相关论文: Chemical evolution of DLA systems

We have extended our chemical and cosmological galaxy evolution model to calculate the abundance evolution for altogether 16 different elements in spiral galaxies in a chemically consistent way which is a considerable step towards a more…

Relative elemental abundances, and in particular the alpha/Fe ratio, are an important diagnostic tool of the chemical evolution of damped Ly alpha systems (DLAs). The S/Zn ratio is not affected by differential dust depletion and is an…

We use cosmological hydrodynamical simulations including star formation and metal enrichment to study the evolution of the chemical properties of galaxy-like objects at high redshift in the range $0.25<z< 2.35$ in a hierarchical clustering…

We take a fresh look at the abundance of nitrogen in DLAs with oxygen abundances between 1/10 and 1/100 of solar. This is a metallicity regime poorly sampled in the local universe and where QSO absorbers may hold clues to both the…

Determination of chemical abundances for elements produced mainly by Type I SNae and intermediate mass stars in high redshift DLAs probes the early chemical build-up on time-scales comparable with their production. Nitrogen shows a peculiar…

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…

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 investigate chemical enrichment in Damped Lyman alpha (DLA) systems in the hierarchical structure formation scenario using a semi-analytic model of galaxy formation. The model developed by Nagashima, Totani, Gouda and Yoshii takes into…

We investigate the evolutionary history of the Universe's metal content focusing on the chemical abundance of several elements (N, O, S, Si, Fe, Cr, Zn) taken from observational data and predictions from chemical evolution models. The…

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…

Nitrogen abundances have been derived in Damped Ly alpha (DLA) galaxies at Zabs = 2.309, 2.827 and 3.025 toward the QSOs 0100+1300, 1425+6039 and 0347-3819 respectively. The behaviour of nitrogen relative to iron-peak and alpha-elements has…

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 study the Oxygen and Nitrogen abundances in the interstellar medium of high-redshift galaxies. We use high resolution and high signal-to-noise ratio spectra of Damped Lyman-alpha (DLA) systems detected along the line-of-sight to quasars…

The damped Lyman alpha systems seen in the spectra of high redshift QSOs offer the means to determine element abundances in galaxies observed while still at an early stage of evolution. Such measurements, which have only recently come…

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…

We present new elemental abundance studies of seven damped Lyman-alpha systems (DLAs). Together with the four DLAs analyzed in Dessauges-Zavadsky et al. (2004), we have a sample of eleven DLA galaxies with uniquely comprehensive and…

The abundance of nitrogen in the interstellar medium is a powerful probe of star for- mation processes over cosmological timescales. Since nitrogen can be produced both in massive and intermediate-mass stars with metallicity-dependent…

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…

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…

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…