Improved Constraints on the Gravitational Lens Q0957+561. I. Weak Lensing (2009)
Nakajima, R., Bernstein, G. M., Fadely, R., Keeton, C. R., Schrabback, T.
Attempts to constrain the Hubble constant using the strong gravitational lens system Q0957+561 are limited by systematic uncertainties in the mass model, since the time delay is known very precisely....
Dark Matter Structures in the Universe: Prospects for Optical Astronomy in the Next Decade (2009)
Marshall, P. J., Auger, M., Bartlett, J. G., Bradac, M., Cooray, A., Dalal, N., ...
The Cold Dark Matter theory of gravitationally-driven hierarchical structure formation has earned its status as a paradigm by explaining the distribution of matter over large spans of cosmic distance...
Is the Optically Unidentified Radio Source, FIRST J121839.7+295325, a Dark Lens? (2008)
Ryan Jr., R. E., Cohen, S. H., Windhorst, R. A., Keeton, C. R., Veach, T. J.
We present evidence that the optically unidentified radio source, FIRST J121839.7+295325, may be strongly lensing a background galaxy. We estimate the redshift of the assumed gravitational arc,...
The geometry of the quadruply imaged quasar PG 1115+080; implications for (2007)
Courbin Magain, F. Courbin, C. R. Keeton, C. S. Kochanek, C. Vanderriest
. Time delay measurements have recently been reported for the lensed quasar PG 1115+080. These measurements can be used to derive H 0 , but only if we can constrain the lensing potential. We have...
Virbhadra, K. S., Keeton, C. R.
We model the massive dark object at the center of the Galaxy as a Schwarzschild black hole as well as Janis-Newman-Winicour naked singularities, characterized by the mass and scalar charge...
Gravitational lensing by Elliptical Galaxies, and the Schwarz Function (2007)
Fassnacht, C. D., Keeton, C. R., Khavinson, D.
We discuss gravitational lensing by elliptical galaxies with some particular mass distributions. Using simple techniques from the theory of quadrature domains and the Schwarz function (cf. \cite{Sh})...
A Time Delay for the Cluster-lensed Quasar SDSS J1004+4112 (2007)
Fohlmeister, J., Kochanek, C. S., Falco, E. E., Wambsganss, J., Morgan N., Morgan, Morgan, C. W., ...
We present 426 epochs of optical monitoring data spanning 1000 days from 2003 December to 2006 June for the gravitationally lensed quasar SDSS J1004+4112. The time delay between the A and B images is...
A Time Delay for the Largest Gravitationally Lensed Quasar: SDSS J1004+4112 (2006)
Fohlmeister, J., Kochanek, C. S., Falco, E. E., Wambsganss, J., Morgan, N., Morgan, C. W., ...
We present 426 epochs of optical monitoring data spanning 1000 days from December 2003 to June 2006 for the gravitationally lensed quasar SDSS J1004+4112. The time delay between the A and B images is...
Peng, C. Y., Impey, C. D., Kochanek, C. S., Keeton, C. R., Falco, E. E., ...
In the present-day universe, supermassive black hole masses (MBH) appear to be strongly correlated with their galaxy's bulge luminosity, among other properties. In this study, we explore the...
Ota, N., Inada, N., Oguri, M., Mitsuda, K., Richards, G. T., Suto, Y., ...
We present results from Chandra observations of SDSS J1004+4112, a strongly lensed quasar system with a maximum image separation of 15". All four bright images of the quasar, as well as resolved...
First Results from a Photometric Survey of Strong Gravitational Lens Environments (2005)
Williams, K. A., Momcheva, I., Keeton, C. R., Zabludoff, A. I., Lehar, J.
Many strong gravitational lenses lie in complex environments, such as poor groups of galaxies, that significantly bias conclusions from lens analyses. We are undertaking a photometric survey of all...
A Spectroscopic Study of the Environments of Gravitational Lens Galaxies (2005)
Momcheva, I., Williams, K. A., Keeton, C. R., Zabludoff, A. I.
(Abridged) We present the first results from our spectroscopic survey of the environments of strong gravitational lenses. The lens galaxy belongs to a poor group of galaxies in six of the eight...
Measuring Supermassive Black Holes in Distant Galaxies with Central Lensed Images (2004)
Rusin, D., Keeton, C. R., Winn, J. N.
The supermassive black hole at the center of a distant galaxy can be weighed, in rare but realistic cases, when the galaxy acts as a strong gravitational lens. The central image that should be...
Improved Cosmological Constraints from Gravitational Lens Statistics (2004)
Mitchell, J. L., Keeton, C. R., Frieman, J. A, Sheth, R. K.
We combine the Cosmic Lens All-Sky Survey (CLASS) with new Sloan Digital Sky Survey (SDSS) data on the local velocity dispersion distribution function of E/S0 galaxies, $\phi(\sigma)$, to derive lens...
Possible supernova associated with Q0957+561 (2004)
Peng, C. Y., Impey, C. D., Kochanek, C. S., Falco, E. E., Lehar, J., ...
IAUC 8298 available courtesy of the Central Bureau for Astronomical Telegrams.
Lensed quasar host galaxies (2004)
Peng, C. Y., Impey, C. D., Falco, E. E., Keeton, C. R., Kochanek, C. S., Lehár, J., ...
A Gravitationally Lensed Quasar with Quadruple Images Separated by 14.62 Arcseconds (2003)
Inada, N., Oguri, M., Pindor, B., Hennawi, J. F., Chiu, K., Zheng, W., ...
Gravitational lensing is a powerful tool for the study of the distribution of dark matter in the Universe. The cold-dark-matter model of the formation of large-scale structures predicts the existence...
Oguri, M., Inada, N., Keeton, C. R., Pindor, B., Hennawi, J. F., Gregg, M. D., ...
We study the recently discovered gravitational lens SDSS J1004+4112, the first quasar lensed by a cluster of galaxies. It consists of four images with a maximum separation of 14.62''. The system has...
Gravitational Lensing Statistics in Universes Dominated by Dark Energy (2003)
Kuhlen, M., Keeton, C. R., Madau, P.
We study lens statistics in flat, low-density universes with different equations of state $w=p_Q/\rho_Q$ for the dark energy component. Dark energy modifies the distance-redshift relation and the...
Self-Similar Models for the Mass Profiles of Early-type Lens Galaxies (2003)
Rusin, D., Kochanek, C. S., Keeton, C. R.
We introduce a self-similar mass model for early-type galaxies, and constrain it using the aperture mass-radius relations determined from the geometries of 22 gravitational lenses. The model consists...
The evolution of a mass-selected sample of early-type field galaxies (2003)
Rusin, D., Kochanek, C. S., Falco, E. E., Keeton, C. R., McLeod, B. A., Impey, C. D., ...
We investigate the evolution of mass-selected early-type field galaxies using a sample of 28 gravitational lenses spanning the redshift range 0 lt;~z lt;~1. Based on the redshift-dependent intercept...
The Evolution of a Mass-Selected Sample of Early-Type Field Galaxies (2002)
Rusin, D., Kochanek, C. S., Falco, E. E., Keeton, C. R., McLeod, B. A., Impey, C. D., ...
We investigate the evolution of mass-selected early-type field galaxies using a sample of 28 gravitational lenses spanning the redshift range 0 < z < 1. Based on the redshift-dependent intercept of...
Cusped Mass Models Of Gravitational Lenses (2001)
Munoz, J. A., Kochanek, C. S., Keeton, C. R.
Recent observations of galaxy luminosity profiles and dark matter simulations find luminosity and mass distributions characterized by central cusps rather than finite core radii. We introduce and...
B1359+154: A Six Image Lens Produced by a z=1 Compact Group of Galaxies (2000)
Rusin, D., Kochanek, C. S., Norbury, M., Falco, E. E., Impey, C. D., Lehar, J., ...
HST V and I-band observations show that the gravitational lens B1359+154 consists of six images of a single z_s=3.235 radio source and its star-forming host galaxy, produced by a compact group of...
Cohn, J. D., Kochanek, C. S., McLeod, B. A., Keeton, C. R.
We consider a wide range of parametric mass models for B 1933+503, a ten-image radio lens, and identify shared properties of the models with the best fits. The approximate rotation curves varies by...
Munoz, J. A., Falco, E. E., Kochanek, C. S., Lehar, J., McLeod, B. A., McNamara, B. R., ...
We report the discovery of a new two-image gravitational lens candidate. The system RX J0921+4529 contains two z_s=1.66 quasars separated by 6."93 with an H band magnitude difference of $\Delta...
What Fraction of Gravitational Lens Galaxies Lie in Groups? (2000)
Keeton, C. R., Christlein, D., Zabludoff, A. I.
We predict how the observed variations in galaxy populations with environment affect the number and properties of gravitational lenses in different environments. Two trends dominate: lensing strongly...
The Importance of Einstein Rings (2000)
Kochanek, C. S., Keeton, C. R., McLeod, B. A.
We develop a theory of Einstein rings and demonstrate it using the infrared Einstein ring images of the quasar host galaxies observed in PG1115+080, B1608+656 and B1938+666. The shape of an Einstein...
Analytic Time Delays and H_0 Estimates for Gravitational Lenses (2000)
Witt, H. J., Mao, S., Keeton, C. R.
We study gravitational lens time delays for a general family of lensing potentials, which includes the popular singular isothermal elliptical potential and singular isothermal elliptical density...
Gravitational Lenses With More Than Four Images: I. Classification of Caustics (2000)
Keeton, C. R., Mao, S., Witt, H. J.
We study the problem of gravitational lensing by an isothermal elliptical density galaxy in the presence of a tidal perturbation. When the perturbation is fairly strong and oriented near the galaxy's...
The Host Galaxy of the Lensed Quasar Q 0957+561 (2000)
Keeton, C. R., Falco, E. E., Impey, C. D., Kochanek, C. S., Lehar, J., McLeod, B. A., ...
Infrared images of the Q 0957+561 gravitational lens obtained with the Hubble Space Telescope show two large (\sim 5 arcsec) lensed images of the z_s=1.41 quasar host galaxy. Parts of the host galaxy...
The Evolution of Gravitational Lens Galaxies (1999)
Kochanek, C. S., Falco, E. E., Impey, C. D., Lehar, J., McLeod, B. A., ...
Most gravitational lens galaxies are early-type galaxies in relatively low density environments. We show that they lie on the same fundamental plane as early-type galaxies in both local and distant...
A New Wide-Separation Gravitational Lens Candidate: RXJ 0921+4529 (1999)
Munoz, J. A., Falco, E. E., Kochanek, C. S., McLeod, B. A., Lehar, J., McNamara, B. R., ...
The lens candidate RXJ 0921+4529 consists of two z_s=1.66 quasar separated by 6."93 with an H band magnitude difference of \Delta m=1.39. The lens appears to be a z_l=0.31 X-ray cluster, including a...
Kochanek, C. S., Falco, E. E., Impey, C. D., Lehar, J., McLeod, B. A., ...
Most gravitational lenses are early-type galaxies in relatively low density environments -- a ``field'' rather than a ``cluster'' population. We show that field early-type galaxies with 0 < z < 1, as...
The Quasar Pair Q 1634+267 A, B and the Binary QSO vs. Dark Lens Hypotheses (1999)
Peng, C. Y., Impey, C. D., Falco, E. E., Kochanek, C. S., Lehar, J., McLeod, B. A., ...
Deep HST/NICMOS H (F160W) band observations of the z=1.96 quasar pair Q 1634+267A,B reveal no signs of a lens galaxy to a 1 sigma threshold of approximately 22.5 mag. The minimum luminosity for a...
Falco, E. E., Impey, C. D., Kochanek, C. S., Lehar, J., McLeod, B. A., Rix, H-W., ...
We determine 37 differential extinctions in 23 gravitational lens galaxies over the range 0 < z_l < 1. Only 7 of the 23 systems have spectral differences consistent with no differential extinction....
Kochanek, C. S., Falco, E. E., Impey, C. D., Lehar, J., McLeod, B. A., ...
We have obtained and modeled new NICMOS images of the lens system MG1131+0456, which show that its lens galaxy is an H=18.6 mag, transparent, early-type galaxy at a redshift of about z_l = 0.85; it...
Keeton, C. R., Kochanek, C. S., Falco, E. E.
We combine photometry and lens modeling to study the properties of 17 gravitational lens galaxies between z=0.1 and 1. Most of the lens galaxies are passively evolving early-type galaxies, with a few...
Gravitational Lensing By Spiral Galaxies (1997)
Keeton, C. R., Kochanek, C. S.
We study gravitational lensing by spiral galaxies, using realistic models consisting of halo, disk, and bulge components combined to produce a flat rotation curve. Proper dynamical normalization of...
The geometry of the quadruply imaged quasar PG 1115+080; implications for Ho (1997)
Courbin, F., Magain, P., Keeton, C. R., Kochanek, C. S., Vanderriest, C., Jaunsen, A. O., ...
Time delay measurements have recently been reported for the lensed quasar PG 1115+080. These measurements can be used to derive Ho, but only if we can constrain the lensing potential. We have applied...
The geometry of the quadruply imaged quasar PG1115+080; implications for H0 (1997)
F. Courbin, P. Magain, C. R. Keeton, C. S. Kochanek, C. Vanderriest
. Time delay measurements have recently been reported for the lensed quasar PG 1115+080. These measurements can be used to derive H 0 , but only if we can constrain the lensing potential. We have...
Determining the Hubble Constant from the Gravitational Lens PG 1115+080 (1996)
Keeton, C. R., Kochanek, C. S.
For the quadruple gravitational lens PG 1115+080, we combine recent measurements of the time delays with new lens models to determine the Hubble constant H_0. We explore the effects of systematic...
Gravitational Lensing Limits on Early-Type Galaxies (1996)
Kochanek, C. S., Keeton, C. R.
Gravitational lenses are a unique new constraint on the structure of galaxies. We review the evidence that most lenses are early-type galaxies, the optical properties of the lens galaxies, the...
Shear and Ellipticity in Gravitational Lenses (1996)
Keeton, C. R., Kochanek, C. S., Seljak, U.
Galaxies modeled as singular isothermal ellipsoids with an axis ratio distribution similar to the observed axis ratio distribution of E and S0 galaxies are statistically consistent with both the...