Related papers: A Study of Gravitational Lens Chromaticity using G…
We report Hubble Space Telescope observations of 6 gravitational lenses with the Advanced Camera for Surveys. We measured the flux ratios between the lensed images in 6 filters from 8140\AA\ to 2200\AA. In 3 of the systems, HE0512$-$3329,…
We present narrowband images of the gravitational lens system Q~2237+0305 made with the Nordic Optical Telescope in eight different filters covering the wavelength interval 3510-8130 \AA. Using point-spread function photometry fitting we…
We use spectroscopic observations of the gravitationally lensed systems SDSS0924+0219(BC), Q1355-2257(AB), and SDSS1029+2623(BC) to analyze microlensing and dust extinction in the observed components. We detect chromatic microlensing…
We present monitoring observations of quasar microlensing in the quadruple quasar HE0435-1223. The microlensing-induced light curves of the quasar images are chromatic, i.e. they depend on the applied filter band. Comparison with…
We report on a program of spectroscopic observations of gravitationally-lensed QSOs with multiple images. We seek to establish whether microlensing is occurring in each QSO image using only single-epoch observations. We calculate flux…
We present new HST WFPC3 imaging of four gravitationally lensed quasars: MG 0414+0534; RXJ 0911+0551; B 1422+231; WFI J2026-4536. In three of these systems we detect wavelength-dependent microlensing, which we use to place constraints on…
The gravitationally lensed quasar HE 1104-1805 has been observed at a variety of wavelengths ranging from the mid-infrared to X-ray for nearly 20 years. We combine flux ratios from the literature, including recent Chandra data, with new…
Using a microlensing analysis of 11-years of OGLE V-band photometry of the four image gravitational lens Q2237+0305, we measure the inclination i of the accretion disk to be cos i > 0.66 at 68% confidence. Very edge on (cos i < 0.39)…
We have made radio- and millimeter-wavelength interferometric observations of a variety of molecular absorption lines toward the gravitational lens systems B0218+357 and PKS1830-211. The absorption occurs in the lensing galaxies at…
We present \emph{Chandra} monitoring data for six gravitationally lensed quasars: QJ 0158$-$4325, HE 0435$-$1223, HE 1104$-$1805, SDSS 0924+0219, SDSS 1004+4112, and Q 2237+0305. We detect X-ray microlensing variability in all six lenses…
Strong gravitational lensing provides a powerful test of Cold Dark Matter (CDM) as it enables the detection and mass measurement of low mass haloes even if they do not contain baryons. Compact lensed sources such as Active Galactic Nuclei…
We present a measurement of the accretion disk size of the quadruple lensed quasar HE 0435-1223 from well-sampled 13-yr COSMOGRAIL optical light curves. Using accurate time delays for the images A, B, C, and D, we modeled and removed the…
We present eight monitoring seasons of the four brightest images of the gravitational lens SDSS J1004+4112 observed between December 2003 and October 2010. Using measured time delays for the images A, B and C and the model predicted time…
The mid-IR flux ratios F_A/F_B = 2.84 +/- 0.06 of the two images of the gravitationally lensed quasar HE 1104-1805 show no wavelength dependence to within 3% across 3.6-8.0 um, no time dependence over 6 months and agree with the broad…
Microlensing perturbations to the flux ratios of gravitationally lensed quasar images can vary with wavelength because of the chromatic dependence of the accretion disk's apparent size. Multiwavelength observations of microlensed quasars…
We present high-resolution CCD images (FWHM=0.6"-0.7") of the compact gravitational lens system B0218+35.7 obtained at the Nordic Optical Telescope. Using aperture and PSF photometry we detect the two closely separated (335 mas) components…
Because follow-up observations of quadruple gravitational lens systems are of extraordinary importance for astrophysics and cosmology, we present single-epoch optical spectra and $r$--band light curves of PS J0147+4630. This recently…
Radio observations establish the B/A magnification ratio of gravitational lens 0957+561 at about 0.75. Yet, for more than 15 years, the optical magnfication ratio has been between 0.9 and 1.12. The accepted explanation is microlensing of…
We spectroscopically re-observed the gravitational lens system SDSS J1339+1310 using OSIRIS on the GTC. We also monitored the $r$-band variability of the two quasar images (A and B) with the LT over 143 epochs in the period 2009$-$2016.…
We combine photometry and lens modeling to study the properties of 17 gravitational lens galaxies between z=0.1 and 1. Most of the lens galaxies are passively evolving early-type galaxies, with a few spirals. The colors, scale lengths, and…