Related papers: The Quintuple Quasar: Mass Models and Interpretati…

A gravitational lens model is presented for the newly discovered 10-image system B1933+503. The underlying object, revealed by modeling, is a triple radio source on the scale of a couple of hundred mas that is well-aligned along the line of…

This paper reviews the question of whether the wide separation double quasar Q2138-431 is a gravitational lens. From early work, the two quasar images are known to have almost identical spectra and redshifts, but no lensing galaxy has so…

Strong gravitational lensing distorts our view of sources at cosmological distances but brings invaluable constraints on the mass content of foreground objects and on the geometry and properties of the Universe. We report the detection of a…

Massive structures, such as galaxies, act as strong gravitational lenses on background sources. When the background source is a quasar, several lensed images are seen, as magnified or de-magnified versions of the same object. The detailed…

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 minor axis, the lens can produce image…

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 been confirmed as a lensed quasar at…

We report the discovery of two new gravitationally lensed quasars, WFI J2026-4536 and WFI J2033-4723, at respective source redshifts of z=2.23 and z=1.66. Both systems are quadruply imaged and have similar PG1115-like image configurations.…

We report the discovery of SDSSJ115517.35+634622.0, a previously unknown gravitationally lensed quasar. The lens system exhibits two images of a $z = 2.89$ quasar, with an image separation of $1{\farcs}832 \pm 0.007$ . Near-IR imaging of…

We report the discovery of a new gravitationally lensed quasar (double) from the Optical Gravitational Lensing Experiment (OGLE) identified inside the $\sim$670 sq. deg area encompassing the Magellanic Clouds. The source was selected as one…

We report the discovery of a new gravitational lens candidate Q2138-431AB, comprising two quasar images at a redshift of 1.641 separated by 4.5 arcsecs. The spectra of the two images are very similar, and the redshifts agree to better than…

We present the discovery of a new quadruply lensed quasar. The lens system, SDSS J1330+1810 at z_s=1.393, was identified as a lens candidate from the spectroscopic sample of the Sloan Digital Sky Survey. Optical and near-infrared images…

Gravitational lensing sometimes dominates the observed properties of apparently very bright objects. We present morphological properties in the high-resolution (FWHM $\sim0.''15$) Atacama Large Millimeter/submillimeter Array (ALMA) 1-mm map…

Aims: The knowledge of the redshift of a lensing galaxy that produces multiple images of a background quasar is essential to any subsequent modeling, whether related to the determination of the Hubble constant H_0 or to the mass profile of…

A single-screen model of the gravitational lens system 2016+112 is proposed, that explains recent Hubble Space Telescope} (HST) infrared (NICMOS-F160W) observations and new high-resolution European VLBI Network (EVN) 5-GHz radio…

In the course of a Cycle 8 snapshot survey, we have discovered that the z=1.565 quasar HE 0512-3329 is a double with image separation 0.644", almost certainly due to gravitational lensing. The two components differ in brightness by only 0.4…

We present new spectroscopic and polarimetric observations of the first discovered gravitational lens Q0957+561 obtained with the 6m telescope of the Special Astrophysical Observatory (SAO, Russia). We explore spectropolarimetric parameters…

We present observations of a new double-image gravitational lens system, ULAS J082016.1+081216, of image separation 2.3" and high (~6) flux ratio. The system is selected from the Sloan Digital Sky Survey spectroscopic quasar list using new…

We present the results of a radio variability study of the gravitational lens PMN J1838-3427. Our motivation was to determine the Hubble constant by measuring the time delay between variations of the two quasar images. We monitored the…

A gravitational lens model of the radio quasar B1422+231 is presented which can account for the image arrangement and approximately for the relative magnifications. The locations of the principal lensing mass and a more distant secondary…

High-redshift binary quasars provide key insights into mergers and quasar activity, and are useful tools for probing the spatial kinematics and chemistry of galaxies along the line-of-sight. However, only three sub-10-kpc binaries have been…