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1. Ogle-2018-BLG-0799lb: A Q ∼ 2.7 × 10(−3) Planet With Spitzer Parallax

Author

Weicheng Zang, Yossi Shvartzvald, Andrzej Udalski, Jennifer C. Yee, Chung-Uk Lee, Takahiro Sumi, Xiangyu Zhang, Hongjing Yang, Shude Mao, Sebastiano Calchi Novati, Andrew Gould, Wei Zhu, Charles A. Beichman, Geoffery Bryden, Sean Carey, B. Scott Gaudi, Calen B. Henderson, Przemek Mroz, Jan Skowron, Radoslaw Poleski, Michał K. Szymanski, Igor Soszynski, Paweł Pietrukowicz, Szymon Kozłowski, Krzysztof Ulaczyk, Krzysztof A. Rybicki, Patryk Iwanek, Marcin Wrona, Michael D. Albrow, Sun-Ju Chung, Cheongho Han, Kyu-Ha Hwang, Youn Kil Jung, Yoon-Hyun Ryu, In-Gu Shin, Richard Barry, and David P. Bennett

Subjects
Astrophysics
Abstract

We report the discovery and analysis of a planet in the microlensing event OGLE-2018-BLG-0799. The planetary signal was observed by several ground-based telescopes, and the planet-host mass ratio is q = (2.65 ± 0.16) × 10(−3). The ground-based observations yield a constraint on the angular Einstein radius θE, and the microlensing parallax vector πE, is strongly constrained by the Spitzer data. However, the 2019 Spitzer baseline data reveal systematics in the Spitzer photometry, so there is ambiguity in the magnitude of the parallax. In our preferred interpretation, a full Bayesian analysis using a Galactic model indicates that the planetary system is composed of an Mplanet = 0.26+0.22 −0.11M(J) planet orbiting an Mhost = 0.093+0.082 −0.038 Mʘ , at a distance of DL = 3.71+3.24 −1.70 kpc. An alternate interpretation of the data shifts the localization of the minima along the arc-shaped microlens parallax constraints. This, in turn, yields a more massive host with median mass of 0.13 Mʘ at a distance of 6.3 kpc. This analysis demonstrates the robustness of the osculating circles formalism, but shows that further investigation is needed to assess how systematics affect the specific localization of the microlens parallax vector and, consequently, the inferred physical parameters.

Published
2022
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2. Systematic KMTNet Planetary Anomaly Search. I. OGLE-2019-BLG-1053Lb, a BuriedTerrestrial Planet

Author

Weicheng Zang, Kyu-Ha Hwang, Andrzej Udalski, Tianshu Wang, Wei Zhu, Takahiro Sumi, Jennifer C. Yee, Andrew Gould, Shude Mao, Xiangyu Zhang, Michael D. Albrow, Sun-Ju Chung, Cheongho Han, Youn Kil Jung, 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, Jan Skowron, Radoslaw Poleski, Michał K. Szymański, Igor Soszyński, Paweł Pietrukowicz, Szymon Kozłowski, Krzysztof Ulaczyk, Krzysztof A. Rybicki, Patryk Iwanek, Marcin Wrona, Mariusz Gromadzki, Ian A. Bond, Fumio Abe, Richard Barry, David P. Bennett, Aparna Bhattacharya, Martin Donachie, Hirosane Fujii, Akihiko Fukui, Yuki Hirao, Yoshitaka Itow, Rintaro Kirikawa, Iona Kondo, Naoki Koshimoto, Man Cheung Alex Li, Yutaka Matsubara, Yasushi Muraki, Shota Miyazaki, Greg Olmschenk, Clément Ranc, Nicholas J. Rattenbury, Yuki Satoh, Hikaru Shoji, Stela Ishitani Silva, Daisuke Suzuki, Yuzuru Tanaka, Paul J. Tristram, Tsubasa Yamawaki, Atsunori Yonehara, Geoffery Bryden, B. Scott Gaudi, and Samson Johnson

Subjects
Astronomy
Abstract

In order to exhume the buried signatures of “missing planetary caustics” in Korea Microlensing Telescope Network (KMTNet) data, we conducted a systematic anomaly search of the residuals from point-source point-lens fits, based on a modified version of the KMTNet Event Finder algorithm. This search revealed the lowest-mass-ratio planetary caustic to date in the microlensing event OGLE-2019-BLG-1053, for which the planetary signal had not been noticed before. The planetary system has a planet–host mass ratio ofq= (1.25±0.13) × 10−5. A Bayesian analysis yielded estimates of the mass of the host star, Mhost =-0.61+0.29 -0.24 Mo, the mass of its planet, Mplanet =-2.48 +1.19 -0.98 Mo, the projected planet – host separation, a^= 3.4 +0.5/-0.5 au, and the lens distance, DL =-6.8 +0.6 -0.90kpc.The discovery of this very-low-mass-ratio planet illustrates the utility of our method and opens a new window for a large and homogeneous sample to study the microlensing planet–host mass ratio function down to q∼ 10−5.

Published
2021
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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. 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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5. 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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6. 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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7. 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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8. 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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9. OGLE-2016-BLG-1093Lb: A Sub-Jupiter-mass Spitzer Planet Located in Galactic Bulge

Author

In-Gu Shin, Jennifer C. Yee, Kyu-Ha Hwang, Andrew Gould, Andrzej Udalski, Ian A. Bond, Michael D. Albrow, Sun-Ju Chung, Cheongho Han, Youn Kil Jung, Hyoun Woo Kim, Yoon-Hyun Ryu, Yossi Shvartzvald, Weicheng Zang, Sang-Mok Cha, Dong-Jin Kim, Seung-Lee Kim, Chung-Uk Lee, 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, Charles A. Beichman, Geoffery Bryden, Sebastiano Calchi Novati, Sean Carey, B. Scott Gaudi, Calen B. Henderson, Wei Zhu, Fumio Abe, Richard K. Barry, David P. Bennett, Aparna Bhattacharya, Hirosane Fujii, Akihiko Fukui, Yuki Hirao, Yoshitaka Itow, Rintaro Kirikawa, Naoki Koshimoto, Iona Kondo, Yutaka Matsubara, Sho Matsumoto, Shota Miyazaki, Yasushi Muraki, Greg Olmschenk, Arisa Okamura, Clément Ranc, Nicholas J. Rattenbury, Yuki Satoh, Stela Ishitani Silva, Takahiro Sumi, Daisuke Suzuki, Taiga Toda, Paul J. Tristram, Aikaterini Vandorou, and Hibiki Yama

Subjects
Earth and Planetary Astrophysics (astro-ph.EP), Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, Astrophysics - Earth and Planetary Astrophysics
Abstract

OGLE-2016-BLG-1093 is a planetary microlensing event that is part of the statistical $Spitzer$ microlens parallax sample. The precise measurement of the microlens parallax effect for this event, combined with the measurement of finite source effects, leads to a direct measurement of the lens masses and system distance: $M_{\rm host} = 0.38$--$0.57\, M_{\odot}$, $m_p = 0.59$--$0.87\, M_{\rm Jup}$, and the system is located at the Galactic bulge ($D_L \sim 8.1$ kpc). Because this was a high-magnification event, we are also able to empirically show that the "cheap-space parallax" concept Gould & Yee (2012) produces well-constrained (and consistent) results for $|π_{\rm E}|$. This demonstrates that this concept can be extended to many two-body lenses. Finally, we briefly explore systematics in the $Spitzer$ light curve in this event and show that their potential impact is strongly mitigated by the color-constraint., 9 Figures, 3 Tables, submitted to the AAS journal

Published
2022
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10. OGLE-2019-BLG-0960 Lb: the Smallest Microlensing Planet

Author

Greg Olmschenk, Steve Hennerley, Igor Soszyński, Yuki Satoh, Yoon-Hyun Ryu, David P. Bennett, Paul J. Tristram, Sebastiano Calchi Novati, Daisuke Suzuki, Szymon Kozłowski, M. Hundertmark, Richard W. Pogge, Yutaka Matsubara, Ian A. Bond, Jennie McCormick, Cheongho Han, Takahiro Sumi, Yoshitaka Itow, Hyoun-Woo Kim, Akihiko Fukui, G. W. Christie, Paweł Pietrukowicz, Krzysztof Ulaczyk, Man Cheung Alex Li, Jennifer C. Yee, Mariusz Gromadzki, Rintaro Kirikawa, Iona Kondo, Sang-Mok Cha, Yuzuru Tanaka, Youn Kil Jung, Fumio Abe, In-Gu Shin, Patryk Iwanek, Yiannis Tsapras, Seung-Lee Kim, Martin Donachie, Etienne Bachelet, Jonathan T. Green, Shude Mao, Nicholas J. Rattenbury, Samson A. Johnson, Rachel Street, Jan Skowron, Tim Natusch, Dong-Joo Lee, Yuki Hirao, Yossi Shvartzvald, Stela Ishitani Silva, Geoffery Bryden, Richard K. Barry, Yasushi Muraki, Matthew T. Penny, Byeong-Gon Park, Aparna Bhattacharya, Atsunori Yonehara, Sean Carey, Yongseok Lee, Krzysztof A. Rybicki, Dan Maoz, Shota Miyazaki, Hirosane Fujii, Calen B. Henderson, Andrew Marmont, Przemek Mróz, Tsubasa Yamawaki, Wei Zhu, Radosław Poleski, Naoki Koshimoto, Charles Beichman, Hikaru Shoji, Dong-Jin Kim, Kyu-Ha Hwang, B. Scott Gaudi, Michael D. Albrow, Sun-Ju Chung, Chung-Uk Lee, Andrzej Udalski, Michał K. Szymański, Andrew Gould, Clément Ranc, Weicheng Zang, and Marcin Wrona

Subjects
Earth and Planetary Astrophysics (astro-ph.EP), Physics, 010308 nuclear & particles physics, FOS: Physical sciences, Astronomy, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic 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, Astrophysics::Earth and Planetary Astrophysics, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract

We report the analysis of OGLE-2019-BLG-0960, which contains the smallest mass-ratio microlensing planet found to date (q = 1.2--1.6 x 10^{-5} at 1-sigma). Although there is substantial uncertainty in the satellite parallax measured by Spitzer, the measurement of the annual parallax effect combined with the finite source effect allows us to determine the mass of the host star (M_L = 0.3--0.6 M_Sun), the mass of its planet (m_p = 1.4--3.1 M_Earth), the projected separation between the host and planet (a_perp = 1.2--2.3 au), and the distance to the lens system (D_L = 0.6--1.2 kpc). The lens is plausibly the blend, which could be checked with adaptive optics observations. As the smallest planet clearly below the break in the mass-ratio function (Suzuki et al. 2016; Jung et al. 2019), it demonstrates that current experiments are powerful enough to robustly measure the slope of the mass-ratio function below that break. We find that the cross-section for detecting small planets is maximized for planets with separations just outside of the boundary for resonant caustics and that sensitivity to such planets can be maximized by intensively monitoring events whenever they are magnified by a factor A > 5. Finally, an empirical investigation demonstrates that most planets showing a degeneracy between (s > 1) and (s < 1) solutions are not in the regime (|log s| >> 0) for which the "close"/"wide" degeneracy was derived. This investigation suggests a link between the "close"/"wide" and "inner/outer" degeneracies and also that the symmetry in the lens equation goes much deeper than symmetries uncovered for the limiting cases., 32 pages, 15 figures, 5 tables. Submitted to AAS Journals

Published
2021

11. Systematic KMTNet Planetary Anomaly Search. I. OGLE-2019-BLG-1053Lb, a Buried Terrestrial Planet

Author

Patryk Iwanek, Andrew Gould, Clément Ranc, B. Scott Gaudi, Weicheng Zang, Sang-Mok Cha, Geoffery Bryden, Nicholas J. Rattenbury, Jan Skowron, Chung-Uk Lee, Igor Soszyński, Andrzej Udalski, Jennifer C. Yee, Michał K. Szymański, Ian A. Bond, Daisuke Suzuki, Cheongho Han, Iona Kondo, In-Gu Shin, Dong-Jin Kim, Akihiko Fukui, Tsubasa Yamawaki, David P. Bennett, Xiangyu Zhang, Rintaro Kirikawa, Samson A. Johnson, Tianshu Wang, Shude Mao, Hyoun-Woo Kim, Yoon-Hyun Ryu, Calen B. Henderson, Martin Donachie, Yuzuru Tanaka, H. Fujii, Yoshitaka Itow, Michael D. Albrow, Greg Olmschenk, Dong-Joo Lee, Kyu-Ha Hwang, Fumio Abe, Mariusz Gromadzki, Przemek Mróz, Sebastiano Calchi Novati, Paul J. Tristram, M. Wrona, Richard W. Pogge, Sean Carey, Yutaka Matsubara, Yasushi Muraki, Yuki Satoh, Man Cheung Alex Li, Krzysztof Ulaczyk, Byeong-Gon Park, Yongseok Lee, Shota Miyazaki, Atsunori Yonehara, Takahiro Sumi, Paweł Pietrukowicz, Yuki Hirao, Youn Kil Jung, Seung-Lee Kim, Charles Beichman, Sun-Ju Chung, Hikaru Shoji, Yossi Shvartzvald, Radosław Poleski, Naoki Koshimoto, Wei Zhu, Stela Ishitani Silva, Aparna Bhattacharya, Krzysztof A. Rybicki, Szymon Kozłowski, and Richard K. Barry

Subjects
Physics, Space and Planetary Science, Terrestrial planet, Astronomy and Astrophysics, Anomaly (physics), Astrophysics - Astrophysics of Galaxies, Astrophysics - Earth and Planetary Astrophysics, Astrobiology
Abstract

In order to exhume the buried signatures of "missing planetary caustics" in the KMTNet data, we conducted a systematic anomaly search to the residuals from point-source point-lens fits, based on a modified version of the KMTNet EventFinder algorithm. This search reveals the lowest mass-ratio planetary caustic to date in the microlensing event OGLE-2019-BLG-1053, for which the planetary signal had not been noticed before. The planetary system has a planet-host mass ratio of $q = (1.25 \pm 0.13) \times 10^{-5}$. A Bayesian analysis yields estimates of the mass of the host star, $M_{\rm host} = 0.61_{-0.24}^{+0.29}~M_\odot$, the mass of its planet, $M_{\rm planet} = 2.48_{-0.98}^{+1.19}~M_{\oplus}$, the projected planet-host separation, $a_\perp = 3.4_{-0.5}^{+0.5}$ au, and the lens distance of $D_{\rm L} = 6.8_{-0.9}^{+0.6}$ kpc. The discovery of this very low mass-ratio planet illustrates the utility of our method and opens a new window for a large and homogeneous sample to study the microlensing planet-host mass-ratio function down to $q \sim 10^{-5}$., Comment: published by AJ

Published
2021

12. 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

13. $Spitzer$ 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

14. 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

15. 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

16. Spitzer microlensing parallax for OGLE-2017-BLG-0896 reveals a counter-rotating low-mass brown dwarf

Author

G. W. Christie, Chung-Uk Lee, John Southworth, Andrzej Udalski, Sean Carey, Michał K. Szymański, Igor Soszyński, Patryk Iwanek, M. Hundertmark, Yuri I. Fujii, Wei Zhu, In-Gu Shin, Kyu-Ha Hwang, Cheongho Han, Sebastiano Calchi Novati, Radosław Poleski, Seung-Lee Kim, Charles A. Beichman, Jan Skowron, Martin Dominik, Hyoun-Woo Kim, Dong-Jin Kim, Christiane Helling, Sohrab Rahvar, Geoffery Bryden, Valerio Bozza, Simona Ciceri, Yongseok Lee, Markus Rabus, Thiam-Guan Tan, P. Longa-Pena, Yoon-Hyun Ryu, Dan Maoz, Stephen C. Lowry, Michał Pawlak, B. Scott Gaudi, Greg Bolt, Sang-Mok Cha, Rachel Street, B. G. Park, Krzysztof Ulaczyk, Michael D. Albrow, Sun-Ju Chung, U. G. Jørgensen, Jesper Skottfelt, Yiannis Tsapras, Colin Snodgrass, Yossi Shvartzvald, Andrew Gould, Weicheng Zang, J. Campbell-White, Martin Burgdorf, Krzysztof A. Rybicki, Youn Kil Jung, Paweł Pietrukowicz, Richard W. Pogge, Tobias C. Hinse, Szymon Kozłowski, Calen B. Henderson, Tim Natusch, Dong-Joo Lee, Przemek Mróz, Sedighe Sajadian, Daniel F. Evans, Jennifer C. Yee, Etienne Bachelet, University of St Andrews. School of Physics and Astronomy, and University of St Andrews. St Andrews Centre for Exoplanet Science

Subjects
Proper motion, 010504 meteorology & atmospheric sciences, Population, Brown dwarf, bulge [Galaxy], FOS: Physical sciences, gravitational lensing: micro, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Gravitational microlensing, 01 natural sciences, Galaxy: bulge, micro [Gravitational lensing], bulge, gravitational lensing: micro [galaxy], 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, QB Astronomy, education, 010303 astronomy & astrophysics, Astronomy and Astrophysics, Space and Planetary Science, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, QC, 0105 earth and related environmental sciences, QB, Physics, education.field_of_study, 3rd-DAS, Galactic plane, Light curve, Galaxy, Radial velocity, QC Physics, Astrophysics - Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, BDC, QB799
Abstract

The kinematics of isolated brown dwarfs in the Galaxy, beyond the solar neighborhood, is virtually unknown. Microlensing has the potential to probe this hidden population, as it can measure both the mass and five of the six phase-space coordinates (all except the radial velocity) even of a dark isolated lens. However, the measurements of both the microlens parallax and finite-source effects are needed in order to recover the full information. Here, we combine $Spitzer$ satellite parallax measurement with the ground-based light curve, which exhibits strong finite-source effects, of event OGLE-2017-BLG-0896. We find two degenerate solutions for the lens (due to the known satellite-parallax degeneracy), which are consistent with each other except for their proper motion. The lens is an isolated brown dwarf with a mass of either $18\pm1M_J$ or $20\pm1M_J$. This is the lowest isolated-object mass measurement to date, only $\sim$45\% more massive than the theoretical deuterium-fusion boundary at solar metallicity, which is the common definition of a free-floating planet. The brown dwarf is located at either $3.9\pm0.1$ kpc or $4.1\pm0.1$ kpc toward the Galactic bulge, but with proper motion in the opposite direction of disk stars, with one solution suggesting it is moving within the Galactic plane. While it is possibly a halo brown dwarf, it might also represent a different, unknown population., 17 pages, 3 figures, 2 tables. Accepted for publication in The Astronomical Journal

Published
2019

17. 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

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