Related papers: Gravitational Lens Time Delays in CDM
The solution proposed by Zhao & Qin to the apparent conflict between gravitational lens time delays, local estimates of the Hubble constant and current expectations for the structure of CDM halos is discussed. Two essential points emerge.…
Photometric monitoring of the gravitational lens system 0957+561A,B in the g and r bands with the Apache Point Observatory (APO) 3.5 m telescope during 1996 shows a sharp g band event in the trailing (B) image light curve at the precise…
Strong gravitational lenses with measured time delays between the multiple images and models of the lens mass distribution allow a one-step determination of the time-delay distance, and thus a measure of cosmological parameters. We present…
We present a determination of the Hubble constant from the joint, free-form analysis of 8 strongly, quadruply lensing systems. In the concordance cosmology, we find $H_0 = 71.8^{+3.9}_{-3.3}\,\mathrm{km}\,\mathrm{s}^{-1}\,\mathrm{Mpc}^{-1}$…
Strong gravitational lensing forms multiple, time delayed images of cosmological sources, with the "focal length" of the lens serving as a cosmological distance probe. Robust estimation of the time delay distance can tightly constrain the…
Given the tension between the values of the Hubble parameter $H_0$ inferred from the cosmic microwave background (CMB) and from supernovae, attention is turning to time delays of strongly lensed quasars. Current time-delay measurements…
Standard $\Omega_0=1$ cold dark matter (CDM) needs $0.27 < \sigma_8 < 0.63$ ($2\sigma$) to fit the observed number of large separation lenses, and the constraint is nearly independent of $H_0=100h^{-1}\kms$ Mpc$^{-1}$. This range is…
We present optical I-band light curves of the gravitationally lensed double QSO B1600+434 from observations obtained at the Nordic Optical Telescope (NOT) between April 1998 and November 1999. The photometry has been performed by…
We present a detailed strong lensing analysis of an HST/ACS legacy dataset for the first gravitational lens, Q0957+561. With deep imaging we identify 24 new strongly lensed features, which we use to constrain mass models. We model the…
We present a new method for determining time delays among the light curves of various images in a gravitational lens. The method is based on constructing a simple model for the source variation and forming a chi squared measure of the…
Strong gravitational lenses with measured time delay are a powerful tool to measure cosmological parameters, especially the Hubble constant ($H_0$). Recent studies show that by combining just three multiply-imaged AGN systems, one can…
The quadruple quasar H1413+117 (z_s = 2.56) has been monitored with the 2.0 m Liverpool Telescope in the r Sloan band from 2008 February to July. This optical follow-up leads to accurate light curves of the four quasar images (A-D), which…
While the Hubble constant can be derived from observable time delays between images of lensed quasars, the result is often highly sensitive to assumptions and systematic uncertainties in the lensing model. Unlike most previous authors we…
In principle, the most straightforward method of estimating the Hubble constant relies on time delays between mirage images of strongly-lensed sources. It is a puzzle, then, that the values of H0 obtained with this method span a range from…
We calculate the time delay between different relativistic images formed by black hole gravitational lensing in the strong field limit. For spherically symmetric black holes, it turns out that the time delay between the first two images is…
The time delay between multiple images of strongly lensed quasars has been used to infer the Hubble constant. The primary systematic uncertainty for time-delay cosmography is the mass-sheet transform (MST), which preserves the lensing…
The dark matter halo has non-negligible effects on the gravitational lensing of supermassive black hole in the galaxy center. Our work presents a study on the time-delay of light in gravitational lensing of black holes enclosed by dark…
We present a new measurement of the Hubble Constant H0 and other cosmological parameters based on the joint analysis of three multiply-imaged quasar systems with measured gravitational time delays. First, we measure the time delay of…
We consider an alternative formula for time delay in gravitational lensing. Imposing a smoothness condition on the gravitationally deformed paths followed by the photons from the source to the observer, we show that our formula displays the…
Time delays between multiple images of lensed sources can probe the geometry of the universe. We propose a novel method based on free-form modelling of gravitational lenses to estimate time-delay distances and, in turn, cosmological…