Related papers: Deep Optical Observations of Compact Groups of Gal…
In this letter, we present the results of our study of galaxy-galaxy lensing in massive cluster-lenses spanning $z = 0.17$ to 0.58, utilizing high-quality archival {\it Hubble Space Telescope} ({\it HST}) data. Local anisotropies in the…
Context : Ultra Diffuse Galaxies are low surface brightness systems which have been detected in HI in the field, where their line widths sometimes indicate significant dark matter deficits. They are rarely detected in HI in clusters, making…
We present Hubble Space Telescope imaging of 14 gas-rich, low surface brightness galaxies in the field at distances of 25-36 Mpc, with mean effective radii and $g$-band central surface brightnesses of 1.9 kpc and 24.2 mag arcsec$^{-2}$.…
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…
Shells in Elliptical Galaxies are faint, sharp-edged features, believed to provide evidence of a recent ($\sim 0.5 - 2 \times 10^9$ years ago) merger event. We analyse the Globular Cluster (GC) systems of six shell elliptical galaxies, to…
Using the TNG100 cosmological simulation, we study the formation and evolution of compact groups of galaxies. Over a redshift range of $0 \lesssim z \lesssim 0.2$, we identify these compact groups as FoF galaxy groups with high mean surface…
The ``MORPHS'' group has completed the cataloging, parameterization, and morphological classification of ~2000 galaxies in 10 rich clusters from 0.36 < z < 0.56. From a weak lensing analysis using these data, which compares the X-ray…
Gravitational lensing provides a unique probe of the inner 10-1000 pc of distant galaxies (z=0.2-1). Lens theory predicts that every strong lens system should have a faint image near the center of the lens galaxy, which should be visible in…
We present the results of our search for faint Local Group dwarf galaxies in compact high-velocity clouds (HVCs). We used digitized Palomar Observatory Sky Survey (POSS) data to examine 1 square degree of sky around each of ~250 northern…
We investigate strong lensing of galaxies in the Hubble Deep Field by foreground groups and clusters of galaxies with masses from $10^{13}$ to $10^{15} \MSun$. Over this mass range, groups with the profile of Navarro, Frenk, & White (1995)…
The HST ACS Coma Cluster Treasury Survey is a deep two passband imaging survey of the nearest very rich cluster of galaxies, covering a range of galaxy density environments. The imaging is complemented by a recent wide field redshift survey…
We report on our search for distant clusters of galaxies based on optical and X-ray follow up observations of X-ray candidates from the SHARC survey. Based on the assumption that the absence of bright optical or radio counterparts to…
We revisit the picture of X-ray emission of groups through the study of systematic differences in the optical properties of groups with and without X-ray emission and study the effect of large-scale density field on scaling relations. We…
We study the correlation between the locations of galaxy-galaxy strong lensing candidates and tracers of large-scale structure from both weak lensing or X-ray emission. The COSMOS survey is a unique data set, combining deep, high resolution…
We present a deep broadband optical imaging study of a complete sample of luminous elliptical galaxies (M_B<-20) at distances 15 Mpc - 50 Mpc, selected from the Tully catalog of nearby galaxies. The images are flat to ~0.35% across the 20'…
We present a sample of 115 very low optical surface brightness, highly extended, HI-rich galaxies carefully selected from the ALFALFA survey that have similar optical absolute magnitudes, surface brightnesses, and radii to recently…
We examine whether a cosmologically significant distribution of dark galaxy group or cluster-sized objects can have an optical depth for multiple imaging of distant background sources which is comparable to that from known galaxies while at…
We use a combined imaging and spectroscopic survey of the nearby central cluster galaxy, M87, to assemble a sample of 34 confirmed ultra compact dwarfs (UCDs) with half-light radii of >~ 10 pc measured from Hubble Space Telescope images.…
We use the two-point correlation function in redshift space, $\xi(s)$, to study the clustering of the galaxies and groups of the Nearby Optical Galaxy (NOG) sample, which is a nearly all-sky, complete, magnitude-limited sample of $\sim$7000…
We report the discovery of a very diverse set of five low-surface brightness (LSB) dwarf galaxy candidates in Hickson Compact Group 90 (HCG 90) detected in deep U- and I-band images obtained with VLT/VIMOS. These are the first LSB dwarf…