相关论文: The link between the Star Formation History and [a…
Theories of thick disk formation can be differentiated by measurements of stellar elemental abundances. We have undertaken a study of metal-poor stars selected from the RAVE spectroscopic survey of bright stars to establish whether or not…
It is well-established that the vast majority of metal-poor Galactic halo stars shows evidence for enrichment by solely massive stars. Recent observations have identified more varied behavior in the pattern of elemental abundances measured…
The evolution of galaxies is imprinted in their stellar populations. Several stellar population properties in massive early-type galaxies have been shown to correlate with intrinsic galaxy properties like the galaxy's central velocity…
Stellar chemical element ratios have well-defined systematic trends as a function of abundance, with an excellent correlation of these trends with stellar populations defined kinematically. This is remarkable, and has significant…
A linear [Fe/H]-[O/H] relation is found for different stellar populations in the Galaxy (halo, thick disk, thin disk) from a data sample obtained in a recent investigation (Ram{\'\i}rez et al. 2013). These correlations support previous…
Unlike spiral galaxies such as the Milky Way, the majority of the stars in massive elliptical galaxies were formed in a short period early in the history of the Universe. The duration of this formation period can be measured using the ratio…
Although evidence is accumulating that abundance ratios in galaxies are often non-solar, they are far from understood. I resume the current evidence for non-solar abundance ratios, supplementing the recent review by Worthey (1998) with some…
Differential enrichment between $\alpha$- and Fe-peak elements is known to be strongly connected with the shape of the star formation history (SFH), the star formation efficiency (SFE), the inflow and outflow of material, and even the shape…
We make use of a semi-analytical model of galaxy formation to investigate the origin of the observed correlation between [a/Fe] abundance ratios and stellar mass in elliptical galaxies. We implement a new galaxy-wide stellar initial mass…
We present an abundance analysis based on high resolution spectra of 10 stars selected to span the full range in metallicity in the Ursa Minor dwarf spheroidal galaxy. We find [Fe/H] for the sample stars ranges from -1.35 to -3.10 dex and…
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…
The supernova yields of several heavy elements including alpha-, iron-group, and r-process elements are obtained as a function of the mass of their progenitor main-sequence stars M_ms from the abundance patterns of extremely metal-poor…
The star formation rate - stellar mass relation (SFR-M*) and its evolution (i.e., the SFR main sequence) describes the growth rate of galaxies of a given stellar mass and at a given redshift. Assuming that present-day star-forming galaxies…
We explore possible correlations between light profile shapes, as parameterized by the Sersic index or the concentration index C_re(1/3), and relevant stellar population parameters in early-type galaxies. Mean luminosity weighted ages,…
We explore the structure of the element abundance--age--orbit distribution of the stars in the Milky Way's low-$\alpha$ disk, by (re-)deriving precise [Fe/H], [X/Fe] and ages, along with orbits, for red clump stars from the APOGEE survey.…
We performed a uniform and detailed analysis of 1112 high-resolution spectra of FGK dwarfs obtained with the HARPS spectrograph at the ESO 3.6 m telescope (La Silla, Chile). Most stars have effective temperatures 4700 K < Teff < 6300 K and…
We investigate the stellar population properties of a sample of 24 massive quenched galaxies at $1.25<z_\mathrm{spec}<2.09$ identified in the COSMOS field with our Subaru/MOIRCS near-IR spectroscopic observations. Tracing the stellar…
Distant galaxies show correlations between their current star-formation rates (SFRs) and stellar masses, implying that their star-formation histories (SFHs) are highly similar. Moreover, observations show that the UV luminosities and…
We explore the environmental dependence of star formation timescales in low mass galaxies using the [$\alpha$/Fe] abundance ratio as an evolutionary clock. We present integrated [$\alpha$/Fe] measurements for 11 low mass ($M_\star \sim…
We derive and analyse the star formation histories of 393 intermediate-redshift (0.1 $\leq$ z $\leq$ 0.9) galaxies with stellar masses between $\sim$10$^{8}$ - 10$^{12}$ M$_{\odot}$. We probe a cosmic time of approximately 6 Gyr and a range…