DongJoo Lee
A5046824926- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Adaptive optics and wavefront sensing
- Gamma-ray bursts and supernovae
- Scheduling and Optimization Algorithms
- Astrophysics and Star Formation Studies
- Mechanical Engineering and Vibrations Research
- Heat Transfer Mechanisms
- Innovations in Concrete and Construction Materials
- Advanced Manufacturing and Logistics Optimization
- Scheduling and Timetabling Solutions
- Assembly Line Balancing Optimization
- Customer Service Quality and Loyalty
- Metaheuristic Optimization Algorithms Research
- Engineering Applied Research
- Structural Behavior of Reinforced Concrete
- Natural Fiber Reinforced Composites
- Consumer Perception and Purchasing Behavior
- Technology Adoption and User Behaviour
- Solar and Space Plasma Dynamics
- Astro and Planetary Science
- Heat Transfer and Optimization
Korea Astronomy and Space Science Institute
2022-2025
Hanyang University
2007
ABSTRACT We report the complete statistical planetary sample from prime fields (Γ ≥ 2 h−1) of 2019 Korea Microlensing Telescope Network (KMTNet) microlensing survey. develop optimized KMTNet AnomalyFinder algorithm and apply it to fields. find a total 13 homogeneously selected planets analysis three events, KMT-2019-BLG-(1042,1552,2974). The planet–host mass ratios, q, for events are 6.34 × 10−4, 4.89 10−3, 6.18 respectively. A Bayesian indicates all cold giant beyond snow line their host...
ABSTRACT In this work, we update and develop algorithms for KMTNet tender-love care (TLC) photometry in order to create a new, mostly automated, TLC pipeline. We then start project systematically apply the new pipeline historic microlensing events, search buried planetary signals. report discovery of such planet candidate event MOA-2019-BLG-421/KMT-2019-BLG-2991. The anomalous signal can be explained by either around lens star or orbital motion source star. For interpretation, despite many...
Abstract Interferometric observations of gravitational microlensing events offer an opportunity for precise, efficient, and direct mass distance measurements lensing objects, especially those isolated neutron stars black holes. However, such have previously been possible only a handful extremely bright events. The recent development dual-field interferometer, GRAVITY Wide, has made it to reach out significantly fainter objects increase the pool amenable interferometric by 2 orders magnitude....
Abstract Traditional microlensing event vetting methods require highly trained human experts, and the process is both complex time consuming. This reliance on manual inspection often leads to inefficiencies constrains ability scale for widespread exoplanet detection, ultimately hindering discovery rates. To address limits of traditional vetting, we have developed LensNet, a machine learning pipeline specifically designed distinguish legitimate events from false positives caused by...
Abstract Blue large-amplitude pulsators (BLAPs), a recently classified type of variable stars, are evolved objects likely formed through interactions between stars in binary system. However, only two BLAPs with stellar companions have been discovered to date. This paper presents photometric data from the Korea Microlensing Telescope Network (KMTNet) for three located direction Galactic bulge: OGLE-BLAP-006, OGLE-BLAP-007, and OGLE-BLAP-009. The were collected over eight consecutive years,...
Exoplanets classified as super-Earths are commonly observed on short-period orbits, close to their host stars, but abundance wider orbits is poorly constrained. Gravitational microlensing sensitive exoplanets wide orbits. We the event OGLE-2016-BLG-0007, which indicates an exoplanet with a planet-to-star mass ratio roughly double Earth-Sun ratio, orbit longer than Saturn's. combined this larger sample from survey determine distribution of ratios for planets infer that there ~0.35 super-Earth...
ABSTRACT We report the discovery and analysis of a candidate triple-lens single-source (3L1S) microlensing event, OGLE-2019-BLG-1470. This event was first classified as normal binary-lens (2L1S) but careful 2L1S modelling showed that it needs an additional lens or source to fit observed data. It is found 3L1S model provides best fit, binary-source (2L2S) only disfavoured by Δχ2 ≃ 18. All feasible models include planet with planet-to-host mass-ratios 10−3 ≲ q 10−2. A Bayesian based on...
Abstract The current studies of microlensing planets are limited by small number statistics. Follow-up observations high-magnification events can efficiently form a statistical planetary sample. Since 2020, the Korea Microlensing Telescope Network (KMTNet) and Las Cumbres Observatory (LCO) global network have been conducting follow-up program for KMTNet events. Here, we report detection analysis event, KMT-2023-BLG-1431, which subtle (0.05 mag) short-lived (5 hr) signature was characterized...
Aims. We investigated the nature of 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 these commonly exhibit initial bumps followed by subsequent troughs that extend across a substantial portion curves. Methods. performed thorough modeling to elucidate their characteristics. Despite prolonged durations, which differ from usual brief observed typical planetary events, our analysis revealed each...
Abstract In the pursuit of understanding population stellar remnants within Milky Way, we analyze sample ∼950 microlensing events observed by Spitzer Space Telescope between 2014 and 2019. this study focus on a subsample nine events, selected based their long timescales, small parallaxes, joint observations Gaia mission, to increase probability that chosen lenses are massive mass is measurable. Among identify lensing black holes neutron star candidates, with potential confirmation through...
We investigated the nature of 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 these commonly exhibit initial bumps followed by subsequent troughs that extend across a substantial portion curves. performed thorough modeling to elucidate their characteristics. Despite prolonged durations, which differ from usual brief observed typical planetary events, our analysis revealed each anomaly originated...
Abstract We report the analysis of four unambiguous planets and one possible planet from subprime fields (Γ ≤ 1 hr −1 ) 2017 Korea Microlensing Telescope Network (KMTNet) microlensing survey, to complete KMTNet AnomalyFinder planetary sample for fields. They are KMT-2017-BLG-0849, KMT-2017-BLG-1057, OGLE-2017-BLG-0364, KMT-2017-BLG-2331 (unambiguous), as well KMT-2017-BLG-0958 (possible). For planets, mean planet–host mass ratios, q , (1.0, 1.2, 4.6, 13) × 10 −4 median masses (6.4, 24, 76,...
In the pursuit of understanding population stellar remnants within Milky Way, we analyze sample $\sim 950$ microlensing events observed by Spitzer Space Telescope between 2014 and 2019. this study focus on a sub-sample nine events, selected based their long timescales, small parallaxes joint observations Gaia mission, to increase probability that chosen lenses are massive mass is measurable. Among identify lensing black holes neutron star candidates, with potential confirmation through...
In this paper, we propose a multi-objective genetic algorithm for effectively solving multistage-based job processing schedules in FMS environment. The proposed method is random-weight approach to obtaining variable search direction toward Pareto solution. objectives are minimize the makespan and total flow time, simultaneously. feasibility adaptability of moGA investigated through experimental results.