MOA-2019-BLG-008Lb: A New Microlensing Detection of an Object at the Planet/Brown Dwarf Boundary

Bachelet, E.; Tsapras, Y.; Gould, Andrew; Street, R. A.; Hundertmark, M.; Bozza, V.; Bramich, D. M.; Cassan, A.; Dominik, M.; Horne, K.; Mao, Shude; Saha, Abhijit; Wambsganß, J.; Zang, Weicheng; Abe, F.; Barry, Richard; Bennett, D. P.; Bhattacharya, Aparna; Bond, I. A.; Fukui, A.; Fujii, Hirosane; Hirao, Yuki; Itow, Y.; Kirikawa, Rintaro; Kondo, Iona; Koshimoto, Naoki; Matsubara, Y.; Matsumoto, Sho; Miyazaki, Shota; Muraki, Y.; Olmschenk, Greg; Ranc, Clément; Okamura, Arisa; Rattenbury, N. J.; Satoh, Yuki; Sumi, T.; Suzuki, D.; Silva, Stela Ishitani; Toda, Taiga; Tristram, P. J.; Vandorou, Aikaterini; Yama, Hibiki; Albrow, M. D.; Chung, Sun-Ju; Han, Cheongho; Hwang, Kyu-Ha; Jung, Youn Kil; Ryu, Yoon-Hyun; Shin, In-Gu; Shvartzvald, Yossi; Yee, Jennifer C.; Cha, Sang-Mok; Kim, Dong-Jin; Kim, S.-L.; Lee, Chung-Uk; Lee, Dong-Joo; Lee, Yongseok; Park, Byeong-Gon; Pogge, Richard W.; Udalski, A.; Mróz, P.; Poleski, R.; Skowron, J.; Szymański, M. K.; Soszyński, I.; Pietrukowicz, P.; Kozłowski, S.; Ulaczyk, K.; Rybicki, K.; Iwanek, P.; Wrona, Marcin; Gromadzki, M.

doi:10.3847/1538-3881/ac78ed

Cited by 3 publications

(2 citation statements)

References 158 publications

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“…The downside is that the results are inevitably biased because of the different models assumptions. For example, Bachelet et al (2022b) found a good agreement with the prediction from the Besançon (Robin et al 2003), GalMod (Pasetto et al 2018), Dominik (2006), andKoshimoto et al (2021) models, but small discrepancies exist.…”

Section: Introductionmentioning

confidence: 64%

“…These measurements will be based on the lightcurve modeling as well as the modeling of the Roman images near the event location. A double point-spread function fit provides strong constraints on the source and lens magnitudes as well as the relative proper motion μ rel (Bachelet et al 2022a), which is included as the last observable. The typical astrometric precision can be approximated by (Lindegren 1978;Sozzetti 2005), where FWHM is the full width at half-maximum of the optical system and S/N is the photometric signal-to-noise ratio.…”

Section: Simulation Of a Sample Of Lenses Seen By Romanmentioning

confidence: 99%

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Estimating Microlensing Parameters from Observables and Stellar Isochrones with pyLIMASS

Bachelet,

Hundertmark,

Calchi Novati

2024

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We present pyLIMASS, a novel algorithm for estimating the physical properties of the lensing system in microlensing events. The main idea of pyLIMASS is to combine all available information regarding the microlensing event, defined as observables, and to estimate the parameter distributions of the system, such as the lens mass and distance. The algorithm is based on isochrones for the stars model and combines the observables using a Gaussian mixture approach. After describing the mathematical formalism and its implementation, we discuss the algorithm’s performance on simulated and published events. Generally, the pyLIMASS estimations are in good agreement (i.e., within 1σ) with the results of the selected published events, making it an effective tool to estimate the lens properties and their distribution. The applicability of the method was tested by using a catalog of realistically simulated events that could be observed by the future Galactic Bulge Time Domain Survey of the Nancy Grace Roman Space Telescope. By solely using constraints from the Roman lightcurves and images, pyLIMASS estimates the masses of the lens of the Roman catalog with a median precision of 20% with almost no bias.

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Section: Introductionmentioning

confidence: 64%

Section: Simulation Of a Sample Of Lenses Seen By Romanmentioning

confidence: 99%

Estimating Microlensing Parameters from Observables and Stellar Isochrones with pyLIMASS

Bachelet,

Hundertmark,

Calchi Novati

2024

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Microlensing brown-dwarf companions in binaries detected during the 2022 and 2023 seasons

Han,

Bond,

Udalski

et al. 2024

A&A

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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 Network (KMTNet) survey during the 2022 and 2023 seasons. Given the difficulty in distinguishing brown-dwarf events from those produced by binary lenses with nearly equal-mass components, we analyze all lensing events detected during the seasons that exhibit anomalies characteristic of binary-lens systems. Using the same criteria consistently applied in previous studies, we identify six additional brown dwarf candidates through the analysis of lensing events KMT-2022-BLG-0412, KMT-2022-BLG-2286, KMT-2023-BLG-0201, KMT-2023-BLG-0601, KMT-2023-BLG-1684, and KMT-2023-BLG-1743. An examination of the mass posteriors shows that the median mass of the lens companions ranges from 0.02\,$M_ to 0.05\,$M_ indicating that these companions fall within the brown-dwarf mass range. The mass of the primary lenses ranges from 0.11\,$M_ to 0.68\,$M_ indicating that they are low-mass stars with substantially lower masses compared to the Sun.

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Gaia22dkvLb: A Microlensing Planet Potentially Accessible to Radial-velocity Characterization

Wu,

Dong,

et al. 2024

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We report discovering an exoplanet from following up a microlensing event alerted by Gaia. The event Gaia22dkv is toward a disk source rather than the traditional bulge microlensing fields. Our primary analysis yields a Jovian planet with M p = 0.59 − 0.05 + 0.15 M J at a projected orbital separation r ⊥ = 1.4 − 0.3 + 0.8 au, and the host is a ∼1.1 M ⊙ turnoff star at ∼1.3 kpc. At r ′ ≈ 14 , the host is far brighter than any previously discovered microlensing planet host, opening up the opportunity to test the microlensing model with radial velocity (RV) observations. RV data can be used to measure the planet’s orbital period and eccentricity, and they also enable searching for inner planets of the microlensing cold Jupiter, as expected from the “inner–outer correlation” inferred from Kepler and RV discoveries. Furthermore, we show that Gaia astrometric microlensing will not only allow precise measurements of its angular Einstein radius θ E but also directly measure the microlens parallax vector and unambiguously break a geometric light-curve degeneracy, leading to the definitive characterization of the lens system.

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MOA-2019-BLG-008Lb: A New Microlensing Detection of an Object at the Planet/Brown Dwarf Boundary

Cited by 3 publications

References 158 publications

Estimating Microlensing Parameters from Observables and Stellar Isochrones with pyLIMASS

Estimating Microlensing Parameters from Observables and Stellar Isochrones with pyLIMASS

Microlensing brown-dwarf companions in binaries detected during the 2022 and 2023 seasons

Gaia22dkvLb: A Microlensing Planet Potentially Accessible to Radial-velocity Characterization

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