Publications (152)
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…
KMT-2021-BLG-2609Lb and KMT-2022-BLG-0303Lb: Microlensing planets identified through signals produced by major-image perturbations
Cheongho Han, Michael D. Albrow, Chung-Uk Lee +18
We investigate microlensing data collected by the Korea Microlensing Telescope Network (KMTNet) survey. Our investigation reveals that the light curves of two lensing events, KMT-2…
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…
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…
KMT-2023-BLG-1866Lb: Microlensing super-Earth around an M dwarf host
Cheongho Han, Ian A. Bond, Andrzej Udalski +64
We investigate the nature of the short-term anomaly that appears in the lensing light curve of KMT-2023-BLG-1866. The anomaly was only partly covered due to its short duration, les…
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…
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…
OGLE-2018-BLG-0532Lb: Cold Neptune With Possible Jovian Sibling
Yoon-Hyun Ryu, Andrzej Udalski, Jennifer C. Yee +34
We report the discovery of the planet OGLE-2018-BLG-0532Lb, with very obvious signatures in the light curve that lead to an estimate of the planet-host mass ratio $q=M_{\rm planet}…
Towards sub-milliarcsecond astrometric precision using seeing-limited imaging
Noam Segev, Eran O. Ofek, Yossi Shvartzvald +21
The Earth's atmospheric turbulence degrades the precision of ground-based astrometry. Here, we discuss these limitations and propose that, with proper treatment of systematics and…
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…
OGLE-2018-BLG-0567Lb and OGLE-2018-BLG-0962Lb: Two Microlensing Planets through Planetary-Caustic Channel
Youn Kil Jung, Cheongho Han, Andrzej Udalski +29
We present the analyses of two microlensing events, OGLE-2018-BLG-0567 and OGLE-2018-BLG-0962. In both events, the short-lasting anomalies were densely and continuously covered by…
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…
KMT-2021-BLG-0240: Microlensing event with a deformed planetary signal
Cheongho Han, Doeon Kim, Hongjing Yang +18
The light curve of the microlensing event KMT-2021-BLG-0240 exhibits a short-lasting anomaly with complex features near the peak at the 0.1~mag level from a single-lens single-sour…
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…
KMT-2021-BLG-1150Lb: Microlensing planet detected through a densely covered planetary-caustic signal
Cheongho Han, Youn Kil Jung, Ian A. Bond +49
Recently, there have been reports of various types of degeneracies in the interpretation of planetary signals induced by planetary caustics. In this work, we check whether such deg…
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-2018-BLG-1292: A Super-Jovian Microlens Planet in the Galactic Plane
Yoon-Hyun Ryu, Maria Gabriela Navarro, Andrew Gould +22
We report the discovery of KMT-2018-BLG-1292Lb, a super-Jovian planet orbiting an F or G dwarf , which lies p…
Systematic KMTNet Planetary Anomaly Search. V. Complete Sample of 2018 Prime-Field
Andrew Gould, Cheongho Han, Weicheng Zang +65
We complete the analysis of all 2018 prime-field microlensing planets identified by the KMTNet AnomalyFinder. Among the 10 previously unpublished events with clear planetary soluti…
KMT-2019-BLG-2073: Fourth Free-Floating-Planet Candidate with $θ_\rm E < 10 \rmμas$
Hyoun-Woo Kim, Kyu-Ha Hwang, Andrew Gould +17
We analyze the very short Einstein timescale ($t_\rm E \simeq 7\,{\rm hr}$) event KMT-2019-BLG-2073. Making use of the pronounced finite-source effects generated by the clump-giant…
Kepler K2 Campaign 9: II. First space-based discovery of an exoplanet using microlensing
D. Specht, R. Poleski, M. T. Penny +83
We present K2-2016-BLG-0005Lb, a densely sampled, planetary binary caustic-crossing microlensing event found from a blind search of data gathered from Campaign 9 of the Kepler K2 m…
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…
Mass Production of 2021 KMTNet Microlensing Planets I
Yoon-Hyun Ryu, Youn Kil Jung, Hongjing Yang +18
We inaugurate a program of ``mass production'' of microlensing planets discovered in 2021 KMTNet data, with the aim of laying the basis for future statistical studies. While we ult…
KMT-2018-BLG-1025Lb: microlensing super-Earth planet orbiting a low-mass star
Cheongho Han, Andrzej Udalski, Chung-Uk Lee +32
We aim to find missing microlensing planets hidden in the unanalyzed lensing events of previous survey data. For this purpose, we conduct a systematic inspection of high-magnificat…
MOA-2022-BLG-091Lb and KMT-2024-BLG-1209Lb: Microlensing planets detected through weak caustic-crossing signals
Cheongho Han, Chung-Uk Lee, Andrzej Udalski +66
The light curves of the microlensing events MOA-2022-BLG-091 and KMT-2024-BLG-1209 exhibit anomalies with very similar features. These anomalies appear near the peaks of the light…
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…
KMT-2022-BLG-0475Lb and KMT-2022-BLG-1480Lb: Microlensing ice giants detected via non-caustic-crossing channel
Cheongho Han, Chung-Uk Lee, Ian A. Bond +49
We investigate the microlensing data collected in the 2022 season from the high-cadence microlensing surveys in order to find weak signals produced by planetary companions to lense…
OGLE-2019-BLG-0825: Constraints on the Source System and Effect on Binary-lens Parameters arising from a Five Day Xallarap Effect in a Candidate Planetary Microlensing Event
Yuki K. Satoh, Naoki Koshimoto, David P. Bennett +86
We present an analysis of microlensing event OGLE-2019-BLG-0825. This event was identified as a planetary candidate by preliminary modeling. We find that significant residuals from…
KMT-2021-BLG-1547Lb: Giant microlensing planet detected through a signal deformed by source binarity
Cheongho Han, Weicheng Zang, Youn Kil Jung +52
We investigate the previous microlensing data collected by the KMTNet survey in search of anomalous events for which no precise interpretations of the anomalies have been suggested…
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…
KMT-2021-BLG-2010Lb, KMT-2022-BLG-0371Lb, and KMT-2022-BLG-1013Lb: Three microlensing planets detected via partially covered signals
Cheongho Han, Chung-Uk Lee, Weicheng Zang +25
We inspect 4 microlensing events KMT-2021-BLG-1968, KMT-2021-BLG-2010, KMT-2022-BLG-0371, and KMT-2022-BLG-1013, for which the light curves exhibit partially covered short-term cen…
KMT-2021-BLG-0912Lb: A microlensing super Earth around a K-type star
Cheongho Han, Ian A. Bond, Jennifer C. Yee +55
The light curve of the microlensing event KMT-2021-BLG-0912 exhibits a very short anomaly relative to a single-lens single-source form. We investigate the light curve for the purpo…
Systematic KMTNet Planetary Anomaly Search. XI. Complete Sample of 2016 Sub-Prime Field Planets
In-Gu Shin, Jennifer C. Yee, Weicheng Zang +63
Following Shin et al. (2023b), which is a part of the Systematic KMTNet Planetary Anomaly Search series (i.e., a search for planets in the 2016 KMTNet prime fields), we conduct a s…
OGLE-2023-BLG-0836L: The sixth microlensing planet in a binary stellar system
Cheongho Han, Andrzej Udalski, Youn Kil Jung +32
Light curves of microlensing events occasionally deviate from the smooth and symmetric form of a single-lens single-source event. While most of these anomalous events can be accoun…
MOA-2019-BLG-008Lb: a new microlensing detection of an object at the planet/brown dwarf boundary
E. Bachelet, Y. Tsapras, Andrew Gould +68
We report on the observations, analysis and interpretation of the microlensing event MOA-2019- BLG-008. The observed anomaly in the photometric light curve is best described throug…
Shortest Microlensing Event with a Bound Planet: KMT-2016-BLG-2605
Yoon-Hyun Ryu, Kyu-Ha Hwang, Andrew Gould +17
KMT-2016-BLG-2605, with planet-host mass ratio , has the shortest Einstein timescale, $t_\e = 3.41\pm 0.13\,$days, of any planetary microlensing event to date. Th…
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…
KMT-2022-BLG-2397: Brown Dwarf at the Upper Shore of the Einstein Desert
Andrew Gould, Yoon-Hyun Ryu, Jennifer C. Yee +17
We measure the Einstein radius of the single-lens microlensing event KMT-2022-BLG-2397 to be theta_E=24.8 +- 3.6 uas, placing it at the upper shore of the Einstein Desert, 9 < thet…
Reevaluating of the feasibility of ground-based earth-mass microlensing planet detections
Youn Kil Jung, Hyuk Park, Cheongho Han +3
One important strength of the microlensing method in detecting extrasolar planets is its high sensitivity to low-mass planets. However, it is often believed that microlensing detec…
OGLE-2015-BLG-1771Lb: A Microlens Planet Orbiting an Ultracool Dwarf?
Xiangyu Zhang, Weicheng Zang, Andrzej Udalski +31
We report the discovery and the analysis of the short (tE < 5 days) planetary microlensing event, OGLE-2015-BLG-1771. The event was discovered by the Optical Gravitational Lensing…
Four microlensing giant planets detected through signals produced by minor-image perturbations
Cheongho Han, Ian A. Bond, Chung-Uk Lee +63
We investigated the nature of the anomalies appearing in four microlensing events KMT-2020-BLG-0757, KMT-2022-BLG-0732, KMT-2022-BLG-1787, and KMT-2022-BLG-1852. The light curves o…
OGLE-2019-BLG-0468Lb,c: two microlensing giant planets around a G-type star
Cheongho Han, Andrzej Udalski, Chung-Uk Lee +37
With the aim of interpreting anomalous lensing events with no suggested models, we conducted a project of reinvestigating microlensing data in and before the 2019 season. In this w…
MOA-2020-BLG-208Lb: Cool Sub-Saturn Planet Within Predicted Desert
Greg Olmschenk, David P. Bennett, Ian A. Bond +74
We analyze the MOA-2020-BLG-208 gravitational microlensing event and present the discovery and characterization of a new planet, MOA-2020-BLG-208Lb, with an estimated sub-Saturn ma…
KMT-2016-BLG-1107: A New Hollywood-Planet Close/Wide Degeneracy
Kyu-Ha Hwang, Yoon-Hyun Ryu, Hyoun-Woo Kim +17
We show that microlensing event KMT-2016-BLG-1107 displays a new type of degeneracy between wide-binary and close-binary Hollywood events in which a giant-star source envelops the…
Systematic KMTNet Planetary Anomaly Search, Paper I: OGLE-2019-BLG-1053Lb, A Buried Terrestrial Planet
Weicheng Zang, Kyu-Ha Hwang, Andrzej Udalski +69
In order to exhume the buried signatures of "missing planetary caustics" in the KMTNet data, we conducted a systematic anomaly search to the residuals from point-source point-lens…
Microlensing Parallax for OGLE-2017-BLG-0896 Reveals a Counter-Rotating Low-Mass Brown Dwarf
Yossi Shvartzvald, Jennifer C. Yee, Jan Skowron +63
The kinematics of isolated brown dwarfs in the Galaxy, beyond the solar neighborhood, is virtually unknown. Microlensing has the potential to probe this hidden population, as it ca…
KMT-2021-BLG-1077L: The fifth confirmed multiplanetary system detected by microlensing
Cheongho Han, Andrew Gould, Ian A. Bond +45
The high-magnification microlensing event KMT-2021-BLG-1077 exhibits a subtle and complex anomaly pattern in the region around the peak. We analyze the lensing light curve of the e…
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…
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…
Detections of Planets in Binaries Through the Channel of Chang-Refsdal Gravitational Lensing Events
Cheongho Han, In-Gu Shin, Youn Kil Jung
Chang-Refsdal (C-R) lensing, which refers to the gravitational lensing of a point mass perturbed by a constant external shear, provides a good approximation in describing lensing b…
KMT-2022-BLG-1818Lb,c: A Cold Super-Jupiter with a Saturn Sibling
Hongyu Li, Jiyuan Zhang, Cheongho Han +72
We present the discovery and analysis of the sixth microlensing two-planet system, KMT-2022-BLG-1818Lb,c, detected by a follow-up program targeting high-magnification events. Both…
KMT-2024-BLG-0404L: A triple microlensing system consisting of a star, a brown dwarf, and a planet
Cheongho Han, Andrzej Udalski, Chung-Uk Lee +29
We have investigated the lensing event KMT-2024-BLG-0404. The light curve of the event exhibited a complex structure with multiple distinct features, including two prominent causti…
Systematic Reanalysis of KMTNet microlensing events, Paper I: Updates of the Photometry Pipeline and a New Planet Candidate
Hongjing Yang, Jennifer C. Yee, Kyu-Ha Hwang +52
In this work, we update and develop algorithms for KMTNet tender-love care (TLC) photometry in order to create an new, mostly automated, TLC pipeline. We then start a project to sy…
KMT-2017-BLG-0673Lb and KMT-2019-BLG-0414Lb: Two microlensing planets detected in peripheral fields of KMTNet survey
Cheongho Han, Chung-Uk Lee, Andrew Gould +18
We investigate the microlensing data collected during the 2017--2019 seasons in the peripheral Galactic bulge fields with the aim of finding planetary signals in microlensing light…
MOA-2022-BLG-563Lb, KMT-2023-BLG-0469Lb, and KMT-2023-BLG-0735Lb: Three sub-Jovian-mass microlensing planets
Cheongho Han, Youn Kil Jung, Ian A. Bond +45
We analyze the anomalies appearing in the light curves of the three microlensing events MOA-2022-BLG-563, KMT-2023-BLG-0469, and KMT-2023-BLG-0735. The anomalies exhibit common sho…
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…
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…
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…
KMT-2019-BLG-1715: planetary microlensing event with three lens masses and two source stars
Cheongho Han, Andrzej Udalski, Doeone Kim +61
We investigate the gravitational microlensing event KMT-2019-BLG-1715, of which light curve shows two short-term anomalies from a caustic-crossing binary-lensing light curve: one w…
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…
KMT-2021-BLG-0322: Severe degeneracy between triple-lens and higher-order binary-lens interpretations
Cheongho Han, Andrew Gould, Yuki Hirao +46
We investigate the microlensing event KMT-2021-BLG-0322, for which the light curve exhibits three distinctive sets of caustic-crossing features. It is found that the overall featur…
MOA-2016-BLG-319Lb: Microlensing Planet Subject to Rare Minor-Image Perturbation Degeneracy in Determining Planet Parameter
Cheongho Han, Ian A. Bond, Andrew Gould +42
We present the analysis of the planetary microlensing event MOA-2016-BLG-319. The event light curve is characterized by a brief ( days) anomaly near the peak produced by mi…
Four binary microlenses with directly measured masses
Cheongho Han, Andrzej Udalski, Chung-Uk Lee +58
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 feature…
Free-Floating Planets, the Einstein Desert, and 'Oumuamua
Andrew Gould, Youn Kil Jung, Kyu-Ha Hwang +18
We complete the survey for finite-source/point-lens (FSPL) giant-source events in 2016-2019 KMTNet microlensing data. The 30 FSPL events show a clear gap in Einstein radius, $9\,μ…
Systematic KMTNet Planetary Anomaly Search, Paper VII: Complete Sample of Planets from the First Four-Year Survey
Weicheng Zang, Youn Kil Jung, Hongjing Yang +36
We present the analysis of seven microlensing planetary events with planet/host mass ratios : KMT-2017-BLG-1194, KMT-2017-BLG-0428, KMT-2019-BLG-1806, KMT-2017-BLG-100…
Systematic Reanalysis of KMTNet Microlensing Events, Paper II: Two New Planets in Giant-Source Events
Hongjing Yang, Jennifer C. Yee, Jiyuan Zhang +61
In this work, we continue to apply the updated KMTNet tender-love care (TLC) photometric pipeline to historical microlensing events. We apply the pipeline to a subsample of events…
HST pre-imaging of a free-floating planet candidate microlensing event
Mateusz Kapusta, Przemek Mroz, Yoon-Hyun Ryu +33
High-cadence microlensing observations uncovered a population of very short-timescale microlensing events, which are believed to be caused by the population of free-floating planet…
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…
Four sub-Jovian-mass planets detected by high-cadence microlensing surveys
Cheongho Han, Doeon Kim, Andrew Gould +57
With the aim of finding short-term planetary signals, we investigated the data collected from the high-cadence microlensing surveys. From this investigation, we found four planetar…
An Earth-mass Planet in a Time of Covid-19: KMT-2020-BLG-0414Lb
Weicheng Zang, Cheongho Han, Iona Kondo +56
We report the discovery of KMT-2020-BLG-0414Lb, with a planet-to-host mass ratio ---- at , which is the lowest mass-ratio micr…
OGLE-2019-BLG-0304: Competing Interpretations between a Planet-binary Model and a Binary-source + Binary-lens model
Cheongho Han, Andrzej Udalski, Chung-Uk Lee +31
We analyze the microlensing event OGLE-2019-BLG-0304, whose light curve exhibits two distinctive features: a deviation in the peak region and a second bump appearing ~days…
KMT-2019-BLG-1339L: an M Dwarf with a Giant Planet or a Companion Near the Planet/Brown Dwarf Boundary
Cheongho Han, Doeon Kim, Andrzej Udalski +31
We analyze KMT-2019-BLG-1339, a microlensing event with an obvious but incompletely resolved brief anomaly feature around the peak of the light curve. Although the origin of the an…
Parallax of OGLE-2018-BLG-0596: A Low-mass-ratio Planet around an M-dwarf
Youn Kil Jung, Andrew Gould, Andrzej Udalski +63
We report the discovery of a microlensing planet OGLE-2018-BLG-0596Lb, with preferred planet-host mass ratio . The planetary signal, which is chara…
Systematic Search for FFPs in KMTNet Full-Frame Images. I. Photometry Pipeline
Qiyue Qian, Hongjing Yang, Weicheng Zang +22
To exhume the buried signatures of free-floating planets (FFPs) with small angular Einstein radius , we build a new full-frame difference image pipeline for the Korean…
KMT-2016-BLG-2052L: Microlensing Binary Composed of M Dwarfs Revealed from a Very Long Time-scale Event
Cheongho Han, Youn Kil Jung, Yossi Shvartzvald +26
We present the analysis of a binary microlensing event KMT-2016-BLG-2052, for which the lensing-induced brightening of the source star lasted for 2 seasons. We determine the lens m…
Three microlensing planets with no caustic-crossing features
Cheongho Han, Andrzej Udalski, Doeon Kim +31
We search for microlensing planets with signals exhibiting no caustic-crossing features, considering the possibility that such signals may be missed due to their weak and featurele…
MOA-2022-BLG-249Lb: Nearby microlensing super-Earth planet detected from high-cadence surveys
Cheongho Han, Andrew Gould, Youn Kil Jung +51
We investigate the data collected by the high-cadence microlensing surveys during the 2022 season in search for planetary signals appearing in the light curves of microlensing even…
KMT-2021-BLG-1898: Planetary microlensing event involved with binary source stars
Cheongho Han, Andrew Gould, Doeon Kim +17
The light curve of the microlensing event KMT-2021-BLG-1898 exhibits a short-term central anomaly with double-bump features that cannot be explained by the usual binary-lens or bin…
OGLE-2017-BLG-1049: Another giant planet microlensing event
Yun Hak Kim, Sun-Ju Chung, A. Udalski +55
We report a giant exoplanet discovery in the microlensing event OGLE-2017-BLG-1049, which is a planet-host star mass ratio of and has a caustic crossin…
OGLE-2018-BLG-1700L: Microlensing Planet in Binary Stellar System
Cheongho Han, Chung-Uk Lee, Andrzej Udalski +58
We report the discovery of a planet in a binary that was discovered from the analysis of the microlensing event OGLE-2018-BLG-1700. We identify the triple nature of the lens from t…
Systematic KMTNet Planetary Anomaly Search, Paper III: One Wide-Orbit Planet And Two Stellar Binaries
Hanyue Wang, Weicheng Zang, Wei Zhu +36
Only a few wide-orbit planets around old stars have been detected, which limits our statistical understanding of this planet population. Following the systematic search for planeta…
OGLE-2016-BLG-0156: Microlensing Event With Pronounced Microlens-Parallax Effects Yielding Precise Lens Mass Measurement
Youn Kil Jung, Cheongho Han, Ian A. Bond +53
We analyze the gravitational binary-lensing event OGLE-2016-BLG-0156, for which the lensing light curve displays pronounced deviations induced by microlens-parallax effects. The li…
Analysis of the full Spitzer microlensing sample I: Dark remnant candidates and Gaia predictions
Krzysztof A. Rybicki, Yossi Shvartzvald, Jennifer C. Yee +70
In the pursuit of understanding the population of stellar remnants within the Milky Way, we analyze the sample of microlensing events observed by the Spitzer Space Teles…
OGLE-2019-BLG-0362Lb: A super-Jovian-mass planet around a low-mass star
Sun-Ju Chung, Jennifer C. Yee, Andrej Udalski +28
We present the analysis of a planetary microlensing event OGLE-2019-BLG-0362 with a short-duration anomaly near the peak of the light curve, which is caused…
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…
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…
Mass Production of 2021 KMTNet Microlensing Planets II
Yoon-Hyun Ryu, In-Gu Shin, Hongjing Yang +18
We continue our program of publishing all planets (and possible planets) found by eye in 2021 Korea Microlensing Telescope Network (KMTNet) online data. We present 4 planets, (KMT-…
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'' (…
KMT-2018-BLG-1988Lb: microlensing super-Earth orbiting a low-mass disk dwarf
Cheongho Han, Andrew Gould, Michael D. Albrow +20
We reexamine high-magnification microlensing events in the previous data collected by the KMTNet survey with the aim of finding planetary signals that were not noticed before. In t…
OGLE-2015-BLG-1670Lb: A Cold Neptune beyond the Snow Line in the Provisional WFIRST Microlensing Survey Field
Clément Ranc, David P. Bennett, Yuki Hirao +56
We present the analysis of the microlensing event OGLE-2015-BLG-1670, detected in a high-extinction field, very close to the Galactic plane. Due to the dust extinction along the li…
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…
KMT-2018-BLG-1743: Planetary Microlensing Event Occurring on Two Source Stars
Cheongho Han, Michael D. Albrow, Sun-Ju Chung +18
We present the analysis of the microlensing event KMT-2018-BLG-1743. The light curve of the event, with a peak magnification , exhibits two anomaly features,…
OGLE-2017-BLG-0448Lb: A Low Mass-Ratio Wide-Orbit Microlensing Planet?
Ruocheng Zhai, RadosÅaw Poleski, Weicheng Zang +38
The gravitational microlensing technique is most sensitive to planets in a Jupiter-like orbit and has detected more than 200 planets. However, only a few wide-orbit () micro…
KMT-2018-BLG-0029Lb: A Very Low Mass-Ratio Spitzer Microlens Planet
Andrew Gould, Yoon-Hyun Ryu, Sebastiano Calchi Novati +29
At , KMT-2018-BLG-0029Lb has the lowest planet-host mass ratio of any microlensing planet to date by more than a factor of two. Hence, it is the…
OGLE-2019-BLG-1180Lb: Discovery of a Wide-orbit Jupiter-mass Planet around a Late-type Star
Sun-Ju Chung, Andrzej Udalski, Jennifer C. Yee +30
We report on the discovery and analysis of the planetary microlensing event OGLE-2019-BLG-1180 with a planet-to-star mass ratio . The event OGLE-2019-BLG-1180 has una…
KMT-2017-BLG-2820 and the Nature of the Free-Floating Planet Population
Yoon-Hyun Ryu, Przemek Mróz, Andrew Gould +28
We report a new free-floating planet (FFP) candidate, KMT-2017-BLG-2820, with Einstein radius $θ_\e\simeq 6\,\muas$, lens-source relative proper motion $μ_\rel \simeq 8\,\masyr$,…
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…
The Korea Microlensing Telescope Network (KMTNet) Alert Algorithm and Alert System
Hyoun-Woo Kim, Kyu-Ha Hwang, Yossi Shvartzvald +17
We describe a new microlensing-event alert algorithm that is tailored to the Korea Microlensing Telescope Network (KMTNet) multi-observatory system. The algorithm focuses on detect…
Spitzer Microlensing of MOA-2016-BLG-231L : A Counter-Rotating Brown Dwarf Binary in the Galactic Disk
Sun-Ju Chung, Andrew Gould, Jan Skowron +60
We analyze the binary microlensing event MOA-2016-BLG-231, which was observed from the ground and from Spitzer. The lens is composed of very low-mass brown dwarfs (BDs) with $M_1 =…
KMT-2019-BLG-0842Lb: A Cold Planet Below the Uranus/Sun Mass Ratio
Youn Kil Jung, Andrzej Udalski, Weicheng Zang +59
We report the discovery of a cold planet with a very low planet/host mass ratio of , which is similar to the ratio of Uranus/Sun ($q=4.37 \times 10^…
KMT-2021-BLG-0171Lb and KMT-2021-BLG-1689Lb: Two Microlensing Planets in the KMTNet High-cadence Fields with Followup Observations
Hongjing Yang, Weicheng Zang, Andrew Gould +56
Follow-up observations of high-magnification gravitational microlensing events can fully exploit their intrinsic sensitivity to detect extrasolar planets, especially those with sma…