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We identify stars with large proper motions that are potential candidates for the astrometric microlensing effect during the Gaia mission i.e. between 2012 and 2019. The effect allows a precise measurement of the mass of a single star that…

Astrophysics of Galaxies · Physics 2012-01-20 Svea Proft , Markus Demleitner , Joachim Wambsganss

Stochastic microlensing is a central tool in probing dark matter on galactic scales. From first principles, we initiate the development of a mathematical theory of stochastic microlensing. Beginning with the random time delay function and…

Astrophysics · Physics 2015-05-13 Arlie O. Petters , Brian Rider , Alberto M. Teguia

We introduce a new method of searching for and characterizing extra-solar planets. We show that by monitoring the center-of-light motion of microlensing alerts using the next generation of high precision astrometric instruments the…

Astrophysics · Physics 2009-10-31 Neda Safizadeh , Neal Dalal , Kim Griest

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

The precision of Cosmic Microwave Background (CMB) experiments, specifically its lensing reconstruction, has reached the limit where non-linear corrections cannot be ignored. Neglecting these corrections results in biased constraints on…

Cosmology and Nongalactic Astrophysics · Physics 2025-02-27 Cynthia Trendafilova , Ali Rida Khalife , Silvia Galli

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…

Astrophysics · Physics 2009-10-30 Geraint F. Lewis , Rodrigo A. Ibata

The detection of microlensing events from stars in the Large Magellanic Cloud and in the Galactic bulge raise important constraints on the distribution of dark matter and on galactic structure, although some events may be due to a new type…

Astrophysics · Physics 2020-11-25 David Valls-Gabaud

In current microlensing experiments, the information about the physical parameters of individual lenses are obtained from the Einstein timescales. However, the nature of MACHOs is still very uncertain despite the large number of detected…

Astrophysics · Physics 2009-09-25 Youngjin Jeong , Cheongho Han , Sung-Hong Park

Microlensing light curves are now being monitored with the precision required to detect small perturbations due to planetary companions of the primary lens. Microlensing is complementary to other planetary search techniques in its potential…

Astrophysics · Physics 2009-10-31 B. Scott Gaudi , Penny D. Sackett

High-resolution N-body simulations of dark matter halos indicate that the Milky Way contains numerous subhalos. When a dark matter subhalo passes in front of a star, the light from that star will be deflected by gravitational lensing,…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-19 Adrienne L. Erickcek , Nicholas M. Law

The biggest uncertainty in determining microlensing parameters comes from the blending of source star images because the current experiments are being carried out toward very dense star fields: the Galactic bulge and Magellanic Clouds. The…

Astrophysics · Physics 2016-08-30 Cheongho Han

For microlensing case angular distances between images or typical astrometric shifts due to microlensing are about $10^{-5}-10^{-6} \mu as$. Such an angular resolution will be reached with the space space--ground interferometer Radioastron.…

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

In this paper, we investigate the color changes of gravitational microlensing events caused by the two different mechanisms of differential amplification for a limb-darkened extended source and blending. From this investigation, we find…

Astrophysics · Physics 2009-10-31 Cheongho Han , Seong-Hong Park , Jang-Hae Jeong

The microlensing monitoring programs have studied large numbers of standard light curves which seem to be due to lensing by a dark point mass. Theory predicts that many microlensing events should display significant deviations from the…

Astrophysics · Physics 2009-10-30 Rosanne Di Stefano , Rosalba Perna

The numerical kernel approach to difference imaging has been implemented and applied to gravitational microlensing events observed by the PLANET collaboration. The effect of an error in the source-star coordinates is explored and a new…

We fit the data for the binary-lens microlensing event MACHO 98-SMC-1 from 5 different microlensing collaborations and find two distinct solutions characterized by binary separation d and mass ratio q: (d,q)=(0.54,0.50) and…

Astrophysics · Physics 2009-10-31 C. Afonso , C. Alcock , S. H. Rhie , A. Udalski et al. , M. Albrow et al.

We describe a method for determining the limb polarization and limb darkening of stars in eclipsing binary systems, by inverting photometric and polarimetric light curves. Because of the ill-conditioning of the problem, we use the…

Astrophysics · Physics 2009-10-30 I J Coleman , N Gray , J F L Simmons

Astrometric measurements are significantly challenged by the relative motion between the point source and the telescope, primarily due to the difficulty in accurately determining the position of the point source at the mid-exposure moment.…

Instrumentation and Methods for Astrophysics · Physics 2025-03-11 Linpeng Wu , Qingfeng Zhang , Valéry Lainey , Nick Cooper , Nicolas Rambaux , Weiheng Zhu

Astronomical instruments generally possess spatially variant point-spread functions, which determine the amount by which an image pixel is blurred as a function of position. Several techniques have been devised to handle this variability in…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 Adam Rogers , Jason D. Fiege