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We present a detailed analysis of a H$_2$-rich, extremely strong intervening Damped Ly-$\alpha$ Absorption system (DLA) at $z_{\rm abs}=2.786$ towards the quasar J$\,$0843+0221, observed with the Ultraviolet and Visual Echelle Spectrograph…

We present chemical abundance measurements from high resolution observations of 7 sub-damped Lyman-alpha absorbers and 1 damped Lyman-alpha system at z<1.5. Three of these objects have high metallicity, with near or super-solar Zn…

We have obtained very deep near-infrared images in the fields of 10 QSOs whose spectra contain damped Lyman-alpha absorption (DLA) systems with 1.7<z_abs <2.5. The main aim of our investigation is to provide new constraints on the…

Astrophysics · Physics 2015-06-24 A. Aragon-Salamanca , R. S. Ellis , K. S. O'Brien

We report results from our mini-survey for molecular hydrogen in eight high redshift damped Lyman-alpha (DLA) systems using the ESO Ultra-violet and Visible Spectrograph on the VLT. In addition, we investigate two systems using ESO public…

Astrophysics · Physics 2007-05-23 Patrick Petitjean , R. Srianand , Cédric Ledoux

We present a VLT/UVES spectrum of a proximate sub-damped Lyman-alpha (sub-DLA) system at z=2.65618 toward the quasar Q0331-4505 (z_qso=2.6785+/-0.0030). Absorption lines of O I, Si II, Si III, Si IV, C II, C III, C IV, Fe II, Al II, and O…

Astrophysics · Physics 2009-11-13 Andrew J Fox , Patrick Petitjean , Cédric Ledoux , Raghunathan Srianand

We report the GMRT detection of HI 21cm absorption from the $z \sim 3.39$ damped Lyman-$\alpha$ absorber (DLA) towards PKS 0201+113, the highest redshift at which 21cm absorption has been detected in a DLA. The absorption is spread over…

Astrophysics · Physics 2008-11-26 N. Kanekar , J. N. Chengalur , W. M. Lane

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

Damped Lyman-$\alpha$ Absorber (DLA), or HI 21cm Absorber (H21A), is an important probe to model-independently measure the acceleration of spectroscopic velocity ($v_\mathrm{S}$) via the Sandage-Loeb (SL) effect. Confined by the shortage of…

Cosmology and Nongalactic Astrophysics · Physics 2023-03-31 Chang-Zhi Lu , Tingting Zhang , Tong-Jie Zhang

It has been demonstrated that one can track down galaxies in absorption 'hidden' in the Lyman-$\alpha$ forest through the use of 'strong, blended Lyman-$\alpha$' (or SBLA) absorption. Specifically a series of publications studied SBLA…

Astrophysics of Galaxies · Physics 2025-07-15 Duarte Muñoz Santos , Matthew M. Pieri , Dylan Nelson , Simon Weng , Teng Hu , Manuel F. Ruiz-Herrera Bernal

We present abundance measurements for two super Lyman Limit systems (SLLS; quasar absorption line systems with 10^19 cm^-2 < N_HI < 10^20.3 cm^-2) selected from a set of metal-strong absorbers in the Sloan Digital Sky Survey quasar…

Damped Lyman-alpha systems (DLAs) and sub-DLAs seen toward background quasars provide the most detailed probes of elemental abundances. Somewhat paradoxically these measurements are more difficult at lower redshifts due to the atmospheric…

Astrophysics · Physics 2009-11-13 C. Peroux , J. D. Meiring , V. P. Kulkarni , P. Khare , J. T. Lauroesch , G. Vladilo , D. G. York

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

We present the first results of a survey designed to understand the origin of the Lyman alpha-forest absorption systems at low redshift. Using the WYFFOS and HYDRA multi-fibre spectrographs on the WHT and WIYN telescopes, we have identified…

Astrophysics · Physics 2009-10-30 David V. Bowen , Max Pettini , Brian Boyle

We have constructed samples of low-ionization metal absorption-line systems selected for the strength of their MgII lambda2796 lines from the SDSS EDR. There are 640 absorption systems in our unbiased sample with lambda2796 REW > 1.0 A…

Astrophysics · Physics 2016-01-27 Daniel B. Nestor , Sandhya Rao , David Turnshek , Eric Furst

We study the formation of damped \lya and Lyman limit absorbers in a hierarchical clustering scenario using a gas dynamical simulation of an $\Omega = 1$, cold dark matter universe. In the simulation, these high column density systems are…

Astrophysics · Physics 2009-10-28 Neal Katz , David H. Weinberg , Lars Hernquist , Jordi Miralda-Escude

A Near-infrared (1.18-1.35 micron) high-resolution spectrum of the gravitationally-lensed QSO APM 08279+5255 was obtained with the IRCS mounted on the Subaru Telescope using the AO system. We detected strong NaI D 5891,5897 doublet…

We present the first clustering measurement of Strong Blended Lyman $\alpha$ (SBLA) absorption systems by measuring their cross-correlation with the Lyman $\alpha$ forest. SBLAs are a new population of absorbers detected within the Lyman…

Cosmology and Nongalactic Astrophysics · Physics 2023-07-18 Ignasi Pérez-Ràfols , Matthew M. Pieri , Michael Blomqvist , Sean Morrison , Debopam Som , Andrei Cuceu

We present results from a survey of galaxies in the fields of six z>3 Damped Lyman alpha systems (DLAs) using the Multi Unit Spectroscopic Explorer (MUSE) at the Very Large Telescope (VLT). We report a high detection rate of up to ~80% of…

We present Giant Metrewave Radio Telescope (GMRT) HI 21cm emission images of the z=0.009 damped Lyman-alpha (DLA) absorber towards the QSO HS 1543+5921. The DLA has been earlier identified as a low surface brightness galaxy SBS 1543+593 at…

Astrophysics · Physics 2009-11-07 Jayaram N. Chengalur , Nissim Kanekar

We present a list of z_abs ~ z_em (Delta v < 3000 km/s) DLAs discovered during the CORALS survey for absorbers in a radio-selected QSO sample. On the assumption that z_abs ~ z_em DLAs are neither ejecta from the QSO, nor part of the host…

Astrophysics · Physics 2009-11-07 Sara L. Ellison , Lin Yan , Isobel M. Hook , Max Pettini , Jasper V. Wall , Peter Shaver