In this work the present day mass functions (PDMF) of T-Tauri Stars (TTS) which are in the pre-main sequence (PMS) evolutionary phase of their evolution in the Taurus-Auriga Molecular Cloud Complex have been calculated. For this purpose, by applying our modified stellar evolutionary code, stellar models in the mass range 0.1 − 2.5 M are used to determine the mass and age mass of TTS. The obtain...

We use galaxy and dark halo data from the public database for the Millennium Simulation to study the growth of galaxies in the De Lucia et al. (2006) model for galaxy formation. Previous work has shown this model to reproduce many aspects of the systematic properties and the clustering of real galaxies, both in the nearby universe and at high redshift. It assumes the stellar masses of galaxies ...

Context. In the last couple of years a population of very massive (M > 1011 M ), high-redshift (z ≥ 2) galaxies has been identified, but its role in galaxy evolution has not yet been fully understood. Aims. It is necessary to perform a systematic study of high-redshift massive galaxies, in order to determine the shape of the very massive tail of the stellar mass function and determine the epoch...

We study the variation of the dark matter mass fraction of elliptical galaxies as a function of their luminosity, stellar mass, and size using a sample of 29,469 elliptical galaxies culled from the Sloan Digital Sky Survey. We model ellipticals as a stellar Hernquist profile embedded in an adiabatically compressed dark matter halo. This model allows us to estimate a dynamical mass (Mdynm) at th...

Aims. We estimate stellar masses of galaxies in the high redshift universe with the intention of determining the influence of newly available Spitzer/IRAC infrared data on the analysis. Based on the results we probe the mass assembly history of the universe. Methods. We use the GOODS–MUSIC catalog which provides multiband photometry from the U–filter to the 8 μm Spitzer band for almost 15.000 g...

We analyze galaxies in 300 nearby groups and clusters identified in the Sloan Digital Sky Survey using a photometric gas mass indicator that is useful for estimating the degree to which the interstellar medium of a cluster galaxy has been depleted. We study the radial dependence of inferred gas mass fractions for galaxies of different stellar masses and stellar surface densities. At fixed clust...

We present the time evolution of the stellar metallicity for SDSS galaxies, a sample that spans five orders of magnitude in stellar mass (10 − 10 M⊙). Assuming the Bruzual & Charlot (2003) stellar population models, we find that more massive galaxies are more metal-rich than less massive ones at all redshifts; the mass-metallicity relation is imprinted in galaxies from the epoch of formation. F...

Many observational results seem to indicate more efficient mixing processes in intermediate mass stars (520 M⊙) than the expected by the standard models. These processes are usually thought to be caused by stellar rotation. Our recent analysis of 19 evolved intermediate mass stars has found them to display different efficiencies of internal mixing. The comparison of these results, and others fr...