Related papers: Chemical Evolution of Damped Lyman Alpha Systems
According to Pei, Fall & Hauser (1999), the global metallicity evolution of the Universe can be represented by the ratio of the total metal content to the total gas content measured in Damped Lyman-alpha (DLA) systems (the ``column density…
Damped Ly_alpha galaxies provide a sample of young galaxies where chemical abundances can be derived throughout the whole universe with an accuracy comparable to that for the local universe. Despite a large spread in redshift, HI column…
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…
We apply a physically motivated stellar feedback model to analyse the statistical properties of damped Lyman-alpha systems (DLAs) expected in the concordance cold dark matter (CDM) model. Our feedback model produces extended low-metallicity…
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,…
Damped Ly-alpha Systems (DLAs), with N(HI)>2*10^20 cm^{-2}, observed in quasars have allowed us to quantify the chemical content of the Universe over cosmological scales. Such studies can be extended to lower N(HI), in the sub-DLA range…
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…
In this paper we point out a previously unnoticed anticorrelation between the observed abundance ratio [X/Zn] (where Zn is assumed to be undepleted and X stands for the refractories Fe, Cr and Ni) and metal column density…
Spectroscopic observations of distant quasars have resulted in the detection of molecular hydrogen in intervening damped Lyman-alpha absorption clouds (DLAs). We use observations compiled from different experimental groups to show that the…
We present a sample of 45 Damped Lyman-$\alpha$ system (DLA, \nhi\ $ \geq 2 \times 10^{20} {\rm cm}^{-2}$) counterparts (33 detections, 12 upper limits) which host gamma-ray bursts (GRB-DLAs) in order to investigate star-formation and…
Recent measurements of nitrogen and alpha elements in over 20 damped Ly-alpha systems (DLA) are compared with similar measurements for numerous emission line objects and stars. It is found that the DLA distribution in the N/alpha-alpha/H…
The history and progress of DLA research over the past several decades is reviewed here. Larger datasets and deeper surveys, particularly over the last couple of years, have improved our knowledge of the neutral gas content and distribution…
We present the chemical abundance measurements of the first large, medium-resolution, uniformly selected damped Lyman alpha system (DLA) survey. The sample contains 99 DLAs towards 89 quasars selected from the SDSS DR5 DLA sample in a…
Comparison of our chemically consistent models for spiral galaxies with observed DLA abundances shows that at high redshift DLA galaxies may well be the progenitors of normal spiral disks of all types from Sa through Sd. Towards lower…
To constrain the conditions for very early nucleosynthesis in the Universe we compare the chemical enrichment pattern of an extremely metal-poor damped Lyman alpha (DLA) absorber with predictions from recent explosive nucleosynthesis model…
We investigate Damped Ly-alpha absorbing galaxies (DLA galaxies) at low redshifts z<1 in the hierarchical structure formation scenario to clarify the nature of DLA galaxies because observational data of such galaxies mainly at low redshifts…
Recent abundance measurements in damped Lyman-alpha galaxies, supplemented with unpublished Keck observations, are discussed. The metallicity distribution with cosmic time is examined for clues about the degree of enrichment, the onset of…
Our knowledge of galactic chemical evolution is currently limited to observations of Milky Way stars and H II regions of nearby galaxies. Damped Lyman~$\alpha$ systems offer a new approach for tracking the evolution of normal galaxies from…
We present a spectroscopic study of six damped Lya absorption (DLA) systems at z<0.65, based on moderate-to-high resolution spectra of the galaxies responsible for the absorbers. Combining known metallicity measurements of the absorbers…
We present a new chemical evolution model for dwarf spheroidal galaxies (dSphs) in the Local Universe. Our main aim is to explain both their observed star formation histories and metallicity distribution functions simultaneously. Applying…