Author:
Han Cheongho,Ryu Yoon-Hyun,Shin In-Gu,Kil Jung Youn,Kim Doeon,Hirao Yuki,Bozza Valerio,Albrow Michael D.,Zang Weicheng,Udalski Andrzej,Bond Ian A.,Chung Sun-Ju,Gould Andrew,Hwang Kyu-Ha,Shvartzvald Yossi,Yang Hongjing,Cha Sang-Mok,Kim Dong-Jin,Kim Hyoun-Woo,Kim Seung-Lee,Lee Chung-Uk,Lee Dong-Joo,Yee Jennifer C.,Lee Yongseok,Park Byeong-Gon,Pogge Richard W.,Mróz Przemek,Szymański Michał K.,Skowron Jan,Poleski Radek,Soszyński Igor,Pietrukowicz Paweł,Kozłowski Szymon,Ulaczyk Krzysztof,Rybicki Krzysztof A.,Iwanek Patryk,Wrona Marcin,Abe Fumio,Barry Richard,Bennett David P.,Bhattacharya Aparna,Fujii Hirosame,Fukui Akihiko,Ishitani Silva Stela,Kirikawa Rintaro,Kondo Iona,Koshimoto Naoki,Matsubara Yutaka,Matsumoto Sho,Miyazaki Shota,Muraki Yasushi,Okamura Arisa,Olmschenk Greg,Ranc Clément,Rattenbury Nicholas J.,Satoh Yuki,Sumi Takahiro,Suzuki Daisuke,Toda Taiga,Tristram Paul J.,Vandorou Aikaterini,Yama Hibiki,Itow Yoshitaka
Abstract
Aims. With the aim of finding microlensing binaries containing brown dwarf (BD) companions, we investigate the microlensing survey data collected during the 2016–2018 seasons.
Methods. For this purpose, we first modeled 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 ≲ 0.1. With this procedure, we identify six binaries with candidate BD companions: 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.
Results. We estimated 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 PBD > 80%. For MOA-2017-BLG-477 and KMT-2018-BLG-0357, the probabilities are relatively low with PBD = 61% and 69%, respectively.
Subject
Space and Planetary Science,Astronomy and Astrophysics