相关论文: Yet another test of Radial Acceleration Relation f…
Recently, gas entropy at the outskirts of galaxy clusters attracts much attention. We propose that the entropy profiles could be used to study cosmic-ray (CR) acceleration around the clusters. If the CRs are effectively accelerated at the…
The X-ray properties of a sample of 11 high-redshift (0.6<z<1.0) clusters observed with Chandra and/or XMM are used to investigate the evolution of the cluster scaling relations. The observed evolution of the L-T and M-L relations is…
We cross-match objects from several different astronomical catalogs to determine the absolute proper proper motions of stars within the 30-arcmin radius fields of 115 Milky-Way globular clusters with the accuracy of 1--2~mas/yr. The proper…
With rapid improvements in the assembly of large samples of galaxy clusters, we are approaching the ability to study clusters at $z\gtrsim2$. Evolutionary studies comparing these distant clusters to the clusters in our local universe depend…
A rapidly growing amount of evidences, mostly coming from the recent gamma-ray observations of Galactic supernova remnants (SNRs), is seriously challenging our understanding of how particles are accelerated at fast shocks. The cosmic-ray…
We compute the cluster auto-correlation function $\xi_{cc}(r)$ of an X-ray flux limited sample of Abell clusters (XBACs, \cite{ebe}). For the total XBACs sample we find a power-law fit $\xi_{cc}=(r/r_0)^{\gamma}$ with $r_0=21.1$ Mpc…
An extensive redshift survey has been conducted on a sample of 15 nearby (0.01 < z < 0.05) clusters of galaxies. A total number of 860 redshifts were determined by fitting of emission--lines and/or cross-correlation techniques. Of this…
Galaxy rotation curves exhibit systematic deviations from the Newtonian expectation inferred from visible matter alone. Existing phenomenological descriptions capture many aspects of these deviations, but a common residual structure across…
We study the total gravitating mass distribution in the central region of 23 clusters of galaxies with Chandra. Using a new deprojection technique, we measure the temperature and gas density in the very central region of the clusters as a…
Dark matter is required in galaxies at galactocentric radii that are larger than the $a_0$-radius, which is where the gravitational acceleration generated by baryons of the galaxy equals the constant $a_0=1.2\times 10^{-10}$ms$^{-2}$ known…
The mass discrepancy in disk galaxies is shown to be well correlated with acceleration, increasing systematically with decreasing acceleration below a critical scale a0 = 3700 km^2/s^2/kpc = 1.2E-10 m/s/s. For each galaxy, there is an…
From the poor cluster catalog of White et al. (1996), we define a sample of 71 optically-selected poor galaxy clusters. The surface-density enhance- ment we require for our clusters falls between that of the loose associations of Turner and…
[abridged] We present a first cosmological analysis of a refined cluster catalog from the Red-Sequence Cluster Survey (RCS). The input cluster sample is derived from 72.07 square degrees of imaging data [...] The catalog contains 956…
Open clusters are known as excellent tracers of the structure and chemical evolution of the Galactic disk, however, the accuracy and reliability of open cluster parameters is poorly known. In recent years, several studies aimed to present…
We use the RASS-SDSS galaxy cluster sample to compare the quality of optical and X-ray luminosities as predictors of other cluster properties such as their masses, temperatures, and velocity dispersions. We use the SDSS spectroscopic data…
We explore the possibility of using the external regions of galaxy clusters to measure their mass accretion rate (MAR). The main goal is to provide a method to observationally investigate the growth of structures on the nonlinear scales of…
In recent years, improvements in galaxy cluster observations have enabled a variety of tests of fundamental physics using these systems. In this work, we test the constancy of the speed of light, $c$, by combining X-ray gas mass fraction…
We study simple models of massive galaxy clusters in which the intracluster medium (ICM) rotates differentially in equilibrium in the cluster gravitational potential. We obtain the X-ray surface brightness maps, evaluating the isophote…
We are engaged in an investigation of the relationship between the properties of BCG candidates and X-ray characteristics of their host clusters for a flux-limited sample of ~250 ACO clusters from the ROSAT all-sky survey. We aim to search…
Following extensive tests on analytical toy-catalogues (paper III), we present the results of a more realistic study over a 711 deg2 template-based cosmological simulation. Dark matter halos from the Aardvark simulation have been ascribed…