相关论文: Are the most metal-poor galaxies young?
The abundance patterns of metal-poor stars provide us a wealth of chemical information about various stages of the chemical evolution of the Galaxy. In particular, these stars allow us to study the formation and evolution of the elements…
The advent of m class telescopes has allowed the detailed spectroscopic study of sizeable numbers of extremely metal-poor Galactic stars which are the witnesses of the formation of the early Galaxy. Their chemical composition displays some…
A brief review concludes that there is now good overall agreement between theoretical estimates of the energy associated with the production of the observed metal content of the Universe and the observed extragalactic background light. In…
We demonstrate a successful strategy for identifying extremely metal poor galaxies. Our preliminary survey of 24 candidates contains 10 metal poor galaxies of which 4 have 12+log(O/H)<7.65, some of the lowest metallicity blue compact…
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…
This is the second paper of a series devoted to study the stellar content of early-type galaxies. The goal of the series is to set constraints on the evolutionary status of these objects. We use a new set of models which include an improved…
The characteristics of the stellar populations in the Galactic Bulge inform and constrain the Milky Way's formation and evolution. The metal-poor population is particularly important in light of cosmological simulations, which predict that…
Metallicity appears to be one the most important tool to study formation and evolution of galaxies. Recently, we have shown that metallicity of local galaxies is tightly related not only to stellar mass, but also to star formation rate…
Local massive early-type galaxies are believed to have completed most of their star formation $\sim10$Gyr ago and evolved without having substantial star formation since. If so, their progenitors should have roughly solar stellar…
We discuss recent developments on the age and metallicity distribution for early type galaxies in different environments.
We have assembled a catalogue of relative ages, metallicities and abundance ratios for about 150 local galaxies in field, group and cluster environments. The galaxies span morphological types from cD and ellipticals, to late type spirals.…
We have determined detailed elemental abundances and stellar ages for a sample of now 38 microlensed dwarf and subgiant stars in the Galactic bulge. Stars with sub-solar metallicities are all old and have enhanced alpha-element abundances…
In integrated-light, some color-color diagrams that use optical and near-infrared photometry show surprisingly orthogonal grids as age and metallicity are varied, and they are coming into common usage for estimating the average age and…
Recent observations show that the number of stars with very low metallicities in the dwarf spheroidal satellites of the Milky Way is low, despite the low average metallicities of stars in these systems. We undertake numerical simulations of…
Metallicity is one of the crucial factors that determine stellar evolution. To characterize the properties of stellar populations one needs to know the fraction of stars forming at different metallicities. Knowing how this fraction evolves…
It has been a long-standing open question why observed globular cluster (GC) populations of different metallicities differ in their ages and spatial distributions, with metal-poor GCs being the older and radially more extended of the two.…
Metal-poor stars provide information on the characteristics and chemical evolution of the halo population of the Galaxy, the first epoch of star formation and Galaxy formation (not just locally but with relevance to high-redshift objects),…
A possible relation between the high dispersion in metallicity of metal-poor halo stars and the minor merger processes in the history of the Galaxy is presented. The foreign populations of stars in the satellites through minor merger…
The age and chemical composition of the stars in present-day galaxies carry important clues about their star formation processes. The latest generation of population synthesis models have allowed to derive age and stellar metallicity…
We present new spectroscopy and metallicity estimates for a sample of 15 star-forming galaxies with redshifts in the range 0.29 - 0.42. These objects were selected in the KPNO International Spectroscopic Survey via their strong emission…