相关论文: Hiding in plain sight: record-breaking compact ste…

We report the discovery of a remarkable ultra-compact dwarf galaxy around the massive Virgo elliptical galaxy NGC 4649 (M60), which we term M60-UCD1. With a dynamical mass of 2.0 x 10^8 M_sun but a half-light radius of only ~ 24 pc,…

We report on the properties of the most massive ultra-compact dwarf galaxy (UCD) in the nearby Virgo Cluster of galaxies using imaging from the Next Generation Virgo Cluster Survey (NGVS) and spectroscopy from Keck/DEIMOS. This object…

Ultracompact dwarf galaxies (UCDs) are among the densest stellar systems in the universe. These systems have masses up to 200 million solar masses, but half light radii of just 3-50 parsecs. Dynamical mass estimates show that many UCDs are…

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 identify nine galaxies with dynamical masses of M_dyn>10^10 M_sol as photometric point sources, but with redshifts between z=0.2 and z=0.6, in the Sloan Digital Sky Survey (SDSS) spectro-photometric database. All nine galaxies have…

We performed a large spectroscopic survey of compact, unresolved objects in the core of the Hydra I galaxy cluster (Abell 1060), with the aim of identifying ultra-compact dwarf galaxies (UCDs), and investigating the properties of the…

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.…

The sample of known star clusters, the fundamental building blocks of galaxies, in the Milky Way is still extremely incomplete for objects beyond a distance of 1-2kpc. Many of the more distant and young clusters are compact and hidden…

We identify 47,600 clusters of galaxies from photometric data of Two Micron All Sky Survey (2MASS), Wide-field Infrared Survey Explorer (WISE), and SuperCOSMOS, among which 26,125 clusters are recognized for the first time and mostly in the…

Recent large-scale galaxy spectroscopic surveys, such as the Sloan Digital Sky Survey (SDSS), enable us to execute a systematic, relatively-unbiased search for galaxy clusters. Such surveys make it possible to measure the 3-d distribution…

In the last decade, a new kind of stellar systems has been established that shows properties in between those of globular clusters (GCs) and early-type dwarf galaxies. These so-called ultra-compact dwarf galaxies (UCDs) have masses in the…

We have made a serendipitous discovery of a massive cD galaxy at z=1.096 in a candidate rich cluster in the HUDF area of GOODS-South. This brightest cluster galaxy is the most distant cD galaxy confirmed to date. Ultra-deep HST/WFC3 images…

Recent high-resolution observations with the Hubble Space Telescope (HST) reveal that star clusters of extraordinary luminosity and compactness are commonly found in a variety of starburst systems. There has been much speculation that these…

We report the discovery of relatively massive, M32-like ultra compact dwarf (UCD) and compact elliptical (CE) galaxy candidates in $0.2<z<0.6$ massive galaxy clusters imaged by the Cluster Lensing And Supernova survey with {\it Hubble}…

We have identified a previously unrecognized population of very compact, embedded low-mass Galactic stellar clusters. These tight (r$ \approx $0.14 pc) groupings appear as bright singular objects at the few arcsec resolution of the Spitzer…

We investigate the connection between globular clusters and ultra-compact dwarf galaxies (UCDs) by examining the properties of several compact objects associated with M87, all of which were previously classified as globular clusters.…

Ultra-compact dwarf galaxies (UCDs) are a new type of galaxy we have discovered in the central region of the Fornax and Virgo clusters. Unresolved in ground-based imaging, UCDs have spectra typical of old stellar systems. Ninety-two have…

Recent studies of the distribution and kinematics of the Milky Way and Andromeda satellite galaxy systems have confirmed the existence of coplanar, corotating structures of galaxies. In addition to the 'missing satellite problem', these…

We recently initiated a search for ultra-compact dwarf galaxies (UCDs) in the Centaurus galaxy cluster (Mieske et al. 2007), resulting in the discovery of 27 compact objects with -12.2<M_V<-10.9 mag. Our overall survey completeness was…

A search of more than 3,000 square degrees of high latitude sky by the Sloan Digital Sky Survey has yielded 251 faint high-latitude carbon stars (FHLCs), the large majority previously uncataloged. We present homogeneous spectroscopy,…