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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 general framework for matching the point-spread function (PSF), photometric scaling, and sky background between two images, a subject which is commonly referred to as difference image analysis (DIA). We introduce the new…

Instrumentation and Methods for Astrophysics · Physics 2015-06-11 D. M. Bramich , Keith Horne , M. D. Albrow , Y. Tsapras , C. Snodgrass , R. A. Street , M. Hundertmark , Noe Kains , A. Arellano Ferro , R. Figuera Jaimes , Sunetra Giridhar

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…

Astrophysics of Galaxies · Physics 2024-06-18 R. Forés-Toribio , E. Mediavilla , J. A. Muñoz , J. Jiménez-Vicente , C. Fian , C. del Burgo

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

Stacking analysis is a means of detecting faint sources using a priori position information to estimate an aggregate signal from individually undetected objects. Confusion severely limits the effectiveness of stacking in deep surveys with…

Instrumentation and Methods for Astrophysics · Physics 2015-05-14 Peter Kurczynski , Eric Gawiser

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

We present a comparison of several Difference Image Analysis (DIA) techniques, in combination with Machine Learning (ML) algorithms, applied to the identification of optical transients associated with gravitational wave events. Each…

If a microlensing event is caused by a star, the event can exhibit change in color due to the light from the lens. In the previous and current lensing surveys, the color shift could not be used to constrain the lens population because the…

Astrophysics · Physics 2009-11-13 Byeong-Gon Park , Cheongho Han

The current modelling of single microlensing light curves neglects the possibility that only a fraction of the light is due to the lensed star, the remaining being due to a close, unresolved blend, which may be related or unrelated to the…

Astrophysics · Physics 2009-10-30 Przemyslaw Wozniak , Bohdan Paczynski

The large number of microlensing events discovered towards the Galactic Bulge bears the promise to reconstruct the stellar mass function. The more interesting issue concerning the mass function is certainly to probe its low mass end.…

Astrophysics · Physics 2009-10-31 C. Alard

If a gravitational microlensing event is caused by a widely separated binary lens and the source approaches both lens components, the source flux is successively magnified by the individual lenses: double microlensing events. If events are…

Astrophysics · Physics 2009-11-07 Cheongho Han , Byeong-Gon Park , Wonyong Han , Young Woon Kang

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

The GAIA satellite can precisely measure the masses of nearby brown dwarfs and lower main sequence stars by the microlensing effect. The scientific yield is maximised if the microlensing event is also followed with ground-based telescopes…

Solar and Stellar Astrophysics · Physics 2014-09-08 N. W. Evans

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

Over the last two decades the Andromeda Galaxy (M31) has been something of a test-bed for methods aimed at obtaining accurate time-domain relative photometry within highly crowded fields. Difference imaging methods, originally pioneered…

Astrophysics of Galaxies · Physics 2015-05-18 E. Kerins , M. J. Darnley , J. P. Duke , A. Gould , C. Han , A. Newsam , B. -G. Park , R. Street

Medical imaging often contains critical fine-grained features, such as tumors or hemorrhages, crucial for diagnosis yet potentially too subtle for detection with conventional methods. In this paper, we introduce \textit{DIA}, dissolving is…

Computer Vision and Pattern Recognition · Computer Science 2024-07-09 Jian Shi , Pengyi Zhang , Ni Zhang , Hakim Ghazzai , Peter Wonka

Massive galactic lenses with large Einstein Radii should cause a measurable astrometric microlensing effect, i.e. the light centroid shift due to the motion of the two images. Such a shift in the position of a background star due to…

Solar and Stellar Astrophysics · Physics 2022-10-26 Maja Jabłońska , Łukasz Wyrzykowski , Krzysztof A. Rybicki , Katarzyna Kruszyńska , Zofia Kaczmarek , Zephyr Penoyre

Source blending in microlensing experiments is known to modify the Einstein time of the observed events. In this paper, we have conducted Monte-Carlo calculations, using the analytical relationships derived by Han (1999) to quantify the…

Astrophysics · Physics 2009-11-11 Yann Alibert , Gilles Chabrier , Gerard Massacrier

Context. Astrometric gravitational microlensing can be used to determine the mass of a single star (the lens) with an accuracy of a few percent. To do so, precise measurements of the angular separations between lens and background star with…

Instrumentation and Methods for Astrophysics · Physics 2020-08-26 J. Klüter , U. Bastian , J. Wambsganss