe by relating the expansion velocity of objects to their distance. There are two broad categories of measurements. The first…
We have derived accurate distances to Galactic globular clusters by combining data from the Gaia Early Data Release 3 with distances based on Hubble Space telescope HST data and literature based distances. We determine distances either…
For a detailed comparison of the appearance of cluster of galaxies in X-rays and in the optical, we have compiled a comprehensive database of X-ray and optical properties of a sample of clusters based on the largest available X-ray and…
In galaxy clusters the thermal Sunyaev-Zel'dovich (SZ) effect from the hot intracluster medium (ICM) provides a direct, self-contained measure of the pressure integrated over crossing lines of sight, that is intrinsically independent of…
The amplitude of the angular two-point galaxy correlation function w(\theta) for galaxies at z~2 is estimated for galaxies in the Hubble Deep Field by using a U < 27 complete sub-sample. (i) It is confirmed that the amplitude of the…
Galaxies which fall into clusters as part of the same infall halo can retain correlations due to their shared origin. N-body simulations are used to study properties of such galaxy subgroups within clusters, including their richnesses and…
We study the influence of the various parameters of scenarios of large-scale structure formation on properties of galaxy clusters, and investigate which cluster properties are most sensitive to these parameters. We present a set of large…
(abridged) The evolution of galaxy clustering from z=0 to z=4.5 is analyzed using the angular correlation function and the photometric redshift distribution of galaxies brighter than I_{AB}\le 28.5 in the HDF North. The reliability of the…
The use of galaxy clusters as precision cosmological probes relies on an accurate determination of their masses. However, inferring the relationship between cluster mass and observables from direct observations is difficult and prone to…
Type Ia supernovae are the best cosmological standard candles available. The intrinsic scatter of their decline-rate- and colour-corrected peak brightnesses in the Hubble diagram is within observational error limits, corresponding to an…
Clusters of galaxies are uniquely important cosmological probes of the evolution of the large scale structure, whose diagnostic power depends quite significantly on the ability to reliably determine their masses. Clusters are typically…
We estimate the distribution of intrinsic shapes of UZC-SSRS2 groups of galaxies from the distribution of their apparent shapes. We measure the projected group axial ratio using the moments of their discrete galaxy distribution. Then using…
Clusters and groups of galaxies are highly aspherical, with shapes approximated by nearly prolate ellipsoids of revolution. An equally fundamental property is the shape of these objects in velocity space which is the anisotropy of the…
We aim to quantify the capability of the inhomogeneous distribution of galaxy clusters, represented by the two-point statistics in Fourier space, to retrieve information on the underlying scaling relations. We make a case study using the…
We discuss the angular correlation function of Sunyaev-Zel'dovich (SZ)-detected galaxy clusters as a cosmological probe. As a projection of the real-space cluster correlation function, the angular function samples the underlying SZ catalog…
We present a quantitative study of the X-ray morphology of galaxy clusters, as a function of their detection method and redshift. We analyze two separate samples of galaxy clusters: a sample of 36 clusters at 0.35 < z < 0.9 selected in the…
Luminous stars in background galaxies straddling the lensing caustic of a foreground galaxy cluster can be individually detected due to extreme magnification factors of $\sim 10^2$--$10^3$, as recently observed in deep HST images. We…