相关论文: Damped Lyman alpha Systems

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…

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…

We argue that the lack of observed damped Lyman alpha (DLA) systems that simultaneously have high HI columns densities and high metallicities results naturally from the formation of molecules in the cold phase of a two-phase atomic medium…

Models are presented for the Lyman alpha emission of dusty high-redshift galaxies by combining the Press-Schechter formalism with a treatment of the inhomogeneous dust distribution inside galaxies. It is found that the amount of Lyman alpha…

Recent observations from the James Webb Space Telescope (JWST) have revealed proximate damped Lyman-$\alpha$ systems (PDLAs) in the foreground of high redshift galaxies ($z \gt 5$), which have been interpreted as neutral circumgalactic…

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…

We report new HST and ground-based observations of a damped Lyman-alpha absorption system toward the QSO 0850+4400. The redshift of the absorption system is z = 0.163770 and the neutral hydrogen column density of the absorption system is…

The last few years have seen a dramatic improvement in our understanding of the origin of Lyman alpha absorption systems. Hydrodynamic numerical simulations of cold dark matter dominated universes have shown that the many properties of the…

Cosmological simulations with gas dynamics suggest that the Lyman-alpha forest is produced mainly by "small scale structure" --- filaments and sheets that are the high redshift analog of today's galaxy superclusters. There is no sharp…

We derive the statistical properties of neutral gas at redshifts 0.11<z<1.65 from UV measurements of quasar Lyman alpha absorption lines corresponding to 369 MgII systems with $W^{\lambda2796}_{0} \ge 0.3$ \AA. In addition to the 41 damped…

We report a quantitative study of the escape of Lyman-alpha photons from an inhomogeneous optically thick medium that mimics the structure of damped Lyman-alpha absorbers. Modeling the optically thick disk with 3 components (massive stars…

The distribution of element abundances with redshift in Damped Ly-alpha (DLA) systems can be adequately reproduced by the same model reproducing the halo and disk components of the Milky Way Galaxy at different galactocentric distances: DLA…

We carried out a comprehensive analysis of the chemical properties of the interstellar medium (ISM) and the stellar population (SP) of current normal galaxies and their progenitors in a hierarchical clustering scenario. We compared the…

We review the Lyan alpha emission in local star-forming galaxies. In most cases as already shown by the IUE, the emission is absent or much weaker than expected. This occurs because Lyman alpha photons can be resonantly scattered by the…

We report {\it HST} COS spectroscopy of 10 quasars with foreground star-forming galaxies at 0.02$<$$z$$<$ 0.14 within impact parameters of $\sim$1-7 kpc. We detect damped/sub-damped Ly$\alpha$ absorption in 100$\%$ of cases where no…

We present results from a survey designed to probe the star formation properties of 32 damped Ly-alpha systems (DLAs) at z~2.7. By using the "double-DLA" technique that eliminates the glare of the bright background quasars, we directly…

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…

We present the observation of a new intermediate redshift damped Lyman-alpha absorption system candidate, discovered in the course of a spectroscopic follow-up for identifying the sources detected in a 150 A wide bandpass UV-imaging survey…

Using the GAEA semi-analytic model, we analyse the connection between Damped Lyman-$\alpha$ systems (DLAs) and HI in galaxies. Our state-of-the-art semi-analytic model is tuned to reproduce the local galaxy HI mass function, and that also…

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…