相关论文: Is Palomar 1 really associated with the Canis Majo…
Malin 1 is a unique, extraordinarily large low surface brightness galaxy. The structure and the origins of the galaxy are poorly understood. The reason for such a situation is an absence of detailed observational data, especially, of…
(Abridged) We derive the structure of the Galactic stellar Warp and Flare using 2MASS RC and RGB stars, selected at mean heliocentric distances of 3, 7 and 17 kpc. Our results are: (i) a clear stellar warp signature is derived for the 3…
We review Galactic halo formation theories and supporting evidence, in particular kinematics and detailed chemical abundances of stars in some relevant globular clusters as well as Local Group dwarf galaxies. Outer halo red HB clusters tend…
Recent work on globular cluster systems in dwarf galaxies outside the Local Group is reviewed. Recent large imaging surveys with the Hubble Space Telescope and follow-up spectroscopy with 8-m class telescopes now allow us to compare the…
We determine the elemental abundances of nine red giant stars belonging to Palomar 14 (Pal 14). Pal 14 is an outer halo globular cluster (GC) at a distance of \sim 70 kpc. Our abundance analysis is based on high-resolution spectra and…
High-redshift galaxy clusters, unlike local counterparts, show diverse star formation activities. However, it is still unclear what keeps some of the high-redshift clusters active in star formation. To address this issue, we performed a…
In order to recognize environmental effects on the evolution of dwarf galaxies in clusters of galaxies, it is first necessary to quantify the properties of objects which have evolved in relative isolation. With oxygen abundance as the gauge…
Globular clusters in the outer halo (R_gc > 15 kpc) are found to be systematically fainter than those at smaller Galactocentric distances. Within the outer halo the compact clusters with half-light radii R_h < 10 pc are only found at R_gc <…
We present a chemical abundance analysis of the tidally disrupted globular cluster (GC) Palomar 5. By co-adding high-resolution spectra of 15 member stars from the cluster's main body, taken at low signal-to-noise with the Keck/HIRES…
We present a study of the surface density profiles of the clusters of galaxies from the Palomar Distant Cluster Survey (Postman et al. 1996). The survey contains a total of 79 clusters of galaxies, covering the estimated redshift range of…
Most star complexes are in fact complexes of stars, clusters and gas clouds; term "star complexes" was introduced as general one disregarding the preferential content of a complex. Generally the high rate of star formation in a complex is…
We investigate recent claims by Secrest et al. of an anomalously large amplitude of the dipole in the distribution of CatWISE-selected quasars on the sky. Two main issues indicate that the systematic uncertainties in the derived…
The ultra-faint Milky Way satellite Willman 1 (W1; $M_V = -2.6$; $r_{\rm half} \sim27$ pc) was the first stellar over-density found via resolved stars in the Sloan Digital Sky Survey, yet its classification as either a dwarf galaxy or star…
It is now well-established that the elemental abundance patterns of stars holds key clues not only to their formation but also to the assembly histories of galaxies. One of the most exciting possibilities is the use of stellar abundance…
We report the possible discovery of a new stellar system (YMCA-1), identified during a search for small scale overdensities in the photometric data of the YMCA survey. The object's projected position lies on the periphery of the Large…
Despite their apparent fragile appearance, dwarf spheroidals are the most common galaxy type in clusters. In this paper we consider some of the issues associated with two major models for the origin of these dwarfs: primeval galaxies which…
In this contribution the hypothesis that the Galactic globular clusters with substantial internal [Fe/H] abundance ranges are the former nuclei of disrupted dwarf galaxies is discussed. Evidence considered includes the form of the…
We analyze the stellar populations of the Canis Major stellar over-density, using quantitative color-magnitude diagram (CMD) fitting techniques. The analysis is based on photometry obtained with the Wide Field Imager at the 2.2m telescope…
We analyse the X-ray surface brightness profiles of 19 moderately distant and luminous clusters of galaxies observed with the \EINOBS. Our aim is to determine cluster gas masses out to radii between 1 and $3\Mpc$, and to confirm the…
We explore the possibility that the anomalous split in the Subgiant branch of the galactic globular cluster NGC 1851 is due to the presence of two distinct stellar populations with very different initial metal mixtures: a normal…