相关论文: Determining Metallicities of Globular Clusters usi…

We present an unbiased method for evaluating the ranges of ages and metallicities which are allowed by the photometric properties of the stellar populations that dominate the light of early-type galaxies in clusters. The method is based on…

In this study, we extend the dust-independent Hatzidimitriou (1991) relation between cluster age and $d_{B-R}$ color difference between the red giant branch (RGB) and red clump to younger cluster ages. We perform membership analysis on…

It is believed that, except for metallicity, some other parameters are needed to explain the horizontal branch (HB) morphology of globular clusters (GCs). Furthermore, these parameters are considered to be correlated with the mass loss of…

Metallicity distributions (MDs) of globular clusters (GCs) provide crucial clues for the assembly and star formation history of their host galaxies. GC colors, when GCs are old, have been used as a proxy of GC metallicities. Bimodal GC…

Size differences of approx. 20% between red (metal-rich) and blue (metal-poor) sub-populations of globular clusters have been observed, generating an ongoing debate as to weather these originate from projection effects or the difference in…

Ages have been derived for 55 globular clusters (GCs) from overlays of isochrones onto the turnoff photometry, assuming distances based on fits of zero-age horizontal branch (ZAHB) models to the lower bound of the observed distributions of…

In previous papers of the series we used a combination of optical and near-infrared colours to derive constraints on the relative age structure in globular cluster systems. Here, we present the details, strength and limitations of our…

The ages and metallicities of globular clusters play an important role not just in testing models for their formation and evolution but in understanding the assembly history for their host galaxies. Here we use a combination of imaging and…

Various galaxy properties are not continuous over a large range in mass, but rather reveal a remarkable transition or `bimodality' at a stellar mass of 3 x 10^{10} Mo. These properties include colors, stellar populations, Xray emission and…

We show how the observed bimodality in the color distribution of galaxies can be explained in the framework of the hierarchical clustering picture in terms of the interplay between the properties of the merging histories and the…

Several population synthesis models now predict integrated colors of simple stellar populations in the mid-infrared bands. To date, the models have not been extensively tested in this wavelength range. In a comparison of the predictions of…

(Abridged) We build a theoretical model to study the origin of the globular cluster metallicity bimodality in the hierarchical galaxy assembly scenario, based on the observed galaxy mass-[O/H] relation and the galaxy stellar mass function…

We present a large sample of over 200 integrated-light spectra of confirmed globular clusters (GCs) associated with the Sombrero (M104) galaxy taken with the DEIMOS instrument on the Keck telescope. A significant fraction of the spectra…

We use the hydrodynamical EAGLE simulation to test if ultra-compact dwarf galaxies (UCDs) can form by tidal stripping by predicting the ages and metallicities of tidally stripped galaxy nuclei in massive galaxy clusters, and compare these…

The bimodal globular cluster (GC) metallicity distributions of many giant elliptical galaxies are often cited as evidence for the formation of such galaxies through mergers involving gas-rich spirals. In such models, the metal- rich GCs are…

The mass distribution and chemical composition of globular cluster (GC) systems preserve fossil record of the early stages of galaxy formation. The observed distribution of GC colors within massive early-type galaxies in the ACS Virgo…

We investigate the influence of Asymptotic Giant Branch stars on integrated colours of star clusters of ages between ~100 Myr and a few gigayears, and composition typical for the Magellanic Clouds. We use state-of-the-art stellar evolution…

We present spectroscopic ages, metallicities, and [alpha/Fe] ratios for 70 globular clusters in M31 that were derived from Lick line-index measurements. In addition to a population of old (>10 Gyr) globular clusters with a wide range of…

Stromgren uvby CCD photometry can be used in a variety of ways to constrain the absolute and relative ages of globular clusters. The reddening corrected (v-y, c1) diagram offers the means to derive ages that are completely independent of…

We discuss the present state of knowledge and thought concerning the spread in age found among Galactic globular clusters, with some discussion of the implications for what happened during the earliest stages of the formation of the Milky…