235 citations · 4.7k across the 242 of their papers we have counts for
54 papers · 1 filter
Four-Body Gravitational Microlensing Events Involving Both a Binary Lens and a Binary Source
Cheongho Han, Chung-Uk Lee, Andrzej Udalski +31
We present detailed analyses of three anomalous microlensing events--KMT-2021-BLG-0209, KMT-2021-BLG-0901, and OGLE-2025-BLG-0356--identified from a systematic re-examination of KM…
The ZTF-ULTRASAT experiment: Characterizing the non-transients in ULTRASAT's high cadence survey
Daniel Warshofsky, Michael W. Coughlin, Theophile Jegou Du Laz +16
The forthcoming launch of the Ultraviolet Transient Astronomy Satellite (ULTRASAT) will transform our understanding of the transient ultraviolet sky by increasing our ability to id…
Candidate Microlensing Brown Dwarfs in Binary Lens Systems from the 2023--2025 Observing Seasons
Cheongho Han, Andrzej Udalski, Ian A. Bond +62
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…
Six binary brown dwarf candidates identified by microlensing
Cheongho Han, Chung-Uk Lee, Ian A. Bond +57
In this study, we analyze microlensing events from the 2023 and 2024 observing seasons to identify cases likely caused by binary systems composed of BDs. By applying criteria that…
Three binary-source binary-lens microlensing events from the 2024 microlensing campaign
Cheongho Han, Chung-Uk Lee, Andrzej Udalski +27
We investigated microlensing events detected by the OGLE and KMTNet surveys during the 2024 observing season, focusing on those that exhibit very complex anomaly features. Through…
KMT-2022-BLG-0086: Another binary-lens binary-source microlensing event
Sun-Ju Chung, Kyu-Ha Hwang, Jennifer C. Yee +40
We present the analysis of a microlensing event KMT-2022-BLG-0086 of which the overall light curve is not described by a binary-lens single-source (2L1S) model, which suggests the…
Analyses of anomalous lensing events detected from the UKIRT microlensing survey
Cheongho Han, Weicheng Zang, Andrzej Udalski +61
The United Kingdom Infrared Telescope (UKIRT) microlensing survey was conducted over four years, from 2016 to 2019, with the goal of serving as a precursor to future near-infrared…
KMT-2021-BLG-0284, KMT-2022-BLG-2480, and KMT-2024-BLG-0412: Three microlensing events involving two lens masses and two source stars
Cheongho Han, Andrzej Udalski, Ian A. Bond +59
We carried out a project involving the systematic analysis of microlensing data from the Korea Microlensing Telescope Network survey. The aim of this project is to identify lensing…
Microlensing brown-dwarf companions in binaries detected during the 2022 and 2023 seasons
Cheongho Han, Ian A. Bond, Andrzej Udalski +63
Building on previous works to construct a homogeneous sample of brown dwarfs in binary systems, we investigate microlensing events detected by the Korea Microlensing Telescope Netw…
OGLE-2018-BLG-0971, MOA-2023-BLG-065, and OGLE-2023-BLG-0136: Microlensing events with prominent orbital effects
Cheongho Han, Andrzej Udalski, Ian A. Bond +60
We undertake a project to reexamine microlensing data gathered from high-cadence surveys. The aim of the project is to reinvestigate lensing events with light curves exhibiting int…
OGLE-2015-BLG-0845L: A low-mass M dwarf from the microlensing parallax and xallarap effects
Zhecheng Hu, Wei Zhu, Andrew Gould +51
We present the analysis of the microlensing event OGLE-2015-BLG-0845, which was affected by both the microlensing parallax and xallarap effects. The former was detected via the sim…
Brown dwarf companions in binaries detected from the 2021 season high-cadence microlensing surveys
Cheongho Han, Youn Kil Jung, Ian A. Bond +45
As a part of the project aiming to build a homogeneous sample of binary-lens (2L1S) events containing brown-dwarf (BD) companions, we investigate the 2021 season microlensing data…
Probable brown dwarf companions detected in binary microlensing events during the 2018-2020 seasons of the KMTNet survey
Cheongho Han, Youn Kil Jung, Doeon Kim +48
We inspect the microlensing data of the KMTNet survey collected during the 2018--2020 seasons in order to find lensing events produced by binaries with brown-dwarf companions. In o…
OGLE-2017-BLG-1038: A Possible Brown-dwarf Binary Revealed by Spitzer Microlensing Parallax
Amber Malpas, Michael D. Albrow, Jennifer C. Yee +41
We report the analysis of microlensing event OGLE-2017-BLG-1038, observed by the Optical Gravitational Lensing Experiment, Korean Microlensing Telescope Network, and Spitzer telesc…
KMT-2021-BLG-1122L: The first microlensing triple stellar system
Cheongho Han, Youn Kil Jung, Andrew Gould +19
We systematically inspect the microlensing data acquired by the KMTNet survey during the previous seasons in order to find anomalous lensing events for which the anomalies in the l…
OGLE-2018-BLG-0584 and KMT-2018-BLG-2119: two microlensing events with two lens masses and two source stars
Cheongho Han, Andrzej Udalski, Youn Kil Jung +34
We conduct a systematic investigation of the microlensing data collected during the previous observation seasons for the purpose of reanalyzing anomalous lensing events with no sug…
Brown-dwarf companions in microlensing binaries detected during the 2016--2018 seasons
Cheongho Han, Yoon-Hyun Ryu, In-Gu Shin +60
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…
Precision measurement of a brown dwarf mass in a binary system in the microlensing event OGLE-2019-BLG-0033/MOA-2019-BLG-035
A. Herald, A. Udalski, V. Bozza +89
Context. Brown dwarfs are poorly understood transition objects between stars and planets, with several competing mechanisms having been proposed for their formation. Mass measureme…
An Isolated Stellar-Mass Black Hole Detected Through Astrometric Microlensing
Kailash C. Sahu, Jay Anderson, Stefano Casertano +90
We report the first unambiguous detection and mass measurement of an isolated stellar-mass black hole (BH). We used the Hubble Space Telescope (HST) to carry out precise astrometry…
Using Source Proper Motion to Validate Terrestrial Parallax: OGLE-2019-BLG-1058
In-Gu Shin, Jennifer C. Yee, Kyu-Ha Hwang +30
We show that because the conditions for producing terrestrial microlens parallax (TPRX; i.e., a nearby disk lens) will also tend to produce a large lens-source relative proper moti…
KMT-2019-BLG-0797: binary-lensing event occurring on a binary stellar system
Cheongho Han, Chung-Uk Lee, Yoon-Hyun Ryu +18
We analyze the microlensing event KMT-2019-BLG-0797. The light curve of the event exhibits two anomalous features from a single-lens single-source model, and we aim to reveal the n…
OGLE-2018-BLG-1269Lb: A Jovian Planet With A Bright, Host
Youn Kil Jung, Andrew Gould, Andrzej Udalski +54
We report the discovery of a planet in the microlensing event OGLE-2018-BLG-1269, with planet-host mass ratio , i.e., times smaller than the Jupiter/Su…
Candidate Brown-dwarf Microlensing Events with Very Short Timescales and Small Angular Einstein Radii
Cheongho Han, Chung-Uk Lee, Andrzej Udalski +62
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 $t…
Spitzer Microlensing parallax reveals two isolated stars in the Galactic bulge
Weicheng Zang, Yossi Shvartzvald, Tianshu Wang +90
We report the mass and distance measurements of two single-lens events from the 2017 Spitzer microlensing campaign. The ground-based observations yield the detection of finite-sour…