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Observations of caustic-crossing galaxies at redshift $0.7<z<1$ show a wealth of transient events. Most of them are believed to be microlensing events of highly magnified stars. Earlier work predicted such events should be common near the…

The only way to detect planets around stars at distances of several kpc is by (photometric or astrometric) microlensing observations. In this paper, we show that the capability of photometric microlensing extends to the detection of signals…

Astrophysics · Physics 2007-05-23 G. Covone , R. de Ritis , M. Dominik , A. A. Marino

I demonstrate that one can detect pixel gravitational microlensing events at the rate $\sim 180\ {\rm events}\ {\rm yr}^{-1}$ and that some fraction of events ($\sim 15$) will be good enough to measure time scales at the $20\%$ level if the…

Astrophysics · Physics 2009-10-28 Cheongho Han

We analyze the data of the gravitational microlensing survey carried out by by the MOA group during 2000 towards the Galactic Bulge (GB). Our observations are designed to detect efficiently high magnification events with faint source stars…

Gravitational lensing is the phenomenon arising when light rays are deflected by the mass between the source and the observer. Largely magnified and highly distorted images of background galaxies are formed by these angular deflections if…

Cosmology and Nongalactic Astrophysics · Physics 2025-07-02 Atınç Çağan Şengül

We investigate gravitational microlensing of point-like lenses surrounded by diffuse gas clouds. Besides gravitational bending, one must also consider refraction and absorption phenomena. According to the cloud density, the light curves may…

Astrophysics · Physics 2009-11-07 V. Bozza , Ph. Jetzer , L. Mancini , G. Scarpetta

In the smooth mass distribution model, the critical curve represents a line with magnification divergence on the image plane in a strong gravitational lensing system. Considering the microlensing effects caused by discrete masses, the…

Astrophysics of Galaxies · Physics 2023-08-29 Xuliu Yang , Xuechun Chen , Wenwen Zheng , Yu Luo

Foundations of standard theory of microlensing are described, namely we consider microlensing stars in Galactic bulge, the Magellanic Clouds or other nearby galaxies. We suppose that gravitational microlenses lie between an Earth observer…

Astrophysics · Physics 2007-05-23 A. F. Zakharov

Extra-solar planets can be efficiently detected in gravitational microlensing events of high magnification. High accuracy photometry is required over a short, well-defined time interval only, of order 10-30 hours. Most planets orbiting the…

Astrophysics · Physics 2007-05-23 Nicholas J. Rattenbury , Ian A. Bond , Jovan Skuljan , Phil Yock

Estimating the number of microlensing events observed in different parts of the Galactic bulge is a crucial point in planning microlensing experiments. Reliable estimates are especially important if observing resources are scarce, as is the…

Astrophysics of Galaxies · Physics 2015-12-09 R. Poleski

Gravitational microlensing method is a powerful method to detect isolated black holes in the Milky Way. During a microlensing event brightness of the source increases and this feature is used by many photometric surveys to alert on…

Solar and Stellar Astrophysics · Physics 2024-02-06 I. Gezer , Ł. Wyrzykowski , P. Zieliński , G. Marton , K. Kruszyńska , K. A. Rybicki , N. Ihanec , M. Jabłońska , O. Ziółkowska

If a light-emitting star is responsible for a gravitational microlensing event, the lens can be characterized by analyzing the blended light from the lens. In this paper, we investigate the feasibility of characterizing lenses by using this…

Astrophysics · Physics 2009-11-13 Cheongho Han

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

Microlensing of stars in strongly lensed galaxies can lead to temporary extreme magnification factors ($\mu\!>\!1000$), enabling their detection at high redshifts. Following the discovery of Icarus, several stars at cosmological distances…

Cosmology and Nongalactic Astrophysics · Physics 2024-07-03 J. M. Palencia , J. M. Diego , B. J. Kavanagh , J. Martinez

Extrapolation of the astrometric motion of the nearby low-mass star VB 10 indicates that sometime in late December 2011 or during the first 2-3 months of 2012, the star will make a close approach to a background point source. Based on…

Solar and Stellar Astrophysics · Physics 2015-06-03 Sebastien Lepine , Rosanne DiStefano

We investigate the chances that neutron stars act as the lense in a gravitational microlensing event towards the galactic bulge or a spiral arm. The observation of neutron stars by means of gravitational microlensing would allow the…

Astrophysics · Physics 2009-11-07 Dominik J. Schwarz , Dirk Seidel

We prove a gravitational lensing theorem: the magnification of a source of uniform brightness by a foreground spherical lens is mu =1+pi(2R_E^2-R_L^2)/A, where A is the area of the source and R_E and R_L are the Einstein radius and size of…

Astrophysics · Physics 2009-11-07 Eric Agol

We measure the dependence of planet frequency on host star mass, $M_{\rm L}$, and distance from the Galactic center, $R_{\rm L}$, using a sample of planets discovered by gravitational microlensing. We compare the two-dimensional…

Gravitational microlensing is a key probe of the nature of dark matter and its distribution on the smallest scales. For many practical purposes, confronting theory to observation requires to model the probability that a light source is…

Cosmology and Nongalactic Astrophysics · Physics 2020-04-29 Pierre Fleury , Juan García-Bellido

For the first time we detected microlensing events at zero latitude in the Galactic bulge using the VISTA Variables in the Via Lactea Survey (VVV) data. We have discovered a total sample of N = 630 events within an area covering 20.7 sq.…