Related papers: Measuring Microlensing using Spectra of Multiply L…
We present a technique for the successive restoration of the branches of the one-dimensional strip brightness distribution across a quasar's accretion disk via the analysis of observations of high magnification events in measured fluxes…
The influence of microlensing in the profiles of the emission lines generated in a biconical geometry is discussed. Microlensing amplification in this anisotropic model is not directly related to the bicone's intrinsic size but depends on…
The quadruple lensed system WGD2038-4008 was recently discovered with the help of new techniques and observations. Even though black hole mass has been estimated for lensed quasars, it has been calculated mostly for one broad emission line…
PG 1115+080 is a quadruply lensed quasar at z=1.72 whose image positions are well fit by simple models of the lens galaxy (at z=0.31). At optical wavelengths, the bright close pair of images exhibits a modest flux ratio anomaly (factors of…
The phase transition responsible for axion dark matter production can create large amplitude isocurvature perturbations which collapse into dense objects known as axion miniclusters. We use microlensing data from the EROS survey, and from…
Cosmological evolution of the QSO luminosity functions (LFs) at NIR/optical/X-ray bands for 1.3 < z < 3.5 is investigated based on the realistic QSO spectra. The accretion-disk theory predicts that although QSO luminosities only depend on…
Microlensing has proven an effective probe of the structure of the innermost regions of quasars, and an important test of accretion disk models. We present light curves of the lensed quasar HE 0435-1223 in the R band and in the ultraviolet,…
Geometrical optics provides an excellent description for quasar images crossing caustics which are formed by gravitational microlensing of objects like Q2237+0305. Within this approximation the source size can be estimated from the maximum…
We report near simultaneous imaging using LMIRCam on the LBTI of the quadruply imaged lensed quasar HS 0810+2554 at wavelengths of 2.16, 3.7 and $4.78~\mu$m with a Full Width Half Max (FWHM) spatial resolution of $0^{\prime\prime}\!\!.13$,…
Lensed quasars are powerful cosmic laboratories; they are used to simultaneously probe various astrophysical phenomena. Microlensing by stars within distant galaxies acts as strong gravitational lenses of multiply imaged quasars, and…
Quadruple gravitational lens systems offer the possibility of measuring time delays for image pairs, microlensing effects, and extinction in distant galaxies. Observations of these systems may be used to obtain estimates of H_o and to study…
We present an extended optical monitoring of the quadruply-imaged gravitationally lensed quasar QSO 2237+0305, the Einstein Cross, including observations from different observatories in both hemispheres and using a new photometric…
We present the discovery of a gravitationally lensed dust-reddened QSO at z = 2.517, identified in a survey for QSOs by infrared selection. Hubble Space Telescope imaging reveals a quadruply lensed system in a cusp configuration, with a…
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…
We examine the effect that the shape of the source brightness profile has on the magnitude fluctuations of images in quasar lens systems due to microlensing. We do this by convolving a variety of accretion disk models (including Gaussian…
Weak gravitational lensing from large-scale structure enhances and reduces the fluxes from extragalactic point sources with an rms amplitude of order 15%. In cosmic microwave background (CMB) experiments, sources exceeding some flux…
We present results from a mini-survey of relatively high redshift (1.7 < z < 4) gravitationally lensed radio-quiet quasars observed with the Chandra X-ray Observatory and with XMM-Newton. The lensing magnification effect allows us to search…
We use multi-wavelength microlensing measurements of a sample of 10 image pairs from 8 lensed quasars to study the structure of their accretion disks. By using spectroscopy or narrow band photometry we have been able to remove contamination…
We examine the wavelength dependence of flux ratios for six gravitationally lensed quasars using K and L' images obtained at the Gemini North 8m telescope. We select lenses with source redshifts z_s < 2.8 so that K-band images probe…
Owing to the advent of large area photometric surveys, the possibility to use broad band photometric data, instead of spectra, to measure the size of the broad line region of active galactic nuclei, has raised a large interest. We describe…