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Related papers: Microlensing optical depth toward the Galactic Bul…

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We present an analysis of the light curves of 9.1 million stars observed during three seasons by EROS (Experience de Recherche d'Objets Sombres), in the Galactic plane away from the bulge. Seven stars exhibit luminosity variations…

Astrophysics · Physics 2012-08-27 EROS Collaboration

Aims: We present a detailed analysis of OGLE 2004-BLG-482, a relatively high-magnification single-lens microlensing event which exhibits clear extended-source effects. These events are relatively rare, but they potentially contain unique…

We present microlensing calculations for a Galactic model based on Han & Gould (2003), which is empirically normalised by star counts. We find good agreement between this model and data recently published by the MACHO and OGLE…

Astrophysics · Physics 2009-11-13 Alexander Wood , Shude Mao

More reliable constraints on the microlensing optical depth comes from a better understanding of the Galactic model. Based on well-constrained Galactic bulge and disk models constructed from survey observations, such as, HST, 2MASS, and…

Astrophysics · Physics 2009-11-13 Yoon-Hyun Ryu , Heon-Young Chang , Myeong-Gu Park , Ki-Won Lee

In the third part of the series presenting the Optical Gravitational Lensing Experiment (OGLE) microlensing studies of the dark matter halo compact objects (MACHOs) we describe results of the OGLE-III monitoring of the Large Magellanic…

The color-magnitude diagrams of $\sim 7 \times 10^5$ stars obtained for 12 fields across the Galactic bulge with the OGLE project reveal a well-defined population of bulge red clump giants. We find that the distributions of the apparent…

Astrophysics · Physics 2009-10-28 K. Z. Stanek , A. Udalski , M. Szymanski , J. Kaluzny , M. Kubiak , M. Mateo , W. Krzeminski

Modern surveys of gravitational microlensing events have progressed to detecting thousands per year. Surveys are capable of probing Galactic structure, stellar evolution, lens populations, black hole physics, and the nature of dark matter.…

For all exoplanet candidates, the reliability of a claimed detection needs to be assessed through a careful study of systematic errors in the data to minimize the false positives rate. We present a method to investigate such systematics in…

In this work, we present the analysis of the binary microlensing event OGLE-2018-BLG-0022 that is detected toward the Galactic bulge field. The dense and continuous coverage with the high-quality photometry data from ground-based…

Some previous studies have suggested that massive and intermediate-mass primordial black holes (PBHs) could comprise a substantial fraction of dark matter in the Universe. Such black holes, if they existed in the Milky Way halo, would give…

We present the analysis of the event OGLE-2017-BLG-1186 from the 2017 Spitzer microlensing campaign. This is a remarkable microlensing event because its source is photometrically bright and variable, which makes it possible to perform an…

Solar and Stellar Astrophysics · Physics 2019-07-26 Shun-Sheng Li , Weicheng Zang , Andrzej Udalski , Yossi Shvartzvald , Daniel Huber , Chung-Uk Lee , Takahiro Sumi , Andrew Gould , Shude Mao , Pascal Fouqué , Tianshu Wang , Subo Dong , Uffe G. Jørgensen , Andrew Cole , Przemek Mróz , Michał K. Szymański , Jan Skowron , Radosław Poleski , Igor Soszyński , Paweł Pietrukowicz , Szymon Kozłowski , Krzysztof Ulaczyk , Krzysztof A. Rybicki , Patryk Iwanek , Jennifer C. Yee , Sebastiano Calchi Novati , Charles A. Beichman , Geoffery Bryden , Sean Carey , B. Scott Gaudi , Calen B. Henderson , Wei Zhu , Michael D. Albrow , Sun-Ju Chung , Cheongho Han , Kyu-Ha Hwang , Youn Kil Jung , Yoon-Hyun Ryu , In-Gu Shin , Sang-Mok Cha , Dong-Jin Kim , Hyoun-Woo Kim , Seung-Lee Kim , Dong-Joo Lee , Yongseok Lee , Byeong-Gon Park , Richard W. Pogge , Ian A. Bond , Fumio Abe , Richard Barry , David P. Bennett , Aparna Bhattacharya , Martin Donachie , Akihiko Fukui , Yuki Hirao , Yoshitaka Itow , Iona Kondo , Naoki Koshimoto , Man Cheung Alex Li , Yutaka Matsubara , Yasushi Muraki , Shota Miyazaki , Masayuki Nagakane , Clément Ranc , Nicholas J. Rattenbury , Haruno Suematsu , Denis J. Sullivan , Daisuke Suzuki , Paul J. Tristram , Atsunori Yonehara , Grant Christie , John Drummond , Jonathan Green , Steve Hennerley , Tim Natusch , Ian Porritt , Etienne Bachelet , Dan Maoz , Rachel A. Street , Yiannis Tsapras , Valerio Bozza , Martin Dominik , Markus Hundertmark , Nuno Peixinho , Sedighe Sajadian , Martin J. Burgdorf , Daniel F. Evans , Roberto Figuera Jaimes , Yuri I. Fujii , Lauri K. Haikala , Christiane Helling , Thomas Henning , Tobias C. Hinse , Luigi Mancini , Penelope Longa-Peña , Sohrab Rahvar , Markus Rabus , Jesper Skottfelt , Colin Snodgrass , John Southworth , Eduardo Unda-Sanzana , Carolina von Essen , Jean-Phillipe Beaulieu , Joshua Blackman , Kym Hill

Perhaps as many as 30 parallax microlensing events are known, thanks to the efforts of the MACHO, OGLE, EROS and MOA experiments monitoring the bulge. Using Galactic models, we construct mock catalogues of microlensing light curves towards…

Astrophysics · Physics 2009-11-11 M. C. Smith , V. Belokurov , N. W. Evans , S. Mao , J. H. An

We describe a few recent microlensing results from the MACHO Collaboration. The aim of the MACHO Project was the identification and quantitative description of dark and luminous matter in the Milky Way using microlensing toward the…

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

I make a new evaluation of the microlensing optical depth toward the Galactic bar from Difference Image Analysis (DIA) of the MACHO Collaboration. First, I present supplementary evidence that MACHO field 104 located at (l,b) = (3.11,-3.01)…

Astrophysics · Physics 2007-05-23 Piotr Popowski

We analyze the photometric data obtained by PLANET and OGLE on the caustic-crossing binary-lens microlensing event OGLE-2002-BLG-069. Thanks to the excellent photometric and spectroscopic coverage of the event, we are able to constrain the…

A large number of microlensing events have been observed in the direction of the Galactic bulge, with a measured optical depth in the range 2 - 3 x 10^{-6}. It has been shown that most of these events are due to bulge stars being lensed by…

Astrophysics · Physics 2009-10-30 Vibhat Nair , Jordi Miralda-Escude

We present an re-analysis of the longest timescale gravitational microlensing event discovered to date: MACHO-99-BLG-22/OGLE-1999-BUL-32, which was discovered by both the MACHO and OGLE microlensing alert systems. Our analysis of this…

The MACHO project carries out regular photometric monitoring of millions of stars in the Magellanic Clouds and Galactic Bulge, to search for very rare gravitational microlensing events due to compact objects in the galactic halo and disk. A…

We present a proper motion (\mu) catalogue of 5,080,236 stars in 49 Optical Gravitational Lensing Experiment II (OGLE-II) Galactic bulge (GB) fields, covering a range of -11 deg. <l< 11 deg. and -6 deg. <b<3 deg., the total area close to 11…