The Fundamental Plane of QSOs and the Relationship Between Host and Nucleus (2008)
Hamilton, Timothy S., Casertano, Stefano, Turnshek, David A.
We present results from an archival study of 70 medium-redshift QSOs observed with the Wide Field Planetary Camera 2 on board the Hubble Space Telescope. The QSOs have magnitudes M_V
Optical properties and spatial distribution of Mg II absorbers from SDSS image stacking (2007)
Zibetti, Stefano, Ménard, Brice, Nestor, D. B., Quider, Anna M., Rao, Sandhya M., Turnshek, David A.
The Environments of Ultra-strong Mg II Absorbers (2006)
Nestor, Daniel B., Turnshek, David A., Rao, Sandhya M., Quider, Anna M.
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 equivalent widths 2.7A \le...
Optical properties and spatial distribution of MgII absorbers from SDSS image stacking (2006)
Zibetti, Stefano, Menard, Brice, Nestor, Daniel B., Quider, Anna M., Rao, Sandhya M., Turnshek, David A.
We present a statistical analysis of the photometric properties and spatial distribution of more than 2,800 MgII absorbers with 0.37
MMT Survey for Intervening MgII Absorption (2006)
Nestor, Daniel B., Turnshek, David A., Rao, Sandhya M.
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 complements our...
The Fundamental Plane of Quasars (2005)
Hamilton, Timothy S., Casertano, Stefano, Turnshek, David A.
We present results from an archival study of 70 medium-redshift QSOs observed with the Wide Field Planetary Camera 2 on board the Hubble Space Telescope. The QSOs have magnitudes M_V < -23 (total...
Damped Lyman Alpha Systems at z (2005)
Rao, Sandhya M., Turnshek, David A., Nestor, Daniel. B.
We present results of our HST Cycle 11 Survey for low-redshift (z
The Metallicity - Kinematics Relation in Large-N(HI) Absorbers (2005)
Turnshek, David A., Rao, Sandhya M., Nestor, Daniel B., Belfort-Mihalyi, Michele, Quider, Anna
Sloan Digital Sky Survey (SDSS) quasar spectroscopy is yielding a database of strong low-ionization MgII absorbers over the redshift interval 0.36
Characteristic QSO Accretion Disk Temperatures from Spectroscopic Continuum Variability (2005)
Pereyra, Nicolas A., Berk, Daniel E. Vanden, Turnshek, David A., Hillier, D. John, Wilhite, Brian C., Kron, Richard G., ...
Using Sloan Digital Sky Survey (SDSS) quasar spectra taken at multiple epochs, we find that the composite flux density differences in the rest frame wavelength range 1300-6000 AA can be fit by a...
On the Steady Nature of Line-Driven Disk Winds: Application to Cataclysmic Variables (2005)
Pereyra, Nicolas A., Turnshek, David A., Hillier, D. John
We apply the semi-analytical analysis of the steady nature of line-driven winds presented in two earlier papers to disk winds driven by the flux distribution of a standard Shakura & Sunyaev (1973)...
Schulte-Ladbeck, Regina E., K"onig, Brigitte, Miller, Christopher J., Hopkins, Andrew M., Drozdovsky, Igor O., Turnshek, David A., ...
We report HST/STIS spectroscopy and Gemini/GMOS-N imaging of the Damped Lyman Alpha (DLA) system toward HS 1543+5921 caused by the host star-forming galaxy (SFG) SBS 1543+593. The Gemini image shows...
Turnshek, David A., Rao, Sandhya M., Nestor, Daniel B., Berk, Daniel Vanden, Belfort, Michele, Monier, Eric M.
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 of N(HI) =...
On the Steady Nature of Line-Driven Disk Winds (2003)
Pereyra, Nicolas A., Owocki, Stanley P., Hillier, D. John, Turnshek, David A.
We perform an analytic investigation of the stability of line-driven disk winds, independent of hydrodynamic simulations. Our motive is to determine whether or not line-driven disk winds can account...
The HII Regions of the Damped Lyman alpha Absorber SBS 1543+593 (2003)
Schulte-Ladbeck, Regina E., Rao, Sandhya M., Drozdovsky, Igor O., Turnshek, David A., Nestor, Daniel B., Pettini, Max
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 the bright...
Damped Lyman Alpha Gas Metallicities at Redshifts z=0.9-2.0 from SDSS Spectra (2003)
Nestor, Daniel B., Rao, Sandhya M., Turnshek, David A., Berk, Daniel Vanden
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. From our previous...
Turnshek, David A., Rao, Sandhya M., Ptak, Andrew F., Griffiths, Richard E., Monier, Eric M.
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 the amount of...
Rao, Sandhya M., Nestor, Daniel B., Turnshek, David A., Lane, Wendy M., Monier, Eric M., Bergeron, Jacqueline
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...
The Non-Damped Nature of Twelve Low-Redshift Damped Lyman Alpha Candidate Systems (2002)
Turnshek, David A., Rao, Sandhya M.
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=0.478 in Q0454-220,...
The Evolution of Neutral Gas in the Universe as Traced by Damped Lyman Alpha Systems (2001)
Rao, Sandhya M., Turnshek, David A.
We discuss our recent results on the statistical properties of damped Lyman alpha systems (DLAs) at low redshift (z
A Comparative Study of Damped Lyman Alpha Galaxies (2001)
Turnshek, David A., Rao, Sandhya M., Nestor, Daniel B.
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...
Properties of Low-Redshift Damped Lyman Alpha Galaxies (2001)
Nestor, Daniel B., Rao, Sandhya M., Turnshek, David A., Monier, Eric, Lane, Wendy, Bergeron, Jacqueline
Images of five QSO fields containing six damped Lyman alpha (DLA) systems at redshifts 0.09
Chae, Kyu-Hyun, Turnshek, David A., Schulte-Ladbeck, Regina E., Rao, Sandhya M., Lupie, Olivia L.
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 gravitationally-lensed broad...
The Luminosity Function of QSO Host Galaxies (2000)
Hamilton, Timothy S., Casertano, Stefano, Turnshek, David A.
We present some results from our HST archival image study of 71 QSO host galaxies. The objects are selected to have z < 0.46 and total absolute magnitude M_V < -23 (H_0=50 km/s/Mpc). This initial...
Rao, Sandhya M., Turnshek, David A.
We report results on the incidence and cosmological mass density of damped Lyman-alpha (DLA) systems at redshifts less that 1.65. We used HST and an efficient non-traditional (but unbiased) survey...
Chae, Kyu-Hyun, Turnshek, David A.
We investigate gravitational lens models for the quadruply-lensed Cloverleaf BAL QSO H1413+1143 based on the HST WFPC/WFPC2 astrometric and photometric data of the system by Turnshek et al. and the...
Gravitational Lensing by Power-Law Mass Distributions: A Fast and Exact Series Approach (1998)
Chae, Kyu-Hyun, Khersonsky, Valery K., Turnshek, David A.
We present an analytical formulation of gravitational lensing using familiar triaxial power-law mass distributions, where the 3-dimensional mass density is given by $\rho(X,Y,Z) = \rho_0 [1 +...
Weymann, Ray J., Jannuzi, Buell T., Lu, Limin, Bahcall, John N., Bergeron, Jacqueline, Boksenberg, Alec, ...
We present an analysis of the evolution of the Ly alpha absorption lines in the redshift interval 0.0 to \sim 1.5 based upon a sample of 987 lines identified in the spectra of 63 QSOs obtained with...
Jannuzi, Buell T., Bahcall, John N., Bergeron, Jacqueline, Boksenberg, Alec, Hartig, George F., Kirhakos, Sofia, ...
We present a catalogue of absorption lines obtained from the analysis of the ultra-violet spectra of 66 quasars. The data were acquired with the Faint Object Spectrograph of the HST as part of the...
Rao, Sandhya M., Turnshek, David A.
The discovery of a z_abs = 0.0912 damped Lyman-alpha absorption-line system in the HST-FOS ultraviolet spectrum of the quasar OI 363 (0738+313) is reported. This is the lowest redshift quasar damped...
The HST Quasar Absorption Line Key Project VII. Absorption Systems at $z_{\rm abs} \leq 1.3$ (1995)
Bahcall, John N., Bergeron, Jacqueline, Boksenberg, Alec, Hartig, George F., Jannuzi, Buell T., Kirhakos, Sofia, ...
We present evidence that clumps of \lya lines are physically associated with about half of the extensive metal-line systems (absorption systems with four or more observed metal-line species) found in...