Candidate Brown-dwarf Microlensing Events with Very Short Timescales and Small Angular Einstein Radii

Cheongho Han, Chung Uk Lee, Andrzej Udalski, Andrew Gould, Andrew Gould, Ian A. Bond, Valerio Bozza, Valerio Bozza, Michael D. Albrow, Sun Ju Chung, Sun Ju Chung, Kyu Ha Hwang, Youn Kil Jung, Yoon Hyun Ryu, In Gu Shin, Yossi Shvartzvald, Jennifer C. Yee, Weicheng Zang, Sang Mok Cha, Sang Mok ChaDong Jin Kim, Hyoun Woo Kim, Seung Lee Kim, Seung Lee Kim, Dong Joo Lee, Yongseok Lee, Yongseok Lee, Byeong Gon Park, Richard W. Pogge, M. James Jee, M. James Jee, Doeon Kim, Przemek Mróz, Przemek Mróz, Michał K. Szymański, Jan Skowron, Radek Poleski, Igor Soszyński, Paweł Pietrukowicz, Szymon Kozłowski, Krzysztof Ulaczyk, Krzysztof A. Rybicki, Patryk Iwanek, Marcin Wrona, Fumio Abe, Richard Barry, David P. Bennett, David P. Bennett, Aparna Bhattacharya, Aparna Bhattacharya, Martin Donachie, Hirosane Fujii, Akihiko Fukui, Akihiko Fukui, Yoshitaka Itow, Yuki Hirao, Yuhei Kamei, Iona Kondo, Naoki Koshimoto, Naoki Koshimoto, Man Cheung Alex Li, Yutaka Matsubara, Yasushi Muraki, Shota Miyazaki, Masayuki Nagakane, Clément Ranc, Nicholas J. Rattenbury, Yuki Satoh, Hikaru Shoji, Haruno Suematsu, Denis J. Sullivan, Takahiro Sumi, Daisuke Suzuki, Paul J. Tristram, Takeharu Yamakawa, Tsubasa Yamawaki, Atsunori Yonehara

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9 Citations (Scopus)


Short-timescale microlensing events are likely to be produced by substellar brown dwarfs (BDs), but it is difficult to securely identify BD lenses based on only event timescales because short-timescale events can also be produced by stellar lenses with high relative lens-source proper motions. In this paper, we report three strong candidate BD-lens events found from the search for lensing events not only with short timescales but also with very small angular Einstein radii among the events that have been found in the 2016-2019 observing seasons. These events include MOA-2017-BLG-147, MOA-2017-BLG-241, and MOA-2019-BLG-256, in which the first two events are produced by single lenses and the last event is produced by a binary lens. From the Monte Carlo simulations of Galactic events conducted with the combined and constraint, it is estimated that the lens masses of the individual events are , and and the probability of the lens mass smaller than the lower limit of stars is ∼80% for all events. We point out that routine lens mass measurements of short-timescale lensing events require survey-mode space-based observations.

Original languageEnglish
Article number134
JournalAstronomical Journal
Issue number4
Publication statusPublished - 2020 Apr 1

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© 2020. The American Astronomical Society. All rights reserved..

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science


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