Related papers: ULAS J234311.93-005034.0: A gravitational lens sys…

We present spectroscopic confirmation of two new lensed quasars via data obtained at the 6.5m Magellan/Baade Telescope. The lens candidates have been selected from the Dark Energy Survey (DES) and WISE based on their multi-band photometry…

Time-delay cosmography (TDC) using multiply-lensed quasars (QSOs) by galaxies has recently emerged as an independent and competitive tool to measure the value of the Hubble constant. Lens galaxy clusters hosting multiply-imaged QSOs, when…

We report on the serendipitous discovery in the Blanco Cosmology Survey (BCS) imaging data of a z = 0.9057 galaxy that is being strongly lensed by a massive galaxy cluster at a redshift of z=0.3838. The lens (BCS J2352-5452) was discovered…

Galaxies located in the environment or on the line of sight towards gravitational lenses can significantly affect lensing observables, and can lead to systematic errors on the measurement of $H_0$ from the time-delay technique. We present…

We present the discovery of CLASS B0739+366, a new gravitational lens system from the Cosmic Lens All-Sky Survey. Radio imaging of the source with the Very Large Array (VLA) shows two compact components separated by $0\farcs54$, with a flux…

H band observations with a spatial resolution of 0.15" carried out with the Canada-France-Hawaii Telescope adaptive optics system show a galaxy between the components of the double BAL quasar SBS 1520+530, thereby confirming this system as…

We report the discovery, spectroscopic confirmation and preliminary characterisation of 24 gravitationally lensed quasars identified using Gaia observations. Candidates were selected in the Pan-STARRS footprint with quasar-like WISE colours…

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…

Galaxy redshift surveys can be used to detect gravitationally-lensed quasars if the spectra obtained are searched for the quasars' emission lines. Previous investigations of this possibility have used simple models to show that the 2 degree…

From 2011 to 2021, LAMOST has released a total of 76,167 quasar data. We try to search for gravitationally lensed QSOs by limiting coordinate differences and redshift differences of these QSOs. The name, brightness, spectrum, photometry and…

It is possible to detect gravitationally-lensed quasars spectroscopically if the spectra obtained during galaxy surveys are searched for the presence of quasar emission lines. The up-coming 6 degree Field (6dF) redshift survey on the United…

In the third paper from the COOL-LAMPS Collaboration, we report the discovery of COOL J0542-2125, a gravitationally lensed quasar at $z=1.84$, observed as three images due to an intervening massive galaxy cluster at $z=0.61$. The lensed…

Luminous objects associated with the 7.06\arcsec\ separation double quasar Q2345+007 have, until now, escaped detection. In this letter we present the results of the deepest known imaging of the region surrounding the quasar. The total…

We report the results of an optical spectroscopic follow-up of four double quasar candidates in the Sloan Digital Sky Survey (SDSS) database. SDSS J1617+3827 is most likely a lensed quasar at z = 2.079, consisting of two images with r ~…

We report the spectroscopic confirmation and modeling of the quadruply imaged quasar GRAL113100-441959, the first gravitational lens (GL) to be discovered mainly from astrometric considerations. Follow-up spectra obtained with Keck/LRIS…

We present the result of Subaru Telescope multi-band adaptive optics observations of the complex gravitationally lensed quasar SDSS J1405+0959, which is produced by two lensing galaxies. These observations reveal dramatically enhanced…

In this paper we present new ESO/VLT FORS1 and ISAAC images of the fields around eight gravitationally lensed quasars: CTQ414, HE0230-2130, LBQS1009-0252, B1030+074, HE1104-1805, B1359+154, H1413+117 and HE2149-2745. When available and deep…

Gravitational lensing directly measures mass density fluctuations along the lines of sight to very distant objects. No assumptions need to be made concerning bias, the ratio of fluctuations in galaxy density to mass density. Hence, lensing…

The gravitational lens system CLASS B2108+213 has two radio-loud lensed images separated by 4.56 arcsec. The relatively large image separation implies that the lensing is caused by a group of galaxies. In this paper, new optical imaging and…

We present spectroscopy and laser guide star adaptive optics (LGSAO) images of the doubly imaged lensed quasar SDSS J1206+4332. We revise the deflector redshift proposed previously to $z_{d}=0.745,$ and measure for the first time its…