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Related papers: The 2dF gravitational lens survey

200 papers

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…

Astrophysics of Galaxies · Physics 2018-06-26 Cameron A. Lemon , Matthew W. Auger , Richard G. McMahon , Fernanda Ostrovski

We try to explain quasar-galaxy associations by gravitational lensing by globular clusters, located in the halos of foreground galaxies. We propose observational test for verification of this hypothesis. We processed SUPERCOSMOS sky survey…

Astrophysics · Physics 2007-05-23 A. Yushchenko , Chulhee Kim , A. Sergeev , P. Niarchos , V. Manimanis

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'' and 2.90'', respectively. The objects were selected as lens…

A total of 10 good candidates for gravitational lensing have been discovered in the WFPC2 images from the HST Medium Deep Survey (MDS) and archival primary observations. These candidate lenses are unique HST discoveries, i.e. they are faint…

Astrophysics · Physics 2009-10-31 K. U. Ratnatunga , R. E. Griffiths , E. J. Ostrander

We calculate the optical bj luminosity function of the 2dF Galaxy Redshift Survey (2dFGRS) for different subsets defined by their spectral properties. These spectrally selected subsets are defined using a new parameter, eta, which is a…

We present a semi-automated method to search for strong galaxy-galaxy lenses in optical imaging surveys. Our search technique constrains the shape of strongly lensed galaxies (or arcs) in a multi-parameter space, which includes the third…

Astrophysics · Physics 2008-11-07 Jeffrey M. Kubo , Ian P. Dell'Antonio

We demonstrate that gravitationally lensed quasars are easily recognized using image subtraction methods as time variable sources that are spatially extended. For Galactic latitudes |b|>20 deg, lensed quasars dominate the population of…

Astrophysics · Physics 2009-11-13 C. S. Kochanek , B. Mochejska , N. D. Morgan , K. Z. Stanek

The 2dF Galaxy Redshift Survey (2dFGRS) has obtained spectra for 245591 sources, mainly galaxies, brighter than a nominal extinction-corrected magnitude limit of b_J=19.45. Reliable redshifts were measured for 221414 galaxies. The galaxies…

We review cosmological inference from galaxy surveys at low and high redshifts, with emphasis on new Southern sky surveys. We focus on several issues: (i) The importance of understanding selection effects in catalogues and matching Northern…

Astrophysics · Physics 2007-05-23 Ofer Lahav

We conduct a search for galaxy-scale strong gravitational lens systems in Data Release 4 of the Hyper Suprime-Cam Subaru Strategic Program (HSC SSP), consisting of data taken up to the S21A semester. We select 103191 luminous red galaxies…

Gravitational lensing is a powerful astrophysical and cosmological probe and is particularly valuable at submillimeter wavelengths for the study of the statistical and individual properties of dusty starforming galaxies. However the…

Methods for compression and classification of galaxy spectra, which are useful for large galaxy redshift surveys (such as the SDSS, 2dF, 6dF and VIRMOS), are reviewed. In particular, we describe and contrast three methods: (i) Principal…

Astrophysics · Physics 2009-10-31 Ofer Lahav

The 6dF Galaxy Survey is measuring around 150000 redshifts and 15000 peculiar velocities from galaxies over the southern sky at |b|>10 degrees. When complete, it will be the largest survey of its kind by more than an order of magnitude.…

Astrophysics · Physics 2009-11-11 D. Heath Jones , Will Saunders , Mike Read , Matthew Colless

The observed lensed fraction of high-redshift quasars $(\sim0.2\%)$ is significantly lower than previous theoretical predictions $(\gtrsim4\%)$. We revisit the lensed fraction of high-redshift quasars predicted by theoretical models, where…

Astrophysics of Galaxies · Physics 2022-02-09 Minghao Yue , Xiaohui Fan , Jinyi Yang , Feige Wang

We present the discovery and preliminary characterization of a gravitationally lensed quasar with a source redshift $z_{s}=2.74$ and image separation of $2.9"$ lensed by a foreground $z_{l}=0.40$ elliptical galaxy. Since the images 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…

Astrophysics of Galaxies · Physics 2021-04-16 M. R. S. Hawkins

The 2dF Galaxy Redshift Survey (2dFGRS) has produced a three-dimensional map of the distribution of 221,000 galaxies covering 5% of the sky and reaching out to a redshift z=0.3. This is first map of the large-scale structure in the local…

Astrophysics · Physics 2007-05-23 Matthew Colless

Bright gravitationally lensed galaxies provide our most detailed view of galaxies at high redshift. Yet as a result of the small number of ultra-bright z~2 lensed systems with confirmed redshifts, most detailed spectroscopic studies have…

The 2dF Galaxy Redshift Survey is the first to observe more than 100,000 redshifts, making possible precise measurements of many aspects of galaxy clustering. The spatial distribution of galaxies can be studied as a function of galaxy…

Astrophysics · Physics 2009-11-07 J. A. Peacock

The Deep Lens Survey (DLS) is a deep BVRz' imaging survey of seven 2x2 degree fields, with all data to be made public. The primary scientific driver is weak gravitational lensing, but the survey is also designed to enable a wide array of…