Related papers: Astrometric Microlensing of Quasars : Dependence o…
Gravitational microlensing of quasars by stars in external galaxies can introduce fluctuations in the centroid of the ``point-like'' macro--images. The induced shifts are extremely small, on micro--arcsecond scales, below the limits of…
Microlensing by stars within distant galaxies acting as strong gravitational lenses of multiply-imaged quasars, provides a unique and direct measurement of the internal structure of the lensed quasar on nano-arcsecond scales. The…
We investigate the spectro-photometric variability of quasars due to lensing of small mass substructure (from several tens to several hundreds solar masses). The aim of this paper is to explore the milli/microlensing influence on the flux…
Variability in gravitationally lensed quasars can be due to intrinsic fluctuations of the quasar or due to ``microlensing'' by compact objects along the line of sight. If disentangled from each other, microlens-induced variability can be…
Microlensing promises to be a powerful tool for studying distant galaxies and quasars. As the data and models improve, there are systematic effects that need to be explored. Quasar continuum and broad-line regions may respond differently to…
We present a quantitative analysis of the effect of microlensing caused by random motion of individual stars in the galaxy which is lensing a background quasar. We calculate a large number of magnification patterns for positions of the…
There are two possible causes of variability in gravitationally lensed quasars: intrinsic fluctuations of the quasar and ``microlensing'' by compact objects along the line of sight. If disentangled from each other, microlens-induced…
Astrometric microlensing will offer in the next future a new channel for investigating the nature of both lenses and sources involved in a gravitational microlensing event. The effect, corresponding to the shift of the position of the…
The micro-arcsecond scale structure of the seemingly point-like images in lensed quasars, though unobservable, is nevertheless much studied theoretically, because it affects the observable (or macro) brightness, and through that provides…
We propose and discuss a new experimental approach to measure the centroid shift induced by gravitational microlensing in the images of lensed quasars (astrometric microlensing). Our strategy is based on taking the photocenter of a region…
The aim of this paper is to investigate the claim that stars in the lensing galaxy of a gravitationally lensed quasar system can always account for the observed microlensing of the individual quasar images. A small sample of gravitationally…
Cosmological gravitational microlensing has been proven to be a powerful tool to constrain the structure of multiply imaged quasars, especially the accretion disc and central supermassive black-hole system. However, the derived constraints…
The fraction of quasar's and gamma-ray burst (GRB) afterglows that vary due to microlensing by the stellar populations of intervening elliptical/S0 galaxies is computed by combining the joint distribution of effective microlensing…
This paper presents an investigation into the gravitational microlensing of quasars by stars and stellar remnants in the Milky Way. We present predictions for the all-sky microlensing optical depth, time-scale distributions and event rates…
Optical and X-ray observations of strongly gravitationally lensed quasars (especially when four separate images of the quasar are produced) determine not only the amount of matter in the lensing galaxy but also how much is in a smooth…
Strong gravitational lensing of quasars has the potential to unlock the poorly understood physics of these fascinating objects, as well as serve as a probe of the lensing mass distribution and of cosmological parameters. In particular,…
Gravitational microlensing is a powerful tool for probing the physical properties of quasar accretion disks and properties of the lens galaxy such as its dark matter fraction and mean stellar mass. Unfortunately the number of lensed quasars…
Quasar microlensing is both a very useful tool in cosmology and astrophysics, and a source of uncertainty in some studies like the determination of the Hubble constant from lensed quasars. Microlensing probability and time-scales have been…
Massive structures, such as galaxies, act as strong gravitational lenses on background sources. When the background source is a quasar, several lensed images are seen, as magnified or de-magnified versions of the same object. The detailed…
Microlensing perturbations to the magnification of gravitationally lensed quasar images are dependent on the angular size of the quasar. If quasar variability at visible wavelengths is caused by a change in the area of the accretion disk,…