Related papers: The Lower Main Sequence and Mass Function of the G…

We present high-resolution I-band imaging of the core of the globular cluster M15 obtained at the 2.5 m Nordic Optical Telescope with FastCam, a low readout noise L3CCD based instrument. Short exposure times (30 ms) were used to record…

We report on the properties of 89 low mass star clusters located in the vicinity of luminous young clusters (blue globulars) in the disk of M31. 82 of the clusters are newly detected. We have determined their integrated magnitudes and…

The Hubble Space Telescope has been used to obtain WFPC2 (V,I) photometry for a large sample of stars in the outer halo of the giant elliptical NGC 5128 (d = 4 Mpc). The globular cluster N5128-C44, at the center of the Planetary Camera…

We present a deep H-band image of the region in the vicinity of the cluster Abell 1942 containing the puzzling dark matter concentration detected in an optical weak lensing study by Erben et al. (2000). We demonstrate that our limiting…

Thanks to its exceptional near-infrared photometry, JWST can effectively contribute to the discovery, characterization, and understanding of multiple stellar populations in globular clusters, especially at low masses where the Hubble Space…

We present the results of a new study of mass segregation in two-component star clusters, based on a large number of numerical N-body simulations using our recently developed dynamical Monte Carlo code. Specifically, we follow the dynamical…

We present the first color-magnitude study for Palomar 2, a distant and heavily obscured globular cluster near the Galactic anticenter. Our (V,V-I) color-magnitude diagram (CMD), obtained with the UH8K camera at the CFHT, reaches V(lim) =…

We present a strong lensing system, composed of 4 multiple images of a source at z = 2.387, created by two lens galaxies, G1 and G2, belonging to the galaxy cluster MACS J1115.9+0129 at z = 0.353. We use observations taken as part of the…

We study the quiescent ultra-diffuse galaxy FCC 224 in the Fornax cluster using Hubble Space Telescope (HST) imaging, motivated by peculiar properties of its globular cluster (GC) system revealed in shallower imaging. The surface brightness…

By means of deep FORS1@VLT and ACS@HST observations of a wide area in the stellar system omega Cen we measured the luminosity function of main sequence stars down to R=22.6 and I_{F814W}=24.5 . The luminosity functions obtained have been…

We present a high resolution dark matter reconstruction of the z=0.165 Abell 901/902 supercluster from a weak lensing analysis of the HST STAGES survey. We detect the four main structures of the supercluster at high significance, resolving…

We present 2MASS $JHK_{\rm s}$ photometry for 913 star clusters and candidates in the field of M31, which are selected from the latest Revised Bologna Catalog of M31 globular clusters (GCs) and candidates. The photometric measurements in…

Galaxy cluster mass distribution are potentially useful probes of $\Omega_0$ and the nature of the dark matter. Large clusters will distort the observed shapes of background galaxies through gravitational lensing allowing the measurement of…

(abridged) We present a comprehensive lensing analysis of the rich cluster Cl0024+1654 based on panoramic sparse-sampled imaging conducted with HST. We demonstrate an ability to detect reliably weak lensing signals to a cluster radius of ~5…

Analyses of their internal stellar kinematics imply that the dwarf spheroidal (dSph) companion galaxies to the Milky Way are among the most dark-matter dominated systems known. Should there be significant dark matter in the form of faint…

Although the James Webb Space Telescope (JWST) has received much attention for its ability to search deeper into the cosmos than ever before, it also enhances our capability to study objects closer to us in the Universe. We apply a…

We used the HST WFPC2 to obtain I-band images of the centers of 81 brightest cluster galaxies (BCGs), drawn from a volume-limited sample of nearby BCGs. The images show a rich variety of morphological features, including multiple or double…

We identify the largest known lensed images of a single spiral galaxy, lying close to the centre of the distant cluster MACS J1149.5+2223 ($z=0.544$). These images cover a total area of $\simeq 150 \Box\arcsec$ and are magnified $\simeq…

We present the results of the analysis of deep photometric data of 32 Galactic globular clusters. We analysed 69 parallel field images observed with the Wide Field Channel of the Advanced Camera for Surveys of the Hubble Space Telescope…

We revisit the problem of the split main sequence (MS) of the globular cluster omega Centauri, and report the results of two-epoch Hubble Space Telescope observations of an outer field, for which proper motions give us a pure sample of…