Four binary microlenses with directly measured masses
Aims. We investigated binary-lens events from the 2022–2024 microlensing surveys, aiming to identify events suitable for lens mass measurements. We focused on two key light curve features: distinct caustic spikes with resolved crossings for measuring the angular Einstein radius ( θ E ), and long durations enabling microlens-parallax ( π E ) measurements. Four events met these criteria: KMT-2022-BLG-1479, KMT-2023-BLG-0932, OGLE-2024-BLG-0142, and KMT-2024-BLG-1309. Methods. We estimated the angular Einstein radius by combining the normalized source radius measured by modeling the resolved caustic spikes with the angular source radius derived from the source color and magnitude. Additionally, we determined the microlens parallax through light curve modeling, taking higher-order effects caused by the orbital motions of Earth and the binary lens into consideration. Results. With measurements of the event timescale, angular Einstein radius, and microlens parallax, we uniquely determined the mass and distance of the lens. For the events KMT-2022-BLG-1479, KMT-2023-BLG-0932, and KMT-2024-BLG-1309, both components of the binary lens have masses lower than that of the Sun, consistent with M-type dwarfs, which are the most common type of lenses in Galactic microlensing events. These lenses are relatively nearby, with distances of ≲2.5 kpc, indicating their location within the Galactic disk. In contrast, for OGLE-2024-BLG-0142, the primary lens component has a mass similar to that of the Sun, while the companion lens component has about half the mass of the primary. This lens system is situated at a greater distance, roughly 4.5 kpc.
Authors
- Yongseok Lee (ORCID: https://orcid.org/0000-0001-7594-8072)
- I. Soszyński (ORCID: https://orcid.org/0000-0002-7777-0842)
- Stela Ishitani Silva
- Weicheng Zang (ORCID: https://orcid.org/0000-0001-6000-3463)
- Hongjing Yang (ORCID: https://orcid.org/0000-0003-0626-8465)
- Yuki Satoh (ORCID: https://orcid.org/0000-0002-1228-4122)
- T. Nagai (ORCID: https://orcid.org/0000-0002-3238-864X)
- M. Gromadzki (ORCID: https://orcid.org/0000-0002-1650-1518)
- Kyu‐Ha Hwang (ORCID: https://orcid.org/0000-0002-9241-4117)
- Akihiko Fukui (ORCID: https://orcid.org/0000-0002-4909-5763)
- Hibiki Yama (ORCID: https://orcid.org/0000-0001-7692-0581)
- Clément Ranc (ORCID: https://orcid.org/0000-0003-2388-4534)
- J. Skowron (ORCID: https://orcid.org/0000-0002-2335-1730)
- Byeong-Gon Park (ORCID: https://orcid.org/0000-0002-6982-7722)
- R. Poleski (ORCID: https://orcid.org/0000-0002-9245-6368)
- Yoon-Hyun Ryu (ORCID: https://orcid.org/0000-0001-9823-2907)
- A. Bond
- Yossi Shvartzvald (ORCID: https://orcid.org/0000-0003-1525-5041)
- Seung-Lee Kim
- Chung‐Uk Lee (ORCID: https://orcid.org/0000-0003-0043-3925)
- Dong-Joo Lee (ORCID: https://orcid.org/0009-0000-5737-0908)
- Naoki Koshimoto (ORCID: https://orcid.org/0000-0003-2302-9562)
- Cheongho Han (ORCID: https://orcid.org/0000-0002-2641-9964)
- T. Sumi (ORCID: https://orcid.org/0000-0002-4035-5012)
- Aikaterini Vandorou (ORCID: https://orcid.org/0000-0002-9881-4760)
- A. Udalski (ORCID: https://orcid.org/0000-0001-5207-5619)
- J. Paul Tristram
- Patryk Iwanek (ORCID: https://orcid.org/0000-0002-6212-7221)
- Shota Miyazaki (ORCID: https://orcid.org/0000-0001-9818-1513)
- P. Pietrukowicz (ORCID: https://orcid.org/0000-0002-2339-5899)
- P. Mróz (ORCID: https://orcid.org/0000-0001-7016-1692)
- K. Ulaczyk (ORCID: https://orcid.org/0000-0001-6364-408X)
- Ryusei Hamada
- K. Michał Szymański
- In-Gu Shin (ORCID: https://orcid.org/0000-0002-4355-9838)
- Greg Olmschenk (ORCID: https://orcid.org/0000-0001-8472-2219)
- M. Kiraga (ORCID: https://orcid.org/0000-0001-8045-9484)
- M. Jaroszyński (ORCID: https://orcid.org/0000-0001-9187-7761)
- Yuki Hirao (ORCID: https://orcid.org/0000-0003-4776-8618)
- Y. Matsubara (ORCID: https://orcid.org/0000-0002-9629-4810)
- S. Kozłowski (ORCID: https://orcid.org/0000-0003-4084-880X)
- Marcin Wrona (ORCID: https://orcid.org/0000-0002-3051-274X)
- Y. Muraki (ORCID: https://orcid.org/0000-0003-1978-2092)
- Kansuke Nunota (ORCID: https://orcid.org/0009-0005-3414-455X)
- W. Richard Pogge
- Dong-Jin Kim (ORCID: https://orcid.org/0000-0001-5828-6732)
- Aparna Bhattacharya (ORCID: https://orcid.org/0009-0007-3522-541X)
- Andrzej Krzysztof Rybicki
- Sang-Mok Cha
- Youn Kil Jung
- Daisuke Suzuki
- Sun-Ju Chung
- Fumio Abe
- C. Jennifer Yee
- P. D. Bennett
- Andrew Gould
- Doeon Kim
- J. Nicholas Rattenbury
- J. Mateusz Mróz
- D. Leading authors Michael Albrow
- K. Sean Terry
Publication Details
- Journal
- Astronomy and Astrophysics
- Published
- 2025-08-29
- DOI
- https://doi.org/10.1051/0004-6361/202555200
- Citations
- 1
- Primary Topic
- Advanced optical system design
- Type
- article
- Field-Weighted Citation Impact
- 0.67