相关论文: The chemical evolution of galaxies causing damped …
Studies of damped Lyman-alpha absorption systems in quasar spectra are yielding very interesting results regarding the chemical evolution of these galaxies. We present some preliminary results from such a program.
Measurements of element abundances in damped Lyman alpha systems are providing new means to investigate the chemical evolution of galaxies, particularly at early times. We review progress in this area, concentrating on recent efforts to…
By means of detailed chemical evolution models for galaxies of different morphological types (i.e. spirals, irregular/starburst galaxies and ellipticals) we study the nature of Damped Lyman-Alpha systems. Our concern is to infer which…
We describe the evolution of galaxies in a chemically consistent way accounting for the increasing initial metallicity of successive generations of stars. The enrichment of various types of model galaxies is compared with Damped Ly$\alpha$…
The chemical abundances in damped Lyman-alpha systems (DLAs) show more than 2 orders of magnitude variation at a given epoch, possibly because DLAs arise in a wide variety of host galaxies. This could significantly bias estimates of…
Recent abundance measurements in damped Lyman-alpha galaxies, supplemented with unpublished Keck observations, are discussed. The metallicity distribution with cosmic time is examined for clues about the degree of enrichment, the onset of…
The evolution of the metallicity of damped Lyman alpha systems (DLAs) is investigated in order to understand the nature of these systems. The observational data on chemical abundances of DLAs are analysed with robust statistical methods,…
We are encouraged by the improving abundance measurements for quasar damped absorption line systems to start a new study of galaxy chemical evolution from high to low redshifts. Our goal is a simple, robust model based on a synthesis of our…
The results of a new spectroscopic survey of 66 $z \simgt 4$ quasars for Damped Lyman-alpha absorption systems are presented. The search led to the discovery of 30 new DLA candidates which are analysed in order to compute the comoving mass…
We study the nature of Damped Lyman -Alpha systems (DLAs) by means of a comparison between observed abundances and models of chemical evolution of galaxies of different morphological type. In particular, we compare for the first time the…
We construct a simple, robust model of the chemical evolution of galaxies from high to low redshift, and apply it to published observations of damped Lyman-alpha quasar absorption line systems (DLAs). The elementary model assumes quiescent…
Observations of absorption lines in the spectra of distant QSOs offer a new approach for tracking the evolution of normal galaxies from early epochs to the present day. The damped Ly alpha systems are particularly suitable for measuring the…
We present results from an ongoing search for galaxy counterparts of a subgroup of Quasar Absorption Line Systems called Damped Ly-alpha Absorbers (DLAs). DLAs have several characteristics that make them essential in the process of…
Damped Lyman-alpha absorption systems found in the spectra of high redshift quasars are believed to trace the interstellar gas in high redshift galaxies. In this paper, we study the elemental abundances of C, N, O, Al, Si, S, Cr, Mn, Fe,…
We investigate the chemical abundances of local star-forming galaxies which cause Damped Lyman Alpha lines. A metallicity versus redshift diagram is constructed, on which the chemical abundances of low-redshift star-forming galaxy…
We present a comparison between the observed properties of damped Lyman alpha systems (DLAs) and the predictions of simple models for the evolution of present day disk galaxies, including both low and high surface brightness galaxies. We…
Assuming that damped Lyman-alpha(DLA) systems are galactic discs, we calculate the corresponding evolution of metal abundances. We use detailed multi-zone models of galactic chemical evolution (reproducing successfully the observed…
Observations of damped Lyman alpha systems offer a unique window on the neutral-gas reservoirs that gave rise to galaxies at high redshifts. This review focuses on critical properties such as the H I and metal content of the gas and on…
Although quasar absorbers, and in particular Damped Lyman-alpha systems (DLAs) have proven a valuable tool to study the early Universe, their exact nature is so far poorly constrained. It has been suggested that outflows in galaxies might…
We have investigated chemical evolution in the young universe by analysing the detailed chemical enrichment pattern of a metal-rich galaxy at high redshift. The recent detection of over 20 elements in the gas-phase of a damped Lyman-alpha…