409 citations · 2.4k across the 42 of their papers we have counts for
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Measurements of CaII absorption, metals, and dust in a sample of z~1 DLAs and subDLAs
Daniel Nestor, Max Pettini, Paul Hewett +2
We present observations of CaII, ZnII, and CrII absorption lines in 16 DLAs and 6 subDLAs at 0.6 < z < 1.3, obtained for the dual purposes of: (i) clarifying the relationship betwe…
The Environments of Ultra-strong Mg II Absorbers
Daniel B. Nestor, David A. Turnshek, Sandhya M. Rao +1
We present r'- or i'-band WIYN images of the fields of 15 Sloan Digital Sky Survey quasars that have spectra exhibiting intervening MgII absorption-line systems with rest equivalen…
Average Extinction Curves and Relative Abundances for QSO Absorption Line Systems at 1 <= z_abs < 2
Donald G. York, Pushpa Khare, Daniel Vanden Berk +21
We have studied a sample of 809 Mg II absorption systems with 1.0 < z_abs < 1.86 in the spectra of SDSS QSOs, with the aim of understanding the nature and abundance of the dust and…
MMT Survey for Intervening MgII Absorption
Daniel B. Nestor, David A. Turnshek, Sandhya M. Rao
We present the results from a spectroscopic survey for intervening MgII absorption in the spectra of 381 background QSOs conducted at the Multiple Mirror Telescope. This survey com…
Damped Lyman Alpha Systems at z<1.65: The Expanded SDSS HST Sample
Sandhya M. Rao, David A. Turnshek, Daniel. B. Nestor
We present results of our HST Cycle 11 Survey for low-redshift (z<1.65) DLAs in the UV spectra of quasars selected from the SDSS Early Data Release. These quasars have strong inter…
The Metallicity - Kinematics Relation in Large-N(HI) Absorbers
David A. Turnshek, Sandhya M. Rao, Daniel B. Nestor +2
Sloan Digital Sky Survey (SDSS) quasar spectroscopy is yielding a database of strong low-ionization MgII absorbers over the redshift interval 0.36<z<2.28 which is over two orders o…
The star formation history of damped Lyman alpha absorbers
A. M. Hopkins, S. M. Rao, D. A. Turnshek
The local power law relationship between the surface densities of neutral hydrogen gas and star formation rate (SFR) can be used to explore the SFR properties of damped Lyman alpha…
Towards an Understanding of the Physical Nature of MgII Absorption Systems
D. B. Nestor, D. A. Turnshek, S. M. Rao
We discuss issues concerning the physical nature of intervening MgII quasar absorption systems in light of results from our recent surveys using SDSS EDR QSO spectra and data obtai…
Mg II Absorption Systems in SDSS QSO Spectra
D. B. Nestor, D. A. Turnshek, S. M. Rao
We present the results of a MgII absorption-line survey using QSO spectra from the SDSS EDR. Over 1,300 doublets with rest equivalent widths greater than 0.3Åand redshifts $0.366 \…
Elemental Abundances in Two High Column Density Damped Lyman Alpha Systems at z < 1.5
Sandhya M. Rao, Jason X. Prochaska, J. Christopher Howk +1
We present Keck/HIRES abundance measurements and metal-line kinematic profiles of the damped Lyman alpha systems (DLAs) towards the quasars Q0933+733 (z_abs=1.479) and Q0948+433 (z…
Double-Damped Lyman Alpha Absorption: A Possible Large Neutral Hydrogen Gas Filament Near Redshift z=1
David A. Turnshek, Sandhya M. Rao, Daniel B. Nestor +3
We report the discovery of two damped Ly-alpha absorption-line systems (DLAs) near redshift z=1 along a single quasar sightline (Q1727+5302) with neutral hydrogen column densities…
The HII Regions of the Damped Lyman alpha Absorber SBS 1543+593
Regina E. Schulte-Ladbeck, Sandhya M. Rao, Igor O. Drozdovsky +3
We report new imaging and spectroscopic observations of the damped Ly alpha (DLA) galaxy SBS 1543+593, a nearby dwarf galaxy whose stellar disk is intersected by the sightline to t…
Damped Lyman Alpha Gas Metallicities at Redshifts z=0.9-2.0 from SDSS Spectra
Daniel B. Nestor, Sandhya M. Rao, David A. Turnshek +1
Using Sloan Digital Sky Survey (SDSS) early data release spectra, we have identified 370 MgII absorption systems with MgII 2796 rest equivalent widths >= 1A and redshifts z=0.9-2.2…
Chandra ACIS-S Observations of Three Quasars with Low-Redshift Damped Ly-alpha Absorption: Constraints on the Cosmic Neutral-Gas-Phase Metallicity at Redshift z \approx 0.4
David A. Turnshek, Sandhya M. Rao, Andrew F. Ptak +2
Chandra X-Ray Observatory (CXO) ACIS-S spectra of three quasars which lie behind three foreground damped Lyman alpha (DLA) absorbers are analyzed in order to attempt to determine t…
Strong Absorption-line Systems at Low Redshift: MgII and Damped Lyman Alpha
Daniel B. Nestor, Sandhya Rao, David Turnshek
We detail a powerful indirect method for the study of damped Lyman alpha systems (DLAs) at low redshift. We increase the probability of finding a low-redshift DLA to nearly 50% by…
Strong MgII Absorption Systems in QSOs from the Sloan Digital Sky Survey Early Data Release
Daniel B. Nestor, Sandhya Rao, David Turnshek +1
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 sys…
Low-Redshift Damped Lyman Alpha Galaxies Toward the Quasars B2 0827+243, PKS 0952+179, PKS 1127-145, and PKS 1629+120
Sandhya M. Rao, Daniel B. Nestor, David A. Turnshek +3
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 spec…
The Non-Damped Nature of Twelve Low-Redshift Damped Lyman Alpha Candidate Systems
David A. Turnshek, Sandhya M. Rao
Hubble Space Telescope (HST) UV spectroscopy of 12 candidate low-redshift damped Lyman alpha (DLA) systems in 11 QSOs (z=0.103 in Q0054+144, z=0.969 and z=0.987 in Q0302-223, z=0.4…
Properties of Low-Redshift Damped Lyman Alpha Galaxies
Daniel B. Nestor, Sandhya M. Rao, David A. Turnshek +3
Images of five QSO fields containing six damped Lyman alpha (DLA) systems at redshifts 0.09<z<0.53 are presented. Identifications for the DLA galaxies giving rise to the DLA system…
A Comparative Study of Damped Lyman Alpha Galaxies
David A. Turnshek, Sandhya M. Rao, Daniel B. Nestor
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…
The Evolution of Neutral Gas in the Universe as Traced by Damped Lyman Alpha Systems
Sandhya M. Rao, David A. Turnshek
We discuss our recent results on the statistical properties of damped Lyman alpha systems (DLAs) at low redshift (z<1.65) (Rao & Turnshek 2000). Contrary to expectations, we found…
Hubble Space Telescope Observations of the Gravitationally Lensed Cloverleaf Broad Absorption Line QSO H1413+1143: Imaging Polarimetry and Evidence for Microlensing of a Scattering Region
Kyu-Hyun Chae, David A. Turnshek, Regina E. Schulte-Ladbeck +2
We report the results of HST WFPC2 broadband F555W and F702W photometric and F555W polarimetric observations of the "Cloverleaf" QSO H1413+1143. This is a four-component gravitatio…
The z=0.0912 and z=0.2212 Damped Lyman Alpha Galaxies Along the Sight-Line Toward the Quasar OI 363
D. A. Turnshek, S. Rao, D. Nestor +4
New optical and infrared observations along the sight-line toward the quasar OI 363 (0738+313) are presented and discussed. Excluding systems which lack confirming UV spectroscopic…
The Cosmological Evolution of Quasar Damped Lyman-Alpha Systems
Sandhya Rao
We present results from an efficient, non-traditional survey to discover damped Lyman-alpha (DLA) absorption-line systems with neutral hydrogen column densities N(HI)>2x10^{20} ato…