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Author: search.filters.author.Mao SSubject: search.filters.subject.Gravitational microlensing exoplanet detection (2147)

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    Systematic Reanalysis of KMTNet Microlensing Events. II. Two New Planets in Giant-source Events
    (IOP Publishing on behalf of the American Astronomical Society., 2025-06-01) Yang H; Yee JC; Zhang J; Lee C-U; Kim D-J; Bond IA; Udalski A; Hwang K-H; Zang W; Qian Q; Gould A; Mao S; Albrow MD; Chung S-J; Han C; Jung YK; Ryu Y-H; Shin I-G; Shvartzvald Y; Cha S-M; Kim H-W; Kim S-L; Lee D-J; Lee Y; Park B-G; Pogge RW; Abe F; Bando K; Bennett DP; Bhattacharya A; Fukui A; Hamada R; Hamada S; Hamasaki N; Hirao Y; Silva SI; Itow Y; Koshimoto N; Matsubara Y; Miyazaki S; Muraki Y; Nagai T; Nunota K; Olmschenk G; Ranc C; Rattenbury NJ; Satoh Y; Sumi T; Suzuki D; Terry SK; Tristram PJ; Vandorou A; Yama H; Mróz P; Skowron J; Poleski R; Szymański MK; Soszyński I; Pietrukowicz P; Kozłowski S; Ulaczyk K; Rybicki KA; Iwanek P; Wrona M
    In this work, we continue to apply the updated KMTNet tender-love care photometric pipeline to historical microlensing events. We apply the pipeline to a subsample of events from the KMTNet database, which we refer to as the giant source sample. Leveraging the improved photometric data, we conduct a systematic search for anomalies within this sample. The search successfully uncovers four new planet-like anomalies and recovers two previously known planetary signals. After detailed analysis, two of the newly discovered anomalies are confirmed as clear planets: KMT-2019-BLG-0578 and KMT-2021-BLG-0736. Their planet-to-host mass ratios are q ∼ 4 × 10−3 and q ∼ 1 × 10−4, respectively. Another event, OGLE-2018-BLG-0421 (KMT-2018-BLG-0831), remains ambiguous. Both a stellar companion and a giant planet in the lens system could potentially explain the observed anomaly. The anomaly signal of the last event, MOA-2022-BLG-038 (KMT-2022-BLG-2342), is attributed to an extra source star. Within this sample, our procedure doubles the number of confirmed planets, demonstrating a significant enhancement in the survey sensitivity.
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    Systematic KMTNet Planetary Anomaly Search. II. Six New q < 2 × 10−4 Mass-ratio Planets
    (IOP Publishing on behalf of the American Astronomical Society, 2022-02-01) Hwang K-H; Zang W; Gould A; Udalski A; Bond IA; Yang H; Mao S; Albrow MD; Chung S-J; Han C; Jung YK; Ryu Y-H; Shin I-G; Shvartzvald Y; Yee JC; Cha S-M; Kim D-J; Kim H-W; Kim S-L; Lee C-U; Lee D-J; Lee Y; Park B-G; Pogge R; Mróz P; Poleski R; Skowron J; Szymański MK; Soszyński I; Pietrukowicz P; Kozłowski S; Ulaczyk K; Rybicki KA; Iwanek P; Wrona M; Gromadzki M; Abe F; Barry R; Bennett DP; Bhattacharya A; Fujii H; Fukui A; Hirao Y; Itow Y; Kirikawa R; Kondo I; Koshimoto N; Munford B; Matsubara Y; Miyazaki S; Muraki Y; Olmschenk G; Ranc C; Rattenbury NJ; Satoh YK; Shoji H; Silva SI; Sumi T; Suzuki D; Tristram PJ; Yonehara A; Zhang X; Zhu W; Penny MT; Fouqué P
    We apply the automated AnomalyFinder algorithm of Paper I to 2018-2019 light curves from the ≃13 deg2 covered by the six KMTNet prime fields, with cadences Γ ≥ 2 hr-1. We find a total of 11 planets with mass ratios q < 2 × 10-4, including 6 newly discovered planets, 1 planet that was reported in Paper I, and recovery of 4 previously discovered planets. One of the new planets, OGLE-2018-BLG-0977Lb, is in a planetary caustic event, while the other five (OGLE-2018-BLG-0506Lb, OGLE-2018-BLG-0516Lb, OGLE-2019-BLG-1492Lb, KMT-2019-BLG-0253, and KMT-2019-BLG-0953) are revealed by a "dip"in the light curve as the source crosses the host-planet axis on the opposite side of the planet. These subtle signals were missed in previous by-eye searches. The planet-host separations (scaled to the Einstein radius), s, and planet-host mass ratios, q, are, respectively, (s, q × 105) = (0.88, 4.1), (0.96 ± 0.10, 8.3), (0.94 ± 0.07, 13), (0.97 ± 0.07, 18), (0.97 ± 0.04, 4.1), and (0.74, 18), where the "± "indicates a discrete degeneracy. The 11 planets are spread out over the range . Together with the two planets previously reported with q ∼ 10-5 from the 2018-2019 nonprime KMT fields, this result suggests that planets toward the bottom of this mass-ratio range may be more common than previously believed.