Related papers: Chemical evolution of DLA systems
We study the distribution of the star formation rate and metallicity of damped Lyman-alpha absorbers using cosmological SPH simulations of the Lambda cold dark matter model in the redshift range z=0-4.5. Our approach includes a…
We present a high spectral resolution survey of the most metal-poor damped Lyman-alpha absorption systems (DLAs) aimed at probing the nature and nucleosynthesis of the earliest generations of stars. Our survey comprises 22 systems with iron…
We have combined new high resolution UVES-VLT observations of a sample of four damped Ly-alpha systems (DLAs) at redshifts between z_abs = 1.7-2.5 with the existing HIRES-Keck spectra to undertake a comprehensive study of their physical…
We derive the abundance of 19 elements in a sample of 64 stars with fundamental parameters very similar to solar, which minimizes the impact of systematic errors in our spectroscopic 1D-LTE differential analysis, using high-resolution…
Utilizing the observational data of 55,318 star-forming galaxies (SFGs) selected from the catalog of MPA-JHU emission-line measurements for the SDSS DR8, we investigate the galaxy downsizing effect of their O and N enrichments, and the…
In these lectures I present a highly opinionated review of the observed patterns of metallicity and element abundance ratios in nearby spiral, irregular, and dwarf elliptical galaxies, with connection to a number of astrophysical issues…
In this paper we analyze the kinematics, chemistry, and physical properties of a sample of the most metal-poor damped Lyman-alpha systems (DLAs), to uncover their links to modern-day galaxies. We present evidence that the DLA population as…
The effects of the dust on the determination of elemental abundances in damped Ly alpha (DLA) absorbers are investigated. Relations between the observed abundances measured in the gas phase and the overall abundances (gas plus dust) are…
We present chemical evolution models aimed at reproducing the observed (N/O) vs. (O/H) abundance pattern of star forming galaxies in the Local Universe. We derive gas-phase abundances from SDSS spectroscopy and a complementary sample of…
Detailed analysis of the spectral lines from two low redshift damped Lyman alpha absorbers (DLA) confirms that they are a heterogeneous population. Both systems have low metal abundances of approximately 0.05 to 0.1 solar. The abundance…
An accurate method to measure the abundance of high-redshift galaxies consists in the observation of absorbers along the line of sight toward a background quasar. Here, we present abundance measurements of 13 z>3 sub-Damped Lyman-alpha…
Sub-damped Lyman-alpha systems (sub-DLAs) have previously been found to exhibit a steeper metallicity evolution than the classical damped Lyman-alpha systems (DLAs), evolving to close to solar metallicity by z~1. From new high-resolution…
Since stellar populations enhance particular element abundances according to the yields and lifetimes of the stellar progenitors, the chemical evolution of galaxies serves as one of the key tools that allows the tracing of galaxy evolution.…
We report two detections of deuterated molecular hydrogen (HD) in QSO absorption-line systems at $z > 2$. Toward J2123-0500, we find $N$(HD) $= 13.84 \pm 0.2$ for a sub-DLA with metallicity $\simeq 0.5Z_{\odot}$ and $N$(H$_2$) = $17.64 \pm…
We present a study of the early build-up of dust in high redshift galaxies. The study is based on the analysis of 38 Damped Ly alpha systems (DLAs) for which we derive the fraction of iron atoms in dust form, f_{Fe}. The sample is…
The abundance of alpha-process elements such as magnesium and carbon relative to iron measured from the broad emission lines of QSOs can serve as a diagnostic of the star formation and chemical enrichment histories of their host galaxies.…
The validity of oxygen and nitrogen abundances derived from the global emission-line spectra of galaxies via the P-method has been investigated using a collection of published spectra of individual HII regions in irregular and spiral…
Ultra diffuse galaxies are a population of extended galaxies but with relatively low luminosities. The origin of these objects remains unclear, largely due to the observational challenges of the low surface brightness Universe. We present…
In order to recognize environmental effects on the evolution of dwarf galaxies in clusters of galaxies, it is first necessary to quantify the properties of objects which have evolved in relative isolation. With oxygen abundance as the gauge…
Understanding the nucleosynthetic origin of nitrogen and the evolution of the N/O ratio in the interstellar medium is crucial for a comprehensive picture of galaxy chemical evolution at high-redshift because most observational metallicity…