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We report spectroscopic observations with the Multiple Mirror Telescope for 11 damped Lyman-alpha absorbers (DLAs) or strong DLA candidates at 0.1 < z < 1.5, including several absorbers discovered in the Sloan Digital Sky Survey. In…

Hydrodynamic simulations of Lyman alpha clouds based on ab inito cosmological models have produced results that are in broad agreement with observations. However, further analyses have revealed that, with progressively higher numerical…

Astrophysics · Physics 2009-10-31 Renyue Cen , Greg L. Bryan

We investigate how damped Lyman-$\alpha$ absorbers (DLAs) at z ~ 2-3, detected in large optical spectroscopic surveys of quasars, trace the population of star-forming galaxies. Building on previous results, we construct a model based on…

Astrophysics of Galaxies · Physics 2020-05-27 J. -K. Krogager , P. Møller , L. B. Christensen , P. Noterdaeme , J. P. U. Fynbo , W. Freudling

Most models of cosmic chemical evolution predict that the mass-weighted mean interstellar metallicity of galaxies should rise with time from a low value $\sim 1/30$ solar at $z \sim 3$ to a nearly solar value at $z = 0$. In the absence of…

An analytical expression is presented that allows gas-to-dust elemental depletions to be estimated in interstellar environments of different types, including Damped Ly alpha systems, by scaling an arbitrary depletion pattern chosen as a…

Astrophysics · Physics 2009-11-07 Giovanni Vladilo

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…

Astrophysics of Galaxies · Physics 2020-08-12 Serafina Di Gioia , Stefano Cristiani , Gabriella De Lucia , Lizhi Xie

We have discovered molecular hydrogen in a fourth quasar damped Ly-alpha system (hereafter DLA). The UVES spectrograph on the 8.2m ESO Kueyen telescope has allowed the detection of H2 in gas with low metallicity, Z/Z_solar ~= 10^{-2}, and…

Astrophysics · Physics 2007-05-23 S. A. Levshakov , P. Molaro , M. Centurion , S. D'Odorico , P. Bonifacio , G. Vladilo

We have collected data for 69 Damped Lyman-alpha (DLA) systems, to investigate the chemical evolution of galaxies in the redshift interval 0.0 < z < 4.4. In doing that, we have adopted the most general approach used so far to correct for…

Astrophysics · Physics 2007-05-23 S. Savaglio , N. Panagia , M. Stiavelli

We report the discovery and analysis of the most metal-poor damped Lyman-alpha (DLA) system currently known, based on observations made with the Keck HIRES spectrograph. The metal paucity of this system has only permitted the determination…

Cosmology and Nongalactic Astrophysics · Physics 2017-01-13 Ryan Cooke , Max Pettini , Charles C. Steidel

The origin of low alpha/Fe ratios in some metal-poor stars, so called low-alpha stars, is discussed. It is found that most of low-alpha stars in the Galaxy are on the main-sequence. This strongly suggests that these stars suffered from…

Astrophysics · Physics 2009-11-10 Toshikazu Shigeyama , Takuji Tsujimoto

We used our database of ESO VLT-UVES spectra of quasars to build up a sample of 67 Damped Lyman-alpha (DLA) systems with redshifts 1.7<zabs<3.7. For each system, we measured average metallicities relative to Solar, [X/H] (with either X=Zn,…

Astrophysics · Physics 2009-11-11 C. Ledoux , P. Petitjean , P. Moller , J. Fynbo , R. Srianand

We aim to study the high-precision chemical abundances of metal-poor gas clouds at cosmic noon (2<z<4) and investigate the associated enrichment histories. We analyse the abundances of four newly discovered metal-poor gas clouds utilising…

Astrophysics of Galaxies · Physics 2024-11-20 Louise Welsh , Ryan Cooke , Michele Fumagalli , Max Pettini , Gwen C. Rudie

We estimate the intrinsic neutral gas density in Damped Lyman Alpha systems ($\Omega_{HI}^{(DLA)}$) in the redshift range $ 2.2 \lesssim z \lesssim 5$ from the DLA SDSS DR_3 sample of optically selected quasars. We take into account…

Astrophysics · Physics 2008-11-26 M. Trenti , M. Stiavelli

We present abundance measurements of elements O, C, Si and Fe for three gas-rich galaxies at z~5 using observations from the Very Large Telescope (VLT) and the Keck telescope in order to better constrain the early chemical enrichment of…

Astrophysics of Galaxies · Physics 2017-10-11 Suraj Poudel , Varsha P. Kulkarni , Sean Morrison , Céline Péroux , Debopam Som , Hadi Rahmani , Samuel Quiret

We compare the properties of a sample of local (z=0) gas-rich galaxies studied in 21 cm emission to a sample of 13 low-redshift (z < 1) damped Lyman alpha (DLA) galaxies identified as the counterparts of low-redshift DLA systems found in…

Astrophysics · Physics 2007-05-23 David A. Turnshek , Sandhya M. Rao , Daniel B. Nestor

Using adaptive mesh-refinement cosmological hydrodynamic simulations with a physically motivated supernova feedback prescription we show that the standard cold dark matter model can account for extant observed properties of damped Lyman…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 Renyue Cen

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…

Astrophysics · Physics 2009-11-13 Patrick Petitjean , Cedric Ledoux , R. Srianand

The cycling of metals between interstellar gas and dust is a critical aspect of the baryon cycle of galaxies, yet our understanding of this process is limited. This study focuses on understanding dust depletion effects in the low…

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…

Astrophysics · Physics 2009-11-07 Kentaro Nagamine , Volker Springel , Lars Hernquist

Recently, the number of detected galaxy counterparts of z > 2 Damped Lyman-alpha Absorbers in QSO spectra has increased substantially so that we today have a sample of 10 detections. M{\o}ller et al. in 2004 made the prediction, based on a…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 J. -K. Krogager , J. P. U. Fynbo , P. Møller , C. Ledoux , P. Noterdaeme , L. Christensen , B. Milvang-Jensen , M. Sparre
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