Related papers: Microlensing probes the AGN structure of the lense…
J1004+4112 is a lensed quasar for which the first broad emission line profile deformations due to microlensing were identified. Detailed interpretations of these features have nevertheless remained controversial. Based on 15 spectra…
We investigate the kinematics and ionization structure of the broad emission line region of the gravitationally lensed quasar QSO2237+0305 (the Einstein cross) using differential microlensing in the high- and low-ionization broad emission…
The physical nature of the material responsible for the high--velocity, broad-absorption line features seen in a small fraction of quasar spectra has been the subject of debate since their discovery. This has been especially compounded by…
Recent estimates of the scale of structures at the heart of quasars suggest that the region responsible for the broad line emission are smaller than previously thought. With this revision of scale, the broad line region is amenable to the…
We present results from a monitoring campaign performed with the Chandra X-ray Observatory of the gravitationally lensed quasars RX J1131-1231 and HE 1104-1805. We detect significant X-ray variability in all images of both quasars. The flux…
The observed enhancement of the Fe K$\alpha$ line in three gravitationally lensed QSOs (MG J0414+0534, QSO 2237+0305, H1413+117) is interpreted in terms of microlensing, even when equivalent X-ray continuum amplification is not observed. In…
Recent studies have shown that line profile distortions are commonly observed in gravitationally lensed quasar spectra. We investigate the effect of gravitational microlensing on quasar broad emission line profiles and their underlying…
Several macrolensed systems exhibit photometric variability consistent with microlensing due to objects of stellar mass located in the lens. The degree of microlensing amplification is dependent upon the size of the source, with smaller…
On the basis of 16 years of spectroscopic observations of the four components of the gravitationally lensed broad absorption line (BAL) quasar H1413+117, covering the ultraviolet to visible rest-frame spectral range, we analyze the spectral…
Selective amplification of the line and continuum source by microlensing in a lensed quasar can lead to changes of continuum spectral slopes and line shapes in the spectra of the quasar components. Comparing the spectra of different…
Line profile distortions are commonly observed in gravitationally lensed quasar spectra. These distortions are caused by microlensing from the stars in the lensing galaxy, which produce differential magnification of spatially and…
We present seven epochs of spectroscopy on the quadruply imaged quasar SDSS J1004+4112, spanning observed-frame time delays from 1 to 322 days. The spectra reveal differences in the emission lines between the lensed images. Specifically,…
SDSS J0924+0219 is the most glaring example of a gravitational lens with anomalous flux ratios: optical broad-band photometry shows image D to be a factor of 12 fainter than expected for smooth lens potentials. We report spectroscopy…
Microlensing by stars in the lens galaxy of a gravitationally lensed quasar is a phenomenon that can selectively magnify quasar subregions, producing observable changes in the continuum brightness or distortions in the emission line…
We present both photometry and spectra of the individual images of the quadruple gravitational lens system Q2237+0305. Comparison of spectra obtained at two epochs, separated by $\sim~3\,$years, shows evidence for significant changes in the…
We review results from our monitoring observations of several lensed quasars performed in the optical, UV, and X-ray bands. Modeling of the multi-wavelength light curves provides constraints on the extent of the optical, UV, and X-ray…
Recent observations have provided strong evidence for the presence of an Electron Scattering Region (ESR) within the central regions of AGNs. This is responsible for reprocessing emission from the accretion disk into polarised radiation.…
RX J1131-1231 is a gravitationally lensed system which includes four images of a quasar lensed by an elliptical galaxy. The flux in the individual images is known to be affected by microlensing effect in the visible and X-ray bands. We…
CONTEXT: Gravitationally lensed quasars constitute an independent tool to derive H0 through time-delays; they offer as well the opportunity to study the mass distribution and interstellar medium of their lensing galaxies and, through…
We present the results of the first long-term (2.2 years) spectroscopic monitoring of a gravitationally lensed quasar, namely the Einstein Cross Q2237+0305. The goal of this paper is to present the observational facts to be compared in…