arXiv subjects

U. Fritze-v. Alvensleben

Publications and source records attributed to U. Fritze-v. Alvensleben.

22 records · Page 2Linked to original sources

arXiv1999

On the Nature and Redshift Evolution of DLA Galaxies

We extend our spiral galaxy models that successfully describe nearby template spectra as well as the redshift evolution of CFRS and HDF spirals to include - in a chemically consistent way - the redshift evolution of a series of individual elements. Comparison with observed DLA abundances shows that DLAs might well be the progenitors of present-day spiral types Sa through Sd. Our models bridge the gap between high redshift DLA and nearby spiral HII region abundances. The slow redshift evolution of DLA abundances is a natural consequence of the long SF timescales for disks, the scatter at any redshift reflects the range of SF timescales from early to late spiral types. We claim that while at high redshift all spiral progenitor types seem to give rise to DLA absorption, towards low redshifts, the early type spirals seem to drop out of DLA samples due to low gas and/or high metal and dust content. Model implications for the spectrophotometric properties of the DLA galaxy population are discussed in the context of campaigns for the optical identifications of DLA galaxies both at low and high redshift.

astro-ph↗

arXiv1998

Predicting Spectral Properties of DLA Galaxies

Comparison of our chemically consistent models for spiral galaxies with observed DLA abundances shows that at high redshift DLA galaxies may well be the progenitors of normal spiral disks of all types from Sa through Sd. Towards lower redshifts z </= 1.5 however, early type spirals drop out of DLA samples due to low gas or/and high dust content. We use the spectrophotometric aspects of our unified spectral, chemical, and cosmological evolution models to predict expected luminosities in different bands for DLA galaxies at various redshifts and compare to the few optical identifications available.

astro-ph↗

arXiv1998

The Mass Function of Young Star Clusters in the Antennae

The Antennae is a pair of late type spirals in the course of merging. The interaction triggered an ongoing strong burst of star formation that also produced a large number of Young Star Clusters (YSCs), many of which seem to be young Globular Clusters (GCs). The observed Luminosity Function of the YSC system is a power-law. We use evolutionary synthesis models for star clusters in comparison with HST WFPC observations of the YSC system in the Antennae to analyse the mass function of this ${\rm \sim 2 \cdot 10^8}$ yr young star cluster system. Properly accounting for age spread effects by individually age-dating the YSCs we find that the intrinsic Mass Function (MF) is log-normal in shape and in intriguing agreement with the MF of old GC systems. We discuss this MF in the context of cluster formation and dynamical effects in the tidal field of the parent galaxy and speculate about its future evolution.

astro-ph↗

arXiv1998

Dwarf Galaxies of Tidal Origin -- Relevant for Cosmology ?

Evolutionary synthesis models for Tidal Dwarf Galaxies (TDGs) are presented that allow to have varying proportions of young stars formed in the merger-induced starburst and of stars from the merging spirals' disks. The specific metallicities as well as the gaseous emission of actively star forming TDGs are consistently accounted for. Comparison of models with observational data (e.g. Duc, this volume) gives information on the present evolutionary state and possible future luminosity evolution of TDGs. The redshift evolution of merger rates and of the gas content and metallicities of spiral galaxies are used to estimate the number of TDGs at various redshifts and to investigate their contribution to magnitude limited surveys.

astro-ph↗