activity
19982026
most citedFirst Sagittarius A* Event Horizon Telescope Results. I. The Shadow of the Supermassive Black Hole in the Center of the Milky Way

1.9k citations · 6k across the 173 of their papers we have counts for

collaborators

183 papers

astro-ph.GA2026

Testing KMTNet--PRIME Optical--Near-Infrared Source-Color Constraints in KMT-2024-BLG-0211 and KMT-2024-BLG-1522

Kansuke Nunota, Jennifer C. Yee, Takahiro Sumi +37

We present analyses of two 2024 microlensing events, KMT-2024-BLG-0211 and KMT-2024-BLG-1522, jointly observed by KMTNet in the optical and PRIME in the near-infrared. For KMT-2024…

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.EP2026

KMT-2025-BLG-2093: Free-Floating Planet Candidate Near the Shore of the Einstein Desert

Yoon-Hyun Ryu, Andrew Gould, Kyu-Ha Hwang +16

We analyze KMT-2025-BLG-2093, with angular Einstein radius , which makes it the second isolated microlens that lies in the ``Einstein Desert'' ($9…

astro-ph.EP2026

Measuring Asteroid Rotation Periods Using the KMTNet Bulge Survey Data

Haitao Huang, Hongjing Yang, Chung-Uk Lee +6

Since 2015, the Korea Microlensing Telescope Network (KMTNet) has conducted high-cadence, near-continuous observations of the Galactic bulge for nearly nine months each year from t…

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.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.EP2026

Systematic KMTNet Planetary Anomaly Search. XIII. Complete Sample of 2021 Prime Field Planets

In-Gu Shin, Jennifer C. Yee, Weicheng Zang +39

The Systematic KMTNet Planetary Anomaly Search series was conducted using the KMTNet data archived from to . From this first phase of the series, we reported a total o…

astro-ph.IM2026

KMTNet Synoptic Survey of Southern Sky III: The First Data Release

Seo-Won Chang, Myungshin Im, Mankeun Jeong +13

We present the first public data release (DR1) of the KMTNet Synoptic Survey of Southern Sky (KS4). This deep, wide-field imaging survey covers a southern footprint of -85$^{\circ}…

astro-ph.IM2026

KMTNet Synoptic Survey of Southern Sky II: Data Reduction and Real-Time Transient Detection Pipeline

Mankeun Jeong, Myungshin Im, Joonho Kim +9

We present a comprehensive pipeline developed for the image processing of the KMTNet Synoptic Survey of the Southern Sky (KS4) Data Release 1. This pipeline encompasses several key…

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

KMT-2025-BLG-1314 and KMT-2025-BLG-1392: two microlensing planetary/brown-dwarf candidates analyzed with differentiable code

Haibin Ren, Weicheng Zang, Wei Zhu +20

Analysis of binary-lens microlensing events typically requires intensive computation because of the multimodal and complex posterior distributions. With the recent development of t…

astro-ph.EP2026

KMT-2024-BLG-3237: Another Free-Floating Planet Candidate with Angular Einstein Radius Measurement

Tanagodchaporn Inyanya, Youn Kil Jung, Hongjing Yang +13

Planet formation theories suggest the presence of free-floating planets (FFPs) that are ejected from their formation sites. While these planets emit very little light, they can be…

astro-ph.EP2026

Four Cold Super-Jupiters Revealed by Extended and Complex Microlensing Signals

Cheongho Han, Chung-Uk Lee, Michael D. Albrow +18

We present the analysis of four microlensing events, KMT-2020-BLG-0202, KMT-2022-BLG-1551, KMT-2023-BLG-0466, and KMT-2025-BLG-0121, which exhibit extended and complex anomalies in…

astro-ph.EP2026★ 3 cited

KMT-2025-BLG-1616Lb: First Microlensing Bound Planet From DREAMS

Hongjing Yang, Weicheng Zang, Yoon-Hyun Ryu +60

We present observations and analysis of the bound planetary microlensing event KMT-2025-BLG-1616. The planetary signal was captured by the Korea Microlensing Telescope Network (KMT…

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.SR2025★ 1 cited

RR Lyrae stars with variable mean magnitudes

Gergely Hajdu, Johanna Jurcsik, Márcio Catelan +6

Context. A number of RR Lyrae stars show variable mean magnitudes in the OGLE survey light curves of the Galactic bulge. Hitherto this phenomenon was not studied, as it was general…

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.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…

astro-ph.EP2025

Six microlensing planets detected via sub-day signals during the 2023 -- 2024 season

Cheongho Han, Chung-Uk Lee, Andrzej Udalski +58

We present analyses of six microlensing events: KMT-2023-BLG-0548, KMT-2023-BLG-0830, KMT-2023-BLG-0949, KMT-2024-BLG-1281, KMT-2024-BLG-2059, and KMT-2024-BLG-2242. These were ide…