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Related papers: A Brown Dwarf Microlens Candidate in the OGLE-II D…

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In the pursuit of understanding the population of stellar remnants within the Milky Way, we analyze the sample of $\sim 950$ microlensing events observed by the Spitzer Space Telescope between 2014 and 2019. In this study we focus on a…

We analyze the very short Einstein timescale ($t_\rm E \simeq 7\,{\rm hr}$) event KMT-2019-BLG-2073. Making use of the pronounced finite-source effects generated by the clump-giant source, we measure the Einstein radius $\theta_\rm E \simeq…

Microlensing events can be used to directly measure the masses of single field stars to a precision of $\sim$1-10\%. The majority of direct mass measurements for stellar and sub-stellar objects typically only come from observations of…

Solar and Stellar Astrophysics · Physics 2018-11-09 M. B. Nielsen , D. M. Bramich

We report the discovery of a planetary system from observation of the high-magnification microlensing event OGLE-2012-BLG-0026. The lensing light curve exhibits a complex central perturbation with multiple features. We find that the…

The microlensing event OGLE-2011-BLG-0417 is an exceptionally bright lens binary that was predicted to present radial velocity variation at the level of several km/s. Pioneer radial velocity follow-up observations with the UVES spectrograph…

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 report on the discovery and analysis of the planetary microlensing event OGLE-2019-BLG-1180 with a planet-to-star mass ratio $q \sim 0.003$. The event OGLE-2019-BLG-1180 has unambiguous cusp-passing and caustic-crossing anomalies, which…

KMT-2018-BLG-0029Lb and OGLE-2019-BLG-0960Lb were the lowest mass-ratio microlensing planets at the time of discovery. For both events, microlensing parallax measurements from the Spitzer Space Telescope implied lens systems that were more…

Earth and Planetary Astrophysics · Physics 2025-08-27 Keming Zhang , Sean K. Terry , Joshua S. Bloom , B. Scott Gaudi , Jessica R. Lu

We analysed microlensing data to uncover the nature of the anomaly that appeared near the peak of the short-timescale microlensing event KMT-2024-BLG-1044. Despite the anomaly's brief duration of less than a day, it was densely observed…

We report the discovery and the analysis of the short (tE < 5 days) planetary microlensing event, OGLE-2015-BLG-1771. The event was discovered by the Optical Gravitational Lensing Experiment (OGLE), and the planetary anomaly (at I ~ 19) was…

We present the analysis of OGLE-2016-BLG-0613, for which the lensing light curve appears to be that of a typical binary-lens event with two caustic spikes but with a discontinuous feature on the trough between the spikes. We find that the…

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…

We investigate the possibility of determining whether microlensing objects towards the Large Magellanic Cloud (LMC) are in a Galactic thick disc, or are in a Galactic halo, by using parallax measurements with an Earth-radius scale baseline.…

Astrophysics · Physics 2009-11-07 T. Sumi , Y. Kan-ya

We report the discovery and analysis of the planetary microlensing event OGLE-2017-BLG-0406, which was observed both from the ground and by the ${\it Spitzer}$ satellite in a solar orbit. At high magnification, the anomaly in the light…

Earth and Planetary Astrophysics · Physics 2020-07-29 Yuki Hirao , David P. Bennett , Yoon-Hyun Ryu , Naoki Koshimoto , Andrzej Udalski , Jennifer C. Yee , Takahiro Sumi , Ian A. Bond , Yossi Shvartzvald , Fumio Abe , Richard K. Barry , Aparna Bhattacharya , Martin Donachie , Akihiko Fukui , Yoshitaka Itow , Iona Kondo , Man Cheung Alex Li , Yutaka Matsubara , Taro Matsuo , Shota Miyazaki , Yasushi Muraki , Masayuki Nagakane , Clement Ranc , Nicholas J. Rattenbury , Haruno Suematsu , Hiroshi Shibai , Daisuke Suzuki , Paul J. Tristram , Atsunori Yonehara , J. Skowron , R. Poleski , P. Mroz , M. K. Szymanski , I. Soszynski , S. Kozlowski , P. Pietrukowicz , K. Ulaczyk , K. Rybicki , P. Iwanek , Michael D. Albrow , Sun-Ju Chung , Andrew Gould , Cheongho Han , Kyu-Ha Hwang , Youn Kil Jung , In-Gu Shin , Weicheng Zang , Sang-Mok Cha , Dong-Jin Kim , Hyoun-Woo Kim , Seung-Lee Kim , Chung-Uk Lee , Dong-Joo Lee , Yongseok Lee , Byeong-Gon Park , Richard W. Pogge , Charles A. Beichman , Geoffery Bryden , Sebastiano Calchi Novati , Sean Carey , B. Scott Gaudi , Calen B. Henderson , Wei Zhu , Etienne Bachelet , Greg Bolt , Grant Christie , Markus Hundertmark , Tim Natusch , Dan Maoz , Jennie McCormick , Rachel A. Street , Thiam-Guan Tan , Yiannis Tsapras , U. G. Jorgensen , M. Dominik , V. Bozza , J. Skottfelt , C. Snodgrass , S. Ciceri , R. Figuera Jaimes , D. F. Evans , N. Peixinho , T. C. Hinse , M. J. Burgdorf , J. Southworth , S. Rahvar , S. Sajadian , M. Rabus , C. von Essen , Y. I. Fujii , J. Campbell-White , S. Lowry , C. Helling , L. Mancini , L. Haikala , Ryo Kandori

Aims. We seek to probe the Galactic bulge IMF starting from microlensing observations. Methods. We analyse the recent results of the microlensing campaigns carried out towards the Galactic bulge presented by the EROS, MACHO and OGLE…

Astrophysics · Physics 2009-06-23 S. Calchi Novati , F. De Luca , Ph. Jetzer , L. Mancini , G. Scarpetta

We present a measurement of the microlensing optical depth toward the Galactic Bulge based on 4 years of the OGLE-II survey using Red Clump Giant (RCG). Using 32 events we find tau=2.55_{-0.46}^{+0.57}* 10^{-6} at (l,b)=(1.16, -2.75).…

We investigate the possibility of constraining the dark energy equation of state by measuring the ratio of Einstein radii in a strong gravitational lens system with two source planes. This quantity is independent of the Hubble parameter and…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Thomas E. Collett , Matthew W. Auger , Vasily Belokurov , Philip J. Marshall , Alex C. Hall

Astrometric observations of microlensing events were originally proposed to determine the lens proper motion with which the physical parameters of lenses can be better constrained. In this proceeding, we demonstrate that besides this…

Astrophysics · Physics 2007-05-23 Cheongho Han