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Point lens microlensing events with impact parameter close to the source stellar radius allow the observer to study the surface brightness profile of the lensed source. We have examined the effect of photospheric star spots on multicolour…

Astrophysics · Physics 2009-11-07 M. A. Hendry , H. M. Bryce , D. Valls-Gabaud

Astrometric observations of microlensing events were originally proposed to determine the lens proper motion with which the physical parameters of lenses can be better constrained. In this proceeding, we demonstrate that besides this…

Astrophysics · Physics 2007-05-23 Cheongho Han

When a source star is microlensed by one stellar component of a widely separated binary stellar components, after finishing the lensing event, the event induced by the other binary star can be additionally detected. In this paper, we…

Solar and Stellar Astrophysics · Physics 2011-02-11 Sun-Ju Chung , Byeong-Gon Park , Yoon-Hyun Ryu , Andrew Humphrey

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

Microlensing consists in two major effects: (1) variation in the apparent position of the background sources (astrometric component) and (2) flux variations of the background sources (photometric component). While the latter has been…

Astrophysics · Physics 2009-09-25 S. Dib , J. Surdej , J. -F. Claeskens

We present the first public code for the calculation of the astrometric centroid shift occurring during microlensing events. The computation is based on the contour integration scheme and covers single and binary lensing of finite sources…

Instrumentation and Methods for Astrophysics · Physics 2021-05-26 Valerio Bozza , Elahe Khalouei , Etienne Bachelet

The afterglow of a cosmological Gamma-Ray Burst (GRB) should appear on the sky as a narrow emission ring of radius 3x10^{16}cm(t/day)^{5/8} which expands faster than light. After a day, the ring radius is comparable to the Einstein radius…

Astrophysics · Physics 2009-10-30 Abraham Loeb , Rosalba Perna

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…

Astrophysics · Physics 2016-08-30 G. F. Lewis , M. J. Irwin , P. C. Hewett

The computation of the magnification of a finite source by an arbitrary gravitational lens can be reduced from a two-dimensional to a one-dimensional integral using a generalization of Stoke's theorem. For a large source lensed by a…

Astrophysics · Physics 2007-05-23 Andrew Gould , Cedric Gaucherel

An extra-solar planet can be detected by microlensing because the planet can perturb the smooth lensing light curve created by the primary lens. However, it was shown by Gaudi that a subset of binary-source events can produce light curves…

Astrophysics · Physics 2009-11-06 Cheongho Han

Gravitational microlensing provides a new technique for studying the surfaces of distant stars. Microlensing events are detected in real time and can be followed up with precision photometry and spectroscopy. This method is particularly…

Astrophysics · Physics 2009-10-31 David Heyrovsky , Dimitar Sasselov , Abraham Loeb

We develop a new method to measure source proper motions in microlensing events, which can partially overcome problems due to blending. It takes advantage of the fact that the source position is known precisely from the microlensing event…

Finite-source effects of gravitationally microlensed stars have been well discussed in the literature, but the role that stellar rotation plays has been neglected. A differential magnification map applied to a differentially Doppler-shifted…

Solar and Stellar Astrophysics · Physics 2013-11-18 Adam R. H. Stevens , Michael D. Albrow

Astrometric microlensing events occur when a massive object passes between a distant source and the observer, causing a shift of the light centroid. The precise astrometric measurements of the Gaia mission provide an unprecedented…

Solar and Stellar Astrophysics · Physics 2025-07-09 T. Jankovič , A. Gomboc , Ł. Wyrzykowski , U. Kostić , M. Karlica , M. Larma , T. Petrushevska , M. Bronikowski , M. Jabłońska , Z. Kaczmarek

This paper presents first results on the line profile shapes from a circumstellar envelope in bulk motion as modified by a microlensing event. Only geometrically and optically thin spherical shells in uniform expansion or rotation are…

Astrophysics · Physics 2007-05-23 R. Ignace , M. A. Hendry

We study the gravitational microlensing of various static and spherically symmetric non-singular black holes (and horizonless, non-singular compact objects of similar size). For pointlike sources we extend the parametrized post-Newtonian…

General Relativity and Quantum Cosmology · Physics 2026-02-05 Jens Boos , Hao Hu

In recent years free-loating planets (FFPs) have drawn a great interest among astrophysicists. Gravitational microlensing is a unique and exclusive method for their investigation which may allow obtaining precious information about their…

Earth and Planetary Astrophysics · Physics 2015-09-23 Lindita Hamolli , Mimoza Hafizi , Francesco De Paolis , Achille A. Nucita

The effect of stars on the lensing properties of the supermassive black hole in the Galactic Center is similar to the effect of planets on microlensing by a star. We show that the dense stellar cluster around SgrA* increases by factors of a…

Astrophysics · Physics 2009-10-31 Tal Alexander , Abraham Loeb

We present an efficient method for computing lightcurves of an elliptical source which is microlensed by a point mass. The amplification of an extended source involves a two-dimensional integral over its surface brightness distribution. We…

Astrophysics · Physics 2009-10-30 David Heyrovsky , Abraham Loeb

The magnification induced by gravitational microlensing is sensitive to the size of a source relative to the Einstein radius, the natural microlensing scale length. This paper investigates the effect of source size in the case where the…

Astrophysics · Physics 2009-11-11 Geraint F. Lewis , Rodrigo Gil-Merino