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We report the discovery of CXOU J191100-595621 and CXOU J191012-595619, two galaxy clusters serendipitously detected in the direction of globular cluster NGC 6752, based on archival {it Chandra} observations with a total exposure time of $sim 344$ ks. The deep {it Chandra} X-ray data enabled us to measure properties of both systems, which result in a redshift of $z=0.239pm0.013$ and $z=0.375pm0.016$, a temperature of $kT=3.32^{+0.57}_{-0.46}$ keV and $kT=3.71^{+1.18}_{-0.86}$ keV, an iron abundance of $Z_{rm Fe}=0.64^{+0.34}_{-0.29}Z_{rm Feodot}$ and $Z_{rm Fe}=1.29^{+0.97}_{-0.65}Z_{rm Feodot}$, and a rest-frame full band (0.5-7 keV) luminosity of $L_{rm X}=9.2^{+1.2}_{-1.1}times 10^{43} {rm , erg, s^{-1}}$ and $L_{rm X}=9.9^{+2.7}_{-2.2}times 10^{43} {rm , erg, s^{-1}}$ for CXOU J191100-595621 and CXOU J191012-595619, respectively. The temperature profile of CXOU J191100-595621 is found to decreases with decreasing radius, indicating a cool core in this cluster. The hydrostatic equilibrium estimation suggests the clusters are moderately weighted, with $M_{500}=(1.3pm0.4)times 10^{14}, M_{odot}$ and $M_{500}=(2.0pm1.5)times 10^{14}, M_{odot}$, respectively. We search for optical and radio counterparts of X-ray point sources in the clusters. Three active galactic nuclei are found, among which one is identified with a narrow-angle-tail radio galaxy, and one is found to associated with the brightest central galaxy (BCG) of CXOU J191100-595621.
We have discovered a previously unreported poor cluster of galaxies (RGZ-CL J0823.2+0333) through an unusual giant wide-angle tail radio galaxy found in the Radio Galaxy Zoo project. We obtained a spectroscopic redshift of $z=0.0897$ for the E0-type
Li abundances for 9 Turnoff (TO) stars of the intermediate metallicity cluster ([Fe/H]=-1.4) NGC6752 are presented. The cluster is known to show abundance anomalies and anticorrelations observed in both evolved and main sequence stars. We find that L
The Ophiuchus galaxy cluster exhibits a curious concave gas density discontinuity at the edge of its cool core. It was discovered in the Chandra X-ray image by Werner and collaborators, who considered a possibility of it being a boundary of an AGN-in
Using a cosmological dark matter simulation of a galaxy-cluster halo, we follow the temporal evolution of its globular cluster population. To mimic the red and blue globular cluster populations, we select at high redshift $(zsim 1)$ two sets of parti
We used optical images acquired with the UVIS channel of the Wide Field Camera 3 on board of the Hubble Space Telescope to construct the first high-resolution extinction map in the direction of NGC 6440, a globular cluster located in the bulge of our