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Studies of the inner regions of micro-lensed AGN during caustic crossing events have often relied upon the approximation that the magnification near a fold caustic is inversely proportional to the square root of the source-caustic distance.…

Astrophysics of Galaxies · Physics 2019-07-31 Luke Weisenbach , Paul Schechter , Joachim Wambsganss

I investigate the effects of source clustering on the weak lensing statistics, more particularly on the statistical properties of the local convergence, kappa, at large angular scales. The Perturbation Theory approach shows that the…

Astrophysics · Physics 2011-05-23 F. Bernardeau

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…

Astrophysics · Physics 2016-08-30 M. Jaroszynski , B. Paczynski

We present a potential test of the origin of the $\gamma$-ray Galactic Centre Excess (GCE). We demonstrate how gravitational microlensing by stellar mass objects along the line of sight to the Galactic Bulge can distinguish between the…

High Energy Astrophysical Phenomena · Physics 2025-08-28 Nada Salama , Florian List , Geraint Lewis

Extended dark matter (DM) substructures may play the role of microlenses in the Milky Way and in extragalactic gravitational lens systems (GLSs). We compare microlensing effects caused by point masses (Schwarzschild lenses) and extended…

Astrophysics of Galaxies · Physics 2022-09-07 E. Fedorova , V. M. Sliusar , V. I. Zhdanov , A. N. Alexandrov , A. Del Popolo , J. Surdej

Microlensing is a powerful tool for studying stellar atmospheres because as the source crosses regions of formally infinite magnification (caustics) the surfaceof the star is resolved, thereby allowing one to measure the radial intensity…

Astrophysics · Physics 2009-10-30 B. Scott Gaudi , Andrew Gould

Among all galactic microlensing events, those involving a passage of the observed source star over the caustic created by a binary lens are particularly useful in providing information about stellar atmospheres, the dynamics of stellar…

Astrophysics · Physics 2009-11-10 M. Dominik

Recent studies have demonstrated that detailed monitoring of gravitational microlensing events can reveal the presence of planets orbiting the microlensed source stars. With the potential of probing planets in the Galactic Bulge and…

Astrophysics · Physics 2009-11-06 Ceri E. Ashton , Geraint F. Lewis

Strong gravitational lensing offers constraints on the Hubble constant that are independent of other methods. However, those constraints are subject to uncertainties in lens models. Previous studies suggest that using an elliptical power…

Cosmology and Nongalactic Astrophysics · Physics 2024-07-02 Dilys Ruan , Charles R. Keeton

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…

Solar and Stellar Astrophysics · Physics 2017-05-10 A. A. Nucita , F. De Paolis , G. Ingrosso , M. Giordano , L. Manni

We investigate the feasibility of reconstructing the radial intensity profile of extended stellar sources by inverting their microlensed light curves. Using a simple, linear, limb darkening law as an illustration, we show that the intensity…

Astrophysics · Physics 2009-10-30 M. A. Hendry , I. J. Coleman , N. Gray , A. M. Newsam , J. F. L. Simmons

We fit binary lens models to the data covering the initial part of real microlensing events in an attempt to predict the time of the second caustic crossing. We use approximations during the initial search through the parameter space for…

Astrophysics · Physics 2017-02-08 Michal Jaroszynski , Shude Mao

Highly magnified stars residing in caustic crossing lensed galaxies at z ~ 0.7-1.5 in galaxy cluster lensing fields inevitably exhibit recurrent brightening events as they traverse a micro caustic network cast down by foreground…

Cosmology and Nongalactic Astrophysics · Physics 2024-03-14 Xu Han , Liang Dai

Lens models appropriate for representing cusped galaxies and clusters are developed. The analogue of the odd number theorem for cusped density distributions is given. Density cusps are classified into strong, isothermal or weak, according…

Astrophysics · Physics 2007-05-23 Wyn Evans , Mark Wilkinson

We report on the results of a visual search for galaxy-scale strong gravitational lenses over 650 arcmin^2 of HST/ACS imaging in the DEEP2-EGS field. In addition to a previously-known Einstein Cross (the "Cross," HST J141735+52264, with…

Weak lensing by large scale structure induces correlated ellipticities in the images of distant galaxies. The two-point correlation is determined by the matter power spectrum along the line of sight. We use the fully nonlinear evolution of…

Astrophysics · Physics 2009-10-28 Bhuvnesh Jain , Uros Seljak

We present a strong lensing system in which a double source is imaged 5 times by 2 early-type galaxies. We take advantage in this target of the multi-band photometry obtained as part of the CLASH program, complemented by the spectroscopic…

With a handful of measurements of limb-darkening coefficients, galactic microlensing has already proven to be a powerful technique for studying atmospheres of distant stars. Survey campaigns such as OGLE-III are capable of providing ~ 10…

Astrophysics · Physics 2009-11-10 M. Dominik

We analyse the effects on the predictions for the microlensing searches toward the Galactic bulge coming from the fact that not all the stars monitored belong to the bulge itself, but that a non--negligible fraction of them actually are in…

Astrophysics · Physics 2009-10-28 S. Mollerach , E. Roulet

We consider the signature and detectability of gravitational microlensing of distant quasars by cosmic strings. Because of the simple image configuration such events will have a characteristic light curve, in which a source would appear to…

Astrophysics · Physics 2009-11-13 Konrad Kuijken , Xavier Siemens , Tanmay Vachaspati
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