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 Cha; Dong 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

doi:10.3847/1538-3881/ab6f66

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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Abstract

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 language	English
Article number	134
Journal	Astronomical Journal
Volume	159
Issue number	4
DOIs	https://doi.org/10.3847/1538-3881/ab6f66
Publication status	Published - 2020 Apr 1

Bibliographical note

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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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10.3847/1538-3881/ab6f66

Cite this

Han, C., Lee, C. U., Udalski, A., Gould, A., Gould, A., Bond, I. A., Bozza, V., Bozza, V., Albrow, M. D., Chung, S. J., Chung, S. J., Hwang, K. H., Jung, Y. K., Ryu, Y. H., Shin, I. G., Shvartzvald, Y., Yee, J. C., Zang, W., Cha, S. M., ... Yonehara, A. (2020). Candidate Brown-dwarf Microlensing Events with Very Short Timescales and Small Angular Einstein Radii. Astronomical Journal, 159(4), Article 134. https://doi.org/10.3847/1538-3881/ab6f66

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title = "Candidate Brown-dwarf Microlensing Events with Very Short Timescales and Small Angular Einstein Radii",

abstract = "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.",

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

year = "2020",

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doi = "10.3847/1538-3881/ab6f66",

language = "English",

volume = "159",

journal = "Astronomical Journal",

issn = "0004-6256",

publisher = "IOP Publishing Ltd.",

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Han, C, Lee, CU, Udalski, A, Gould, A, Gould, A, Bond, IA, Bozza, V, Bozza, V, Albrow, MD, Chung, SJ, Chung, SJ, Hwang, KH, Jung, YK, Ryu, YH, Shin, IG, Shvartzvald, Y, Yee, JC, Zang, W, Cha, SM, Cha, SM, Kim, DJ, Kim, HW, Kim, SL, Kim, SL, Lee, DJ, Lee, Y, Lee, Y, Park, BG, Pogge, RW, Jee, MJ, Jee, MJ, Kim, D, Mróz, P, Mróz, P, Szymański, MK, Skowron, J, Poleski, R, Soszyński, I, Pietrukowicz, P, Kozłowski, S, Ulaczyk, K, Rybicki, KA, Iwanek, P, Wrona, M, Abe, F, Barry, R, Bennett, DP, Bennett, DP, Bhattacharya, A, Bhattacharya, A, Donachie, M, Fujii, H, Fukui, A, Fukui, A, Itow, Y, Hirao, Y, Kamei, Y, Kondo, I, Koshimoto, N, Koshimoto, N, Li, MCA, Matsubara, Y, Muraki, Y, Miyazaki, S, Nagakane, M, Ranc, C, Rattenbury, NJ, Satoh, Y, Shoji, H, Suematsu, H, Sullivan, DJ, Sumi, T, Suzuki, D, Tristram, PJ, Yamakawa, T, Yamawaki, T & Yonehara, A 2020, 'Candidate Brown-dwarf Microlensing Events with Very Short Timescales and Small Angular Einstein Radii', Astronomical Journal, vol. 159, no. 4, 134. https://doi.org/10.3847/1538-3881/ab6f66

TY - JOUR

T1 - Candidate Brown-dwarf Microlensing Events with Very Short Timescales and Small Angular Einstein Radii

AU - Han, Cheongho

AU - Lee, Chung Uk

AU - Udalski, Andrzej

AU - Gould, Andrew

AU - Bond, Ian A.

AU - Bozza, Valerio

AU - Albrow, Michael D.

AU - Chung, Sun Ju

AU - Hwang, Kyu Ha

AU - Jung, Youn Kil

AU - Ryu, Yoon Hyun

AU - Shin, In Gu

AU - Shvartzvald, Yossi

AU - Yee, Jennifer C.

AU - Zang, Weicheng

AU - Cha, Sang Mok

AU - Kim, Dong Jin

AU - Kim, Hyoun Woo

AU - Kim, Seung Lee

AU - Lee, Dong Joo

AU - Lee, Yongseok

AU - Park, Byeong Gon

AU - Pogge, Richard W.

AU - Jee, M. James

AU - Kim, Doeon

AU - Mróz, Przemek

AU - Szymański, Michał K.

AU - Skowron, Jan

AU - Poleski, Radek

AU - Soszyński, Igor

AU - Pietrukowicz, Paweł

AU - Kozłowski, Szymon

AU - Ulaczyk, Krzysztof

AU - Rybicki, Krzysztof A.

AU - Iwanek, Patryk

AU - Wrona, Marcin

AU - Abe, Fumio

AU - Barry, Richard

AU - Bennett, David P.

AU - Bhattacharya, Aparna

AU - Donachie, Martin

AU - Fujii, Hirosane

AU - Fukui, Akihiko

AU - Itow, Yoshitaka

AU - Hirao, Yuki

AU - Kamei, Yuhei

AU - Kondo, Iona

AU - Koshimoto, Naoki

AU - Li, Man Cheung Alex

AU - Matsubara, Yutaka

AU - Muraki, Yasushi

AU - Miyazaki, Shota

AU - Nagakane, Masayuki

AU - Ranc, Clément

AU - Rattenbury, Nicholas J.

AU - Satoh, Yuki

AU - Shoji, Hikaru

AU - Suematsu, Haruno

AU - Sullivan, Denis J.

AU - Sumi, Takahiro

AU - Suzuki, Daisuke

AU - Tristram, Paul J.

AU - Yamakawa, Takeharu

AU - Yamawaki, Tsubasa

AU - Yonehara, Atsunori

PY - 2020/4/1

Y1 - 2020/4/1

N2 - 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.

AB - 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.

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DO - 10.3847/1538-3881/ab6f66

M3 - Article

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SN - 0004-6256

VL - 159

JO - Astronomical Journal

JF - Astronomical Journal

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ER -

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

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