Candidate Microlensing Brown Dwarfs in Binary Lens Systems from the 2023--2025 Observing Seasons
Abstract
We present detailed light-curve analyses of ten binary-lens microlensing events observed during the 2023--2025 seasons and selected as candidates for hosting brown-dwarf companions. The sample includes OGLE-2023-BLG-0249, KMT-2023-BLG-1246, OGLE-2023-BLG-0079, KMT-2024-BLG-0072, KMT-2024-BLG-0897, KMT-2024-BLG-1876, KMT-2024-BLG-2379, KMT-2025-BLG-0922, KMT-2025-BLG-1056, and KMT-2025-BLG-2427. For each event, we carry out modeling of the light curve, explore relevant degeneracies, and, when finite-source effects are present, determine the angular Einstein radius. For OGLE-2023-BLG-0249, we additionally measure the microlens parallax, which allows a direct determination of the lens masses and distance. For the remaining events, we estimate the physical lens properties via Bayesian analyses incorporating Galactic priors. The resulting posteriors show that the lens companions in all systems have median masses in the brown-dwarf regime, and the lenses of two events (KMT-2025-BLG-0922 and KMT-2025-BLG-1056) are consistent with binaries in which both lens components fall within the brown-dwarf mass range. Spanning a wide range of projected separations and distances, these detections illustrate the power of high-cadence microlensing surveys to build a census of brown-dwarf companions, including faint and distant systems beyond the reach of flux-limited methods.
Keywords
Cite
@article{arxiv.2604.07932,
title = {Candidate Microlensing Brown Dwarfs in Binary Lens Systems from the 2023--2025 Observing Seasons},
author = {Cheongho Han and Andrzej Udalski and Ian A. Bond and Chung-Uk Lee and Michael D. Albrow and Sun-Ju Chung and Andrew Gould and Youn Kil Jung and Kyu-Ha Hwang and Yoon-Hyun Ryu and Yossi Shvartzvald and In-Gu Shin and Jennifer C. Yee and Weicheng Zang and Hongjing Yang and Doeon Kim and Dong-Jin Kim and Seung-Lee Kim and Dong-Joo Lee and Sang-Mok Cha and Yongseok Lee and Byeong-Gon Park and Richard W. Pogge and Przemek Mróz and Michał K. Szymański and Jan Skowron and Radosław Poleski and Igor Soszyński and Paweł Pietrukowicz and Szymon Kozłowski and Krzysztof A. Rybicki and Patryk Iwanek and Krzysztof Ulaczyk and Marcin Wrona and Mariusz Gromadzki and Mateusz J. Mróz and Fumio Abe and David P. Bennett and Aparna Bhattacharya and Ryusei Hamada and Yuki Hirao and Asahi Idei and Stela Ishitani Silva and Shuma Makida and Shota Miyazaki and Yasushi Muraki and Tutumi Nagai and Togo Nagano and Seiya Nakayama and Mayu Nishio and Kansuke Nunota and Ryo Ogawa and Ryunosuke Oishi and Yui Okumoto and Greg Olmschenk and Clément Ranc and Nicholas J. Rattenbury and Yuki Satoh and Takahiro Sumi and Daisuke Suzuki and Takuto Tamaoki and Sean K. Terry and Paul J. Tristram and Aikaterini Vandorou and Hibiki Yama},
journal= {arXiv preprint arXiv:2604.07932},
year = {2026}
}
Comments
17 pages, 12 figures