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Related papers: Distribution of Caustic-Crossing Intervals for Gal…

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A new window to observing individual stars and other small sources at cosmological distances was opened recently, with the detection of several caustic-crossing events in galaxy cluster fields. Many more such events are expected soon from…

Instrumentation and Methods for Astrophysics · Physics 2022-08-15 Ashish Kumar Meena , Ofir Arad , Adi Zitrin

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.…

Recently, from the Hubble Space Telescope (HST) images of one of the Large Magellanic Cloud (LMC) events taken 6.3 years after the original lensing measurement, Alcock et al. were able to directly image the lens. Although the first resolved…

Astrophysics · Physics 2009-11-07 Cheongho Han , Heon-Young Chang

We present the analysis of stellar binary microlensing event OGLE-2015-BLG-0060 based on observations obtained from 13 different telescopes. Intensive coverage of the anomalous parts of the light curve was achieved by automated follow-up…

Gravitational microlensing depends primarily on the lens mass and presents a larger occurrence rate in crowded regions, which makes it the best tool to uncover the initial mass function (IMF) of low-mass stars in the Galactic bulge. The…

If the objects responsible for gravitational microlensing (ML) of Galactic-bulge stars are faint dwarfs, then blended light from the lens will distort the shape of the ML light curve and shift the color of the observed star during the…

Astrophysics · Physics 2009-10-28 Ari Buchalter , Marc Kamionkowski , R. Michael Rich

The recent discovery of fast transient events near critical curves of massive galaxy clusters, which are interpreted as highly magnified individual stars in giant arcs due to caustic crossing, opens up the possibility of using such…

Cosmology and Nongalactic Astrophysics · Physics 2018-01-24 Masamune Oguri , Jose M. Diego , Nick Kaiser , Patrick L. Kelly , Tom Broadhurst

We report the result of the analysis of the light curve of a caustic-crossing binary-lens microlensing event OGLE-2009-BLG-023/MOA-2009-BLG-028. Even though the event was observed solely by survey experiments, we could uniquely determine…

We report the first mass and distance measurement of a caustic-crossing binary system OGLE-2014-BLG-1050L using the space-based microlens parallax method. \emph{Spitzer} captured the second caustic-crossing of the event, which occurred…

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 present an analysis of the longest timescale microlensing events discovered by the MACHO Collaboration during a 7 year survey of the Galactic bulge. We find 6 events that exhibit very strong microlensing parallax signals due, in part, to…

Under the current microlensing planet search strategy of monitoring events caused by stellar-mass lenses, only planets located within a narrow region of separations from central stars can be effectively detected. However, with the dramatic…

Astrophysics · Physics 2009-11-07 Cheongho Han , Young Woon Kang

Despite astrophysical importance of binary star systems, detections are limited to those located in small ranges of separations, distances, and masses and thus it is necessary to use a variety of observational techniques for a complete view…

Solar and Stellar Astrophysics · Physics 2016-08-14 I. -G. Shin , C. Han , J. -Y. Choi , A. Udalski , T. Sumi , A. Gould , V. Bozza , M. Dominik , P. Fouqué , K. Horne , M. , K. Szymański , M. Kubiak , I. Soszyński , G. Pietrzyński , R. Poleski , K. Ulaczyk , P. Pietrukowicz , S. Kozłowski , J. Skowron , Ł. Wyrzykowski , F. Abe , D. P. Bennett , I. A. Bond , C. S. Botzler , P. Chote , M. Freeman , A. Fukui , K. Furusawa , Y. Itow , S. Kobara , C. H. Ling , K. Masuda , Y. Matsubara , N. Miyake , Y. Muraki , K. Ohmori , K. Ohnishi , N. J. Rattenbury , To. Saito , D. J. Sullivan , D. Suzuki , K. Suzuki , W. L. Sweatman , S. Takino , P. J. Tristram , K. Wada , P. C. M. Yock , D. M. Bramich , C. Snodgrass , I. A. Steele , R. A. Street , Y. Tsapras , K. A. Alsubai , P. Browne , M. J. Burgdorf , S. Calchi Novati , P. Dodds , S. Dreizler , X. -S. Fang , F. Grundahl , C. -H. Gu , S. Hardis , K. Harpsøe , T. C. Hinse , A. Hornstrup , M. Hundertmark , J. Jessen-Hansen , U. G. Jørgensen , N. Kains , E. Kerins , C. Liebig , M. Lund , M. Lunkkvist , L. Mancini , M. Mathiasen , M. T. Penny , S. Rahvar , D. Ricci , G. Scarpetta , J. Skottfelt , J. Southworth , J. Surdej , J. Tregloan-Reed , J. Wambsganss , O. Wertz , L. A. Almeida , V. Batista , G. Christie , D. L. DePoy , Subo Dong , B. S. Gaudi , C. Henderson , F. Jablonski , C. -U. Lee , J. McCormick , D. McGregor , D. Moorhouse , T. Natusch , H. Ngan , S. -Y. Park , R. W. Pogge , T. -G. Tan , G. Thornley , J. C. Yee , M. D. Albrow , E. Bachelet , J. -P. Beaulieu , S. Brillant , A. Cassan , A. A. Cole , E. Corrales , C. Coutures , S. Dieters , D. Dominis Prester , J. Donatowicz , J. Greenhill , D. Kubas , J. -B. Marquette , J. W. Menzies , K. C. Sahu , M. Zub

We compute a microlensing map for the Galactic bar. The predicted event rate and event duration distribution are consistent with the $55$ events recently reported by the MACHO and OGLE collaborations. Most of the events are due to lensing…

Astrophysics · Physics 2015-06-24 HongSheng Zhao , R. M. Rich , D. N. Spergel

The light received by source stars in microlensing events may be significantly polarized if both an efficient photon scattering mechanism is active in the source stellar atmosphere and a differential magnification is therein induced by the…

Solar and Stellar Astrophysics · Physics 2015-06-17 G. Ingrosso , F. De Paolis , A. A. Nucita , F. Strafella , S. Calchi Novati , Ph. Jetzer , G. Liuzzi , A. Zakharov

We investigate the possibility of lens mass determination for a caustic crossing microlensing event based on a space telescope observation. We demonstrate that the parallax due to the orbital motion of a space telescope causes a periodic…

Astrophysics · Physics 2009-10-31 Mareki Honma

We analyze PLANET collaboration data for MACHO 97-BLG-41, the only microlensing event observed to date in which the source transits two disjoint caustics. The PLANET data, consisting of 46 V-band and 325 I-band observations from five…

First, we review the current status of the detection of strong `external' variability in the CLASS gravitational B1600+434, focusing on the 1998 VLA 8.5-GHz and 1998/9 WSRT multi-frequency observations. We show that this data can best be…

Astrophysics · Physics 2007-05-23 L. V. E. Koopmans , A. G. de Bruyn , J. Wambsganss , C. D. Fassnacht

To provide criteria in the selection of target events preferable for planetary lensing follow-up observations, we investigate the variation of the probability of detecting planetary signals depending on the observables of the lensing…

Astrophysics · Physics 2009-06-23 Cheongho Han

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