ﻻ يوجد ملخص باللغة العربية
A detailed imaging analysis of the globular cluster (GC) system of the Sombrero galaxy (NGC 4594) has been accomplished using a six-image mosaic from the Hubble Space Telescope Advanced Camera for Surveys. The quality of the data is such that contamination by foreground stars and background galaxies is negligible for all but the faintest 5% of the GC luminosity function (GCLF). This enables the study of an effectively pure sample of 659 GCs until ~2 mags fainter than the turnover magnitude, which occurs at M_V=-7.60+/-0.06 for an assumed m-M=29.77. Two GC metallicity subpopulations are easily distinguishable, with the metal-poor subpopulation exhibiting a smaller intrinsic dispersion in color compared to the metal-rich subpopulation. Three new discoveries include: (1) A metal-poor GC color-magnitude trend. (2) Confirmation that the metal-rich GCs are ~17% smaller than the metal-poor ones for small projected galactocentric radii (less than ~2 arcmin). However, the median half-light radii of the two subpopulations become identical at ~3 arcmin from the center. This is most easily explained if the size difference is the result of projection effects. (3) The brightest (M_V < -9.0) members of the GC system show a size-magnitude upturn where the average GC size increases with increasing luminosity. Evidence is presented that supports an intrinsic origin for this feature rather than a being result from accreted dwarf elliptical nuclei. In addition, the metal-rich GCs show a shallower positive size-magnitude trend, similar to what is found in previous studies of young star clusters.
We present preliminary results of a wide field study of the globular cluster system of NGC4594, the Sombrero galaxy. The galaxy was observed in B, V, and R using the Wide Field Imager on the ESO 2.2m telescope. Using color and shape criteria to selec
Intracluster stellar populations are a natural result of tidal interactions in galaxy clusters. Measuring these populations is difficult, but important for understanding the assembly of the most massive galaxies. The Coma cluster is one of the neares
We present HST/ACS $g$ and $z$ photometry and half-light radii $R_{rm h}$ measurements of 360 globular cluster (GC) candidates around the nearby S0 galaxy NGC 3115. We also include Subaru/Suprime-Cam $g$, $r$, and $i$ photometry of 421 additional can
(Abriged)This work studies in more detail the stellar population, including its photometric properties and characteristics, in the rarely studied southern Galactic globular cluster NGC 1261. We focus on the brighter sequences of the clusters color-ma
We present new wide-field photometry and spectroscopy of the globular clusters (GCs) around NGC 4649 (M60), the third brightest galaxy in the Virgo cluster. Imaging of NGC 4649 was assembled from a recently-obtained HST/ACS mosaic, and new Subaru/Sup