activity
20052026
most citedVISTA Variables in the Via Lactea (VVV): The public ESO near-IR variability survey of the Milky Way

1k citations · 10.1k across the 321 of their papers we have counts for

collaborators

345 papers

astro-ph.EP2026

Two Low-Mass-Ratio Microlensing Planets from High-Magnification Events: KMT-2021-BLG-0247 and MOA-2023-BLG-169

Kansuke Nunota, Andrew Gould, Takahiro Sumi +56

We present an analysis of two planetary microlensing events, KMT-2021-BLG-0247 and MOA-2023-BLG-169, both of which exhibit high magnifications and low planet--host mass ratios, but…

astro-ph.SR2026

A Search For Stellar-mass Black Holes Via Astrometric Microlensing II: 2012-2015 Keck Candidates

Mace J. Huston, Jessica R. Lu, Casey Y. Lam +58

The Milky Way is expected to host 10 stellar-mass black holes with an uncertain binary fraction. The only proven method to detect isolated stellar mass black holes is gra…

astro-ph.EP2026

KMT-2026-BLG-0083L: A Two-Jovian-Planet System Orbiting an M Dwarf Discovered by Microlensing

Cheongho Han, Chung-Uk Lee, Zhixing Li +65

We present the analysis of the microlensing event KMT-2026-BLG-0083, which was independently detected by the KMTNet, OGLE, and PRIME surveys and also monitored by the DREAMS survey…

astro-ph.EP2026

KMT-2025-BLG-0975Lb and KMT-2025-BLG-1160Lb: Two Uranus-Mass Planets Beyond the Snow Line Discovered by Microlensing

Cheongho Han, Chung-Uk Lee, Andrzej Udalski +27

We present the analysis of two planetary microlensing events, KMT-2025-BLG-0975 and KMT-2025-BLG-1160, discovered during the 2025 Galactic bulge microlensing season through high-ca…

astro-ph.EP2026

Four Cold Giant Planets Discovered by High-Cadence Microlensing Surveys

Cheongho Han, Chung-Uk Lee, Andrzej Udalski +52

We report the discovery of four cold giant planets identified through the analysis of microlensing events detected by high-cadence surveys: OGLE-2016-BLG-0261, KMT-2025-BLG-0026, K…

astro-ph.SR2026

Incorporating physical source parameters into microlensing modeling

Mateusz J. Mróz, Radosław Poleski, Andrzej Udalski +14

Modeling of complex microlensing events suffers from many difficult-to-disentangle degeneracies. This is especially the case for orbital motion of the source in a binary system, th…

astro-ph.SR2026

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…

astro-ph.SR2026

Thirty Circumbinary Disk Occultation Systems (KH 15D-like stars) from the OGLE Project

M. A. Urbanowicz, I. Soszyński, P. Pietrukowicz +14

We present a catalog of 30 stars that are candidates for KH 15D-like binary systems, in which the observed brightness variations are caused by a circumbinary dusty disk that period…

astro-ph.EP2026

Mass Production of 2023 KMTNet Microlensing Planets. III: Three Planets from the Subprime Field

Hongyu Li, Zhixing Li, Weicheng Zang +56

To complete the analysis of the 2023 KMTNet subprime-field microlensing planetary events identified by its AlertFinder system, we present the analysis of six events, KMT-2023-BLG-(…

astro-ph.SR2026

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…

astro-ph.EP2026

Mass Production of 2023 KMTNet Microlensing Planets. II: Two Planets and A Brown Dwarf

Zhixing Li, Hongyu Li, Weicheng Zang +63

To expand the homogeneous microlensing planetary sample of the Korea Microlensing Telescope Network (KMTNet), we investigate six planetary candidates identified by the AnomalyFinde…

astro-ph.EP2026

Mass Production of 2023 KMTNet Microlensing Planets I: Low Mass Ratio

Yoon-Hyun Ryu, Andrzej Udalski, Hongjing Yang +34

We initiate the systematic search for planets in the 2023 data of the Korea Microlensing Telescope Network (KMTNet), focusing on those planets found by the KMTNet AnomalyFinder wit…

astro-ph.EP2026

Two Low Mass-Ratio Microlensing Planets and Two Types of Central-Resonant Degeneracy

Yuchen Tang, Weicheng Zang, Yoon-Hyun Ryu +39

We present observations and analysis of two low planet/host mass-ratio () microlensing planets discovered in high-magnification events. KMT-2025-BLG-0811Lb has $q \sim 4.5 \time…

astro-ph.EP2026

Three Saturn-mass Microlensing Planets Identified through Signals from Peripheral-caustic Perturbations

Cheongho Han, Chung-Uk Lee, Andrzej Udalski +63

We present the discovery and analysis of three microlensing planets identified through brief positive anomalies on the wings of their light curves. The events, KMT-2021-BLG-0852, K…

astro-ph.EP2026

KMT-2016-BLG-1337L: A Saturn-mass planet orbiting within a binary system of low-mass stars

Cheongho Han, Chung-Uk Lee, Ian A. Bond +55

We report the discovery and characterization of a planetary companion in the microlensing event KMT-2016-BLG-1337, which was produced by a binary system of low-mass stars. The ligh…

astro-ph.EP2026

A Newly Identified Degeneracy Keeps the Planetary Interpretation Viable for OGLE-2011-BLG-0950

Jiyuan Zhang, Weicheng Zang, Andrzej Udalski +12

The microlensing event OGLE-2011-BLG-0950 exhibits the well-known ``Planet/Binary'' degeneracy, in which distinct lens configurations produce similar light curves but imply substan…

astro-ph.EP2026

KMT-2024-BLG-0816/OGLE-2024-BLG-0519 -- A Microlensing Event with Candidate Free-Floating Planet Lens and Blended Light

R. Poleski, Y. -H. Ryu, A. Udalski +27

We present the discovery of a free-floating planet microlensing event KMT-2024-BLG-0816. The event shows finite-source effect, significant blending light, and no microlensing signa…

astro-ph.EP2025★ 6 cited

A free-floating-planet microlensing event caused by a Saturn-mass object

Subo Dong, Zexuan Wu, Yoon-Hyun Ryu +39

A population of free-floating planets is known from gravitational microlensing surveys. None have a directly measured mass, owing to a degeneracy with the distance, but the populat…

astro-ph.EP2025

Four Giant Planets from 2024 KMTNet Microlensing Campaign

Cheongho Han, Andrzej Udalski, Ian A. Bond +56

In this work, we present analyses of four newly discovered planetary microlensing events from the 2024 KMTNet survey season: KMT-2024-BLG-0176, KMT-2024-BLG-0349, KMT-2024-BLG-1870…

astro-ph.SR2025

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…

astro-ph.SR2025

Doubling the Number of Blue Large-Amplitude Pulsators: Final Results of Searches for BLAPs in the OGLE Inner Galactic Bulge Fields

J. Borowicz, P. Pietrukowicz, J. Skowron +13

Blue Large-Amplitude Pulsators (BLAPs) are rare short-period (80 min) pulsating variable stars exhibiting large-amplitude brightness variations (typically between 0.1 and…

astro-ph.CO2025

Eppur non si trovano: Comments on the Primordial Black Hole Limits in the Galactic Halo

P. Mróz, A. Udalski, M. K. Szymański +13

In a recent arXiv post, Hawkins & Garcia-Bellido raised doubts on the results of 20-yr long OGLE photometric monitoring, which did not find a large number of gravitational microlen…

astro-ph.EP2025

A Comprehensive Analysis of Three Microlensing Planet Candidates with the Planet/Binary Degeneracy

Jiyuan Zhang, Weicheng Zang, Yoon-Hyun Ryu +65

We present observations and analyses of three high-magnification microlensing events: KMT-2022-BLG-0954, KMT-2024-BLG-0697, and MOA-2024-BLG-018. All three exhibit the "Planet/Bina…

astro-ph.SR2025

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…