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1. OGLE-2016-BLG-0156: Microlensing Event With Pronounced Microlens-Parallax Effects Yielding Precise Lens Mass Measurement

Author

Jung, Youn Kil, Han, Cheongho, Bond, Ian A., Udalski, Andrzej, Gould, Andrew, Albrow, Michael D., Chung, Sun-Ju, Hwang, Kyu-Ha, Lee, Chung-Uk, Ryu, Yoon-Hyun, Shin, In-Gu, Shvartzvald, Yossi, Yee, Jennifer C., Jee, M. James, Kim, Doeon, Cha, Sang-Mok, Kim, Dong-Jin, Kim, Hyoun-Woo, Kim, Seung-Lee, Lee, Dong-Joo, Lee, Yongseok, Park, Byeong-Gon, Pogge, Richard W., Abe, Fumio, Barry, Richard, Bennett, David P., Bhattacharya, Aparna, Donachie, Martin, Fukui, Akihiko, Hirao, Yuki, Itow, Yoshitaka, Kawasaki, Kohei, Kondo, Iona, Koshimoto, Naoki, Li, Man Cheung Alex, Matsubara, Yutaka, Muraki, Yasushi, Miyazaki, Shota, Masayuki~Nagakane, Ranc, Clément, Rattenbury, Nicholas J., Suematsu, Haruno, Sullivan, Denis J., Sumi, Takahiro, Suzuki, Daisuke, Tristram, Paul J., Yonehara, Atsunori, Mróz, Przemek, Poleski, Radek, Skowron, Jan, Szymański, Michał K., Soszyński, Igor, Kozłowski, Szymon, Pietrukowicz, Paweł, Ulaczy, Krzysztof, and Pawlak, Michał

Subjects
Astrophysics - Solar and Stellar Astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract

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 light curve exhibits 3 distinctive widely-separated peaks and we find that the multiple-peak feature provides a very tight constraint on the microlens-parallax effect, enabling us to precisely measure the microlens parallax $\pi_{\rm E}$. All the peaks are densely and continuously covered from high-cadence survey observations using globally located telescopes and the analysis of the peaks leads to the precise measurement of the angular Einstein radius $\theta_{\rm E}$. From the combination of the measured $\pi_{\rm E}$ and $\theta_{\rm E}$, we determine the physical parameters of the lens. It is found that the lens is a binary composed of two M dwarfs with masses $M_1=0.18\pm 0.01\ M_\odot$ and $M_2=0.16\pm 0.01\ M_\odot$ located at a distance $D_{\rm L}= 1.35\pm 0.09\ {\rm kpc}$. According to the estimated lens mass and distance, the flux from the lens comprises an important fraction, $\sim 25\%$, of the blended flux. The bright nature of the lens combined with the high relative lens-source motion, $\mu=6.94\pm 0.50\ {\rm mas}\ {\rm yr}^{-1}$, suggests that the lens can be directly observed from future high-resolution follow-up observations., Comment: 9 pages, 9 figures

Published
2019
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2. KMT-2019-BLG-0842Lb: A Cold Planet below the Uranus/Sun Mass Ratio

Author

Youn Kil Jung, Andrzej Udalski, Weicheng Zang, Ian A. Bond, Jennifer C. Yee, Cheongho Han, Michael D. Albrow, Sun-Ju Chung, Andrew Gould, Kyu-Ha Hwang, Yoon-Hyun Ryu, In-Gu Shin, Yossi Shvartzvald, Sang-Mok Cha, Dong-Jin Kim, Hyoun-Woo Kim, Seung-Lee Kim, Chung-Uk Lee, Dong-Joo Lee, Yongseok Lee, Byeong-Gon Park, Richard W. Pogge, Przemek Mróz, Michał Krzysztof Szymański, Jan Skowron, Radek Poleski, Igor Soszyński, Paweł Pietrukowicz, Szymon Kozłowski, Krzysztof Ulaczyk, Krzysztof A. Rybicki, Patryk Iwanek, Marcin Wrona, Fumio Abe, Richard Barry, David P. Bennett, Aparna Bhattacharya, Martin Donachie, Hirosame Fujii, Akihiko Fukui, Yuki Hirao, Yoshitaka Itow, Yukei Kamei, Iona Kondo, Naoki Koshimoto, Man Cheung Alex Li, Yutaka Matsubara, Shota Miyazaki, Yasushi Muraki, Masayuki Nagakane, Clément Ranc, Nicholas j. Rattenbury, Yuki Satoh, Hikaru Shoji, Haruno Suematsu, Denis J. Sullivan, Takahiro Sumi, Daisuke Suzuki, Paul J. Tristram, Takeharu Yamakawa, Tsubasa Yamamwaki, and Atsunori Yonehara

Subjects
Astronomy, Astrophysics
Abstract

We report the discovery of a cold planet with a very low planet/host mass ratio of q = (4.09 ± 0.27) × 10^−5, which is similar to the ratio of Uranus/Sun (q = 4.37 × 10^−5) in the solar system. The Bayesian estimates for the host mass, planet mass, system distance, and planet–host projected separation are M(host) = 0.76 ± 0.40Mꙩ, M(planet) = 10.3 ± 5.5Mꚛ, D(L) = 3.3 ± 1.3 kpc, and a(⊥) = 3.3 ± 1.4 au, respectively. The consistency of the color and brightness expected from the estimated lens mass and distance with those of the blend suggests the possibility that the most blended light comes from the planet host, and this hypothesis can be established if high-resolution images are taken during the next (2020) bulge season. We discuss the importance of conducting optimized photometry and aggressive follow-up observations for moderately or very high magnification events to maximize the detection rate of planets with very low mass ratios.

Published
2020
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3. OGLE-2017-BLG-0406: Spitzer Microlens Parallax Reveals Saturn-mass Planet Orbiting M-dwarf Host in the Inner Galactic Disk

Author

Yuki Hirao, David P. Bennett, Yoon-Hyun Ryu, Naoki Koshimoto, Andrzej Udalski, Jennifer C. Yee, Takahiro Sumi, Ian A. Bond, Yossi Shvartzvald, Fumio Abe, Richard K. Barry, Aparna Bhattacharya, Martin Donachie, Akihiko Fukui, Yoshitaka Itow, Iona Kondo, Man Cheung Alex Li, Yutaka Matsubara, Taro Matsuo, Shota Miyazaki, Yasushi Muraki, Masayuki Nagakane, Clément Ranc, Nicholas J. Rattenbury, Haruno Suematsu, Hiroshi Shibai, Daisuke Suzuki, Paul J. Tristram, Atsunori Yonehara, J. Skowron, R. Poleski, P. Mróz, M. K. Szymański, I. Soszyński, S. Kozłowski, P. Pietrukowicz, K. Ulaczyk, K. Rybicki, P. Iwanek, Michael D. Albrow, Sun-Ju Chung, Andrew Gould, Cheongho Han, Kyu-Ha Hwang, Youn Kil Jung, In-Gu Shin, Weicheng Zang, Sang-Mok Cha, Dong-Jin Kim, Hyoun-Woo Kim, Seung-Lee Kim, Chung-Uk Lee, Dong-Joo Lee, Yongseok Lee, Byeong-Gon Park, Richard W. Pogge, Charles A. Beichman, Geoffery Bryden, Sebastiano Calchi Novati, Sean Carey, B. Scott Gaudi, Calen B. Henderson, Wei Zhu, Etienne Bachelet, Greg Bolt, Grant Christie, Markus Hundertmark, Tim Natusch, Dan Maoz, Jennie McCormick, Rachel A. Street, Thiam-Guan Tan, Yiannis Tsapras, U. G. Jørgensen, M. Dominik, V. Bozza, J. Skottfelt, C. Snodgrass, S. Ciceri, R. Figuera Jaimes, D. F. Evans, N. Peixinho, T. C. Hinse, M. J. Burgdorf, J. Southworth, S. Rahvar, S. Sajadian, M. Rabus, C. von Essen, Y. I. Fujii, J. Campbell-White, S. Lowry, C. Helling, L. Mancini, L. Haikala, and Ryo Kandori

Subjects
Astronomy, Astrophysics
Abstract

We report the discovery and analysis of the planetary microlensing event OGLE-2017-BLG-0406, which was observed both from the ground and by the Spitzer satellite in a solar orbit. At high magnification, the anomaly in the light curve was densely observed by ground-based-survey and follow-up groups, and it was found to be explained by a planetary lens with a planet/host mass ratio of q = 7.0 x 10^-4 from the light-curve modeling. The ground-only and Spitzer-"only" data each provide very strong one-dimensional (1D) constraints on the 2D microlens parallax vector π(E). When combined, these yield a precise measurement of π(E) and of the masses of the host M(host) = 0.56 ± 0.07 Mꙩ and planet M(planet) = 0.41 ± 0.05 M(Jup). The system lies at a distance D(L) = 5.2 ± 0.5 kpc from the Sun toward the Galactic bulge, and the host is more likely to be a disk population star according to the kinematics of the lens. The projected separation of the planet from the host is a(┴) = 3.5 ± 0.3 au (i.e., just over twice the snow line). The Galactic-disk kinematics are established in part from a precise measurement of the source proper motion based on OGLE-IV data. By contrast, the Gaia proper-motion measurement of the source suffers from a catastrophic 10σ error.

Published
2020
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4. One Planet or Two Planets? The Ultra-sensitive Extreme-magnification Microlensing Event KMT-2019-BLG-1953

Author

Cheongho Han, Doeon Kim, Youn Kil Jung, Andrew Gould, Ian A. Bond, Michael D. Albrow, Sun-Ju Chung, Kyu-Ha Hwang, Chung-Uk Lee, Yoon-Hyun Ryu, In-Gu Shin, Yossi Shvartzvald, Jennifer C. Yee, Weicheng Zang, Sang-Mok Cha, Dong-Jin Kim, Hyoun-Woo Kim, Seung-Lee Kim, Dong-Joo Lee, Yongseok Lee, Byeong-Gon Park, Richard W. Pogge, Woong-Tae Kim, Fumio Abe, Richard Barry, David P. Bennett, Aparna Bhattacharya, Martin Donachie, Hirosane Fujii, Akihiko Fukui, Yoshitaka Itow, Yuki Hirao, Rintaro Kirikawa, Iona Kondo, Naoki Koshimoto, Man Cheung Alex Li, Yutaka Matsubara, Yasushi Muraki, Shota Miyazaki, Masayuki Nagakane, Clément Ranc, Nicholas J. Rattenbury, Yuki Satoh, Hikaru Shoji, Haruno Suematsu, Takahiro Sumi, Daisuke Suzuki, Yuzuru Tanaka, Paul J. Tristram, Tsubasa Yamawaki, and Atsunori Yonehara

Subjects
Astronomy, Astrophysics
Abstract

We present the analysis of a very high-magnification (A ~ 900) microlensing event KMT-2019-BLG-1953. A single-lens single-source (1L1S) model appears to approximately delineate the observed light curve, but the residuals from the model exhibit small but obvious deviations in the peak region. A binary-lens (2L1S) model with a mass ratio of q ~ 2 × 10^−3 improves the fits by Δχ2 = 181.8, indicating that the lens possesses a planetary companion. From additional modeling by introducing an extra planetary lens component (3L1S model) and an extra source companion (2L2S model), it is found that the residuals from the 2L1S model further diminish, but claiming these interpretations is difficult due to the weak signals with Δχ2 = 16.0 and 13.5 for the 3L1S and 2L2L models, respectively. From a Bayesian analysis, we estimate that the host of the planets has a mass of M(host)=0.31 (+0.37, -0.17) Mꙩ and that the planetary system is located at a distance of D9L)=7.04 (+1.10, -1.33) kpc toward the Galactic center. The mass of the securely detected planet is M(p)=0.64 (+0.76, -0.35) M(J). The signal of the potential second planet could have been confirmed if the peak of the light curve had been more densely observed by follow-up observations, and thus the event illustrates the need for intensive follow-up observations for very high-magnification events even in the current generation of high-cadence surveys.

Published
2020
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5. A Wide-orbit Exoplanet OGLE-2012-BLG-0838Lb

Author

R. Poleski, Daisuke Suzuki, A. Udalski, Xiaojia Xie, J. C. Yee, Naoki Koshimoto, B. S. Gaudi, A. Gould, J. Skowron, M. K. Szymanski, I. Soszynski, P. Pietrukowicz, S. Kozlowski, L. Wyrzykowski, K. Ulaczyk, Fumio Abe, Richard K Barry, David P Bennett, Aparna Bhattacharya, Ian A. Bond, Martin Donachie, Hirosane Fujii, Akihiko Fukui, Yoshitaka Itow, Yuki Hirao, Yuhei Kamei, Iona Kondo, Man Cheung Alex Li, Yutaka Matsubara, Shota Miyazaki, Yasushi Muraki, Masayuki Nagakane, Clement Ranc, Nicholas J. Rattenbury, Yuki K. Satoh, Hikaru Shoji, Haruno Suematsu, Denis J. Sullivan, Takahiro Sumi, Paul J. Tristram, Takeharu Yamakawa, Tsubasa Yamawaki, Atsunori Yonehara, C. Han, Subo Dong, K. M. Morzinski, J. R. Males, L. M. Close, R. W. Pogge, J.-P. Beaulieu, and J.-B. Marquette

Subjects
Astronomy
Abstract

We present the discovery of a planet on a very wide orbit in the microlensing event OGLE-2012-BLG-0838. The signal of the planet is well separated from the main peak of the event and the planet–star projected separation is found to be twice the Einstein ring radius, which corresponds to a projected separation of ≈4au. Similar planets around low-mass stars are very hard to find using any technique other than microlensing. We discuss microlensing model fitting in detail and discuss the prospects for measuring the mass and distance of the lens system directly.

Published
2020
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6. Candidate Brown-dwarf Microlensing Events with Very Short Timescales and Small Angular Einstein Radii

Author

Cheongho Han, Chung Uk Lee, Andrzej Udalski, Andrew Gould, Ian A. Bond, Valerio Bozza, Michael D. Albrow, Sun Ju Chung, Kyu Ha Hwang, Youn Kil Jung, Yoon-Hyun Ryu, In Gu Shin, Yossi Shvartzvald, Jennifer C. Yee, Weicheng Zang, Sang Mok Cha, Dong-Jin Kim, Hyoun Woo Kim, Seung Lee Kim, Dong-Joo Lee, Yongseok Lee, Byeong Gon Park, Richard W. Pogge, M. James Jee, Doeon Kim, Przemek Mroz, Michal K. Szymański, Jan Skowron, Radek Poleski, Igor Soszynski, Pawel Pietrukowicz, Szymon Kozłowski, Krzysztof Ulaczyk, Krzysztof A. Rybicki, Patryk Iwanek, Marcin Wrona, Fumio Abe, Barry Richardson, David P. Bennett, Aparna Bhattacharya, Martin Donachie, Hirosane Fujii, Akihiko Fukui, Yoshitaka Itow, Yuki Hirao, Yuhei Kamei, Iona Kondo, Naoki Koshimoto, Man Cheung Alex Li, Yutaka Matsubara, Yasushi Muraki, Shota Miyazaki, Masayuki Nagakane, Clement Ranc, Nicholas J. Rattenbury, Yuki Satoh, Hikaru Shoji, Haruno Suematsu, Denis J. Sullivan, Takahiro Sumi, Daisuke Suzuki, Paul J. Tristram, Takeharu Yamakawa, Tsubasa Yamawaki, and and Atsunori Yonehara

Subjects
Astronomy, Astrophysics
Abstract

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 because short-timescale events can also be produced by stellar lenses with high relative lens-source proper motions. In this paper, we report three strong candidate BD-lens events found from the search for lensing events not only with short timescales (t(E) ≲ 6 days) but also with very small angular Einstein radii (θ(E) ≲ 0.05 mas) among the events that have been found in the 2016–2019 observing seasons. These events include MOA-2017-BLG-147, MOA-2017-BLG-241, and MOA-2019-BLG-256, in which the first two events are produced by single lenses and the last event is produced by a binary lens. From the Monte Carlo simulations of Galactic events conducted with the combined t(E) and θ(E) constraint, it is estimated that the lens masses of the individual events are 0.051 (sup +0.100, sub -0.027) M(ʘ), 0.044 (sup +0.090, sub -0.023) M(ʘ), and 0.046 (sup +0.067, sub -0.023) M(ʘ)/0.038 (sup +0.056, sub -0.019) M(ʘ) and the probability of the lens mass smaller than the lower limit of stars is ~80% for all events. We point out that routine lens mass measurements of short-timescale lensing events require survey-mode space-based observations.

Published
2020
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7. Spitzer Microlensing Parallax Reveals Two Isolated Stars in the Galactic Bulge

Author

Weicheng Zang, Yossi Shvartzvald, Tianshu Wang, Andrzej Udalski, Chung-Uk Lee, Takahiro Sumi, Jesper Skottfelt, Shun-Sheng Li, Shude Mao, Wei Zhu, Jennifer C. Yee, Sebastiano Calchi Novati, Charles A. Beichman, Geoffery Bryden, Sean Carey, B. Scott Gaudi, Calen B. Henderson, Przemek Mróz, Jan Skowron, Radoslaw Poleski, Michał K. Szymański, Igor Soszyński, Paweł Pietrukowicz, Szymon Kozłowski, Krzysztof Ulaczyk, Krzysztof A. Rybicki, Patryk Iwanek, Etienne Bachelet, Grant Christie, Jonathan Green, Steve Hennerley, Dan Maoz, Tim Natusch, Richard W. Pogge, Rachel A. Street, Yiannis Tsapras, Michael D. Albrow, Sun-Ju Chung, Andrew Gould, Cheongho Han, Kyu-Ha Hwang, Youn Kil Jung, Yoon-Hyun Ryu, In-Gu Shin, Sang-Mok Cha, Dong-Jin Kim, Hyoun-Woo Kim, Seung-Lee Kim, Dong-Joo Lee, Yongseok Lee, Byeong-Gon Park, Ian A. Bond, Fumio Abe, Richard K Barry, David P Bennett, Aparna Bhattacharya, Martin Donachie, Akihiko Fukui, Yuki Hirao, Yoshitaka Itow, Iona Kondo, Naoki Koshimoto, Man Cheung Alex Li, Yutaka Matsubara, Yasushi Muraki, Shota Miyazaki, Masayuki Nagakane, Clement Ranc, Nicholas J. Rattenbury, Haruno Suematsu, Denis J. Sullivan, Daisuke Suzuki, Paul J. Tristram, Atsunori Yonehara, Martin Dominik, Markus Hundertmark, Uffe G. Jørgensen, Sohrab Rahvar, Sedighe Sajadian, Colin Snodgrass, Valerio Bozza, Martin J. Burgdorf, Daniel F. Evans, R. Figuera Jaimes, Yuri I. Fujii, Luigi Mancini, Penelope Longa-Peña, Christiane Helling, Nuno Peixinho, Markus Rabus, John Southworth, Eduardo Unda-Sanzana, and Carolina von Essen

Subjects
Astrophysics, Astronomy
Abstract

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-source effects, and the microlens parallaxes are derived from the joint analysis of ground-based observations and Spitzer observations. We find that the lens of OGLE-2017-BLG-1254 is a 0.60 ± 0.03 M⊙ star with D(LS) = 0.53 ± 0.11 kpc, where D(LS) is the distance between the lens and the source. The second event, OGLE-2017-BLG-1161, is subject to the known satellite parallax degeneracy, and thus is either a 0.51(sup +0.12, sub 3-0.10)M⊙ star with D(LS) = 0.40 ± 0.12 kpc or a 0.38(sup +0.13, sub -0.12) M⊙ star with D(LS) = 0.53 ± 0.19 kpc. Both of the lenses are therefore isolated stars in the Galactic bulge. By comparing the mass and distance distributions of the eight published Spitzer finite-source events with the expectations from a Galactic model, we find that the Spitzer sample is in agreement with the probability of finite-source effects occurring in single-lens events.

Published
2020
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8. OGLE-2018-BLG-1700L: Microlensing Planet in Binary Stellar System

Author

Cheongho Han, Chung-Uk Lee, Andrzej Udalski, Andrew Gould, Ian A. Bond, Michael D. Albrow, Sun-Ju Chung, Kyu-Ha Hwang, Youn Kil Jung, Yoon-Hyun Ryu, In-Gu Shin, Yossi Shvartzvald, Jennifer C. Yee, Weicheng Zang, Sang-Mok Cha, Dong-Jin Kim, Hyoun-Woo Kim, Seung-Lee Kim, Dong-Joo Lee, Yongseok Lee, Byeong-Gon Park, Richard W. Pogge, M. James Jee, Doeon Kim, Przemek Mróz, Michał K. Szymański, Jan Skowron, Radek Poleski, Igor Soszyński, Paweł Pietrukowicz, Szymon Kozłowski, Krzysztof Ulaczyk, Krzysztof A. Rybicki, Patryk Iwanek, Marcin Wrona, Fumio Abe, Richard K Barry, David P Bennett, Aparna Bhattacharya, Martin Donachie, Hirosane Fujii, Akihiko Fukui, Yoshitaka Itow, Yuki Hirao, Yuhei Kamei, Iona Kondo, Naoki Koshimoto, Man Cheung Alex Li, Yutaka Matsubara, Yasushi Muraki, Shota Miyazaki, Masayuki Nagakane, Clement Ranc, Nicholas J. Rattenbury, Haruno Suematsu, Denis J. Sullivan, Takahiro Sumi, Daisuke Suzuki, Paul J. Tristram, Takeharu Yamakawa, and Atsunori Yonehara

Subjects
Astrophysics, Astronomy
Abstract

We report 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 the fact that the anomaly pattern can be decomposed into two parts produced by two binary-lens events, in which one binary pair has a mass ratio of ∼0.01 between the lens components and the other pair has a mass ratio of ∼0.3. We find two sets of degenerate solutions, in which one solution has a projected separation between the primary and its stellar companion less than the angular Einstein radius θ(E) (close solution), while the other solution has a separation greater than θ(E) (wide solution). From the Bayesian analysis with the constraints of the event timescale and angular Einstein radius, we find that the planet has a mass of 4.4(sup +3.0, sub -2.0) M(J) and the stellar binary components have masses of 0.42 (sup +0.29, sub -0.19) M(ʘ) and 0.12 (sup +0.08, sub -0.05) M(ʘ) , respectively, and the distance to the lens is D(L) = 7.6 (sup +1.2, sub -0.9) kpc. The planet is a circumstellar planet according to the wide solution, while it is a circumbinary planet according to the close solution.

Published
2020
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9. MOA-bin-29b: A Microlensing Gas-giant Planet Orbiting a Low-mass Host Star

Author

Iona Kondo, Takahiro Sumi, David P Bennett, Andrzej Udalski, Ian A. Bond, Nicholas J. Rattenbury, Valerio Bozza, Yuki Hirao, Daisuke Suzuki, Naoki Koshimoto, Masayuki Nagakane, Shota Miyazaki, F. Abe, R Barry, A. Bhattacharya, M. Donachie, A. Fukui, H. Fujii, Y. Itow, Y. Kamei, M. C. A. Li, Y. Matsubara, T. Matsuo, Y. Muraki, Clement Ranc, H. Shibai, H. Suematsu, D. J. Sullivan, P. J. Tristram, T. Yamakawa, A. Yonehara, P. Mroz, M. K. Szymański, I. Soszyński, and and K. Ulaczyk

Subjects
Astrophysics, Astronomy
Abstract

We report the discovery of a gas-giant planet orbiting a low-mass host star in the microlensing event MOA-bin-29 that occurred in 2006. We find five degenerate solutions with the planet/host-star mass ratio of q ∼ 10(exp−2). The Einstein radius crossing time of all models are relatively short (∼4–7 days), which indicates that the mass of host star is likely low. The measured lens-source proper motion is 5–9 mas/yr depending on the models. Since only finite source effects are detected, we conduct a Bayesian analysis in order to obtain the posterior probability distribution of the lens physical properties. As a result, we find the lens system is likely to be a gas-giant orbiting a brown dwarf or a very late M-dwarf in the Galactic bulge. The probability distributions of the physical parameters for the five degenerate models are consistent within the range of error. By combining these probability distributions, we conclude that the lens system is a gas giant with a mass of M(p)= 0.63(sub +1.13, sub 0.39) M(Jup) orbiting a brown dwarf with a mass of M(h)= 0.06 (sup +0.11, sub -0.04) M(ʘ) at a projected star–planet separation of r⊥ = 0.53(sup +0.89, sub -0.18)au . The lens distance is D(L)= 6.89(sup +1.19, sub -1.19) kpc, i.e., likely within the Galactic bulge.

Published
2019
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10. OGLE-2018-BLG-1011Lb,c: Microlensing Planetary System with Two Giant Planets Orbiting a Low-mass Star

Author

Cheongho Han, David P Bennett, Andrzej Udalski, Andrew Gould, Ian A. Bond, Yossi Shvartzvald, Kay-Sebastian Nikolaus, Markus Hundertmark, Valerio Bozza, Arnaud Cassan, Yuki Hirao, Etienne Bachelet, Pascal Fouqué, Michael D. Albrow, Sun-Ju Chung, Kyeongsoo Hong, Kyu-Ha Hwang, Chung-Uk Lee, Yoon-Hyun Ryu, In-Gu Shin, Jennifer C. Yee, Youn Kil Jung, Sang-Mok Cha, Doeon Kim, Dong-Jin Kim, Hyoun-Woo Kim, Seung-Lee Kim, Dong-Joo Lee, Yongseok Lee, Byeong-Gon Park, Richard W. Pogge, Przemek Mróz, Michał K. Szymański, Jan Skowron, Radek Poleski, Igor Soszyński, Paweł Pietrukowicz, Szymon Kozłowski, Krzysztof Ulaczyk, Krzysztof A. Rybicki, Patryk Iwanek, Marcin Wrona, Fumio Abe, Richard Barry, Aparna Bhattacharya, Martin Donachie, Akihiko Fukui, Yoshitaka Itow, Kohei Kawasaki, Iona Kondo, Naoki Koshimoto, Man Cheung Alex Li, Yutaka Matsubara, Yasushi Muraki, Shota Miyazaki, Masayuki Nagakane, Clement Ranc, Nicholas J. Rattenbury, Haruno Suematsu, Denis J. Sullivan, Takahiro Sumi, Daisuke Suzuki, Paul J. Tristram, Atsunori Yonehara, Shude Mao, Tianshu Wang, Weicheng Zang, Wei Zhu, Matthew T. Penny, Charles A. Beichman, Geoffery Bryden, Sebastiano Calchi Novati, B. Scott Gaudi, Calen B. Henderson, Savannah Jacklin, and Keivan G. Stassun

Subjects
Astrophysics, Astronomy
Abstract

We report a multiplanetary system found from the analysis of microlensing event OGLE-2018-BLG-1011, for which the light curve exhibits a double-bump anomaly around the peak. We find that the anomaly cannot be fully explained by the binary-lens or binary-source interpretations and its description requires the introduction of an additional lens component. The 3L1S (three lens components and a single source) modeling yields three sets of solutions, in which one set of solutions indicates that the lens is a planetary system in a binary, while the other two sets imply that the lens is a multiplanetary system. By investigating the fits of the individual models to the detailed light curve structure, we find that the multiple-planet solution with planet-to-host mass ratios ∼9.5 X 10(exp −3) and ∼15 X 10(eap −3) are favored over the other solutions. From the Bayesian analysis, we find that the lens is composed of two planets with masses 1.8 (sup +3.4, sub -1.1) M(J) and 2.8 (sup +5.8, sub -1.7) M(J) around a host with a mass 0.18 (sup +0.33,sub - 0.10) M(ʘ) and located at a distance 7.1(sup +1.1, sub -1.5) kpc. The estimated distance indicates that the lens is the farthest system among the known multiplanetary systems. The projected planet–host separations are a(⊥,2) = 1.8 (sup +2.1, sub -1.5)au (0.8 (sup +0.9,sub -0.6 au) and a(⊥,3) = 0.8 (sup +0.9, sub -0.6)au , where the values of a(⊥,2) inside and outside the parenthesis are the separations corresponding to the two degenerate solutions, indicating that both planets are located beyond the snow line of the host, as with the other four multiplanetary systems previously found by microlensing.

Published
2019
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11. Spectroscopic Mass and Host-star Metallicity Measurements for Newly Discovered Microlensing Planet OGLE-2018-BLG-0740Lb

Author

Cheongho Han, Jennifer C. Yee, Andrzej Udalski, Ian A. Bond, Valerio Bozza, Arnaud Cassan, Yuki Hirao, Subo Dong, Juna A. Kollmeier, Nidia Morrell, Konstantina Boutsia, Michael D. Albrow, Sun-Ju Chung, Andrew Gould, Kyu-Ha Hwang, Chung-Uk Lee, Yoon-Hyun Ryu, In-Gu Shin, Yossi Shvartzvald, Youn Kil Jung, Doeon Kim, Woong-Tae Kim, Sang-Mok Cha, Dong-Jin Kim, Hyoun-Woo Kim, Kyeongsoo Hong, Seung-Lee Kim, Dong-Joo Lee, Yongseok Lee, Byeong-Gon Park, Richard W. Pogge, Weicheng Zang, Przemek Mróz, Michał K. Szymański, Jan Skowron, Radek Poleski, Igor Soszyński, Paweł Pietrukowicz, Szymon Kozłowski, Krzysztof Ulaczyk, Krzysztof A. Rybicki, Patryk Iwanek, Marcin Wrona, Fumio Abe, Richard Barry, David P Bennett, Aparna Bhattacharya, Martin Donachie, Akihiko Fukui, Yoshitaka Itow, Kohei Kawasaki, Iona Kondo, Naoki Koshimoto, Man Cheung Alex Li, Yutaka Matsubara, Yasushi Muraki, Shota Miyazaki, Masayuki Nagakane, Clement Ranc, Nicholas J. Rattenbury, Haruno Suematsu, Denis J. Sullivan, Takahiro Sumi, Daisuke Suzuki, Paul J. Tristram, and Atsunori Yonehara

Subjects
Astrophysics, Astronomy
Abstract

We report the discovery of the microlensing planet OGLE-2018-BLG-0740Lb. The planet is detected with a very strong signal of Δχ(exp 2) ∼ 4630, but the interpretation of the signal suffers from two types of degeneracies. One type is caused by the previously known close/wide degeneracy, and the other is caused by an ambiguity between two solutions, in which one solution requires the incorporation of finite-source effects, while the other solution is consistent with a point-source interpretation. Although difficult to be firmly resolved based on only the photometric data, the degeneracy is resolved in strong favor of the point-source solution with the additional external information obtained from astrometric and spectroscopic observations. The small astrometric offset between the source and baseline object supports that the blend is the lens and this interpretation is further secured by the consistency of the spectroscopic distance estimate of the blend with the lensing parameters of the point-source solution. The estimated mass of the host is 1.0 ± 0.1 M(ʘ) and the mass of the planet is 4.5 ± 0.6 M(J) (close solution) or 4.8 ± 0.6 M(J) (wide solution) and the lens is located at a distance of 3.2 ± 0.5 kpc. The bright nature of the lens, with I ∼ 17.1 (V ∼ 18.2), combined with its dominance of the observed flux suggest that radialvelocity (RV) follow-up observations of the lens can be done using high-resolution spectrometers mounted on large telescopes, e.g., Very Large Telescope/ESPRESSO, and this can potentially not only measure the period and eccentricity of the planet but also probe for close-in planets. We estimate that the expected RV amplitude would be ~60 sin i m/s.

Published
2019
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12. Spitzer Parallax of OGLE-2018-BLG-0596: A Low-mass-ratio Planet around an M Dwarf

Author

Youn Kil Jung, Andrew Gould, Andrzej Udalski, Takahiro Sumi, Jennifer C. Yee, Yossi Shvartzvald, Weicheng Zang, Cheongho Han, Michael D. Albrow, Sun-Ju Chung, Kyu-Ha Hwang, Yoon-Hyun Ryu, In-Gu Shin, Wei Zhu, Sang-Mok Cha, Dong-Jin Kim, Hyoun-Woo Kim, Seung-Lee Kim, Chung-Uk Lee, Dong-Joo Lee, Yongseok Lee, Byeong-Gon Park, Richard W. Pogge, Przemek Mroz, Michalł K. Szymański, Jan Skowron, Radek Poleski, Igor Soszynski, Pawel Pietrukowicz, Szymon Kozłowski, Krzystof Ulaczyk, Krzysztof A. Rybicki, Patryk Iwanek, Marcin Wrona, Charles A. Beichman, Geoffery Bryden, Sebastiano Calchi Novati, Sean Carey, B. Scott Gaudi, Calen B. Henderson, Fumio Abe, Richard Barry, David P Bennett, Ian A. Bond, Aparna Bhattacharya, Martin Donachie, Akihiko Fukui, Yuki Hirao, Yoshitaka Itow, Iona Kondo, Naoki Koshimoto, Man Cheung Alex Li, Yutaka Matsubara, Shota Miyazaki, Yasushi Muraki, Masayuki Nagakane, Clement Ranc, Nicholas J. Rattenbury, Haruno Suematsu, Denis J. Sullivan, Daisuke Suzuki, Paul J. Tristram, Atsunori Yonehara, Savannah Jacklin, Matthew T. Penny, and Keivan G. Stassun

Subjects
Astronomy
Abstract

We report the discovery of a Spitzer microlensing planet OGLE-2018-BLG-0596Lb, with preferred planet-host mass ratio q ~ 2 × 10(exp −4). The planetary signal, which is characterized by a short (~1 day) "bump" on the rising side of the lensing light curve, was densely covered by ground-based surveys. We find that the signal can be explained by a bright source that fully envelops the planetary caustic, i.e., a "Hollywood" geometry. Combined with the source proper motion measured from Gaia, the Spitzer satellite parallax measurement makes it possible to precisely constrain the lens physical parameters. The preferred solution, in which the planet perturbs the minor image due to lensing by the host, yields a Uranus-mass planet with a mass of M(p) = 13.9 ± 1.6 M(⊕) orbiting a mid M-dwarf with a mass of M(h) = 0.23 ± 0.03 M(⊙). There is also a second possible solution that is substantially disfavored but cannot be ruled out, for which the planet perturbs the major image. The latter solution yields M(p) = 1.2 ± 0.2 M(⊕) and M(h) = 0.15 ± 0.02 M(⊙). By combining the microlensing and Gaia data together with a Galactic model, we find in either case that the lens lies on the near side of the Galactic bulge at a distance D(L) ~ 6 ± 1 kpc. Future adaptive optics observations may decisively resolve the major image/minor image degeneracy.

Published
2019
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13. OGLE-2015-BLG-1670Lb: A Cold Neptune beyond the Snow Line in the Provisional WFIRST Microlensing Survey Field

Author

Clément Ranc, David P Bennett, Yuki Hirao, Andrzej Udalski, Cheongho Han, Ian A. Bond, Jennifer C. Yee, Michael D. Albrow, Sun-Ju Chung, Andrew Gould, Kyu-Ha Hwang, Youn-Kil Jung, Yoon-Hyun Ryu, In-Gu Shin, Yossi Shvartzvald, Weicheng Zang, Wei Zhu, Sang-Mok Cha, Dong-Jin Kim, Hyoun-Woo Kim, Seung-Lee Kim, Chung-Uk Lee, Dong-Joo Lee, Yong-Seok Lee, Byeong-Gon Park, Richard W. Pogge, Fumio Abe, Richard K Barry, Aparna Bhattacharya, Martin Donachie, Akihiko Fukui, Yoshitaka Itow, Kohei Kawasaki, Iona Kondo, Naoki Koshimoto, Man Cheung Alex Li, Yutaka Matsubara, Shota Miyazaki, Yasushi Muraki, Masayuki Nagakane, Nicholas J. Rattenbury, Haruno Suematsu, Denis J. Sullivan, Takahiro Sumi, Daisuke Suzuki, Paul J. Tristram, and Atsunori Yonehara

Subjects
Astrophysics, Astronomy
Abstract

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 line of sight, this event was too faint to be detected before it reached the peak of magnification. The microlensing light-curve models indicate a high-magnification event with a maximum of A(max)≳ 200, very sensitive to planetary deviations. An anomaly in the light curve has been densely observed by the microlensing surveys MOA, KMTNet, and OGLE. From the light-curve modeling, we find a planetary anomaly characterized by a planet-to-host mass ratio, q=(1.00 (sup+0.18, sub -0.16) x 10(exp -4), at the peak recently identified in the mass-ratio function of microlensing planets. Thus, this event is interesting to include in future statistical studies about planet demography. We have explored the possible degeneracies and find two competing planetary models resulting from the s ↔ 1/s degeneracy. However, because the projected separation is very close to s = 1, the physical implications for the planet for the two solutions are quite similar, except for the value of s. By combining the light-curve parameters with a Galactic model, we have estimated the planet mass M(2)=17.9(sup +9.6,sub-8.8)M(ꚛ) and the lens distance D(L) = 6.7(sup +1.0, sub -1.3) kpc, corresponding to a Neptune-mass planet close to the Galactic bulge. Such events with a low absolute latitude (|b| ≈1ᵒ.1) are subject to both high extinction and more uncertain source distances, two factors that may affect the mass measurements in the provisional Wide Field Infrared Survey Telescope fields. More events are needed to investigate the potential trade-off between the higher lensing rate and the difficulty in measuring masses in these low-latitude fields.

Published
2019
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14. OGLE-2018-BLG-0022: First Prediction of an Astrometric Microlensing Signal from a Photometric Microlensing Event

Author

Cheongho Han, Ian A. Bond, Andrzej Udalski, Andrew Gould, Valerio Bozza, Yuki Hirao, Arnaud Cassan, Michael D. Albrow, Sun-Ju Chung, Kyu-Ha Hwang, Chung-Uk Lee, Yoon-Hyun Ryu, In-Gu Shin, Yossi Shvartzvald, Jennifer C. Yee, Youn Kil Jung, Doeon Kim, Woong-Tae Kim, Sang-Mok Cha, Dong-Jin Kim, Hyoun-Woo Kim, Seung-Lee Kim, Dong-Joo Lee, Yongseok Lee, Byeong-Gon Park, Richard W. Pogge, Weicheng Zang, Fumio Abe, Richard Barry, David P. Bennett, Aparna Bhattacharya, Martin Donachie, Akihiko Fukui, Yoshitaka Itow, Kohei Kawasaki, Iona Kondo, Naoki Koshimoto, Man Cheung Alex Li, Yutaka Matsubara, Yasushi Muraki, Shota Miyazaki, Masayuki Nagakane, Clement Ranc, Nicholas J. Rattenbury, Haruno Suematsu, Denis J. Sullivan, Takahiro Sumi, Daisuke Suzuki, Paul J. Tristram, Atsunori Yonehara, Przemek Mroz, Michal K. Szymanski, Jan Skowron, Radek Poleski, Igor Soszynski, Pawel Pietrukowicz, Szymon Kozłowski, Krzysztof Ulaczyk, Krzysztof A. Rybicki, Patryk Iwanek, Marcin Wrona, Charles A. Beichman, Geoffery Bryden, Sean Carey, B. Scott Gaudi, Calen B. Henderson, and Sebastiano Calchi Novatil

Subjects
Astrophysics, Astronomy
Abstract

In this work, we present the analysis of the binary microlensing event OGLE-2018-BLG-0022 that is detected toward the Galactic bulge field. The dense and continuous coverage with the high-quality photometry data from ground-based observations combined with the space-based Spitzer observations of this long timescale event enables us to uniquely determine the masses M 1 = 0.40 ± 0.05 M ⊙ and M 2 = 0.13 ± 0.01 M ⊙ of the individual lens components. Because the lens-source relative parallax and the vector lens-source relative proper motion are unambiguously determined, we can likewise unambiguously predict the astrometric offset between the light centroid of the magnified images (as observed by the Gaia satellite) and the true position of the source. This prediction can be tested when the individual-epoch Gaia astrometric measurements are released.

Published
2019
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15. OGLE-2014-BLG-0962 and a Comparison of Galactic Model Priors to Microlensing Data

Author

Yutong Shan, Jennifer C. Yee, Andrzej Udalski, Ian A. Bond, Yossi Shvartzvald, In-Gu Shin, Youn-Kil Jung, Sebastiano Calchi Novati, Charles A. Beichman, Sean Carey, B. Scott Gaudi, Andrew Gould, Richard W. Pogge, Radoslaw Poleski, Jan Skowron, Szymon Kozłowski, Przemyslaw Mroz, Pawel Pietrukowicz, Michal K. Szymanski, Igor Soszynski, Krzysztof Ulaczyk, Lukasz Wyrzykowski, Fumio Abe, Richard K Barry, David P Pearson, Aparna Bhattacharya, Martin Donachie, Akihiko Fukui, Yuki Hirao, Yoshitaka Itow, Kohei Kawasaki, Iona Kondo, Naoki Koshimoto, Man Cheung Alex Li, Yutaka Matsubara, Yasushi Muraki, Shota Miyazaki, Masayuki Nagakane, Clement Ranc, Nicholas J. Rattenbury, Haruno Suematsu, Denis J. Sullivan, Takahiro Sumi, Daisuke Suzuki, Paul J. Tristram, Atsunori Yonehara, Dan Maoz, Shai Kaspi, and Matan Friedmann

Subjects
Astrophysics
Abstract

OGLE-2014-BLG-0962 (OB140962) is a stellar binary microlensing event that was well covered by observations from the Spitzer satellite as well as ground-based surveys. Modeling yields a unique physical solution: a mid-M+M-dwarf binary with M(prim) = 0.20 ± 0.01 M(☉) and M(sec) = 0.16 ± 0.01 M(☉), with projected separation of 2.0 ± 0.3 au. The lens is only D(LS) = 0.41 ± 0.06 kpc in front of the source, making OB140962 a bulge lens and the most distant Spitzer binary lens to date. In contrast, because the Einstein radius (θ(E) = 0.143 ± 0.007 mas) is unusually small, a standard Bayesian analysis, conducted in the absence of parallax information, would predict a brown dwarf binary. We compare the results of Bayesian analysis using two commonly used Galactic model priors to the measured values for a set of Spitzer lenses. We find all models tested predict lens properties consistent with the Spitzer data. Furthermore, we illustrate the methodology for probing the Galactic distribution of planets by comparing the cumulative distance distribution of the Spitzer two-body lenses to that of the Spitzer single lenses.

Published
2019
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16. Two new free-floating or wide-orbit planets from microlensing

Author

Przemek Mróz, Andrzej Udalski, David P. Bennett, Yoon-Hyun Ryu, Takahiro Sumi, Yossi Shvartzvald, Jan Skowron, Radosław Poleski, Paweł Pietrukowicz, Szymon Kozłowski, Michał K. Szymanski, Łukasz Wyrzykowski, Igor Soszynski, Krzysztof Ulaczyk, Krzysztof Rybicki, Patryk Iwanek, Michael D. Albrow, Sun-Ju Chung, Andrew Gould, Cheongho Han, Kyu-Ha Hwang, Youn Kil Jung, In-Gu Shin, Jennifer C. Yee, Weicheng Zang, Sang-Mok Cha, Dong-Jin Kim, Hyoun-Woo Kim, Seung-Lee Kim, Chung-Uk Lee, Dong-Joo Lee, Yongseok Lee, Byeong-Gon Park, Richard W. Pogge, Fumio Abe, Richard Barry, Aparna Bhattacharya, Ian A. Bond, Martin Donachie, Akihiko Fukui, Yuki Hirao, Yoshitaka Itow, Kohei Kawasaki, Iona Kondo, Naoki Koshimoto, Man Cheung Alex Li, Yutaka Matsubara, Yasushi Muraki, Shota Miyazaki, Masayuki Nagakane, Clément Ranc, Nicholas J. Rattenbury, Haruno Suematsu, Denis J. Sullivan, Daisuke Suzuki, Paul J. Tristram, Atsunori Yonehara, Dan Maoz, Shai Kaspi, and Matan Friedmann

Subjects
Astronomy, Astrophysics
Abstract

Planet formation theories predict the existence of free-floating planets that have been ejected from their parent systems. Although they emit little or no light, they can be detected during gravitational microlensing events. Microlensing events caused by rogue planets are characterized by very short timescales t(E) (typically below two days) and small angular Einstein radii θ(E)) (up to several μas). Here we present the discovery and characterization of two ultra-short microlensing events identified in data from the Optical Gravitational Lensing Experiment (OGLE) survey, which may have been caused by free-floating or wide-orbit planets. OGLE-2012-BLG-1323 is one of the shortest events discovered thus far (t(E) = 0.155 ± 0.005 d, θ(E) = 2.37 ± 0.10μas) and was caused by an Earth-mass object in the Galactic disk or a Neptune-mass planet in the Galactic bulge. OGLE-2017-BLG-0560 (t(E) = 0.905 ± 0.005 d, θ(E) = 38.7 ± 1.6μas) was caused by a Jupiter-mass planet in the Galactic disk or a brown dwarf in the bulge. We rule out stellar companions up to a distance of 6.0 and 3.9 au, respectively. We suggest that the lensing objects, whether located on very wide orbits or free-floating, may originate from the same physical mechanism. Although the sample of ultrashort microlensing events is small, these detections are consistent with low-mass wide-orbit or unbound planets being more common than stars in the Milky Way.

Published
2019
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17. OGLE-2016-BLG-0156: Microlensing Event with Pronounced Microlens-parallax Effects Yielding a Precise Lens Mass Measurement

Author

Youn Kil Jung, Cheongho Han, Ian A. Bond, Andrzej Udalski, Andrew Gould, Michael D. Albrow, Sun-Ju Chung, Kyu-Ha Hwang, Chung-Uk Lee, Yoon-Hyun Ryu, In-Gu Shin, Yossi Shvartzvald, Jennifer C. Yee, M. James Jee, Doeon Kim, Sang-Mok Cha, Dong-Jin Kim, Hyoun-Woo Kim, Seung-Lee Kim, Dong-Joo Lee, Yongseok Lee, Byeong-Gon Park, Richard W. Pogge, Fumio Abe, Richard K Barry, David P Bennett, Aparna Bhattacharya, Martin Donachie, Akihiko Fukui, Yuki Hirao, Yoshitaka Itow, Kohei Kawasaki, Iona Kondo, Naoki Koshimoto, Man Cheung Alex Li, Yutaka Matsubara, Yasushi Muraki, Shota Miyazaki, Masayuki Nagakane, Clement Ranc, Nicholas J. Rattenbury, Haruno Suematsu, Denis J. Sullivan, Takahiro Sumi, Daisuke Suzuki, Paul J. Tristram, Atsunori Yonehara, Przemek Mroz, Radek Poleski, Jan Skowron, Michal K. Szymanski, Igor Soszynski, Szymon Kozlowski, Pawel Pietrukowicz, Krzysztof Ulaczyk, and Michal Pawlak

Subjects
Astrophysics
Abstract

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 light curve exhibits three distinctive widely separated peaks and we find that the multiple-peak feature provides a very tight constraint on the microlens-parallax effect, enabling us to precisely measure the microlens parallax . All the peaks are densely and continuously covered from high-cadence survey observations using globally located telescopes and the analysis of the peaks leads to the precise measurement of the angular Einstein radius . From the combination of the measured and , we determine the physical parameters of the lens. It is found that the lens is a binary composed of two M dwarfs with masses M(1) = 0.18 ± 0.01 M(⊙) and M(2) = 0.16 ± 0.01 M(⊙) located at a distance D(L) = 1.35 ± 0.09 kpc. According to the estimated lens mass and distance, the flux from the lens comprises an important fraction, ~25%, of the blended flux. The bright nature of the lens combined with the high relative lens-source motion, μ = 6.94 ± 0.50 mas/yr, suggests that the lens can be directly observed from future high-resolution follow-up observations.

Published
2019
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18. Spitzer Microlensing of MOA-2016-BLG-231L: A Counter-rotating Brown Dwarf Binary in the Galactic Disk

Author

Sun-Ju Chung, Andrew Gould, Jan Skowron, Ian A. Bond, Wei Zhu, Michael D. Albrow, Youn Kil Jung, Cheongho Han, Kyu-Ha Hwang, Yoon-Hyun Ryu, In-Gu Shin, Yossi Shvartzvald, Jennifer C. Yee, Weicheng Zang, Sang-Mok Cha, Dong-Jin Kim, Hyoun-Woo Kim, Seung-Lee Kim, Yun-Hak Kim, Chung-Uk Lee, Dong-Joo Lee, Yongseok Lee, Byeong-Gon Park, Richard W. Pogge, Andrzej Udalski, Radek Poleski, Przemek Mroz, Pawel Pietrukowicz, Michal K. Szymanski, Igor Soszynski, Szymon Kozłowski, Krzysztof Ulaczyk, Michal Pawlak, Charles A. Beichman, Geoffery Bryden, Sebastiano Calchi Novati, Sean Carey, B. Scott Gaudi, Calen B. Henderson, Fumio Abe, Richard Barry, David Bennett, Aparna Bhattacharya, Martin Donachie, Akihiko Fukui, Yuki Hirao, Yoshitaka Itow, Kohei Kawasaki, Iona Kondo, Naoki Koshimoto, Man Cheung Alex Li, Yutaka Matsubara, Yasushi Muraki, Shota Miyazaki, Masayuki Nagakane, Clement Ranc, Nicholas J. Rattenbury, Haruno Suematsu, Denis J. Sullivan, Takahiro Sumi, Daisuke Suzuki, Paul J. Tristram, and Atsunori Yonehara

Subjects
Astrophysics
Abstract

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)= 21(+12, -5) M(J) and M(2)=9(+5. -2) M(J), and it is located in the Galactic disk D(L)=2.85(+0.88, -0.50) kpc. This is the fifth binary brown dwarf discovered by microlensing, and the BD binary is moving counter to the orbital motion of disk stars. Constraints on the lens physical properties come from late-time, non-caustic-crossing features of the Spitzer light curve. Thus, MOA-2016-BLG-231 shows how Spitzer plays a crucial role in resolving the nature of BDs in binary BD events with short timescales (≲10 days).

Published
2019
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19. OGLE-2013-BLG-0911Lb: A Secondary on the Brown-dwarf Planet Boundary around an M Dwarf

Author

Hiroshi Shibai, Valerio Bozza, Markus Rabus, N. Kains, R. W. Pogge, Shota Miyazaki, Y. Kamei, Giuseppe D'Ago, Darren L. DePoy, David P. Bennett, Man Cheung Alex Li, Michael D. Albrow, Masayuki Nagakane, P. Verma, Yoshitaka Itow, Shude Mao, Ian A. Bond, K. Ohnishi, S. KozŁowski, Daniel F. Evans, S. Calchi Novati, Dan Maoz, M. Friedmann, C. H. Ling, Jennifer C. Yee, P. Mróz, Nicholas J. Rattenbury, Haruno Suematsu, Jan Skowron, M. Hundertmark, To. Saito, Shai Kaspi, John Southworth, I. Porritt, Eamonn Kerins, Etienne Bachelet, Daisuke Suzuki, Akihiko Fukui, Ilan Manulis, Wise Team, Arnaud Cassan, Jesper Skottfelt, Yuki Hirao, Colin Snodgrass, Yutaka Matsubara, Andrzej Udalski, Tobias C. Hinse, Michał K. Szymański, C.-U. Lee, H. Ngan, Avishay Gal-Yam, Nuno Peixinho, Krzysztof Ulaczyk, R. W. Schmidt, Fumio Abe, Yossi Shvartzvald, Martin Donachie, Denis J. Sullivan, R. Figuera Jaimes, Gaetano Scarpetta, Hirosane Fujii, Luigi Mancini, Iain A. Steele, Andrew Gould, Clément Ranc, Tim Natusch, J. W. Menzies, A. Sharan, Iona Kondo, Taro Matsuo, Rachel Street, Yasushi Muraki, Atsunori Yonehara, T. Yamakawa, Keith Horne, Takahiro Sumi, Simona Ciceri, Jennie McCormick, G. W. Christie, Joachim Wambsganss, U. G. Jørgensen, Yiannis Tsapras, A. Popovas, P. Pietrukowicz, Radosław Poleski, Naoki Koshimoto, Łukasz Wyrzykowski, Martin Dominik, D. M. Bramich, Igor Soszyński, Heidi Korhonen, Richard K. Barry, Aparna Bhattacharya, RoboNet Collabofratino, Martin Burgdorf, Sohrab Rahvar, Paul J. Tristram, Science & Technology Facilities Council, University of St Andrews. School of Physics and Astronomy, and University of St Andrews. St Andrews Centre for Exoplanet Science

Subjects
astro-ph.SR, Extrasolar gas giants, 010504 meteorology & atmospheric sciences, Exoplanet astronomy, astro-ph.GA, Microlensing, Brown dwarf, FOS: Physical sciences, Boundary (topology), Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Gravitational microlensing, M dwarf stars, 01 natural sciences, Einstein radius, Planet, 0103 physical sciences, Exoplanet detection methods, QB Astronomy, Astrophysics::Solar and Stellar Astrophysics, Exoplanet systems, 010303 astronomy & astrophysics, QC, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, QB, 0105 earth and related environmental sciences, Earth and Planetary Astrophysics (astro-ph.EP), Physics, Brown dwarfs, Settore FIS/05, Exoplanets, Order (ring theory), Astronomy and Astrophysics, 3rd-DAS, Mass ratio, Astrophysics - Astrophysics of Galaxies, QC Physics, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), astro-ph.EP, High Energy Physics::Experiment, Astrophysics::Earth and Planetary Astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract

We present the analysis of the binary-lens microlensing event OGLE-2013-BLG-0911. The best-fit solutions indicate the binary mass ratio of q~0.03 which differs from that reported in Shvartzvald+2016. The event suffers from the well-known close/wide degeneracy, resulting in two groups of solutions for the projected separation normalized by the Einstein radius of s~0.15 or s~7. The finite source and the parallax observations allow us to measure the lens physical parameters. The lens system is an M-dwarf orbited by a massive Jupiter companion at very close (M_{host}=0.30^{+0.08}_{-0.06} M_{Sun}, M_{comp}=10.1^{+2.9}_{-2.2} M_{Jup}, a_{exp}=0.40^{+0.05}_{-0.04} au) or wide (M_{host}=0.28^{+0.10}_{-0.08} M_{Sun}, M_{comp}=9.9^{+3.8}_{-3.5}M_{Jup}, a_{exp}=18.0^{+3.2}_{-3.2} au) separation. Although the mass ratio is slightly above the planet-brown dwarf (BD) mass-ratio boundary of q=0.03 which is generally used, the median physical mass of the companion is slightly below the planet-BD mass boundary of 13M_{Jup}. It is likely that the formation mechanisms for BDs and planets are different and the objects near the boundaries could have been formed by either mechanism. It is important to probe the distribution of such companions with masses of ~13M_{Jup} in order to statistically constrain the formation theories for both BDs and massive planets. In particular, the microlensing method is able to probe the distribution around low-mass M-dwarfs and even BDs which is challenging for other exoplanet detection methods., Comment: 22 pages, 10 figures, Accepted for publication in The Astronomical Journal

Published
2020

20. Candidate Brown-dwarf Microlensing Events with Very Short Timescales and Small Angular Einstein Radii

Author

David P. Bennett, Yoshitaka Itow, Yoon-Hyun Ryu, Kyu-Ha Hwang, D. J. Sullivan, Ian A. Bond, Cheongho Han, Tsubasa Yamawaki, Szymon Kozłowski, Valerio Bozza, Igor Soszyński, Yuki Hirao, T. Yamakawa, Haruno Suematsu, Marcin Wrona, Yossi Shvartzvald, Yongseok Lee, Byeong-Gon Park, In-Gu Shin, Yuhei Kamei, Hikaru Shoji, Jennifer C. Yee, Krzysztof Ulaczyk, Chung-Uk Lee, Paul J. Tristram, Hirosane Fujii, Andrzej Udalski, Michał K. Szymański, Andrew Gould, Patryk Iwanek, Daisuke Suzuki, M. James Jee, Nicholas J. Rattenbury, Jan Skowron, Masayuki Nagakane, Michael D. Albrow, Sun-Ju Chung, Akihiko Fukui, Yasushi Muraki, Doeon Kim, Hyoun-Woo Kim, Atsunori Yonehara, Radek Poleski, Przemek Mróz, Shota Miyazaki, Fumio Abe, Clément Ranc, Weicheng Zang, Man Cheung Alex Li, Yuki Satoh, Takahiro Sumi, Seung-Lee Kim, Sang-Mok Cha, Dong-Jin Kim, Richard Barry, Richard W. Pogge, Yutaka Matsubara, Martin Donachie, Dong-Joo Lee, Iona Kondo, Youn Kil Jung, Naoki Koshimoto, Aparna Bhattacharya, Krzysztof A. Rybicki, and Paweł Pietrukowicz

Subjects
010504 meteorology & atmospheric sciences, Monte Carlo method, Brown dwarf, Binary number, FOS: Physical sciences, Astrophysics, Gravitational microlensing, 01 natural sciences, law.invention, symbols.namesake, law, 0103 physical sciences, Einstein, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), 0105 earth and related environmental sciences, Event (probability theory), Physics, Earth and Planetary Astrophysics (astro-ph.EP), Brown dwarfs, Astronomy and Astrophysics, Lens (optics), Stars, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, symbols, Astrophysics - Earth and Planetary Astrophysics
Abstract

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 $t_{\rm E}$ because short-timescale events can also be produced by stellar lenses with high relative lens-source proper motions. In this paper, we report three strong candidate BD-lens events found from the search for lensing events not only with short timescales ($t_{\rm E} \lesssim 6~{\rm days}$) but also with very small angular Einstein radii ($\theta_{\rm E}\lesssim 0.05~{\rm mas}$) among the events that have been found in the 2016--2019 observing seasons. These events include MOA-2017-BLG-147, MOA-2017-BLG-241, and MOA-2019-BLG-256, in which the first two events are produced by single lenses and the last event is produced by a binary lens. From the Bayesian analysis conducted with the combined $t_{\rm E}$ and $\theta_{\rm E}$ constraint, it is estimated that the lens masses of the individual events are $0.051^{+0.100}_{-0.027}~M_\odot$, $0.044^{+0.090}_{-0.023}~M_\odot$, and $0.046^{+0.067}_{-0.023}~M_\odot/0.038^{+0.056}_{-0.019}~M_\odot$ and the probability of the lens mass smaller than the lower limit of stars is $\sim 80\%$ for all events. We point out that routine lens mass measurements of short time-scale lensing events require survey-mode space-based observations., Comment: 9 pages, 6 figures

Published
2020

21. The lowest mass ratio planetary microlens: OGLE 2016–BLG–1195Lb

Author

Igor Soszyński, Aparna Bhattacharya, Fumio Abe, David P. Bennett, Masayuki Nagakane, Yasushi Muraki, Richard K. Barry, To. Saito, Man Cheung Alex Li, Yutaka Matsubara, Michał Pawlak, Atsunori Yonehara, Phil Evans, K. Ohnishi, C. H. Ling, Yoshitaka Itow, Yuichiro Asakura, Krzysztof Ulaczyk, A. Sharan, Daisuke Suzuki, T. Yamada, Kimiaki Masuda, Ian A. Bond, P. Pietrukowicz, Radosław Poleski, Naoki Koshimoto, Clément Ranc, Martin Donachie, Denis J. Sullivan, P. Mróz, Nicholas J. Rattenbury, Jan Skowron, Andrzej Udalski, Michał K. Szymański, Yuki Hirao, Valerio Bozza, Paul J. Tristram, Akihiko Fukui, Takahiro Sumi, and S. Kozlowski

Subjects
Earth and Planetary Astrophysics (astro-ph.EP), Physics, Solar mass, FOS: Physical sciences, Astronomy, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Mass ratio, Earth mass, Light curve, Gravitational microlensing, 01 natural sciences, Exoplanet, Space and Planetary Science, Planet, 0103 physical sciences, Astrophysics::Earth and Planetary Astrophysics, 010306 general physics, 010303 astronomy & astrophysics, Planetary mass, Astrophysics::Galaxy Astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract

We report discovery of the lowest mass ratio exoplanet to be found by the microlensing method in the light curve of the event OGLE~2016--BLG--1195. This planet revealed itself as a small deviation from a microlensing single lens profile from an examination of the survey data soon after the planetary signal. The duration of the planetary signal is $\sim 2.5\,$hours. The measured ratio of the planet mass to its host star is $q = 4.2\pm 0.7 \times10^{-5}$. We further estimate that the lens system is likely to comprise a cold $\sim$3 Earth mass planet in a $\sim\,$2 AU wide orbit around a 0.2 Solar mass star at an overall distance of 7.1 kpc., 8 pages, 5 figures, accepted for publication in MNRAS

Published
2017

22. The 2L1S/1L2S Degeneracy for Two Microlensing Planet Candidates Discovered by the KMTNet Survey in 2017

Author

C. Han, C.-U. Lee, Yutaka Matsubara, Akihiko Fukui, Aparna Bhattacharya, Paul J. Tristram, Fumio Abe, Masayuki Nagakane, T. Yamakawa, D.-J. Kim, Hirosane Fujii, Iona Kondo, Pascal Fouqué, Martin Donachie, In-Gu Shin, Hyoun-Woo Kim, Yasushi Muraki, Yoon-Hyun Ryu, Naoki Koshimoto, Denis J. Sullivan, Daisuke Suzuki, Yongseok Lee, Atsunori Yonehara, Harmon Suematsu, Sang-Mok Cha, Richard K. Barry, Shinyoung Kim, Jennifer C. Yee, Byeong-Gon Park, Y. Kamei, David P. Bennett, Ian A. Bond, Y. K. Jung, Nicholas J. Rattenbury, Yoshitaka Itow, Yuki Hirao, R. W. Pogge, Shota Miyazaki, Yossi Shvartzvald, Michael D. Albrow, Duk-Hang Lee, Andrew Gould, Clément Ranc, Weicheng Zang, Kyu-Ha Hwang, Takahiro Sumi, S. J. Chung, Man Cheung Alex Li, and Matthew T. Penny

Subjects
Physics, Earth and Planetary Astrophysics (astro-ph.EP), planets and satellites: detection, Proper motion, 010504 meteorology & atmospheric sciences, Astronomy, FOS: Physical sciences, Astronomy and Astrophysics, gravitational lensing: micro, Gravitational microlensing, 01 natural sciences, law.invention, Telescope, Space and Planetary Science, Planet, law, 0103 physical sciences, Degeneracy (biology), Astrophysics::Earth and Planetary Astrophysics, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Astrophysics - Earth and Planetary Astrophysics
Abstract

著者人数: 49名 (所属. 宇宙航空研究開発機構宇宙科学研究所(JAXA)(ISAS): 鈴木, 大介), Number of authors: 49 (Affiliation. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency(JAXA)(ISAS): Suzuki, Daisuke), Accepted: 2019-09-20, 資料番号: SA1190158000

Published
2019

23. OGLE-2018-BLG-1700L: Microlensing Planet in Binary Stellar System

Author

Igor Soszyński, Patryk Iwanek, Cheongho Han, Shota Miyazaki, Nicholas J. Rattenbury, Jan Skowron, In-Gu Shin, David P. Bennett, Hirosane Fujii, Yoshitaka Itow, Byeong-Gon Park, Andrew Gould, Clément Ranc, Daisuke Suzuki, Haruno Suematsu, Weicheng Zang, Masayuki Nagakane, Kyu-Ha Hwang, Paul J. Tristram, Takahiro Sumi, Radek Poleski, Ian A. Bond, Martin Donachie, Sang-Mok Cha, Denis J. Sullivan, Iona Kondo, Man Cheung Alex Li, M. James Jee, Dong-Joo Lee, Chung-Uk Lee, Akihiko Fukui, Andrzej Udalski, Michał K. Szymański, Doeon Kim, Jennifer C. Yee, Yuki Hirao, Przemek Mróz, Yossi Shvartzvald, Fumio Abe, Michael D. Albrow, Sun-Ju Chung, Richard W. Pogge, Yutaka Matsubara, Yuhei Kamei, Krzysztof Ulaczyk, Szymon Kozłowski, Youn Kil Jung, Dong-Jin Kim, Yoon-Hyun Ryu, Richard K. Barry, M. Wrona, Aparna Bhattacharya, Hyoun-Woo Kim, Krzysztof A. Rybicki, Yasushi Muraki, Yongseok Lee, Atsunori Yonehara, T. Yamakawa, Paweł Pietrukowicz, Seung-Lee Kim, and Naoki Koshimoto

Subjects
Physics, Earth and Planetary Astrophysics (astro-ph.EP), 010504 meteorology & atmospheric sciences, Binary number, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Mass ratio, Gravitational microlensing, 01 natural sciences, Einstein radius, 13. Climate action, Space and Planetary Science, Primary (astronomy), Planet, 0103 physical sciences, Binary star, Astrophysics::Earth and Planetary Astrophysics, Circumbinary planet, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Astrophysics - Earth and Planetary Astrophysics
Abstract

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 the fact that the complex anomaly pattern can be decomposed into two parts produced by two binary-lens events, in which one binary pair has a very low mass ratio of $\sim 0.01$ between the lens components and the other pair has a mass ratio of $\sim 0.3$. We find two sets of degenerate solutions, in which one solution has a projected separation between the primary and its stellar companion less than the angular Einstein radius $\thetae$ (close solution), while the other solution has a separation greater than $\thetae$ (wide solution). From the Bayesian analysis with the constraints of the event time scale and angular Einstein radius together with the location of the source lying in the far disk behind the bulge, we find that the planet is a super-Jupiter with a mass of $4.4^{+3.0}_{-2.0}~M_{\rm J}$ and the stellar binary components are early and late M-type dwarfs with masses $0.42^{+0.29}_{-0.19}~M_\odot$ and $0.12^{+0.08}_{-0.05}~M_\odot$, respectively, and the planetary system is located at a distance of $D_{\rm L}=7.6^{+1.2}_{-0.9}~{\rm kpc}$. The planet is a circumstellar planet according to the wide solution, while it is a circumbinary planet according to the close solution. The projected primary-planet separation is $2.8^{+3.2}_{-2.5}~{\rm au}$ commonly for the close and wide solutions, but the primary-secondary binary separation of the close solution, $0.75^{+0.87}_{-0.66}~{\rm au}$, is widely different from the separation, $10.5^{+12.1}_{-9.2}~{\rm au}$, of the wide solution., 10 pages, 8 figures

Published
2019

24. OGLE-2018-BLG-1011Lb,c: Microlensing Planetary System with Two Giant Planets Orbiting a Low-mass Star

Author

B. Scott Gaudi, Masayuki Nagakane, Andrzej Udalski, Man Cheung Alex Li, Michał K. Szymański, Radek Poleski, Charles Beichman, Jennifer C. Yee, Sun-Ju Chung, Kohei Kawasaki, Igor Soszyński, Matthew T. Penny, Paweł Pietrukowicz, Dong-Jin Kim, M. Hundertmark, Keivan G. Stassun, Etienne Bachelet, Chung-Uk Lee, Byeong-Gon Park, In-Gu Shin, Cheongho Han, Marcin Wrona, Richard Barry, Sebastiano Calchi Novati, Youn Kil Jung, Fumio Abe, Andrew Gould, Clément Ranc, Yasushi Muraki, Weicheng Zang, Yongseok Lee, Atsunori Yonehara, D. J. Lee, K. H. Hwang, Richard W. Pogge, Aparna Bhattacharya, Paul J. Tristram, Daisuke Suzuki, Yutaka Matsubara, Seung-Lee Kim, Michael D. Albrow, Haruno Suematsu, Arnaud Cassan, Yoon-Hyun Ryu, Kay-Sebastian Nikolaus, David P. Bennett, Hyoun-Woo Kim, K. A. Rybicki, Szymon Kozłowski, Krzysztof Ulaczyk, Pascal Fouqué, Valerio Bozza, Sang-Mok Cha, Kyeongsoo Hong, Yoshitaka Itow, Wei Zhu, Geoffery Bryden, Martin Donachie, Tianshu Wang, Shota Miyazaki, Denis J. Sullivan, Naoki Koshimoto, Calen B. Henderson, Savannah Jacklin, Shude Mao, Patryk Iwanek, Przemek Mróz, Nicholas J. Rattenbury, Jan Skowron, Ian A. Bond, Iona Kondo, Akihiko Fukui, Doeon Kim, Takahiro Sumi, Yuki Hirao, and Yossi Shvartzvald

Subjects
gravitational lensing: micro, planetary systems, Physics, Earth and Planetary Astrophysics (astro-ph.EP), 010504 meteorology & atmospheric sciences, Lens (geology), Binary number, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Planetary system, Gravitational microlensing, Light curve, 01 natural sciences, Space and Planetary Science, Planet, 0103 physical sciences, Anomaly (physics), Low Mass, 010303 astronomy & astrophysics, Astrophysics - Earth and Planetary Astrophysics, 0105 earth and related environmental sciences
Abstract

著者人数: Leading authors 13名, The KMTNet Collaboration 18名, The OGLE Collaboration 11名, The MOA Collaboration 22名, The CFHT Collaboration 5名, The UKIRT Microlensing Team 7名, 全66名 (所属. 宇宙航空研究開発機構宇宙科学研究所(JAXA)(ISAS): 鈴木, 大介), Number of authors: Leading authors 13, The KMTNet Collaboration 18, The OGLE Collaboration 11, The MOA Collaboration 22, The CFHT Collaboration 5, The UKIRT Microlensing Team 7, Total 66 (Affiliation. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency(JAXA)(ISAS): Suzuki, Daisuke), Accepted: 2019-07-02, 資料番号: SA1190106000

Published
2019

25. OGLE-2015-BLG-1649Lb: A gas giant planet around a low-mass dwarf

Author

M. Hundertmark, Man Cheung Alex Li, Nicholas J. Rattenbury, Jan Skowron, R. W. Schmidt, Igor Soszyński, Daisuke Suzuki, Yasushi Muraki, Y. Kamei, Atsunori Yonehara, Arnaud Cassan, Jean-Philippe Beaulieu, Jesper Skottfelt, Keith Horne, S. Kozlowski, Heidi Korhonen, Ian A. Bond, D. M. Bramich, Akihiko Fukui, Clément Ranc, John Southworth, Michael I. Andersen, Masayuki Nagakane, Martin Donachie, Denis J. Sullivan, Etienne Bachelet, Joachim Wambsganss, Richard K. Barry, Hirosane Fujii, Iain A. Steele, Nuno Peixinho, Andrzej Udalski, Michał K. Szymański, J. W. Menzies, Aparna Bhattacharya, U. G. Jørgensen, Yiannis Tsapras, Shota Miyazaki, Martin Burgdorf, Sohrab Rahvar, Yutaka Matsubara, Tobias C. Hinse, M. Rabus, Krzysztof Ulaczyk, Paul J. Tristram, P. Mróz, Haruno Suematsu, Giuseppe D'Ago, T. Yamakawa, Chien-Hsiu Lee, Daniel F. Evans, Shude Mao, Fumio Abe, Colin Snodgrass, Valerio Bozza, P. Pietrukowicz, Radosław Poleski, Naoki Koshimoto, Martin Dominik, R. Figuera Jaimes, Yuki Hirao, Iona Kondo, Taro Matsuo, Rachel Street, Takahiro Sumi, David P. Bennett, Yoshitaka Itow, Hiroshi Shibai, P. Longa, Osaka University [Osaka], Astronomical Observatory [Warsaw], Faculty of Physics [Warsaw] (FUW), University of Warsaw (UW)-University of Warsaw (UW), Institut d'Astrophysique de Paris (IAP), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Department of Physics [Notre Dame], University of Notre Dame [Indiana] (UND), University of Auckland [Auckland], Nagoya University, Department of Physics [Osaka], Osaka University, NASA Goddard Space Flight Center (GSFC), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Max-Planck-Institut für Astronomie (MPIA), Max-Planck-Gesellschaft, Ohio State University [Columbus] (OSU), Space Science Department of ESA, European Space Research and Technology Centre (ESTEC), European Space Agency (ESA)-European Space Agency (ESA), Max-Planck-Institut für Sonnensystemforschung (MPS), Niels Bohr Institute [Copenhagen] (NBI), Faculty of Science [Copenhagen], University of Copenhagen = Københavns Universitet (KU)-University of Copenhagen = Københavns Universitet (KU), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), University of Copenhagen = Københavns Universitet (KU), Kuopio Unit [FMI], Finnish Meteorological Institute (FMI), Instituto de Astrofisica de Canarias (IAC), University of St Andrews. School of Physics and Astronomy, University of St Andrews. St Andrews Centre for Exoplanet Science, Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), University of Copenhagen = Københavns Universitet (UCPH)-University of Copenhagen = Københavns Universitet (UCPH), and University of Copenhagen = Københavns Universitet (UCPH)

Subjects
Gas giant, Exoplanet astronomy, NDAS, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, Gravitational microlensing, 01 natural sciences, 0103 physical sciences, QB Astronomy, Astrophysics::Solar and Stellar Astrophysics, 010306 general physics, 010303 astronomy & astrophysics, QB600, QC, Astrophysics::Galaxy Astrophysics, QB, Earth and Planetary Astrophysics (astro-ph.EP), Physics, Exoplanet astronomy (486), Astronomy, Astronomy and Astrophysics, QC Physics, Space and Planetary Science, astro-ph.EP, Astrophysics::Earth and Planetary Astrophysics, Low Mass, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Gravitational microlensing (672), QB799, Astrophysics - Earth and Planetary Astrophysics
Abstract

著者人数: 69名 (所属. 宇宙航空研究開発機構宇宙科学研究所(JAXA)(ISAS): 鈴木, 大介), Number of authors: 69 (Affiliation. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency(JAXA)(ISAS): Suzuki, Daisuke), Accepted: 2019-09-25, 資料番号: SA1190157000

Published
2019

26. $Spitzer$ Parallax of OGLE-2018-BLG-0596: A Low-mass-ratio Planet around an M-dwarf

Author

C. Han, Richard Barry, Seung-Lee Kim, K. A. Rybicki, Chung-Uk Lee, Akihiko Fukui, Tianshu Wang, Fumio Abe, Shude Mao, Paul J. Tristram, Naoki Koshimoto, Takahiro Sumi, Sebastiano Calchi Novati, Masayuki Nagakane, Sang-Mok Cha, Igor Soszyński, Dong-Jin Kim, Richard W. Pogge, Yutaka Matsubara, Geoffery Bryden, Man Cheung Alex Li, W. Zang, Jennifer C. Yee, R. Poleski, Wei Zhu, S. Miyazaki, Haruno Suematsu, D. J. Lee, Yoon-Hyun Ryu, Andrzej Udalski, Clément Ranc, Michał K. Szymański, Calen B. Henderson, Keivan G. Stassun, Yasushi Muraki, Yuki Hirao, Yongseok Lee, Atsunori Yonehara, Yossi Shvartzvald, Aparna Bhattacharya, In-Gu Shin, Martin Donachie, Denis J. Sullivan, Pascal Fouqué, Spitzer Team, Przemek Mróz, Michael D. Albrow, Marcin Wrona, David P. Bennett, B. G. Park, Ian A. Bond, Sean Carey, B. Scott Gaudi, Szymon Kozłowski, Yoshitaka Itow, Youn Kil Jung, Iona Kondo, Matthew T. Penny, Charles A. Beichman, Andrew Gould, Paweł Pietrukowicz, Hyoun-Woo Kim, K. Ulaczyk, K. H. Hwang, Savannah Jacklin, Sun-Ju Chung, Daisuke Suzuki, Patryk Iwanek, Nicholas J. Rattenbury, and Jan Skowron

Subjects
Physics, Earth and Planetary Astrophysics (astro-ph.EP), Proper motion, 010504 meteorology & atmospheric sciences, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Mass ratio, Planetary system, Light curve, Gravitational microlensing, 01 natural sciences, Space and Planetary Science, Planet, Bulge, 0103 physical sciences, Astrophysics::Earth and Planetary Astrophysics, Low Mass, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Astrophysics - Earth and Planetary Astrophysics
Abstract

We report the discovery of a $Spitzer$ microlensing planet OGLE-2018-BLG-0596Lb, with preferred planet-host mass ratio $q \sim 2\times10^{-4}$. The planetary signal, which is characterized by a short $(\sim 1~{\rm day})$ "bump" on the rising side of the lensing light curve, was densely covered by ground-based surveys. We find that the signal can be explained by a bright source that fully envelops the planetary caustic, i.e., a "Hollywood" geometry. Combined with the source proper motion measured from $Gaia$, the $Spitzer$ satellite parallax measurement makes it possible to precisely constrain the lens physical parameters. The preferred solution, in which the planet perturbs the minor image due to lensing by the host, yields a Uranus-mass planet with a mass of $M_{\rm p} = 13.9\pm1.6~M_{\oplus}$ orbiting a mid M-dwarf with a mass of $M_{\rm h} = 0.23\pm0.03~M_{\odot}$. There is also a second possible solution that is substantially disfavored but cannot be ruled out, for which the planet perturbs the major image. The latter solution yields $M_{\rm p} = 1.2\pm0.2~M_{\oplus}$ and $M_{\rm h} = 0.15\pm0.02~M_{\odot}$. By combining the microlensing and $Gaia$ data together with a Galactic model, we find in either case that the lens lies on the near side of the Galactic bulge at a distance $D_{\rm L} \sim 6\pm1~{\rm kpc}$. Future adaptive optics observations may decisively resolve the major image/minor image degeneracy., 34 pages, 8 figures, Submitted to AAS journal

Published
2019

27. OGLE-2018-BLG-0022: First Prediction of an Astrometric Microlensing Signal from a Photometric Microlensing Event

Author

B. Scott Gaudi, K. A. Rybicki, Valerio Bozza, Andrzej Udalski, Michał K. Szymański, Yasushi Muraki, Jennifer C. Yee, Yongseok Lee, Paweł Pietrukowicz, Atsunori Yonehara, Masayuki Nagakane, Aparna Bhattacharya, Marcin Wrona, Seung-Lee Kim, David P. Bennett, Radek Poleski, Calen B. Henderson, Yoshitaka Itow, Sean Carey, K. H. Hwang, Takahiro Sumi, Andrew Gould, Woong-Tae Kim, Clément Ranc, Paul J. Tristram, Youn Kil Jung, Weicheng Zang, Kohei Kawasaki, Szymon Kozłowski, Przemek Mróz, Byeong-Gon Park, Dong-Jin Kim, Charles Beichman, D. J. Lee, Sun-Ju Chung, Ian A. Bond, Yuki Hirao, Man Cheung Alex Li, Richard W. Pogge, Cheongho Han, Yutaka Matsubara, Yossi Shvartzvald, Michael D. Albrow, Akihiko Fukui, Yoon-Hyun Ryu, Hyoun-Woo Kim, Doeon Kim, Daisuke Suzuki, Geoffery Bryden, Iona Kondo, Richard Barry, Krzysztof Ulaczyk, Arnaud Cassan, Shota Miyazaki, Naoki Koshimoto, Martin Donachie, Denis J. Sullivan, Patryk Iwanek, Nicholas J. Rattenbury, Jan Skowron, Igor Soszyński, In-Gu Shin, Chung-Uk Lee, Fumio Abe, Haruno Suematsu, and Sang-Mok Cha

Subjects
Physics, Proper motion, binaries: general, gravitational lensing: micro, 010308 nuclear & particles physics, FOS: Physical sciences, Astronomy, Centroid, Astronomy and Astrophysics, Gravitational microlensing, 01 natural sciences, Photometry (optics), Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Bulge, 0103 physical sciences, Satellite, Parallax, 010303 astronomy & astrophysics, Event (particle physics), Solar and Stellar Astrophysics (astro-ph.SR)
Abstract

著者人数: Leading authors 7名, The KMTNet Collaboration 20名, The MOA Collaboration 23名, The OGLE Collaboration 11名, Spitzer Microlensing Team 5名, 全66名 (所属. 宇宙航空研究開発機構宇宙科学研究所(JAXA)(ISAS): 鈴木, 大介), Number of authors: Leading authors 7, The KMTNet Collaboration 20, The MOA Collaboration 23, The OGLE Collaboration 11, Spitzer Microlensing Team 5, Total 66 (Affiliation. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency(JAXA)(ISAS): Suzuki, Daisuke), Accepted: 2019-04-02, 資料番号: SA1190031000

Published
2019

28. OGLE-2014-BLG-0962 and a Comparison of Galactic Model Priors to Microlensing Data

Author

Łukasz Wyrzykowski, Kohei Kawasaki, Masayuki Nagakane, Takahiro Sumi, Nicholas J. Rattenbury, Jan Skowron, Charles Beichman, Andrew Gould, Clément Ranc, Y. K. Jung, Haruno Suematsu, Daisuke Suzuki, Radosław Poleski, Naoki Koshimoto, Iona Kondo, Yasushi Muraki, Jennifer C. Yee, Atsunori Yonehara, Richard Barry, Yutong Shan, Yuki Hirao, Fumio Abe, David P. Bennett, M. Friedmann, Sean Carey, Yossi Shvartzvald, Yoshitaka Itow, Akihiko Fukui, Paweł Pietrukowicz, Spitzer Team, Paul J. Tristram, Shota Miyazaki, Szymon Kozłowski, P. Mróz, Man Cheung Alex Li, Richard W. Pogge, Yutaka Matsubara, Ian A. Bond, Krzysztof Ulaczyk, Dan Maoz, Igor Soszyński, In-Gu Shin, Aparna Bhattacharya, Shai Kaspi, Martin Donachie, Denis J. Sullivan, Sebastiano Calchi Novati, B. Scott Gaudi, Andrzej Udalski, and Michał K. Szymański

Subjects
Physics, methods: statistical, Astronomy and Astrophysics, Astrophysics, gravitational lensing: micro, Astrophysics::Cosmology and Extragalactic Astrophysics, Gravitational microlensing, Galaxy: bulge, Methods statistical, binaries: general, Space and Planetary Science, Bulge, stars: low-mass, Prior probability, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Astrophysics::Galaxy Astrophysics
Abstract

著者人数: 49名ほか (所属. 宇宙航空研究開発機構宇宙科学研究所 (JAXA)(ISAS): 鈴木, 大介), 資料番号: SA1180374000

Published
2019

29. Spitzer Microlensing Parallax for OGLE-2016-BLG-1067: A Sub-Jupiter Orbiting an M Dwarf in the Disk

Author

Charles A. Beichman, Radosław Poleski, Naoki Koshimoto, Yasushi Muraki, Yongseok Lee, Atsunori Yonehara, Clément Ranc, K. Kawasaki, David P. Bennett, Michał Pawlak, Yoshitaka Itow, Hyoun-Woo Kim, Takahiro Sumi, Richard Barry, Andrew Gould, K. H. Hwang, Paweł Pietrukowicz, Wei Zhu, Igor Soszyński, Nicholas J. Rattenbury, Jan Skowron, Sang-Mok Cha, Masayuki Nagakane, Yuki Hirao, K. Ulaczyk, W. Zang, Yossi Shvartzvald, Michael D. Albrow, Y. Asakura, Sean Carey, Spitzer Team, Ian A. Bond, Daisuke Suzuki, Geoffery Bryden, In-Gu Shin, Valerio Bozza, Paul J. Tristram, S. Miyazaki, C. H. Ling, P. Evans, Seung-Lee Kim, To. Saito, S. Calchi Novati, Chung-Uk Lee, C. Han, D. J. Lee, Dong-Jin Kim, Jennifer C. Yee, Fumio Abe, Andrzej Udalski, B. G. Park, Michał K. Szymański, Szymon Kozłowski, Man Cheung Alex Li, K. Ohnishi, S. J. Chung, Aparna Bhattacharya, Youn Kil Jung, Yoon-Hyun Ryu, Calen B. Henderson, Przemek Mróz, Martin Donachie, Denis J. Sullivan, B. S. Gaudi, Akihiko Fukui, Richard W. Pogge, Yutaka Matsubara, T. Yamada, and A. Sharan

Subjects
Earth and Planetary Astrophysics (astro-ph.EP), Physics, 010504 meteorology & atmospheric sciences, FOS: Physical sciences, Astronomy, Astronomy and Astrophysics, gravitational lensing: micro, planetary systems, Space and Planetary Science, Astrophysics::Cosmology and Extragalactic Astrophysics, Planetary system, Gravitational microlensing, 01 natural sciences, Jupiter, 0103 physical sciences, Astrophysics::Earth and Planetary Astrophysics, Parallax, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Astrophysics - Earth and Planetary Astrophysics, 0105 earth and related environmental sciences
Abstract

We report the discovery of a sub-Jupiter mass planet orbiting beyond the snow line of an M-dwarf most likely in the Galactic disk as part of the joint Spitzer and ground-based monitoring of microlensing planetary anomalies toward the Galactic bulge. The microlensing parameters are strongly constrained by the light curve modeling and in particular by the Spitzer-based measurement of the microlens parallax, $\pi_\mathrm{E}$. However, in contrast to many planetary microlensing events, there are no caustic crossings, so the angular Einstein radius, $\theta_\mathrm{E}$ has only an upper limit based on the light curve modeling alone. Additionally, the analysis leads us to identify 8 degenerate configurations: the four-fold microlensing parallax degeneracy being doubled by a degeneracy in the caustic structure present at the level of the ground-based solutions. To pinpoint the physical parameters, and at the same time to break the parallax degeneracy, we make use of a series of arguments: the $\chi^2$ hierarchy, the Rich argument, and a prior Galactic model. The preferred configuration is for a host at $D_L=3.73_{-0.67}^{+0.66}~\mathrm{kpc}$ with mass $M_\mathrm{L}=0.30_{-0.12}^{+0.15}~\mathrm{M_\odot}$, orbited by a Saturn-like planet with $M_\mathrm{planet}=0.43_{-0.17}^{+0.21}~\mathrm{M_\mathrm{Jup}}$ at projected separation $a_\perp = 1.70_{-0.39}^{+0.38}~\mathrm{au}$, about 2.1 times beyond the system snow line. Therefore, it adds to the growing population of sub-Jupiter planets orbiting near or beyond the snow line of M-dwarfs discovered by microlensing. Based on the rules of the real-time protocol for the selection of events to be followed up with Spitzer, this planet will not enter the sample for measuring the Galactic distribution of planets., Comment: Submitted to AAS Journals

Published
2019

30. Spitzer Microlensing of MOA-2016-BLG-231L : A Counter-Rotating Brown Dwarf Binary in the Galactic Disk

Author

Cheongho Han, David P. Bennett, Sang-Mok Cha, Kyu-Ha Hwang, Yasushi Muraki, Martin Donachie, Denis J. Sullivan, Atsunori Yonehara, Yongseok Lee, Yun Hak Kim, Wei Zhu, K. Kawasaki, Yoshitaka Itow, Hyoun-Woo Kim, Charles Beichman, Youn Kil Jung, Masayuki Nagakane, Shota Miyazaki, Sean Carey, Akihiko Fukui, Radek Poleski, Dong-Joo Lee, Yoon-Hyun Ryu, B. Scott Gaudi, Dong-Jin Kim, Ian A. Bond, Paweł Pietrukowicz, Andrew Gould, Clément Ranc, Nicholas J. Rattenbury, Jan Skowron, Chung-Uk Lee, Weicheng Zang, Andrzej Udalski, Michał K. Szymański, In-Gu Shin, Richard Barry, Seung-Lee Kim, Michał Pawlak, Igor Soszyński, Calen B. Henderson, Przemek Mróz, Yuki Hirao, Michael D. Albrow, Sun-Ju Chung, Naoki Koshimoto, Paul J. Tristram, Geoffery Bryden, Jennifer C. Yee, Sebastiano Calchi Novati, Yossi Shvartzvald, Man Cheung Alex Li, Richard W. Pogge, Yutaka Matsubara, Krzysztof Ulaczyk, Takahiro Sumi, Iona Kondo, Aparna Bhattacharya, Byeong-Gon Park, Fumio Abe, Szymon Kozłowski, Daisuke Suzuki, and Haruno Suematsu

Subjects
Physics, 010504 meteorology & atmospheric sciences, Brown dwarf, Binary number, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, gravitational lensing: micro, Gravitational microlensing, Light curve, 01 natural sciences, Stars, binaries: general, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, 0103 physical sciences, Orbital motion, Counter rotating, Disc, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), 0105 earth and related environmental sciences, brown dwarfs
Abstract

著者人数: 63名ほか(所属. 宇宙航空研究開発機構宇宙科学研究所 (JAXA)(ISAS): 鈴木, 大介), Accepted: 2018-12-11, 資料番号: SA1180353000

Published
2019

31. OGLE-2017-BLG-1186: first application of asteroseismology and Gaussian processes to microlensing

Author

R. Figuera Jaimes, Man Cheung Alex Li, Daniel Huber, Andrew A. Cole, K. H. Hwang, Calen B. Henderson, Masayuki Nagakane, I.-G. Shin, Wei Zhu, Sohrab Rahvar, Yasushi Muraki, Nuno Peixinho, C.-U. Lee, Steve Hennerley, Yuri I. Fujii, M. Rabus, Paul J. Tristram, Yongseok Lee, Andrzej Udalski, G. Bryden, Michał K. Szymański, C. von Essen, Penélope Longa-Peña, Radek Poleski, Atsunori Yonehara, Eduardo Unda-Sanzana, D. J. Lee, Lauri K. Haikala, Szymon Kozłowski, Naoki Koshimoto, Patryk Iwanek, B. S. Gaudi, Julie Green, Przemek Mróz, P. Fouqué, Daniel F. Evans, Thomas Henning, Jennifer C. Yee, M. Hundertmark, J.-P. Beaulieu, Iona Kondo, Richard W. Pogge, Yutaka Matsubara, Martin Dominik, K. Hill, Akihiko Fukui, Nicholas J. Rattenbury, Etienne Bachelet, Jan Skowron, Richard Barry, Tobias C. Hinse, Tianshu Wang, Michael D. Albrow, Igor Soszyński, Krzysztof Ulaczyk, Fumio Abe, Shota Miyazaki, Yoon-Hyun Ryu, S. Calchi Novati, Rachel Street, Aparna Bhattacharya, K. A. Rybicki, Byeong-Gon Park, Martin Donachie, Denis J. Sullivan, J. W. Blackman, J. Drummond, Sedighe Sajadian, Tim Natusch, Sang-Mok Cha, Takahiro Sumi, Martin Burgdorf, Daisuke Suzuki, Andrew Gould, Clément Ranc, Yuki Hirao, Weicheng Zang, Jesper Skottfelt, Yossi Shvartzvald, G. W. Christie, Luigi Mancini, Haruno Suematsu, I. Porritt, Dong-Jin Kim, S. S. Li, Ian A. Bond, John Southworth, D. Maoz, Shude Mao, Sean Carey, David P. Bennett, Yoshitaka Itow, Y. K. Jung, Valerio Bozza, Charles A. Beichman, Hyoun-Woo Kim, Chang S. Han, Colin Snodgrass, Christiane Helling, Paweł Pietrukowicz, Subo Dong, U. G. Jørgensen, Yiannis Tsapras, Seung-Lee Kim, S. J. Chung, University of St Andrews. School of Physics and Astronomy, and University of St Andrews. St Andrews Centre for Exoplanet Science

Subjects
oscillations [stars], Red giant, fundamental parameters [stars], DWARF STARS, Astrophysics, gravitational lensing: micro, 01 natural sciences, STANDARD, Angular diameter, Bulge, QB460, PROGRAM, QB Astronomy, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, QB, Earth and Planetary Astrophysics (astro-ph.EP), Physics, PLANET PHOTOMETRY, 3rd-DAS, Astrophysics - Solar and Stellar Astrophysics, stars: fundamental parameters, stars: oscillations, Astrophysics::Earth and Planetary Astrophysics, astro-ph.SR, STELLAR OSCILLATIONS, Brown dwarf, FOS: Physical sciences, asteroseismology, Astrophysics::Cosmology and Extragalactic Astrophysics, SUBGIANTS, Gravitational microlensing, Asteroseismology, Settore FIS/05 - Astronomia e Astrofisica, ANGULAR SIZES, SYSTEMS, 0103 physical sciences, Solar and Stellar Astrophysics (astro-ph.SR), DISTANCES, Astrophysics::Galaxy Astrophysics, 010308 nuclear & particles physics, Astronomy and Astrophysics, Light curve, SURFACE BRIGHTNESS RELATIONS, Space and Planetary Science, astro-ph.EP, micro [gravitational lensing], Parallax, QB799, Astrophysics - Earth and Planetary Astrophysics
Abstract

著者人数: 105名 (所属. 宇宙航空研究開発機構宇宙科学研究所(JAXA)(ISAS): 鈴木, 大介), Number of authors: 105 (Affiliation. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency(JAXA)(ISAS): Suzuki, Daisuke), Accepted: 2019-07-03, 資料番号: SA1190108000

Published
2019

32. OGLE-2016-BLG-0156: Microlensing Event With Pronounced Microlens-Parallax Effects Yielding Precise Lens Mass Measurement

Author

Paweł Pietrukowicz, Naoki Koshimoto, Kohei Kawasaki, Seung-Lee Kim, K. H. Hwang, Yasushi Muraki, Dong-Jin Kim, Yongseok Lee, Atsunori Yonehara, Chung-Uk Lee, David P. Bennett, Nicholas J. Rattenbury, Ian A. Bond, Jan Skowron, Yoshitaka Itow, Hyoun-Woo Kim, Richard Barry, Sun-Ju Chung, Daisuke Suzuki, Masayuki Nagakane, Fumio Abe, Aparna Bhattacharya, Radek Poleski, Sang-Mok Cha, Byeong-Gon Park, Yuki Hirao, Yossi Shvartzvald, Akihiko Fukui, Paul J. Tristram, Cheongho Han, Igor Soszyński, Haruno Suematsu, Doeon Kim, Iona Kondo, D. J. Lee, In-Gu Shin, Youn Kil Jung, Szymon Kozłowski, Richard W. Pogge, Yutaka Matsubara, Krzysztof Ulaczyk, Martin Donachie, Denis J. Sullivan, Takahiro Sumi, Andrzej Udalski, Michał K. Szymański, Michał Pawlak, M. James Jee, Yoon-Hyun Ryu, Michael D. Albrow, Przemek Mróz, Andrew Gould, Clément Ranc, Man Cheung Alex Li, Shota Miyazaki, and Jennifer C. Yee

Subjects
010504 meteorology & atmospheric sciences, Flux, FOS: Physical sciences, gravitational lensing: micro, Astrophysics, Gravitational microlensing, 01 natural sciences, law.invention, Einstein radius, Gravitation, law, 0103 physical sciences, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), 0105 earth and related environmental sciences, Physics, Microlens, Earth and Planetary Astrophysics (astro-ph.EP), Astronomy and Astrophysics, Light curve, Lens (optics), Astrophysics - Solar and Stellar Astrophysics, binaries: general, Space and Planetary Science, Parallax, Astrophysics - Earth and Planetary Astrophysics
Abstract

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 light curve exhibits 3 distinctive widely-separated peaks and we find that the multiple-peak feature provides a very tight constraint on the microlens-parallax effect, enabling us to precisely measure the microlens parallax $\pi_{\rm E}$. All the peaks are densely and continuously covered from high-cadence survey observations using globally located telescopes and the analysis of the peaks leads to the precise measurement of the angular Einstein radius $\theta_{\rm E}$. From the combination of the measured $\pi_{\rm E}$ and $\theta_{\rm E}$, we determine the physical parameters of the lens. It is found that the lens is a binary composed of two M dwarfs with masses $M_1=0.18\pm 0.01\ M_\odot$ and $M_2=0.16\pm 0.01\ M_\odot$ located at a distance $D_{\rm L}= 1.35\pm 0.09\ {\rm kpc}$. According to the estimated lens mass and distance, the flux from the lens comprises an important fraction, $\sim 25\%$, of the blended flux. The bright nature of the lens combined with the high relative lens-source motion, $\mu=6.94\pm 0.50\ {\rm mas}\ {\rm yr}^{-1}$, suggests that the lens can be directly observed from future high-resolution follow-up observations., Comment: 9 pages, 9 figures

Published
2019
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33. A Wide Orbit Exoplanet OGLE-2012-BLG-0838Lb

Author

Yuhei Kamei, Xiaojia Xie, Akihiko Fukui, Richard K. Barry, C. Han, Igor Soszyński, Daisuke Suzuki, David P. Bennett, Katie M. Morzinski, Łukasz Wyrzykowski, Yoshitaka Itow, Man Cheung Alex Li, Aparna Bhattacharya, Fumio Abe, J. P. Beaulieu, S. Kozlowski, Yasushi Muraki, Richard W. Pogge, Yutaka Matsubara, Y. Hirao, Atsunori Yonehara, Masayuki Nagakane, Yuki Satoh, Krzysztof Ulaczyk, Jared R. Males, Takahiro Sumi, Shota Miyazaki, Tsubasa Yamawaki, Ian A. Bond, Martin Donachie, Denis J. Sullivan, Hikaru Shoji, Iona Kondo, Paul J. Tristram, Hirosane Fujii, Haruno Suematsu, Jennifer C. Yee, J.-B. Marquette, Laird M. Close, Nicholas J. Rattenbury, Jan Skowron, P. Pietrukowicz, Radosław Poleski, Naoki Koshimoto, Andrzej Udalski, Michał K. Szymański, B. S. Gaudi, T. Yamakawa, Subo Dong, Andrew Gould, Clément Ranc, Department of Astronomy (Ohio State University), Ohio State University [Columbus] (OSU), Institut d'Astrophysique de Paris (IAP), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), M2A 2019, Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), and Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
010504 meteorology & atmospheric sciences, Einstein ring, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, Gravitational microlensing, 01 natural sciences, symbols.namesake, Planet, 0103 physical sciences, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Physics, Earth and Planetary Astrophysics (astro-ph.EP), Astronomy, Astronomy and Astrophysics, Radius, Exoplanet, [SDU.ASTR.IM]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], Orbit, Stars, Space and Planetary Science, symbols, Astrophysics::Earth and Planetary Astrophysics, Event (particle physics), Astrophysics - Earth and Planetary Astrophysics
Abstract

We present the discovery of a planet on a very wide orbit in the microlensing event OGLE-2012-BLG-0838. The signal of the planet is well separated from the main peak of the event and the planet-star projected separation is found to be twice larger than the Einstein ring radius, which roughly corresponds to a projected separation of ~4 AU. Similar planets around low-mass stars are very hard to find using any technique other than microlensing. We discuss microlensing model fitting in detail and discuss the prospects for measuring the mass and distance of lens system directly., Comment: 26 pages, 11 figures

Published
2019
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34. OGLE-2018-BLG-1269Lb: A Jovian Planet with a Bright I = 16 Host

Author

Masayuki Nagakane, Wei Zhu, Radek Poleski, Richard K. Barry, Richard W. Pogge, Andrzej Udalski, Michał K. Szymański, Yutaka Matsubara, Michael D. Albrow, Sang-Mok Cha, Sun-Ju Chung, Hyoun-Woo Kim, Yasushi Muraki, Akihiko Fukui, Atsunori Yonehara, Martin Donachie, Denis J. Sullivan, Byeong-Gon Park, Yongseok Lee, Cheongho Han, Marcin Wrona, Paweł Pietrukowicz, Kyu-Ha Hwang, Jennifer C. Yee, Andrew Gould, Clément Ranc, Weicheng Zang, Naoki Koshimoto, Takahiro Sumi, K. Ulaczyk, Haruno Suematsu, In-Gu Shin, Igor Soszyński, Yoon-Hyun Ryu, Szymon Kozłowski, Iona Kondo, Daisuke Suzuki, Chung-Uk Lee, Ian A. Bond, Seung-Lee Kim, Shota Miyazaki, Fumio Abe, Aparna Bhattacharya, Dong-Jin Kim, Man Cheung Alex Li, Yuki Hirao, Krzysztof A. Rybicki, Yossi Shvartzvald, Patryk Iwanek, Nicholas J. Rattenbury, Jan Skowron, David P. Bennett, Paul J. Tristram, Yoshitaka Itow, Youn Kil Jung, Dong-Joo Lee, and Przemek Mróz

Subjects
Earth and Planetary Astrophysics (astro-ph.EP), Physics, Proper motion, 010504 meteorology & atmospheric sciences, Subgiant, Metallicity, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Mass ratio, Gravitational microlensing, Astrophysics - Astrophysics of Galaxies, 01 natural sciences, Jovian, Gravitational lens, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Planet, Astrophysics of Galaxies (astro-ph.GA), 0103 physical sciences, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics - Earth and Planetary Astrophysics, 0105 earth and related environmental sciences
Abstract

We report the discovery of a planet in the microlensing event OGLE-2018-BLG-1269, with planet-host mass ratio $q \sim 6\times10^{-4}$, i.e., $0.6$ times smaller than the Jupiter/Sun mass ratio. Combined with the $Gaia$ parallax and proper motion, a strong one-dimensional constraint on the microlens parallax vector allows us to significantly reduce the uncertainties of lens physical parameters. A Bayesian analysis that ignores any information about light from the host yields that the planet is a cold giant $(M_{2} = 0.69_{-0.22}^{+0.44}\,M_{\rm J})$ orbiting a Sun-like star $(M_{1} = 1.13_{-0.35}^{+0.72}\,M_{\odot})$ at a distance of $D_{\rm L} = 2.56_{-0.62}^{+0.92}\,{\rm kpc}$. The projected planet-host separation is $a_{\perp} = 4.61_{-1.17}^{+1.70}\,{\rm au}$. Using {\it Gaia} astrometry, we show that the blended light lies $\lesssim 12\,$mas from the host and therefore must be either the host star or a stellar companion to the host. An isochrone analysis favors the former possibility at $>99.6\%$. The host is therefore a subgiant. For host metallicities in the range of $0.0 \leq {\rm [Fe/H]} \leq +0.3$, the host and planet masses are then in the range of $1.16 \leq M_{1}/M_{\odot} \leq 1.38$ and $0.74 \leq M_{2}/M_{\rm J} \leq 0.89$, respectively. Low host metallicities are excluded. The brightness and proximity of the lens make the event a strong candidate for spectroscopic followup both to test the microlensing solution and to further characterize the system., 40 pages, 11 figures, and 3 tables

Published
2020

35. One Planet or Two Planets? The Ultra-sensitive Extreme-magnification Microlensing Event KMT-2019-BLG-1953

Author

Martin Donachie, Clément Ranc, Naoki Koshimoto, Weicheng Zang, In-Gu Shin, Yoon-Hyun Ryu, Michael D. Albrow, Sun-Ju Chung, Shota Miyazaki, Akihiko Fukui, Daisuke Suzuki, Cheongho Han, Doeon Kim, Ian A. Bond, Tsubasa Yamawaki, Seung-Lee Kim, Jennifer C. Yee, Richard K. Barry, Richard W. Pogge, Yutaka Matsubara, Haruno Suematsu, Man Cheung Alex Li, Woong-Tae Kim, Masayuki Nagakane, Sang-Mok Cha, Hikaru Shoji, Andrew Gould, Rintaro Kirikawa, Yuzuru Tanaka, Dong-Jin Kim, Byeong-Gon Park, Paul J. Tristram, Nicholas J. Rattenbury, Fumio Abe, Hirosane Fujii, D. J. Lee, Kyu-Ha Hwang, Yuki Satoh, Takahiro Sumi, Chung-Uk Lee, Yuki Hirao, Aparna Bhattacharya, Iona Kondo, David P. Bennett, Yoshitaka Itow, Youn Kil Jung, Hyoun-Woo Kim, Yasushi Muraki, Yongseok Lee, Atsunori Yonehara, and Yossi Shvartzvald

Subjects
Earth and Planetary Astrophysics (astro-ph.EP), Physics, 010504 meteorology & atmospheric sciences, Event (relativity), FOS: Physical sciences, Magnification, Astronomy, Astronomy and Astrophysics, Gravitational microlensing, Astrophysics - Astrophysics of Galaxies, 01 natural sciences, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Planet, Astrophysics of Galaxies (astro-ph.GA), 0103 physical sciences, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics - Earth and Planetary Astrophysics, 0105 earth and related environmental sciences, Ultra sensitive
Abstract

We present the analysis of a very high-magnification ($A\sim 900$) microlensing event KMT-2019-BLG-1953. A single-lens single-source (1L1S) model appears to approximately delineate the observed light curve, but the residuals from the model exhibit small but obvious deviations in the peak region. A binary lens (2L1S) model with a mass ratio $q\sim 2\times 10^{-3}$ improves the fits by $\Delta\chi^2=181.8$, indicating that the lens possesses a planetary companion. From additional modeling by introducing an extra planetary lens component (3L1S model) and an extra source companion (2L2S model), it is found that the residuals from the 2L1S model further diminish, but claiming these interpretations is difficult due to the weak signals with $\Delta\chi^2=16.0$ and $13.5$ for the 3L1S and 2L2L models, respectively. From a Bayesian analysis, we estimate that the host of the planets has a mass of $M_{\rm host}=0.31^{+0.37}_{-0.17}~M_\odot$ and that the planetary system is located at a distance of $D_{\rm L}=7.04^{+1.10}_{-1.33}~{\rm kpc}$ toward the Galactic center. The mass of the securely detected planet is $M_{\rm p}=0.64^{+0.76}_{-0.35}~M_{\rm J}$. The signal of the potential second planet could have been confirmed if the peak of the light curve had been more densely observed by followup observations, and thus the event illustrates the need for intensive followup observations for very high-magnification events even in the current generation of high-cadence surveys., Comment: 10 pages, 9 figures

Published
2020

36. A Planetary Microlensing Event with an Unusually Red Source Star: MOA-2011-BLG-291

Author

Martin Donachie, Shai Kaspi, Paul J. Tristram, M. Friedmann, Igor Soszyński, David P. Bennett, Daisuke Suzuki, Fumio Abe, Man Cheung Alex Li, Richard W. Pogge, Łukasz Wyrzykowski, Jennifer C. Yee, B. Scott Gaudi, Koji Ohnishi, Paweł Pietrukowicz, Yutaka Matsubara, Yasushi Muraki, Naoki Koshimoto, Atsunori Yonehara, Masayuki Nagakane, Iona Kondo, Kohei Kawasaki, Radek Poleski, Krzysztof Ulaczyk, Szymon Kozłowski, Ian A. Bond, Darren L. DePoy, Akihiko Fukui, Richard Barry, Haruno Suematsu, Cheongho Han, Thiam-Guan Tan, Andrzej Udalski, Aparna Bhattacharya, Michał K. Szymański, Nicholas J. Rattenbury, Jan Skowron, D. Maoz, Takahiro Sumi, Yuki Hirao, Yossi Shvartzvald, Yoon-Hyun Ryu, Andrew Gould, Clément Ranc, Subo Dong, Shota Miyazaki, and V. Batista

Subjects
010504 meteorology & atmospheric sciences, FOS: Physical sciences, gravitational lensing: micro, Astrophysics::Cosmology and Extragalactic Astrophysics, Gravitational microlensing, 01 natural sciences, Planet, Bulge, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, planetary systems, 010303 astronomy & astrophysics, Red clump, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Physics, Earth and Planetary Astrophysics (astro-ph.EP), Subgiant, Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy, Astronomy and Astrophysics, Planetary system, Exoplanet, Stars, Space and Planetary Science, Astrophysics::Earth and Planetary Astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract

著者人数: 47名ほか（所属. 宇宙航空研究開発機構宇宙科学研究所(JAXA)(ISAS): 鈴木, 大介), Accepted: 2018-07-22, 資料番号: SA1180098000

Published
2018

37. A study of light travel time effect in short-period MOA eclipsing binaries via eclipse timing

Author

Ian A. Bond, Daisuke Suzuki, Paul J. Tristram, Masayuki Nagakane, Yutaka Matsubara, Man Cheung Alex Li, K. Ohnishi, Nicholas J. Rattenbury, Phil Evans, Akihiko Fukui, Yasushi Muraki, Martin Donachie, Denis J. Sullivan, Atsunori Yonehara, Yuichiro Asakura, Aparna Bhattacharya, A. Sharan, To. Saito, Naoki Koshimoto, Fumio Abe, Takahiro Sumi, David P. Bennett, Yoshitaka Itow, Yuki Hirao, Kimiaki Masuda, and Richard Barry

Subjects
Physics, 010308 nuclear & particles physics, media_common.quotation_subject, Library science, FOS: Physical sciences, Astronomy and Astrophysics, 01 natural sciences, Travel time, Promotion (rank), Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, 0103 physical sciences, Christian ministry, ECLIPSE (reservoir simulator), 010303 astronomy & astrophysics, Period (music), Solar and Stellar Astrophysics (astro-ph.SR), media_common
Abstract

A sample of 542 eclipsing binaries (EBs) with periods shorter than 2 d were selected from the Microlensing Observations in Astrophysics (MOA) EB catalogue (Li et al. 2017) for eclipse-time variation analysis. For this sample we were able to obtain the time series from MOA-II that span 9.5yr. We discovered 91 EBs, out of the 542 EBs, with detected light-travel-time effect signals suggesting the presence of tertiary companions of orbiting periods from 250 d-28 yr. The frequency of EBs with tertiary companions in our sample increases as the period decreases and reaches a value of 0.65 for contact binaries with periods shorter than 0.3 d. If only the contact binaries of periods < 0.26d are considered, the frequency even goes to the unit. Our results suggest that contact binaries with periods close to the 0.22-d contact binary limit are commonly accompanied by relatively close tertiary companions., 22 pages, 17 figures, MNRAS accepted

Published
2018

38. OGLE-2017-BLG-0482Lb: A Microlensing Super-Earth Orbiting a Low-mass Host Star

Author

Woong-Tae Kim, Krzysztof Ulaczyk, Igor Soszyński, Richard Barry, Yasushi Muraki, In-Gu Shin, Yongseok Lee, Atsunori Yonehara, Aparna Bhattacharya, Paul J. Tristram, S. Kozlowski, Akihiko Fukui, T. Yamada, Przemek Mróz, Patryk Iwanek, Wei Zhu, Kyu-Ha Hwang, Michał Pawlak, Doeon Kim, Valerio Bozza, To. Saito, Kohei Kawasaki, Krzysztof A. Rybicki, Nicholas J. Rattenbury, Jan Skowron, Andrew Gould, Clément Ranc, Yoon-Hyun Ryu, Shota Miyazaki, Phil Evans, Hyoun-Woo Kim, Masayuki Nagakane, Y. K. Jung, Daisuke Suzuki, H. Munakata, Jennifer C. Yee, Shinyoung Kim, Takahiro Sumi, S. J. Chung, Radek Poleski, Byeong-Gon Park, David P. Bennett, Ian A. Bond, D.-J. Kim, Fumio Abe, Andrzej Udalski, Michał K. Szymański, C.-U. Lee, Paweł Pietrukowicz, Yuki Hirao, Yoshitaka Itow, Yossi Shvartzvald, Naoki Koshimoto, Sang-Mok Cha, C. H. Ling, Michael D. Albrow, Duk-Hang Lee, Martin Donachie, Denis J. Sullivan, Richard W. Pogge, Yutaka Matsubara, Man Cheung Alex Li, K. Ohnishi, C. Han, and A. Sharan

Subjects
Earth and Planetary Astrophysics (astro-ph.EP), Physics, 010504 meteorology & atmospheric sciences, FOS: Physical sciences, Library science, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, gravitational lensing: micro, planetary systems, Space and Planetary Science, Gravitational microlensing, 01 natural sciences, Internet service, 0103 physical sciences, Astrophysics::Earth and Planetary Astrophysics, Space Science, Space research, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Astrophysics - Earth and Planetary Astrophysics
Abstract

著者人数: 65名ほか (所属. 宇宙航空研究開発機構宇宙科学研究所(JAXA)(ISAS): 鈴木, 大介), Accepted: 2018-03-27, 資料番号: SA1180046000

Published
2018

39. OGLE-2016-BLG-1190Lb: The First Spitzer Bulge Planet Lies Near the Planet/Brown-dwarf Boundary

Author

Yuki Hirao, Yossi Shvartzvald, Kimiaki Masuda, Hyoun-Woo Kim, Chang S. Han, B. S. Gaudi, Colin Snodgrass, R. W. Schmidt, I.-G. Shin, Z. Li, Sang-Mok Cha, Kouji Ohnishi, Sohrab Rahvar, Shinyoung Kim, S. J. Chung, Yoon-Hyun Ryu, Simon Cross, C.-U. Lee, Ian A. Bond, Masayuki Nagakane, G. Bryden, Matthew T. Penny, Calen B. Henderson, P. Mróz, S. Calchi Novati, Paul J. Tristram, J. MacKenzie, S. Kozlowski, Andrzej Udalski, Nicholas J. Rattenbury, C. von Essen, Michał K. Szymański, Jan Skowron, M. Hundertmark, A. Popovas, P. Pietrukowicz, Jennifer C. Yee, P. Longa, Y. K. Jung, Radosław Poleski, Naoki Koshimoto, Valerio Bozza, Richard K. Barry, Savannah Jacklin, C. H. Ling, Etienne Bachelet, Yasushi Muraki, Fumio Abe, C. A. Beichman, Rachel Street, Tianshu Wang, Shota Miyazaki, Yongseok Lee, Markus Rabus, Sedighe Sajadian, David P. Bennett, Atsunori Yonehara, Martin Donachie, Denis J. Sullivan, To. Saito, Man Cheung Alex Li, Daniel F. Evans, Kohei Kawasaki, Yoshitaka Itow, D. Maoz, R. Figuera Jaimes, Martin Dominik, Keith Horne, Joachim Wambsganss, Phil Evans, Iain A. Steele, Takahiro Sumi, A. Bhattacharya, Steve B. Howell, Simona Ciceri, Akihiko Fukui, Byeong-Gon Park, Dong-Joo Lee, U. G. Jørgensen, Yiannis Tsapras, John Southworth, Chelsea X. Huang, Igor Soszyński, Eamonn Kerins, Sean Carey, Wei Zhu, Kyu-Ha Hwang, Giuseppe D'Ago, Shude Mao, T. Yamada, Richard W. Pogge, Yutaka Matsubara, Tobias C. Hinse, D.-J. Kim, Krzysztof Ulaczyk, Daisuke Suzuki, M. Pawlak, Arnaud Cassan, Jesper Skottfelt, Yuichiro Asakura, S. K. Ment, Andrew Gould, Clément Ranc, Weicheng Zang, Michael D. Albrow, A. Sharan, Rosita Kokotanekova, Martin Burgdorf, Pascal Fouqué, Science & Technology Facilities Council, University of St Andrews. St Andrews Centre for Exoplanet Science, and University of St Andrews. School of Physics and Astronomy

Subjects
Gas giant, GRAVITATIONAL LENSING EXPERIMENT, Brown dwarf, FOS: Physical sciences, gravitational lensing: micro, Astrophysics::Cosmology and Extragalactic Astrophysics, Cathie Marsh Institute, Gravitational microlensing, 01 natural sciences, EARTH-MASS, MAGNIFICATION MICROLENSING EVENTS, JUPITER/SATURN ANALOG, micro [Gravitational lensing], 3rd-NDAS, GAS GIANTS, SYSTEMS, Bulge, Planet, QB460, 0103 physical sciences, PHOTOMETRY, QB Astronomy, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, QC, Astrophysics::Galaxy Astrophysics, QB, Earth and Planetary Astrophysics (astro-ph.EP), Physics, 010308 nuclear & particles physics, Astronomy, Astronomy and Astrophysics, MASS PLANET, Earth mass, Orbital period, TIME, micro, Astrophysics - Earth and Planetary Astrophysics [gravitational lensing], Stars, Space and Planetary Science, ResearchInstitutes_Networks_Beacons/cathie_marsh_institute, Astrophysics::Earth and Planetary Astrophysics, STARS, Astrophysics - Earth and Planetary Astrophysics
Abstract

著者人数: 110名(JAXA職員: 鈴木, 大介), Accepted: 2017-11-17, 資料番号: SA1170210000

Published
2018

40. OGLE-2014-BLG-0289: Precise Characterization of a Quintuple-peak Gravitational Microlensing Event

Author

Daisuke Suzuki, Paul J. Tristram, Wei Zhu, Chas Beichman, M. Hundertmark, Woong-Tae Kim, Fumio Abe, T. Yamada, Man Cheung Alex Li, Igor Soszyński, To. Saito, Cheongho Han, R. Figuera Jaimes, Richard Barry, Akihiko Fukui, S. Calchi Novati, C. H. Ling, S. Kozłowski, N. Kains, Giuseppe D'Ago, In-Gu Shin, Przemek Mróz, Richard W. Pogge, Kouji Ohnishi, Paweł Pietrukowicz, Yutaka Matsubara, Joachim Wambsganss, A. Sharan, Masayuki Nagakane, Jennifer C. Yee, Phil Evans, Andrew Gould, Valerio Bozza, Yasushi Muraki, Radosław Poleski, Naoki Koshimoto, Atsunori Yonehara, Krzysztof Ulaczyk, H. Munakata, Keith Horne, Etienne Bachelet, Clément Ranc, Nicholas J. Rattenbury, Jan Skowron, David P. Bennett, Takahiro Sumi, Andrzej Udalski, Michał K. Szymański, Sean Carey, Martin Donachie, Denis J. Sullivan, Yoshitaka Itow, Martin Dominik, Iain A. Steele, Łukasz Wyrzykowski, Yuki Hirao, Aparna Bhattacharya, Shota Miyazaki, Kohei Kawasaki, D. M. Bramich, Youn Kil Jung, Ian A. Bond, Kimiaki Masuda, J. W. Menzies, Colin Snodgrass, R. W. Schmidt, University of St Andrews. School of Physics and Astronomy, and University of St Andrews. St Andrews Centre for Exoplanet Science

Subjects
FOS: Physical sciences, Astrophysics, gravitational lensing: micro, Gravitational microlensing, 01 natural sciences, Einstein radius, law.invention, micro [Gravitational lensing], law, 0103 physical sciences, QB Astronomy, 010303 astronomy & astrophysics, QC, Solar and Stellar Astrophysics (astro-ph.SR), QB, Cusp (singularity), Physics, general [Binaries], 010308 nuclear & particles physics, DAS, Astronomy and Astrophysics, Light curve, binaries: general, Space and Planetary Science, Lens (optics), QC Physics, Astrophysics - Solar and Stellar Astrophysics, Caustic (optics), Parallax, Event (particle physics)
Abstract

著者人数: 66名(所属. 宇宙航空研究開発機構宇宙科学研究所(JAXA)(ISAS): 鈴木, 大介), Accepted: 2017-12-11, 資料番号: SA1170274000

Published
2018

41. OGLE-2015-BLG-1459L: The Challenges of Exo-Moon Microlensing

Author

Yoon-Hyun Ryu, Richard W. Pogge, Yutaka Matsubara, K. H. Hwang, Wei Zhu, Youn Kil Jung, Szymon Kozłowski, T. Yamada, Sang-Mok Cha, David P. Bennett, Shinyoung Kim, Takahiro Sumi, Kohei Kawasaki, Paweł Pietrukowicz, Dong-Jin Kim, Ian A. Bond, Paul J. Tristram, Byeong-Gon Park, Yoshitaka Itow, Phil Evans, Masayuki Nagakane, Martin Donachie, Denis J. Sullivan, Richard Barry, Aparna Bhattacharya, Igor Soszyński, Hyoun-Woo Kim, Yasushi Muraki, Fumio Abe, Nicholas J. Rattenbury, Jan Skowron, Yongseok Lee, Atsunori Yonehara, In-Gu Shin, Yuki Hirao, Radek Poleski, Shota Miyazaki, Akihiko Fukui, C. H. Ling, Kimiaki Masuda, Daisuke Suzuki, D. J. Lee, Michał Pawlak, Michael D. Albrow, Przemek Mróz, S. J. Chung, Andrew Gould, Clément Ranc, Yuichiro Asakura, Andrzej Udalski, Michał K. Szymański, A. Sharan, C. Han, Jennifer C. Yee, Krzysztof Ulaczyk, To. Saito, C.-U. Lee, Man Cheung Alex Li, K. Ohnishi, and Naoki Koshimoto

Subjects
Earth and Planetary Astrophysics (astro-ph.EP), Physics, 010504 meteorology & atmospheric sciences, FOS: Physical sciences, Library science, Astronomy and Astrophysics, gravitational lensing: micro, Astrophysics::Cosmology and Extragalactic Astrophysics, Gravitational microlensing, 01 natural sciences, Space and Planetary Science, 0103 physical sciences, Astrophysics::Earth and Planetary Astrophysics, Space Science, planetary systems, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Astrophysics - Earth and Planetary Astrophysics
Abstract

著者人数: 61名ほか (所属. 宇宙航空研究開発機構宇宙科学研究所(JAXA)(ISAS): 鈴木, 大介), Accepted: 2018-05-02, 資料番号: SA1180047000

Published
2017

42. Pluto Occultation on 2015 June 29 UTC With Central Flash and Atmospheric Spikes Just Before the New Horizons Flyby

Author

Masayuki Nagakane, Molly R. Kosiarek, Fumio Abe, Paul J. Tristram, Amanda S. Bosh, Carlos A. Zuluaga, Anicia Arredondo, Stephen E. Levine, Jay M. Pasachoff, Daisuke Suzuki, Rebecca F. Durst, Bryce A. Babcock, C. H. Seeger, and Amanda A. Sickafoose

Subjects
010504 meteorology & atmospheric sciences, Stratospheric Observatory for Infrared Astronomy, Astronomy, Astronomy and Astrophysics, 01 natural sciences, Occultation, law.invention, Pluto, Atmosphere, Telescope, Photometry (astronomy), Space and Planetary Science, law, Observatory, 0103 physical sciences, Magnitude (astronomy), 010303 astronomy & astrophysics, Geology, 0105 earth and related environmental sciences
Abstract

We observed the occultation by Pluto of a 12th magnitude star, one of the two brightest occultation stars ever in our dozen years of continual monitoring of Pluto's atmosphere through such studies, on 2015 June 29 UTC. At the Univ. of Canterbury Mt. John Observatory (New Zealand), under clear skies throughout, we used a POETS frame-transfer CCD at 10 Hz with GPS timing on the 1-m McLellan telescope as well as an infrared camera on an 0.6-m telescope and three-color photometry at a slower cadence on a second 0.6-m telescope. At the Auckland Observatory, we used a POETS and a PICO on 0.5-m and 0.4-m telescopes, with 0.4 s and 2 s cadences, respectively, obtaining ingress observations before clouds moved in. The Mt. John light curves show a central flash, indicating that we were close to the center of the occultation path. Analysis of our light curves show that Pluto's atmosphere remains robust. The presence of spikes at both sites in the egress and ingress shows atmospheric layering. We coordinated our observations with aircraft observations (Bosh et al., 2017) with the Stratospheric Observatory for Infrared Astronomy (SOFIA). Our chords helped constrain the path across Pluto that SOFIA saw. Our ground-based and airborne stellar-occultation effort came only just over two weeks of Earth days and two Pluto days before the flyby of NASA's New Horizons spacecraft.

Published
2017

43. The First Planetary Microlensing Event with Two Microlensed Source Stars

Author

Martin Donachie, Denis J. Sullivan, Michael D. Albrow, Andrew Williams, D. Dominis Prester, Kailash C. Sahu, K. R. Pollard, Joachim Wambsganss, Andrzej Udalski, Michał K. Szymański, Takahiro Sumi, Richard W. Pogge, Yutaka Matsubara, Masayuki Nagakane, S. R. Kane, M. Zub, J.-B. Marquette, Yuki Hirao, M. M. Rosenthal, M. Hundertmark, J.-P. Beaulieu, Krzysztof Ulaczyk, Man Cheung Alex Li, Darren L. DePoy, Ian A. Bond, Paul J. Tristram, Andrew A. Cole, C. H. Ling, Radosław Poleski, Andrew Gould, Clément Ranc, Yuichiro Asakura, Aparna Bhattacharya, Naoki Koshimoto, V. Batista, A. Sharan, Yasushi Muraki, Igor Soszyński, Atsunori Yonehara, R. Bowens-Rubin, S. Brillant, Keith Horne, P. Fouqué, Ch. Coutures, John A. R. Caldwell, S. Dieters, Phil Evans, Kimiaki Masuda, Chang S. Han, J. W. Menzies, N. Kains, Daisuke Suzuki, J. Donatowicz, Kouji Ohnishi, B. S. Gaudi, Nicholas J. Rattenbury, Jan Skowron, Fumio Abe, David P. Bennett, Yoshitaka Itow, Łukasz Wyrzykowski, Richard Barry, To. Saito, H. Oyokawa, Akihiko Fukui, Jennifer C. Yee, Etienne Bachelet, Institut d'Astrophysique de Paris (IAP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), CSNSM PCI, Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Okayama Astrophysical Observatory, National Astronomical Observatory of Japan (NAOJ), Laboratoire d'Etude et de Recherche sur le Matériau Bois (LERMAB), Université de Lorraine (UL), Institute of Geology and Geoinformation, Department of Materials Science [Tokyo], Tokyo Institute of Technology [Tokyo] (TITECH), Department of Earth and Space Science [Toyonaka-shi], Osaka University, Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Max-Planck-Institut für Astronomie (MPIA), Max-Planck-Gesellschaft, Department of Astronomy (Ohio State University), Ohio State University [Columbus] (OSU), Cyclotron Réunion Océan Indien (CYROI), Université de La Réunion (UR)-Centre Hospitalier Universitaire de La Réunion (CHU La Réunion), School of Mathematics and Physics, University of Tasmania [Hobart, Australia] (UTAS), Laboratoire Astrophysique de Toulouse-Tarbes (LATT), Centre National de la Recherche Scientifique (CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, M2A 2018, Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Department of Physics and Astronomy [Leicester], University of Leicester, Astronomische Rechen-Institut [Heidelberg] (ARI), Zentrum für Astronomie der Universität Heidelberg (ZAH), Universität Heidelberg [Heidelberg]-Universität Heidelberg [Heidelberg], Cranfield University, University of St Andrews. School of Physics and Astronomy, and University of St Andrews. St Andrews Centre for Exoplanet Science

Subjects
NDAS, FOS: Physical sciences, gravitational lensing: micro, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Gravitational microlensing, 01 natural sciences, micro [Gravitational lensing], Planet, 0103 physical sciences, Binary star, QB Astronomy, Astrophysics::Solar and Stellar Astrophysics, planetary systems, 010303 astronomy & astrophysics, QC, ComputingMilieux_MISCELLANEOUS, Astrophysics::Galaxy Astrophysics, QB, Earth and Planetary Astrophysics (astro-ph.EP), Physics, 010308 nuclear & particles physics, Astronomy and Astrophysics, Planetary system, Light curve, Exoplanet, [SDU.ASTR.IM]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], Planetary systems, Stars, QC Physics, Gravitational lens, Space and Planetary Science, Astrophysics::Earth and Planetary Astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract

著者人数: 68名(所属. 宇宙航空研究開発機構宇宙科学研究所(JAXA)(ISAS): 鈴木, 大介), Accepted: 2018-02-06, 資料番号: SA1170273000

Published
2017

44. The First Eclipsing Binary Catalogue from the MOA-II database

Author

Naoki Koshimoto, To. Saito, Paul J. Tristram, Yasushi Muraki, Atsunori Yonehara, Yutaka Matsubara, Masayuki Nagakane, Richard K. Barry, Man Cheung Alex Li, Ian A. Bond, K. Ohnishi, Akihiko Fukui, Phil Evans, Yuichiro Asakura, Martin Donachie, Denis J. Sullivan, Aparna Bhattacharya, A. Sharan, Takahiro Sumi, Fumio Abe, Kimiaki Masuda, Yuki Hirao, David P. Bennett, Yoshitaka Itow, C. H. Ling, M. Freeman, Nicholas J. Rattenbury, and Daisuke Suzuki

Subjects
Physics, 010308 nuclear & particles physics, media_common.quotation_subject, Library science, FOS: Physical sciences, Astronomy and Astrophysics, Base (topology), 01 natural sciences, Promotion (rank), Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Christian ministry, Astrophysics::Earth and Planetary Astrophysics, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, media_common
Abstract

We present the first catalogue of eclipsing binaries in two MOA fields towards the Galactic bulge, in which over 8,000 candidates, mostly contact and semi-detached binaries of periods < 1 d, were identified. In this paper, the light curves of a small number of interesting candidates including eccentric binaries, binaries with noteworthy phase modulations and eclipsing RS CVn type stars are shown as examples. In addition, we identified three triple object candidates by detecting the light-travel-time effect in their eclipse time variation curves., 13 pages, 9 figures, MNRAS accepted

Published
2017

45. OGLE-2016-BLG-1003: First Resolved Caustic-crossing Binary-source Event Discovered by Second-generation Microlensing Surveys

Author

Y. K. Jung, S. Kozlowski, Sang-Mok Cha, N. J. Rattenbury, Daisuke Suzuki, Takahiro Sumi, Igor Soszyński, C. H. Ling, Man Cheung Alex Li, Yuki Hirao, Akihiko Fukui, Andrzej Udalski, Paul J. Tristram, Y. Lee, Michał K. Szymański, R. W. Pogge, A. Bhattacharya, Byeong-Gon Park, Michael D. Albrow, Sun-Ju Chung, Yutaka Matsubara, Yuichiro Asakura, A. Sharan, C. Han, In-Gu Shin, Andrew Gould, Martin Donachie, Denis J. Sullivan, Michał Pawlak, Jan Skowron, P. A. Evans, Jennifer C. Yee, Kimiaki Masuda, Yoon-Hyun Ryu, K.-H. Hwang, Wei Zhu, K. Ulaczyk, David P. Bennett, P. Pietrukowicz, Radosław Poleski, Naoki Koshimoto, P. Mróz, Masayuki Nagakane, Seung-Lee Kim, Yoshitaka Itow, Fumio Abe, Ian A. Bond, C.-U. Lee, T. Yamada, H.-W. Kim, D.-J. Kim, Yasushi Muraki, Atsunori Yonehara, and Richard K. Barry

Subjects
Physics, 010504 meteorology & atmospheric sciences, Event (relativity), Binary number, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Gravitational microlensing, 01 natural sciences, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, 0103 physical sciences, Caustic (optics), 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), 0105 earth and related environmental sciences
Abstract

We report the analysis of the first resolved caustic-crossing binary-source microlensing event OGLE-2016-BLG-1003. The event is densely covered by the round-the-clock observations of three surveys. The light curve is characterized by two nested caustic-crossing features, which is unusual for typical caustic-crossing perturbations. From the modeling of the light curve, we find that the anomaly is produced by a binary source passing over a caustic formed by a binary lens. The result proves the importance of high-cadence and continuous observations, and the capability of second-generation microlensing experiments to identify such complex perturbations that are previously unknown. However, the result also raises the issues of the limitations of current analysis techniques for understanding lens systems beyond two masses and of determining the appropriate multiband observing strategy of survey experiments., 7 pages, 6 figures, Accepted for the publication in ApJ

Published
2017

46. A companion on the planet/brown dwarf mass boundary on a wide orbit discovered by gravitational microlensing

Author

J. B. Marquette, David P. Bennett, Yoshitaka Itow, Łukasz Wyrzykowski, Christian Clanton, Akihiko Fukui, Paul J. Tristram, Yutaka Matsubara, Aparna Bhattacharya, Krzysztof Ulaczyk, Clément Ranc, Kimiaki Masuda, Yuichiro Asakura, Martin Donachie, Denis J. Sullivan, Yasushi Muraki, J.-P. Beaulieu, A. Sharan, Atsunori Yonehara, Igor Soszyński, Richard Barry, V. Batista, Andrzej Udalski, Michał K. Szymański, Phil Evans, C. H. Ling, Szymon Kozłowski, Man Cheung Alex Li, Masayuki Nagakane, Paweł Pietrukowicz, To. Saito, Yuki Hirao, Daisuke Suzuki, Radosław Poleski, Naoki Koshimoto, Scott Gaudi, Takahiro Sumi, Kouji Ohnishi, Toru Yamada, Nicholas J. Rattenbury, Jan Skowron, Ian A. Bond, Fumio Abe, Ohio State University [Columbus] (OSU), Astronomical Observatory [Warsaw], Faculty of Physics [Warsaw] (FUW), University of Warsaw (UW)-University of Warsaw (UW), Massey University, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Institut d'Astrophysique de Paris (IAP), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), University of Tasmania [Hobart, Australia] (UTAS), NASA Ames Research Center (ARC), University of Warwick [Coventry], NASA Goddard Space Flight Center (GSFC), Osaka University [Osaka], University of Auckland [Auckland], Nagoya University, The University of Notre Dame [Sydney], Okayama Astrophysical Observatory (OAO), National Astronomical Observatory of Japan (NAOJ), College of Physics and Energy, Shenzhen University, National Institute of Technology, Nagano College (NIT Nagano), Tokyo Metropolitan College of Industrial Technology, Victoria University [Melbourne], Mount John Observatory, University of Canterbury [Christchurch], Kyoto Sangyo University, and Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Earth and Planetary Astrophysics (astro-ph.EP), [PHYS]Physics [physics], 010308 nuclear & particles physics, Giant planet, Brown dwarf, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Mass ratio, Planetary system, Gravitational microlensing, 01 natural sciences, Orbit, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Primary (astronomy), Planet, 0103 physical sciences, 10. No inequality, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), ComputingMilieux_MISCELLANEOUS, Astrophysics - Earth and Planetary Astrophysics
Abstract

We present the discovery of a substellar companion to the primary host lens in the microlensing event MOA-2012-BLG-006. The companion-to-host mass ratio is 0.016, corresponding to a companion mass of $\approx8~M_{\rm Jup} (M_*/0.5M_\odot)$. Thus, the companion is either a high-mass giant planet or a low-mass brown dwarf, depending on the mass of the primary $M_*$. The companion signal was separated from the peak of the primary event by a time that was as much as four times longer than the event timescale. We therefore infer a relatively large projected separation of the companion from its host of $\approx10~{\rm a.u.}(M_*/0.5M_\odot)^{1/2}$ for a wide range (3-7 kpc) of host star distances from the Earth. We also challenge a previous claim of a planetary companion to the lens star in microlensing event OGLE-2002-BLG-045., 16 pages, 5 figures

Published
2017

47. Ground-based parallax confirmed by Spitzer: binary microlensing event MOA-2015-BLG-020

Author

Jennifer C. Yee, Igor Soszyński, K.-H. Hwang, David P. Bennett, Andrew Gould, Clément Ranc, Martin Donachie, Denis J. Sullivan, Iain A. Steele, Valerio Bozza, Y. Yee, Etienne Bachelet, Yoshitaka Itow, M. Hundertmark, Man Cheung Alex Li, S. L. Kim, I.-G. Shin, K. Kawasaki, Wei Zhu, Richard K. Barry, J. W. Menzies, Sean Carey, M. Pawlak, P. Pietrukowicz, Yuki Hirao, Radosław Poleski, Naoki Koshimoto, Michael D. Albrow, Sun-Ju Chung, Ian A. Bond, C.-U. Lee, Paul J. Tristram, Hyoun-Woo Kim, T. Yamada, B. Wibking, Yoon-Hyun Ryu, C. H. Ling, Calen B. Henderson, Shude Mao, Hiroshi Shibai, C. A. Beichman, Masayuki Nagakane, Kimiaki Masuda, Yossi Shvartzvald, Andrzej Udalski, Akihiko Fukui, Michael Fausnaugh, Michał K. Szymański, Richard W. Pogge, Yutaka Matsubara, Satoshi Miyazaki, Chang S. Han, P. Mróz, Martin Dominik, B. S. Gaudi, Krzysztof Ulaczyk, Colin Snodgrass, R. Figuera Jaimes, To. Saito, D.-J. Kim, G. Bryden, Yasushi Muraki, Atsunori Yonehara, R. W. Schmidt, Joachim Wambsganss, Keith Horne, Yiannis Tsapras, Y. K. Jung, S. Kozlowski, Rachel Street, Kouji Ohnishi, Yuichiro Asakura, Tianshu Wang, Nicholas J. Rattenbury, Jan Skowron, Takahiro Sumi, A. Sharan, Daisuke Suzuki, Arnaud Cassan, P. A. Evans, S. Calchi Novati, Sang-Mok Cha, Fumio Abe, Byeong-Gon Park, A. Bhattacharya, D. M. Bramich, University of St Andrews. School of Physics and Astronomy, and University of St Andrews. St Andrews Centre for Exoplanet Science

Subjects
010504 meteorology & atmospheric sciences, bulge [Galaxy], FOS: Physical sciences, Astrophysics, gravitational lensing: micro, Astrophysics::Cosmology and Extragalactic Astrophysics, Gravitational microlensing, 01 natural sciences, Galaxy: bulge, Einstein radius, general [binaries], Bulge, 0103 physical sciences, QB Astronomy, Astrophysics::Solar and Stellar Astrophysics, Disc, 010303 astronomy & astrophysics, Red clump, QC, Astrophysics::Galaxy Astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), 0105 earth and related environmental sciences, QB, Physics, Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy and Astrophysics, 3rd-DAS, Light curve, Stars, QC Physics, binaries: general, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, micro [gravitational lensing], Astrophysics::Earth and Planetary Astrophysics, Parallax
Abstract

著者人数: 86名 (JAXA職員: 鈴木, 大介), Accepted: 2017-07-14, 資料番号: SA1170116000

Published
2017
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48. OGLE-2016-BLG-0263L\lowercase{b}: Microlensing Detection of a Very Low-mass Binary Companion Through a Repeating Event Channel

Author

Yutaka Matsubara, C.-U. Lee, Michał Pawlak, Krzysztof Ulaczyk, I.-G. Shin, David P. Bennett, Jennifer C. Yee, Paul J. Tristram, Yoshitaka Itow, Richard K. Barry, Andrew Gould, Clément Ranc, Phil Evans, Yasushi Muraki, Yongseok Lee, Atsunori Yonehara, Ian A. Bond, C. Han, Martin Donachie, Denis J. Sullivan, Wei Zhu, T. Yamada, Byeong-Gon Park, Dong-Jin Kim, Masayuki Nagakane, C. H. Ling, Man Cheung Alex Li, Y. K. Jung, K. Ohnishi, P. Pietrukowicz, Radosław Poleski, Naoki Koshimoto, P. Mróz, Takahiro Sumi, Michael D. Albrow, To. Saito, Yuichiro Asakura, Nicholas J. Rattenbury, Jan Skowron, Igor Soszyński, A. Sharan, Yoon-Hyun Ryu, Fumio Abe, Daisuke Suzuki, Yuki Hirao, Kimiaki Masuda, Sang-Mok Cha, S. J. Chung, Andrzej Udalski, Michał K. Szymański, Seung-Lee Kim, Aparna Bhattacharya, Akihiko Fukui, and S. Kozlowski

Subjects
Physics, Earth and Planetary Astrophysics (astro-ph.EP), 010504 meteorology & atmospheric sciences, Channel (digital image), Event (relativity), Brown dwarf, Binary number, FOS: Physical sciences, Astronomy and Astrophysics, gravitational lensing: micro, Astrophysics, Planetary system, Gravitational microlensing, 01 natural sciences, Space and Planetary Science, 0103 physical sciences, Low Mass, planetary systems, 010303 astronomy & astrophysics, Astrophysics - Earth and Planetary Astrophysics, brown dwarfs, 0105 earth and related environmental sciences
Abstract

著者人数: 55名 (JAXA職員: 鈴木, 大介), Accepted: 2017-08-08, 資料番号: SA1170115000

Published
2017
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49. Chemical evolution of the Galactic bulge as traced by microlensed dwarf and subgiant stars. VI. Age and abundance structure of the stellar populations in the central sub-kpc of the Milky Way

Author

Krzysztof Ulaczyk, Daisuke Suzuki, J. M. Pawlak, Igor Soszyński, Masayuki Nagakane, Jennifer A. Johnson, L. M. Howes, A. Wyrzykowski, Jennifer C. Yee, Thomas Bensby, P. J. Tristram, Takahiro Sumi, Jan Skowron, Jorge Melendez, Yuki Hirao, P. Mróz, Aparna Bhattacharya, Andrzej Udalski, Michał K. Szymański, Sara Lucatello, P. Pietrukowicz, Yuichiro Asakura, Radosław Poleski, Naoki Koshimoto, Fumio Abe, Andrew Gould, Andrew McWilliam, S. Kozlowski, Martin Asplund, Ian A. Bond, Sofia Feltzing, David P. Bennett, ITA, USA, GBR, FRA, DEU, and SWE

Subjects
Physics, 010308 nuclear & particles physics, Star formation, Metallicity, Milky Way, Galactic Center, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Astrophysics - Astrophysics of Galaxies, Galaxy, Space and Planetary Science, Bulge, Astrophysics of Galaxies (astro-ph.GA), 0103 physical sciences, Thick disk, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, 10. No inequality, ABUNDÂNCIA ESTELAR, 010303 astronomy & astrophysics, Red clump, Astrophysics::Galaxy Astrophysics
Abstract

We present a detailed elemental abundance study of 90 F and G dwarf, turn-off and subgiant stars in the Galactic bulge. Based on high-resolution spectra acquired during gravitational microlensing events, stellar ages and abundances for 11 elements (Na, Mg, Al, Si, Ca, Ti, Cr, Fe, Zn, Y and Ba) have been determined. We find that the Galactic bulge has a wide metallicity distribution with significant peaks at [Fe/H]=-1.09, -0.63, -0.20, +0.12, +0.41. We also find a high fraction of intermediate-age to young stars: at [Fe/H]>0 more than 35 % are younger than 8 Gyr. For [Fe/H], Comment: Accepted for publication in A&A

Published
2017

50. OGLE-2016-BLG-1469L: Microlensing Binary Composed of Brown Dwarfs

Author

P. Pietrukowicz, Radosław Poleski, Naoki Koshimoto, Yuichiro Asakura, Yasushi Muraki, Atsunori Yonehara, A. Sharan, Michael D. Albrow, Nicholas J. Rattenbury, Paul J. Tristram, Jan Skowron, Andrew Gould, C. Han, Richard K. Barry, Ian A. Bond, Michał Pawlak, David P. Bennett, S. Kozlowski, Igor Soszyński, C.-U. Lee, Daisuke Suzuki, Yoshitaka Itow, C. H. Ling, In-Gu Shin, Sang-Mok Cha, D.-J. Kim, M. Freeman, To. Saito, Y. Lee, Wei Zhu, Andrzej Udalski, Michał K. Szymański, T. Yamada, Byeong-Gon Park, Masayuki Nagakane, Fumio Abe, Kimiaki Masuda, Yoon-Hyun Ryu, Y. K. Jung, S. J. Chung, H. Oyokawa, Akihiko Fukui, Jennifer C. Yee, S. L. Kim, P. Mróz, Yutaka Matsubara, Man Cheung Alex Li, K. Ohnishi, Yuki Hirao, Krzysztof Ulaczyk, Martin Donachie, Denis J. Sullivan, Takahiro Sumi, and Aparna Bhattacharya

Subjects
Physics, Earth and Planetary Astrophysics (astro-ph.EP), Solar mass, 010504 meteorology & atmospheric sciences, Brown dwarf, Binary number, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Gravitational microlensing, 01 natural sciences, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Physics::Space Physics, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), 0105 earth and related environmental sciences, Astrophysics - Earth and Planetary Astrophysics
Abstract

We report the discovery of a binary composed of two brown dwarfs, based on the analysis of the microlensing event OGLE-2016-BLG-1469. Thanks to detection of both finite-source and microlens-parallax effects, we are able to measure both the masses $M_1\sim 0.05\ M_\odot$, $M_2\sim 0.01\ M_\odot$, and distance $D_{\rm L} \sim 4.5$ kpc, as well as the projected separation $a_\perp \sim 0.33$ au. This is the third brown-dwarf binary detected using the microlensing method, demonstrating the usefulness of microlensing in detecting field brown-dwarf binaries with separations less than 1 au., Comment: 8 pages, 8 figures

Published
2017
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