We demonstrate that a massive asymptotic giant branch (AGB) star is a good candidate as the main source of short-lived radionuclides in the early solar system. Recent identification of massive (4-8 M?) AGB stars in the galaxy, which are both lithium- and rubidium-rich, demonstrates that these stars experience proton captures at the base of the

We present the results of a survey of radial velocities over a wide region extending from r ~= 10 out to 80 arcmin (~1.5 tidal radii) within the massive star cluster ω Centauri (ω Cen). The survey was performed with FLAMES@VLT, to study the velocity dispersion profile in the outer regions of this stellar system. We derived accurate radial

Aims: We analyse the current build-up of stellar mass within the disks and bulges of nearby galaxies through a comparison of the spatial distributions of forming and old stellar populations. Methods: Hα and R-band imaging are used to determine the distributions of young and old stellar populations in 313 S0a-Im field galaxies out to ~40 Mpc

Aims: We characterise the underlying stellar host in a sample of 20 blue compact galaxies (BCGs), by fitting their two-dimensional light distributions. Their derived host structural parameters and those of eight other BCGs already obtained in a previous paper are related to galaxy properties, such as colours and gas content. These properties are

Aims: The importance of disc-disc major mergers in galaxy evolution remains uncertain. We study the major merger fraction in a SPITZER/IRAC-selected catalogue in the GOODS-S field up to z 1 for luminosity- and mass-limited samples. Methods: We select disc-disc merger remnants on the basis of morphological asymmetries/distortions, and address three

We present a large sample of fully self-consistent hydrodynamical Nbody/Tree-SPH simulations of isolated dwarf spheroidal galaxies (dSphs). It has enabled us to identify the key physical parameters and mechanisms at the origin of the observed variety in the Local Group dSph properties. The initial total mass (gas + dark matter) of these galaxies is