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We present a systematic search for molecular hydrogen absorption systems at high redshift in quasar spectra from the Sloan Digital Sky Survey (SDSS) II Data Release 7 and SDSS-III Data Release 9. We have selected candidates using a modified…

Cosmology and Nongalactic Astrophysics · Physics 2014-03-20 S. A. Balashev , V. V. Klimenko , A. V. Ivanchik , D. A. Varshalovich , P. Petitjean , P. Noterdaeme

We use cosmological smoothed-particle hydrodynamics (SPH) simulations of the Lambda cold dark matter (CDM) model to study the abundance of damped Lyman-alpha absorbers (DLAs) in the redshift range z=0-4.5. We compute the cumulative DLA…

Astrophysics · Physics 2008-11-26 Kentaro Nagamine , Volker Springel , Lars Hernquist

We present the first results from a survey of SDSS quasars selected for strong H I damped Lyman-{\alpha} (DLA) absorption with corresponding low equivalent width absorption from strong low-ion transitions (e.g. C II {\lambda}1334 and Si II…

Cosmology and Nongalactic Astrophysics · Physics 2010-06-22 Bryan E. Penprase , J. Xavier Prochaska , Wallace L. W. Sargent , Irene Toro Martinez , Daniel J. Beeler

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

We present a new catalogue of Damped Lyman-$\alpha$ absorbers from SDSS DR16Q, as well as new estimates of their statistical properties. Our estimates are computed with the Gaussian process models presented in Garnett et al. (2017); Ho et…

Astrophysics of Galaxies · Physics 2021-08-24 Ming-Feng Ho , Simeon Bird , Roman Garnett

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…

Damped Lyman-{\alpha} Absorbers (DLAs) as a class of QSO absorption-line systems are currently our most important source of detailed information on the cosmic chemical evolution of galaxies. However, the degree to which this information is…

Though observationally rare, damped Lya absorption systems dominate the mass density of neutral gas in the Universe. Eleven high redshift damped Lya systems covering 2.8<z<4.4 were discovered in 26 QSOs from the APM z>4 QSO Survey,…

Astrophysics · Physics 2016-06-08 L. J. Storrie-Lombardi , R. G. McMahon , M. J. Irwin

We present the Damped Ly$\alpha$ Toolkit for automated detection and characterization of Damped Ly$\alpha$ absorbers (DLA) in quasar spectra. Our method uses quasar spectral templates with and without absorption from intervening DLAs to…

We use the existing catalog of Damped Lyman-Alpha (DLA) systems to place constraints on the amount of evolution in the baryonic content of galaxies and on the value of the cosmological constant. The density of cold gas at redshifts z=3+-1…

Astrophysics · Physics 2007-05-23 Eric Woods , Abraham Loeb

We present optical and near-infrared ground-based imaging results on four low-redshift damped Ly-alpha (DLA) galaxies. The corresponding DLA systems were discovered in our HST spectroscopic surveys for DLA lines in known strong MgII…

We report the discovery of 59 new ghostly absorbers from the Sloan Digital Sky Survey (SDSS) Data Release 14 (DR14). These absorbers, with $z_{\rm abs}$$\sim$$z_{\rm QSO}$, reveal no Ly$\alpha$ absorption, and they are mainly identified…

Astrophysics of Galaxies · Physics 2020-10-07 Hassan Fathivavsari

We develop an automated technique to measure quasar redshifts in the Baryon Oscillation Spectroscopic Survey (BOSS) of the Sloan Digital Sky Survey (SDSS). Our technique is an extension of an earlier Gaussian process method for detecting…

Astrophysics of Galaxies · Physics 2020-09-16 Leah Fauber , Ming-Feng Ho , Simeon Bird , Christian R. Shelton , Roman Garnett , Ishita Korde

We present a measurement of the DLA mean bias from the cross-correlation of DLA and the Ly$\alpha$ forest, updating earlier results of Font-Ribera et al. 2012 with the final BOSS Data Release and an improved method to address continuum…

We present here a dataset of quasars observed with the Ultraviolet Visual Echelle Spectrograph (UVES) on the VLT and available in the ESO UVES Advanced Data Products archive. The sample is made up of a total of 250 high resolution quasar…

Cosmology and Nongalactic Astrophysics · Physics 2013-08-16 Tayyaba Zafar , Attila Popping , Celine Peroux

We present chemical abundance measurements for 47 damped Lyman-alpha systems (DLAs), 30 at z>4, observed with the Echellette Spectrograph and Imager and the High Resolution Echelle Spectrometer on the Keck telescopes. HI column densities of…

Cosmology and Nongalactic Astrophysics · Physics 2012-08-10 Marc Rafelski , Arthur M. Wolfe , J. Xavier Prochaska , Marcel Neeleman , Alexander J. Mendez

We report new observations of ZnII and CrII absorption lines in 10 damped \lya systems (DLAs), mostly at redshift $z_{abs} \simgt 2.5$ . By combining these results with those from our earlier survey (Pettini et al. 1994) and other recent…

Astrophysics · Physics 2015-06-24 Max Pettini , Linda J. Smith , David L. King , Richard W. Hunstead

The results of a new spectroscopic survey of 66 $z \simgt 4$ quasars for Damped Lyman-alpha absorption systems are presented. The search led to the discovery of 30 new DLA candidates which are analysed in order to compute the comoving mass…

Astrophysics · Physics 2009-10-31 Celine Peroux , Mike J. Irwin , Richard G. McMahon , Lisa J. Storrie-Lombardi

We use Sloan Digital Sky Survey Data Release 2 QSO spectra to constrain the dust-reddening caused by intervening damped Lyman-alpha systems (DLAs). Comparing the spectral index distribution of a 70 sight-line DLA sample with that of a large…

Astrophysics · Physics 2009-11-10 M. T. Murphy , J. Liske

If damped Lyman alpha systems (DLAs) contain even modest amounts of dust, the ultraviolet luminosity of the background quasar can be severely diminished. When the spectrum is redshifted, this leads to a bias in optical surveys for DLAs.…

Astrophysics · Physics 2009-11-13 Andrew Pontzen , Max Pettini