相关论文: The G-dwarf problem in the Galaxy
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…
The Stellar Initial Mass Function (IMF) characterizes the mass distribution of newly formed stars in various cosmic environments, serving as a fundamental assumption in astrophysical research. Recent findings challenge the prevalent notion…
We investigate the origin of the abundance variations observed among similarly aged F and G dwarfs in the local Galactic disk. We present arguments in support of combined infall of metal-deficient gas and sequential enrichment by successive…
We combine star-formation histories derived from observations of high redshift galaxies with measurements of the z~0 relation between gas-phase metallicity, stellar mass, and star formation rate to make an explicit and completely empirical…
We obtain a new determination of the metallicity distribution function (MDF) of stars within $\sim5$-$10$ kpc of the Sun, based on recently improved co-adds of $ugriz$ photometry for Stripe 82 from the Sloan Digital Sky Survey. Our new…
We present the metallicity distribution function (MDF) for 24,270 G and 16,847 K dwarfs at distances from 0.2 to 2.3 kpc from the Galactic plane, based on spectroscopy from the Sloan Extension for Galactic Understanding and Exploration…
Stellar migration is an important dynamical process in Galactic disk. Here we model the radial stellar migration in the Galactic disk with an analytical method, then add it to detailed Galactic chemical evolution model to study the…
The alpha element to iron peak element ratio, for example [Mg/Fe], is a commonly applied indicator of the galaxy star formation timescale (SFT) since the two groups of elements are mainly produced by different types of supernovae that…
Due to its proximity, the stellar populations of the Galactic bulge (GB) can be resolved and can be studied in detail. This allows tracing the bulge metallicity distribution function (MDF) for different spatial regions within the bulge,…
K-dwarfs have life-times older than the present age of the Galactic disc, and are thus ideal stars to investigate the disc's chemical evolution. We have developed several photometric metallicity indicators for K dwarfs, based an a sample of…
Studies of elemental abundances in stars belonging to the thin and the thick disk of our Galaxy are reviewed. Edvardsson et al. (1993) found strong evidence of [alpha/Fe] variations among F and G main sequence stars with the same [Fe/H] and…
We estimated the galactic model parameters for a set of 20 intermediate-latitude fields with galactic longitudes 0<l<100 and 160<l<240, included in the currently available Data Release 6 (DR6) of SDSS, to explore their possible variation…
The distributions of a galaxy's gas and stars in chemical space encodes a tremendous amount of information about that galaxy's physical properties and assembly history. However, present methods for extracting information from chemical…
The chemical abundances measured in stars of the Galactic bulge offer an unique opportunity to test galaxy formation models as well as impose strong constraints on the history of star formation and stellar nucleosynthesis. The aims of this…
Based on high-resolution spectra obtained during gravitational microlensing events we present a detailed elemental abundance analysis of 32 dwarf and subgiant stars in the Galactic bulge. [ABRIDGED], we now have 58 microlensed bulge dwarfs…
The presented study gives a comprehensive overview of the theory and the evidence for a systematically varying stellar initial mass function (IMF). Then we focus on the impact of this paradigm change, that is, from the universal invariant…
We performed an uniform spectroscopic analysis of 1111 FGK dwarfs observed as part of the HARPS GTO planet search program. We applied a purely chemical approach, based on [alpha/Fe] ratio, to distinguish the various stellar components in…
We present a novel method to retrieve the chemical structure of galaxies using integral field spectroscopy data through the stellar Metallicity Distribution Function (MDF). This is the probability distribution of observing stellar…
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…
The evolution of the Milky Way bulge and its relationship with the other Galactic populations is still poorly understood. The bulge has been suggested to be either a merger-driven classical bulge or the product of a dynamical instability of…