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arXiv · 2209.04607

Brown-dwarf companions in microlensing binaries detected during the 2016--2018 seasons

Cheongho Han·Yoon-Hyun Ryu·In-Gu Shin·Youn Kil Jung·Doeon Kim·Yuki Hirao·Valerio Bozza·Michael D. Albrow·Weicheng Zang·Andrzej Udalski·Ian A. Bond·Sun-Ju Chung·Andrew Gould·Kyu-Ha Hwang·Yossi Shvartzvald·Hongjing Yang·Sang-Mok Cha·Dong-Jin Kim·Hyoun-Woo Kim·Seung-Lee Kim·Chung-Uk Lee·Dong-Joo Lee·Jennifer C. Yee·Yongseok Lee·Byeong-Gon Park·Richard W. Pogge·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·Aparna Bhattacharya·Hirosame Fujii·Akihiko Fukui·Stela Ishitani Silva·Rintaro Kirikawa·Iona Kondo·Naoki Koshimoto·Yutaka Matsubara·Sho Matsumoto·Shota Miyazaki·Yasushi Muraki·Arisa Okamura·Greg Olmschenk·Clément Ranc·Nicholas J. Rattenbury·Yuki Satoh·Takahiro Sumi·Daisuke Suzuki·Taiga Toda·Paul J. Tristram·Aikaterini Vandorou·Hibiki Yama·Yoshitaka Itow
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Abstract

With the aim of finding microlensing binaries containing brown-dwarf (BD) companions, we investigate the microlensing survey data collected during the 2016--2018 seasons. For this purpose, we first conducted modeling of lensing events with light curves exhibiting anomaly features that are likely to be produced by binary lenses. We then sorted out BD-companion binary-lens events by applying the criterion that the companion-to-primary mass ratio is $q \lesssim 0.1$. From this procedure, we identify 6 binaries with candidate BD companions, including OGLE-2016-BLG-0890L, MOA-2017-BLG-477L, OGLE-2017-BLG-0614L, KMT-2018-BLG-0357L, OGLE-2018-BLG-1489L, and OGLE-2018-BLG-0360L. We estimate the masses of the binary companions by conducting Bayesian analyses using the observables of the individual lensing events. According to the Bayesian estimation of the lens masses, the probabilities for the lens companions of the events OGLE-2016-BLG-0890, OGLE-2017-BLG-0614, OGLE-2018-BLG-1489, and OGLE-2018-BLG-0360 to be in the BD mass regime are very high with $P_{\rm BD}> 80\%$. For MOA-2017-BLG-477 and KMT-2018-BLG-0357, the probabilities are relatively low with $P_{\rm BD}=61\%$ and 69\%, respectively.

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Cheongho Han, Yoon-Hyun Ryu, In-Gu Shin, Youn Kil Jung, Doeon Kim, Yuki Hirao, Valerio Bozza, Michael D. Albrow, Weicheng Zang, Andrzej Udalski, Ian A. Bond, Sun-Ju Chung, Andrew Gould, Kyu-Ha Hwang, Yossi Shvartzvald, Hongjing Yang, Sang-Mok Cha, Dong-Jin Kim, Hyoun-Woo Kim, Seung-Lee Kim, Chung-Uk Lee, Dong-Joo Lee, Jennifer C. Yee, Yongseok Lee, Byeong-Gon Park, Richard W. Pogge, 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, Aparna Bhattacharya, Hirosame Fujii, Akihiko Fukui, Stela Ishitani Silva, Rintaro Kirikawa, Iona Kondo, Naoki Koshimoto, Yutaka Matsubara, Sho Matsumoto, Shota Miyazaki, Yasushi Muraki, Arisa Okamura, Greg Olmschenk, Clément Ranc, Nicholas J. Rattenbury, Yuki Satoh, Takahiro Sumi, Daisuke Suzuki, Taiga Toda, Paul J. Tristram, Aikaterini Vandorou, Hibiki Yama, Yoshitaka Itow. 2022-09-10. Brown-dwarf companions in microlensing binaries detected during the 2016--2018 seasons. https://doi.org/10.1051/0004-6361%2F202244186

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