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We present a first attempt to reveal the possible existence of large foreground mass condensations directly responsible for the gravitational magnification of four distant luminous radiosources and one optical QSO. The technique uses a weak…

天体物理学 · 物理学 2007-05-23 B. Fort , Y. Mellier , M. Dantel-Fort , H. Bonnet , J. -P. Kneib

We present new sub-arcsecond-resolution Karl G. Jansky Very Large Array (VLA) imaging at 10 GHz of 155 ultra-luminous ($L_{\rm bol}\sim10^{11.7-14.2} L_\odot$) and heavily obscured quasars with redshifts $z \sim0.4-3$. The sample was…

We present results from a comprehensive lensing analysis in HST data, of the complete CLASH cluster sample. We identify new multiple-images previously undiscovered allowing improved or first constraints on the cluster inner mass…

Weak gravitational lensing has the potential to constrain cosmological parameters to high precision. However, as shown by the Shear TEsting Programmes (STEP) and GRavitational lEnsing Accuracy Testing (GREAT) Challenges, measuring galaxy…

宇宙学与河外天体物理 · 物理学 2015-06-04 Tomasz Kacprzak , Joe Zuntz , Barnaby Rowe , Sarah Bridle , Alexandre Refregier , Adam Amara , Lisa Voigt , Michael Hirsch

Weak gravitational lensing measurements based on photometry are limited by shape noise, the variance in the unknown unlensed orientations of the source galaxies. If the source is a disk galaxy with a well-ordered velocity field, however,…

宇宙学与河外天体物理 · 物理学 2021-01-08 David Wittman , Matthew Self

Weak gravitational lensing is a powerful probe for constraining cosmological parameters, but its success relies on accurate shear measurements. In this paper, we use image simulations to investigate how a joint analysis of high-resolution…

宇宙学与河外天体物理 · 物理学 2025-10-22 Shiyang Zhang , Shun-Sheng Li , Henk Hoekstra

The mergers of supermassive black hole binaries (SMBHBs) can serve as standard sirens: the gravitational wave (GW) analog of standard candles. The upcoming space-borne GW detectors will be able to discover such systems and estimate their…

宇宙学与河外天体物理 · 物理学 2023-05-09 Zhao-Feng Wu , Lok W. L. Chan , Martin Hendry , Otto A. Hannuksela

The first half of this paper explores the origin of systematic biases in the measurement of weak gravitational lensing. Compared to previous work, we expand the investigation of PSF instability and fold in for the first time the effects of…

We present a simulation analysis of weak gravitational lensing flexion and shear measurement using shapelet decomposition, and identify differences between flexion and shear measurement noise in deep survey data. Taking models of galaxies…

宇宙学与河外天体物理 · 物理学 2015-06-12 Barnaby Rowe , David Bacon , Richard Massey , Catherine Heymans , Boris Haeussler , Andy Taylor , Jason Rhodes , Yannick Mellier

We investigate the cross-correlation between astrometric and timing-residual observables for distant sources, such as pulsars and galaxies, and equivalent observables for nearby solar system bodies. Using the unified spin-weighted formalism…

广义相对论与量子宇宙学 · 物理学 2025-10-31 Elias Fink , Carlo Contaldi , Giorgio Mentasti

Gravitational wave sources are a promising cosmological standard candle because their intrinsic luminosities are determined by fundamental physics (and are insensitive to dust extinction). They are, however, affected by weak lensing…

宇宙学与河外天体物理 · 物理学 2010-06-29 Christopher M. Hirata , Daniel E. Holz , Curt Cutler

A sample of 123 radio sources that exhibit significant variations at 1.4 GHz on a seven year base-line has been created using FIRST VLA B-array data from 1995 and 2002 on a strip at dec=0 near the south Galactic cap. This sample spans the…

天体物理学 · 物理学 2009-11-10 W. H. de Vries , R. H. Becker , R. L. White , D. J. Helfand

We study weak gravitational lensing by the cosmic large-scale structure of the 21-cm radiation background in the 3d-weak lensing formalism. The interplay between source distance measured at finite resolution, visibility and lensing terms is…

宇宙学与河外天体物理 · 物理学 2022-05-10 Jose Agustin Lozano Torres , Bjoern Malte Schaefer

Weak gravitational lensing has proven to be a powerful tool to map directly the distribution of dark matter in the Universe. The technique, currently used, relies on the accurate measurement of the gravitational shear that corresponds to…

宇宙学与河外天体物理 · 物理学 2015-05-19 S. Pires , A. Amara

We measure the weak lensing shear around galaxy troughs, i.e. the radial alignment of background galaxies relative to underdensities in projections of the foreground galaxy field over a wide range of redshift in Science Verification data…

We report on the first wide-field, very long baseline interferometry (VLBI) survey at 90 cm. The survey area consists of two overlapping 28 deg^2 fields centred on the quasar J0226+3421 and the gravitational lens B0218+357. A total of 618…

天体物理学 · 物理学 2009-11-13 Emil Lenc , Mike A. Garrett , Olaf Wucknitz , James M. Anderson , Steven J. Tingay

We explore the sensitivity of weak lensing surveys to gravitational waves (GWs) emitted by inspiraling supermassive black hole binaries (SMBHBs) in the nanohertz to microhertz frequency band, bridging the gap between pulsar timing arrays…

宇宙学与河外天体物理 · 物理学 2026-05-13 Tal Adi , Kris Pardo , Olivier Doré

The Very Large Array (VLA) has been used in C-configuration to map an area \~0.3 square degrees at 1.4 GHz with 5sigma sensitivities of 0.305, 0.325, 0.380 and 0.450 mJy/beam over four equal subareas. Radio properties are presented for 62…

天体物理学 · 物理学 2009-10-31 Frank J. Masci , J. J. Condon , T. A. Barlow , C. J. Lonsdale , D. L. Shupe , O. Pevunova , F. Fang , R. Cutri

We present new radio observations of the large-separation gravitationally-lensed quasar SDSS J1004+4112, taken in a total of 6 hours of observations with the Extended Very Large Array (EVLA). The maps reach a thermal noise level of…

宇宙学与河外天体物理 · 物理学 2020-08-18 Neal Jackson

(abridged) We study the composition of the faint radio population selected from the VLA-COSMOS 3GHz Large Project. The survey covers a 2.6sq.deg. area with a mean rms of ~2.3uJy/b, cataloging 10830 sources (>5sigma). Combining these radio…