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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…

Given its extraordinary spatial resolution and sensitivity, the projected Next Generation Space Telescope (NGST) is likely to detect a large number of high-redshift QSOs lensed by spiral galaxies. Using realistic models for the QSO and…

Astrophysics · Physics 2007-05-23 Matthias Bartelmann

Millimetre-band scans of the frequency space towards optically dim quasars is potentially a highly efficient method for detecting new high redshift molecular absorption systems. Here we describe scans towards 7 quasars over wide bandwidths…

Astrophysics · Physics 2007-05-23 S. J. Curran , J. K. Webb , M. T. Murphy , N. Kuno

We introduce a new method for constraining the redshift distribution of a set of galaxies, using weak gravitational lensing shear. Instead of using observed shears and redshifts to constrain cosmological parameters, we ask how well the…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-11 D. Wittman , W. A. Dawson

The main objective of the Chinese LAMOST spectroscopic quasar survey is to discover 0.4 million new quasars from 1 million quasar candidates brighter than the magnitude limit i=20.5 in the next 5 years. This will hopefully provide the…

Cosmology and Nongalactic Astrophysics · Physics 2019-08-14 Xue-Bing Wu

Gravitational lensing provides a means to measure mass that does not rely on detecting and analysing light from the lens itself. Compact objects are ideal gravitational lenses, because they have relatively large masses and are dim. In this…

Instrumentation and Methods for Astrophysics · Physics 2017-06-15 A. J. Harding , R. Di Stefano , S. Lépine , J. Urama , D. Pham , C. Baker

We have analyzed images from the VST ATLAS survey to identify candidate gravitationally lensed quasar systems in a sample of WISE sources with W1 - W2 > 0.7. Results from followup spectroscopy with the Baade 6.5 m telescope are presented…

Astrophysics of Galaxies · Physics 2017-04-26 Paul L. Schechter , Nicholas D. Morgan , B. Chehade , N. Metcalfe , T. Shanks , Michael McDonald

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…

Astrophysics · Physics 2007-05-23 Joachim Wambsganss , Renyue Cen , Jeremiah P. Ostriker

High-redshift quasars are currently the only probes of the growth of supermassive black holes and potential tracers of structure evolution at early cosmic time. Here we present our candidate selection criteria from the Panoramic Survey…

Over the last decade, quasar sample sizes have increased from several thousand to several hundred thousand, thanks mostly to SDSS imaging and spectroscopic surveys. LSST, the next-generation optical imaging survey, will provide hundreds of…

Instrumentation and Methods for Astrophysics · Physics 2015-06-18 Zeljko Ivezic , W. Niel Brandt , Xiaohui Fan , Chelsea L. MacLeod , Gordon T. Richards , Peter Yoachim

Observed magnitudes of many quasars with redshifts exceeding $z=5$ correspond to luminosities $L_{\rm bol} > 10^{14}\,L_\odot$. The standard mechanism of quasar energy release by accretion suggests that masses of superluminous quasars…

Cosmology and Nongalactic Astrophysics · Physics 2022-09-28 Alexander Raikov , Nikita Lovyagin , Vladimir Yershov

Gaia's exceptional resolution (FWHM $\sim$ 0.1$^{\prime\prime}$) allows identification and cataloguing of the multiple images of gravitationally lensed quasars. We investigate a sample of 49 known lensed quasars in the SDSS footprint, with…

Astrophysics of Galaxies · Physics 2018-03-22 Cameron A. Lemon , Matthew W. Auger , Richard G. McMahon , Sergey E. Koposov

Strong gravitational lensing provides a powerful probe of the physical properties of quasars and their host galaxies. A high fraction of the most luminous high-redshift quasars was predicted to be lensed due to magnification bias. However,…

Only galaxies bright enough and large enough to be unambiguously identified and measured are included in galaxy surveys used to estimate cosmic shear. We demonstrate that because gravitational lensing can scatter galaxies across the…

Cosmology and Nongalactic Astrophysics · Physics 2009-08-17 Fabian Schmidt , Eduardo Rozo , Scott Dodelson , Lam Hui , Erin Sheldon

LISA might detect gravitational waves from mergers of massive black hole binaries strongly lensed by intervening galaxies (Sereno et al. 2010). The detection of multiple gravitational lensing events would provide a new tool for cosmography.…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 M. Sereno , Ph. Jetzer , A. Sesana , M. Volonteri

Diffraction limited 30m class telescopes will play an important role in gravitational lensing studies, coming online in approximately 2015. As imaging telescopes they will complement the ~6m JWST, probing to smaller angular scales in…

Astrophysics · Physics 2009-11-10 R. G. Carlberg

The time delay between multiple images of strongly lensed quasars is a powerful tool for measuring the Hubble constant (H0). To achieve H0 measurements with higher precision and accuracy using the time delay, it is crucial to expand the…

Cosmology and Nongalactic Astrophysics · Physics 2023-12-14 C. Dawes , C. Storfer , X. Huang , G. Aldering , A. Cikota , A. Dey , D. J. Schlegel

Quasars continue to be the most luminous objects known in the universe but are now rivaled by galaxies for having the largest redshifts. I review current techniques for finding quasars at z > 5 and the status of current optical surveys. I…

Astrophysics · Physics 2007-05-23 Patrick S. Osmer

The discovery of the first strongly lensed $(\mu \approx 50)$ quasar at $z>6$ (J0439+1634) represents a breakthrough in our understanding of the early Universe. We derive the theoretical consequences of the new discovery. We predict that…

Astrophysics of Galaxies · Physics 2019-01-08 Fabio Pacucci , Abraham Loeb

The four observables associated with gravitational lensing of distant quasars by intervening galaxies: image splittings, relative amplifications, time delays, and optical depths, provide separate measures of the strength of the…

Astrophysics · Physics 2009-08-18 Lawrence Krauss , Martin White