Related papers: The G Dwarf Problem Exists in Other Galaxies
We compute the chemical evolution of the Galactic bulge to explain the existence of two main stellar populations recently observed. After comparing model results and observational data we suggest that the old more metal poor stellar…
In this work, we study the formation and chemical evolution of the Galactic bulge with particular focus on the abundance pattern ([Mg/Fe] vs. [Fe/H]), metallicity and age distribution functions. We consider detailed chemical evolution…
We examine the biases inherent to chemical abundance distributions when targets are selected from the red giant branch (RGB), using simulated giant branches created from isochrones. We find that even when stars are chosen from the entire…
We derive a new metallicity distribution of G dwarfs in the solar neighbourhood, using uvby photometry and up-to-date parallaxes. Our distribution comprises 287 G dwarfs within 25 pc from the Sun, and differs considerably from the classic…
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…
Scaling from the empirical metal yield as measured in clusters of galaxies, it is inferred that early in the evolution of the Galaxy the bulge stellar population has produced $\sim 10^9\msun$ of metals, at least 5 times more than the total…
Because of their low gravitational energies dwarf galaxies are greatly exposed to energetical influences by the interstellar medium, like e.g.\ stellar radiation, winds or explosions, or by their environment. While the metallicity depletion…
We present a revised metallicity distribution of dwarfs in the solar neighbourhood. This distribution is centred on solar metallicity. We show that previous metallicity distributions, selected on the basis of spectral type, are biased…
The immediate Solar neighborhood should be a fair sample of the local Galaxy. However, the chemical abundance distribution of long-lived disk stars very near the Sun contains a factor of five to ten more metal-poor stars, $-1 \simlt {\rm…
Because of their low gravitational energies dwarf galaxies are greatly exposed to energetical influences by the interstellar medium, like e.g. stellar radiation, winds or explosions, or by their environment. While the metallicity depletion…
The predictions of the abundances of D and \he3 from Big Bang Nucleosynthesis (BBN) and recent observations of these two isotopes suggest the need to develop new chemical evolution models. In particular, we examine the role of an early…
Dwarf irregular and blue compact galaxies are very interesting objects since they are relatively simple and unevolved. We present new models for the chemical evolution of these galaxies by assuming different regimes of star formation…
Due to their low gravitational energies, dwarf galaxies are greatly exposed to energetical influences from internal and external sources. By means of chemodynamical models we show that their star formation is inherently self-regulated, that…
The metallicity distribution function (MDF) of the Galactic bulge features a multi-peak shape, with a metal-poor peak at [Fe/H]=-0.3 dex and a metal-rich peak at [Fe/H]=+0.3 dex. This bimodality is also seen in [alpha/Fe] versus [Fe/H]…
We examine the possibility of the inclusion of objects having lifetimes lower than the disk age in the database of recent determinations of the G dwarf metallicity distribution for the solar neighbourhood. As a preliminary step, stars with…
Dwarf irregular galaxies appear to have undergone very slow chemical evolution since they have low nebular abundances, but have had ongoing star formation over the past 15 Gyr. They are too distant for red giant abundance analyses to…
We combine spectroscopic metallicity values with integrated narrowband continuum colors to explore the internal metallicity distribution in early-type galaxies. The different techniques for determining metallicity (indices versus colors)…
The Bulge is the least understood major stellar population of the Milky Way. Most of what we know about the formation and evolution of the Bulge comes from bright giant stars. The underlying assumption that giants represent all the stars,…
[ABRIDGED] Based on high-resolution (R~42000 to 48000) and high signal-to-noise (S/N~50 to 150) spectra obtained with UVES/VLT, we present detailed elemental abundances (O, Na, Mg, Al, Si, Ca, Ti, Cr, Fe, Ni, Zn, Y, and Ba) and stellar ages…
The so-called ``G-dwarf problem'' emerged in the 1960's when it was noticed that the observed metal distribution of nearby stars differs from what is expected in simple models of the evolution of the Galaxy. We have determined metallicities…