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Quasar Clustering from SDSS DR5: Dependences on Physical Properties
Yue Shen, Michael A. Strauss, Nicholas P. Ross +12
Using a homogenous sample of 38,208 quasars with a sky coverage of drawn from the SDSS Data Release Five quasar catalog, we study the dependence of quasar cluste…
A z = 3 Lyman Alpha Blob Associated with a Damped Lyman Alpha System Proximate to its Background Quasar
Joseph F. Hennawi, J. Xavier Prochaska, Juna Kollmeier +1
We report on the discovery of a bright Lyman alpha blob associated with the z=3 quasar SDSSJ124020.91+145535.6 which is also coincident with strong damped Lyman alpha absorption fr…
Quasars Probing Quasars III: New Clues to Feedback, Quenching, and the Physics of Massive Galaxy Formation
J. Xavier Prochaska, Joseph F. Hennawi
Galaxies hosting z~2 quasars are the high- progenitors of today's massive `red-and-dead' galaxies. With close pairs of quasars at different redshifts, a background quasar can be…
Discovery of Four Gravitationally Lensed Quasars from the Sloan Digital Sky Survey
Masamune Oguri, Naohisa Inada, Alejandro Clocchiatti +7
We present the discovery of four gravitationally lensed quasars selected from the spectroscopic quasar catalog of the Sloan Digital Sky Survey. We describe imaging and spectroscopi…
The Sloan Digital Sky Survey Quasar Lens Search. II. Statistical Lens Sample from the Third Data Release
Naohisa Inada, Masamune Oguri, Robert H. Becker +31
We report the first results of our systematic search for strongly lensed quasars using the spectroscopically confirmed quasars in the Sloan Digital Sky Survey (SDSS). Among 46,420…
The Sloan Digital Sky Survey Quasar Lens Search. III. Constraints on Dark Energy from the Third Data Release Quasar Lens Catalog
Masamune Oguri, Naohisa Inada, Michael A. Strauss +31
We present cosmological results from the statistics of lensed quasars in the Sloan Digital Sky Survey (SDSS) Quasar Lens Search. By taking proper account of the selection function,…
Coincident, 100 kpc-scale damped Lyman alpha absorption towards a binary QSO: how large are galaxies at z ~ 3?
Sara L. Ellison, Joseph F. Hennawi, Crystal L. Martin +1
We report coincident damped Lyman alpha (DLA) and sub-DLA absorption at z = 2.66 and z = 2.94 towards the z ~ 3 13.8 arcsecond separation binary quasar SDSS 1116+4118 AB. At the re…
The SDSS-DR5 Survey for Proximate Damped Lya Systems
Jason X. Prochaska, Joseph F. Hennawi, Stephane Herbert-Fort
Using the Sloan Digital Sky Survey, Data Release 5, we survey proximate damped Lya systems (PDLAs): absorption line systems with HI column density N(HI)> 2x10^20 cm^{-2} at velocit…
Clustering of High Redshift () Quasars from the Sloan Digital Sky Survey
Yue Shen, Michael A. Strauss, Masamune Oguri +13
(Abridged) We study the two-point correlation function of a uniformly selected sample of 4,426 luminous optical quasars with redshift selected over 4041 deg…
SDSS J1029+2623: A Gravitationally Lensed Quasar with an Image Separation of 22.5 Arcseconds
Naohisa Inada, Masamune Oguri, Tomoki Morokuma +16
We report the discovery of a cluster-scale lensed quasar, SDSS J1029+2623, selected from the Sloan Digital Sky Survey. The lens system exhibits two lensed images of a quasar at z_s…
A New Survey for Giant Arcs
Joseph F. Hennawi, Michael D. Gladders, Masamune Oguri +11
We report on the first results of an imaging survey to detect strong gravitational lensing targeting the richest clusters selected from the photometric data of the Sloan Digital Sk…
Quasars Probing Quasars II: The Anisotropic Clustering of Optically Thick Absorbers around Quasars
Joseph F. Hennawi, Jason X. Prochaska
With close pairs of quasars at different redshifts, a background quasar sightline can be used to study a foreground quasar's environment in absorption. We used a sample of 17 Lyman…
QSO Absorption Lines from QSOs
David V. Bowen, Joseph F. Hennawi, Brice Menard +7
We present the results of a search for metal absorption lines in the spectra of background QSOs whose sightlines pass close to foreground QSOs. We detect MgII(2796,2803) absorption…
The Sloan Digital Sky Survey Quasar Lens Search. I. Candidate Selection Algorithm
Masamune Oguri, Naohisa Inada, Bartosz Pindor +8
We present an algorithm for selecting an uniform sample of gravitationally lensed quasar candidates from low-redshift (0.6<z<2.2) quasars brighter than i=19.1 that have been spectr…
Quasars Probing Quasars I: Optically Thick Absorbers Near Luminous Quasars
Joseph F. Hennawi, Jason X. Prochaska, Scott Burles +11
With close pairs of quasars at different redshifts, a background quasar sightline can be used to study a foreground quasar's environment in absorption. We search 149 moderate resol…
A Survey of z>5.7 Quasars in the Sloan Digital Sky Survey IV: Discovery of Seven Additional Quasars
Xiaohui Fan, Michael A. Strauss, Gordon T. Richards +27
We present the discovery of seven quasars at z>5.7, selected from ~2000 deg^2 of multicolor imaging data of the Sloan Digital Sky Survey (SDSS). The new quasars have redshifts z fr…
Characterizing the Shapes of Galaxy Clusters Using Moments of the Gravitational Lensing Shear
A. E. Schulz, Joseph Hennawi, Martin White
We explore the use of the tangential component of weak lensing shear to characterize the ellipticity of clusters of galaxies. We introduce an ellipticity estimator, and quantify it…
Statistics of Quasars Multiply Imaged by Galaxy Clusters
Joseph F. Hennawi, Neal Dalal, Paul Bode
We compute the expected number of quasars multiply imaged by cluster size dark halos for current wide field quasar surveys by carrying out a large ensemble of ray tracing simulatio…
Characterizing the Cluster Lens Population
Joseph F. Hennawi, Neal Dalal, Paul Bode +1
We present a detailed investigation into which properties of CDM halos make them effective strong gravitational lenses. Strong lensing cross sections of 878 clusters from an N-body…
Binary Quasars in the Sloan Digital Sky Survey: Evidence for Excess Clustering on Small Scales
Joseph F. Hennawi, Michael A. Strauss, Masamune Oguri +16
We present a sample of 218 new quasar pairs with proper transverse separations R_prop < 1 Mpc/h over the redshift range 0.5 < z < 3.0, discovered from an extensive follow up campai…
Discovery of a Fifth Image of the Large Separation Gravitationally Lensed Quasar SDSS J1004+4112
Naohisa Inada, Masamune Oguri, Charles R. Keeton +10
We report the discovery of a fifth image in the large separation lensed quasar system SDSS J1004+4112. A faint point source located 0.2'' from the center of the brightest galaxy in…
Discovery of Two Gravitationally Lensed Quasars with Image Separations of 3 Arcseconds from the Sloan Digital Sky Survey
Masamune Oguri, Naohisa Inada, Joseph F. Hennawi +15
We report the discovery of two doubly-imaged quasars, SDSS J100128.61+502756.9 and SDSS J120629.65+433217.6, at redshifts of 1.838 and 1.789 and with image separations of 2.86'' an…
Noise in strong lensing cosmography
Neal Dalal, Joseph Hennawi, Paul Bode
Giant arcs in strong lensing galaxy clusters can provide a purely geometric determination of cosmological parameters, such as the dark energy density and equation of state. We inve…
A Survey of z>5.7 Quasars in the Sloan Digital Sky Survey III: Discovery of Five Additional Quasars
Xiaohui Fan, Joseph F. Hennawi, Gordon T. Richards +11
We present the discovery of five new quasars at z>5.7, selected from the multicolor imaging data of the Sloan Digital Sky Survey (SDSS). Three of them, at redshifts 5.93, 6.07, and…