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746 results on '"Park, B. -G."'

104. OGLE-2018-BLG-1185b: A Low-mass Microlensing Planet Orbiting a Low-mass Dwarf

Author

Kondo, Iona, primary, Yee, Jennifer C., additional, Bennett, David P., additional, Sumi, Takahiro, additional, Koshimoto, Naoki, additional, Bond, Ian A., additional, Gould, Andrew, additional, Udalski, Andrzej, additional, Shvartzvald, Yossi, additional, Jung, Youn Kil, additional, Zang, Weicheng, additional, Bozza, Valerio, additional, Bachelet, Etienne, additional, Hundertmark, Markus P. G., additional, Rattenbury, Nicholas J., additional, Abe, F., additional, Barry, R., additional, Bhattacharya, A., additional, Donachie, M., additional, Fukui, A., additional, Fujii, H., additional, Hirao, Y., additional, Silva, S. Ishitani, additional, Itow, Y., additional, Kirikawa, R., additional, Li, M. C. A., additional, Matsubara, Y., additional, Miyazaki, S., additional, Muraki, Y., additional, Olmschenk, G., additional, Ranc, C., additional, Satoh, Y., additional, Shoji, H., additional, Suzuki, D., additional, Tanaka, Y., additional, Tristram, P. J., additional, Yamawaki, T., additional, Yonehara, A., additional, Mróz, P., additional, Poleski, R., additional, Skowron, J., additional, Szymański, M. K., additional, Soszyński, I., additional, Kozłowski, S., additional, Pietrukowicz, P., additional, Ulaczyk, K., additional, Rybicki, K. A., additional, Iwanek, P., additional, Wrona, M., additional, Albrow, M. D., additional, Chung, S.-J., additional, Han, C., additional, Hwang, K.-H., additional, Kim, H.-W., additional, Shin, I.-G., additional, Cha, S.-M., additional, Kim, D.-J., additional, Kim, S.-L., additional, Lee, C.-U., additional, Lee, D.-J., additional, Lee, Y., additional, Park, B.-G., additional, Pogge, R. W., additional, Ryu, Y.-H., additional, Beichman, C. A., additional, Bryden, G., additional, Novati, S. Calchi, additional, Carey, S., additional, Gaudi, B. S., additional, Henderson, C. B., additional, Zhu, W., additional, Maoz, D., additional, Penny, M. T., additional, Dominik, M., additional, Jørgensen, U. G., additional, Longa-Peña, P., additional, Peixinho, N., additional, Sajadian, S., additional, Skottfelt, J., additional, Snodgrass, C., additional, Tregloan-Reed, J., additional, Burgdorf, M. J., additional, Campbell-White, J., additional, Dib, S., additional, Fujii, Y. I., additional, Hinse, T. C., additional, Khalouei, E., additional, Rahvar, S., additional, Rabus, M., additional, Southworth, J., additional, Tsapras, Y., additional, Street, R. A., additional, Bramich, D. M., additional, Cassan, A., additional, Horne, K., additional, Wambsganss, J., additional, Mao, S., additional, and Saha, A., additional

Published
2021
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108. Discovery of a Jupiter/Saturn analog with gravitational microlensing

Author

Gaudi, B.S., Bennett, D.P., Udalski, A., Gould, A., Christie, G.W., Maoz, D., Dong, S., McCormick, J., Szymanski, M.K., Tristram, P.J., Nikolaev, S., Paczynski, B., Kubiak, M., Pietrzynski, G., Soszynski, I., Szewczyk, O., Ulaczyk, K., Wyrzykowski, L., DePoy, D.L., Han, C., Kaspi, S., Lee, C.-U., Mallia, F., Natusch, T., Pogge, R.W., Park, B.-G., Abe, F., Bond, I.A., Botzler, C.S., Fukui, A., Hearnshaw, J.B., Itow, Y., Kamiya, K., Korpela, A.V., Kilmartin, P.M., Lin, W, Masuda, K., Matsubara, Y., Motomura, M., Muraki, Y., Nakamura, S., Okumura, T., Ohnishi, K., Rattenbury, N.J., Sako, T., Saito, To., Sato, S., Skuljan, L., Sullivan, D.J., Sumi, T., Sweatman, W.L., Yock, P.C.M., Albrow, M.D., Allan, A., Beaulieu, J.-P., Burgdorf, M.J., Cook, K.H., Coutures, C., Dominik, M., Dieters, S., Fouque, P., Greenhill, J., Horne, K., Steele, I., Tsapras, Y., Chaboyer, B., Crocker, A., Frank, S., and Macintosh, B.

Subjects
Extrasolar planets -- Discovery and exploration, Gravitational lenses -- Observations
Published
2008

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

Author

Hirao, Y, Bennett, DP, Ryu, Y-H, Koshimoto, N, Udalski, A, Yee, JC, Sumi, T, Bond, IA, Shvartzvald, Y, Abe, F, Barry, RK, Bhattacharya, A, Donachie, M, Fukui, A, Itow, Y, Kondo, I, Li, MCA, Matsubara, Y, Matsuo, T, Miyazaki, S, Muraki, Y, Nagakane, M, Ranc, C, Rattenbury, NJ, Suematsu, H, Shibai, H, Suzuki, D, Tristram, PJ, Yonehara, A, Skowron, J, Poleski, R, Mroz, P, Szymanski, MK, Soszynski, I, Kozlowski, S, Pietrukowicz, P, Ulaczyk, K, Rybicki, K, Iwanek, P, Albrow, MD, Chung, S-J, Gould, A, Han, C, Hwang, K-H, Jung, YK, Shin, I-G, Zang, W, Cha, S-M, Kim, D-J, Kim, H-W, Kim, S-L, Lee, C-U, Lee, D-J, Lee, Y, Park, B-G, Pogge, RW, Beichman, CA, Bryden, G, Novati, SC, Carey, S, Gaudi, BS, Henderson, CB, Zhu, W, Bachelet, E, Bolt, G, Christie, G, Hundertmark, M, Natusch, T, Maoz, D, McCormick, J, Street, RA, Tan, T-G, Tsapras, Y, Jorgensen, UG, Dominik, M, Bozza, V, Skottfelt, J, Snodgrass, C, Ciceri, S, Jaimes, RF, Evans, DF, Peixinho, N, Hinse, TC, Burgdorf, MJ, Southworth, J, Rahvar, S, Sajadian, S, Rabus, M, von Essen, C, Fujii, YI, Campbell-White, J, Lowry, S, Helling, C, Mancini, L, Haikala, L, Kandori, R, Collaboration, MOA, Collaboration, OGLE, Collaboration, K, Team, S, Teams, LCOFF-U, Collaboration, M, Team, IRSF, 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, GRAVITATIONAL LENSING EXPERIMENT, Astrophysics, 01 natural sciences, JUPITER/SATURN ANALOG, Bulge, Planet, Saturn, QB Astronomy, 010303 astronomy & astrophysics, QC, QB, Earth and Planetary Astrophysics (astro-ph.EP), Physics, education.field_of_study, Settore FIS/05, LUMINOSITY-RELATION, INTERSTELLAR EXTINCTION LAW, Astrophysics - Solar and Stellar Astrophysics, MILKY-WAY, Astrophysics::Earth and Planetary Astrophysics, Proper motion, astro-ph.SR, astro-ph.GA, Population, NDAS, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, Gravitational microlensing, Gravitational microlensing exoplanet detection, EVENTS, SYSTEMS, 0103 physical sciences, PHOTOMETRY, DETERMINISTIC MODEL, education, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Astronomy and Astrophysics, Mass ratio, Light curve, Astrophysics - Astrophysics of Galaxies, QC Physics, 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), astro-ph.EP, STARS, Astrophysics - Earth and Planetary 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 ${\it Spitzer}$ 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 $q=7.0 \times 10^{-4}$ from the light-curve modeling. The ground-only and ${\it Spitzer}$-"only" data each provide very strong one-dimensional (1-D) constraints on the 2-D microlens parallax vector $\bf{\pi_{\rm E}}$. When combined, these yield a precise measurement of $\bf{\pi_{\rm E}}$, and so of the masses of the host $M_{\rm host}=0.56\pm0.07\,M_\odot$ and planet $M_{\rm planet} = 0.41 \pm 0.05\,M_{\rm Jup}$. The system lies at a distance $D_{\rm L}=5.2 \pm 0.5 \ {\rm kpc}$ 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 $a_{\perp} = 3.5 \pm 0.3 \ {\rm au}$, 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 ${\it Gaia}$ proper-motion measurement of the source suffers from a catastrophic $10\,\sigma$ error., Comment: 40 pages, 12 figures, 10 tables, accepted for publication in The Astronomical Journal

Published
2020

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

Author

Li, S. -S., Zang, W., Udalski, A., Shvartzvald, Y., Huber, D., Lee, C. -U., Sumi, T., Gould, A., Mao, S., Fouque, P., Wang, T., Dong, S., Jorgensen, U. G., Cole, A., Mroz, P., Szymanski, M. K., Skowron, J., Poleski, R., Soszynski, I., Pietrukowicz, P., Kozlowski, S., Ulaczyk, K., Rybicki, K. A., Iwanek, P., Yee, J. C., Novati, S. Calchi, Beichman, C. A., Bryden, G., Carey, S., Gaudi, B. S., Henderson, C. B., Zhu, W., Albrow, M. D., Chung, S. -J., Han, C., Hwang, K. -H., Jung, Y. K., Ryu, Y. -H., Shin, I. -G., Cha, S. -M., Kim, D. -J., Kim, H. -W., Kim, S. -L., Lee, D. -J., Lee, Y., Park, B. -G., Pogge, R. W., Bond, I. A., Abe, F., Barry, R., Bennett, D. P., Bhattacharya, A., Donachie, M., Fukui, A., Hirao, Y., Itow, Y., Kondo, I., Koshimoto, N., Li, M. C. A., Matsubara, Y., Muraki, Y., Miyazaki, S., Nagakane, M., Ranc, C., Rattenbury, N. J., Suematsu, H., Sullivan, D. J., Suzuki, D., Tristram, P. J., Yonehara, A., Christie, G., Drummond, J., Green, J., Hennerley, S., Natusch, T., Porritt, I., Bachelet, E., Maoz, D., Street, R. A., Tsapras, Y., Bozza, V., Dominik, M., Hundertmark, M., Peixinho, N., Sajadian, S., Burgdorf, M. J., Evans, D. F., Jaimes, R. Figuera, Fujii, Y. I., Haikala, L. K., Helling, C., Henning, T., Hinse, T. C., Mancini, L., Longa-Pena, P., Rahvar, S., Rabus, M., Skottfelt, J., Snodgrass, C., Southworth, J., Unda-Sanzana, E., von Essen, C., Beaulieu, J. -P., Blackman, J., Hill, K., Li, S. -S., Zang, W., Udalski, A., Shvartzvald, Y., Huber, D., Lee, C. -U., Sumi, T., Gould, A., Mao, S., Fouque, P., Wang, T., Dong, S., Jorgensen, U. G., Cole, A., Mroz, P., Szymanski, M. K., Skowron, J., Poleski, R., Soszynski, I., Pietrukowicz, P., Kozlowski, S., Ulaczyk, K., Rybicki, K. A., Iwanek, P., Yee, J. C., Novati, S. Calchi, Beichman, C. A., Bryden, G., Carey, S., Gaudi, B. S., Henderson, C. B., Zhu, W., Albrow, M. D., Chung, S. -J., Han, C., Hwang, K. -H., Jung, Y. K., Ryu, Y. -H., Shin, I. -G., Cha, S. -M., Kim, D. -J., Kim, H. -W., Kim, S. -L., Lee, D. -J., Lee, Y., Park, B. -G., Pogge, R. W., Bond, I. A., Abe, F., Barry, R., Bennett, D. P., Bhattacharya, A., Donachie, M., Fukui, A., Hirao, Y., Itow, Y., Kondo, I., Koshimoto, N., Li, M. C. A., Matsubara, Y., Muraki, Y., Miyazaki, S., Nagakane, M., Ranc, C., Rattenbury, N. J., Suematsu, H., Sullivan, D. J., Suzuki, D., Tristram, P. J., Yonehara, A., Christie, G., Drummond, J., Green, J., Hennerley, S., Natusch, T., Porritt, I., Bachelet, E., Maoz, D., Street, R. A., Tsapras, Y., Bozza, V., Dominik, M., Hundertmark, M., Peixinho, N., Sajadian, S., Burgdorf, M. J., Evans, D. F., Jaimes, R. Figuera, Fujii, Y. I., Haikala, L. K., Helling, C., Henning, T., Hinse, T. C., Mancini, L., Longa-Pena, P., Rahvar, S., Rabus, M., Skottfelt, J., Snodgrass, C., Southworth, J., Unda-Sanzana, E., von Essen, C., Beaulieu, J. -P., Blackman, J., and Hill, K.

Published
2019

118. OGLE-2017-BLG-1434Lb: Eighth q < 1 x 10(-4) Mass-Ratio Microlens Planet Confirms Turnover in Planet Mass-Ratio Function

Author

Udalski, A, Ryu, Y-H, Sajadian, S, Gould, A, Mroz, P, Poleski, R, Szymanski, MK, Skowron, J, Soszynski, I, Kozlowski, S, Pietrukowicz, P, Ulaczyk, K, Pawlak, M, Rybicki, K, Iwanek, P, Albrow, MD, Chung, S-J, Han, C, Hwang, K-H, Jung, YK, Shin, I-G, Shvartzvald, Y, Yee, JC, Zang, W, Zhu, W, Cha, S-M, Kim, D-J, Kim, H-W, Kim, S-L, Lee, C-U, Lee, D-J, Lee, Y, Park, B-G, Pogge, RW, Bozza, V, Dominik, M, Helling, C, Hundertmark, M, Jorgensen, UG, Longa-Pena, P, Lowry, S, Burgdorf, M, Campbell-White, J, Ciceri, S, Evans, D, Jaimes, RF, Fujii, YI, Haikala, LK, Henning, T, Hinse, TC, Mancini, L, Peixinho, N, Rahvar, S, Rabus, M, Skottfelt, J, Snodgrass, C, Southworth, J, von Essen, C, Collaboration, OGLE, Collaboration, K, and Collaboration, M

Subjects
QB460, humanities
Abstract

We report the discovery of a cold Super-Earth planet (m(p) = 4.4 +/- 0.5 M-circle plus) orbiting a low-mass (M = 0.23 +/- 0.03 M-circle dot) M dwarf at projected separation a(perpendicular to) l = 1.18 +/- 0.10 a.u., i.e., about 1.9 times the distance the snow line. The system is quite nearby for a microlensing planet, D-L = 0.86 +/- 0.09 kpc. Indeed, it was the large lens-source relative parallax pi(rel) = 1.0 mas (combined with the low mass M) that gave rise to the large, and thus well-measured, "microlens parallax" pi(E) proportional to (pi(rel)/M)(1)(/2) that enabled these precise measurements. OGLE-2017-BLG-1434Lb is the eighth microlensing planet with planet-host mass ratio q < 1 x 10(-4).\ud \ud We apply a new planet-detection sensitivity method, which is a variant of "V/V-max", to seven of these eight planets to derive the mass-ratio function in this regime. We find dN/ d lnq proportional to q(P) , with p =1.05(-0.68)(+0.78), which confirms the "turnover" in the mass function found by Suzuki et al. relative to the power law of opposite sign n = -0.93 +/- 0.13 at higher mass ratios q greater than or similar to 2 x 10(-4). We combine our result with that of Suzuki et al. to obtain p = 0.73(-0.34)(+0.42.)

Published
2018

119. OGLE-2017-BLG-0039: Microlensing Event with Light from a Lens Identified from Mass Measurement

Author

Han, C., Jung, Y. K., Udalski, A., Bond, I., Bozza, V., The, KMTNet Collaboration, Albrow, M. D., Chung, S.-J., Gould, A., Hwang, K.-H., Kim, D., Lee, C.-U., Kim, H.-W., Ryu, Y.-H., Shin, I.-G., Yee, J. C., Shvartzvald, Y., Cha, S.-M., Kim, S.-L., Kim, D.-J., Lee, D.-J., Lee, Y., Park, B.-G., Pogge, R. W., The, OGLE Collaboration Szymański M. K., Mróz, P., Skowron, J., Poleski, R., Soszyński, I., Kozłowski, S., Pietrukowicz, P., Ulaczyk, K., Pawlak, M., The, MOA Collaboration Abe F., Barry, R., Bennett, D. P., Bhattacharya, A., Donachie, M., Evans, P., Fukui, A., Hirao, Y., Itow, Y., Kawasaki, K., Koshimoto, N., Li, M. C. A., Ling, C. H., Matsubara, Y., Miyazaki, S., Munakata, H., Muraki, Y., Nagakane, M., Ohnishi, K., Ranc, C., Rattenbury, N., Saito, T., Sharan, A., Sullivan, D. J., Sumi, T., Suzuki, Daisuke, Tristram, P. J., Yamada, T., and Yonehara, A.

Subjects
Brightness, 010504 meteorology & atmospheric sciences, Event (relativity), FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, gravitational lensing: micro, Gravitational microlensing, 01 natural sciences, Einstein radius, law.invention, law, 0103 physical sciences, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), 0105 earth and related environmental sciences, Physics, Astronomy and Astrophysics, binaries: general, Space and Planetary Science, Lens (optics), Stars, Astrophysics - Solar and Stellar Astrophysics, Caustic (optics), Astrophysics::Earth and Planetary Astrophysics, Parallax
Abstract

著者人数: 61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: 2018-09-27, 資料番号: SA1180205000

Published
2018

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

Author

Li, S-S, primary, Zang, W, primary, Udalski, A, primary, Shvartzvald, Y, primary, Huber, D, primary, Lee, C-U, primary, Sumi, T, primary, Gould, A, primary, Mao, S, primary, Fouqué, P, primary, Wang, T, primary, Dong, S, primary, Jørgensen, U G, primary, Cole, A, primary, Mróz, P, primary, Szymański, M K, primary, Skowron, J, primary, Poleski, R, primary, Soszyński, I, primary, Pietrukowicz, P, primary, Kozłowski, S, primary, Ulaczyk, K, primary, Rybicki, K A, primary, Iwanek, P, primary, Yee, J C, primary, Calchi Novati, S, primary, Beichman, C A, primary, Bryden, G, primary, Carey, S, primary, Gaudi, B S, primary, Henderson, C B, primary, Zhu, W, primary, Albrow, M D, primary, Chung, S-J, primary, Han, C, primary, Hwang, K-H, primary, Jung, Y K, primary, Ryu, Y-H, primary, Shin, I-G, primary, Cha, S-M, primary, Kim, D-J, primary, Kim, H-W, primary, Kim, S-L, primary, Lee, D-J, primary, Lee, Y, primary, Park, B-G, primary, Pogge, R W, primary, Bond, I A, primary, Abe, F, primary, Barry, R, primary, Bennett, D P, primary, Bhattacharya, A, primary, Donachie, M, primary, Fukui, A, primary, Hirao, Y, primary, Itow, Y, primary, Kondo, I, primary, Koshimoto, N, primary, Li, M C A, primary, Matsubara, Y, primary, Muraki, Y, primary, Miyazaki, S, primary, Nagakane, M, primary, Ranc, C, primary, Rattenbury, N J, primary, Suematsu, H, primary, Sullivan, D J, primary, Suzuki, D, primary, Tristram, P J, primary, Yonehara, A, primary, Christie, G, primary, Drummond, J, primary, Green, J, primary, Hennerley, S, primary, Natusch, T, primary, Porritt, I, primary, Bachelet, E, primary, Maoz, D, primary, Street, R A, primary, Tsapras, Y, primary, Bozza, V, primary, Dominik, M, primary, Hundertmark, M, primary, Peixinho, N, primary, Sajadian, S, primary, Burgdorf, M J, primary, Evans, D F, primary, Figuera Jaimes, R, primary, Fujii, Y I, primary, Haikala, L K, primary, Helling, C, primary, Henning, T, primary, Hinse, T C, primary, Mancini, L, primary, Longa-Peña, P, primary, Rahvar, S, primary, Rabus, M, primary, Skottfelt, J, primary, Snodgrass, C, primary, Southworth, J, primary, Unda-Sanzana, E, primary, von Essen, C, primary, Beaulieu, J-P, primary, Blackman, J, primary, and Hill, K, primary

Published
2019
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126. Two Jupiter-mass Planets Discovered by the KMTNet Survey in 2017

Author

Shin, I.-G., primary, Ryu, Y.-H., additional, Yee, J. C., additional, Gould, A., additional, Albrow, M. D., additional, Chung, S.-J., additional, Han, C., additional, Hwang, K.-H., additional, Jung, Y. K., additional, Shvartzvald, Y., additional, Zang, W., additional, Lee, C.-U., additional, Cha, S.-M., additional, Kim, D.-J., additional, Kim, H.-W., additional, Kim, S.-L., additional, Lee, Y., additional, Lee, D.-J., additional, Park, B.-G., additional, and Pogge, R. W., additional

Published
2019
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128. Observation of second spin reorientation transition within ultrathin region in Fe films on Ag(001) surface.

Author

Khim, T.-Y., Shin, M., Park, B.-G., Lee, H., and Park, J.-H.

Subjects
MAGNETIC moments, IRON, X-rays, MAGNETIC circular dichroism, NUCLEAR spin, MAGNETIC anisotropy, THICKNESS measurement
Abstract

We acquired direct measurements for in-plane and perpendicular-to-plane magnetic moments of Fe films using an x-ray magnetic circular dichroism technique with increase of the Fe thickness (up to 40Å) on the Ag(001) surface. Epitaxial Fe/Ag(001) films were grown in situ with the thickness varying from 2Å to 40Å, and the magnetic anisotropy was carefully investigated as a function of the film thickness. We found re-entrance of the in-plane magnetic anisotropy of the Fe film in ultrathin region. The results manifest that the epitaxial Fe/Ag(001) film undergoes two distinct spin reorientation transitions from in-plane to out-of-plane at the film thickness t≈9Å and back to in-plane at t≈18Å as t increases. [ABSTRACT FROM AUTHOR]

Published
2014
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129. OGLE-2017-BLG-1434Lb : Eighth q < 1 x 10(-4) Mass-Ratio Microlens Planet Confirms Turnover in Planet Mass-Ratio Function

Author

Udalski, A., Ryu, Y-H, Sajadian, S., Gould, A., Mroz, P., Poleski, R., Szymanski, M. K., Skowron, J., Soszynski, I, Kozlowski, S., Pietrukowicz, P., Ulaczyk, K., Pawlak, M., Rybicki, K., Iwanek, P., Albrow, M. D., Chung, S-J, Han, C., Hwang, K-H, Jung, Y. K., Shin, I-G, Shvartzvald, Y., Yee, J. C., Zang, W., Zhu, W., Cha, S-M, Kim, D-J, Kim, H-W, Kim, S-L, Lee, C-U, Lee, D-J, Lee, Y., Park, B-G, Pogge, R. W., Bozza, V, Dominik, M., Helling, C., Hundertmark, M., Jorgensen, U. G., Longa-Pena, P., Lowry, S., Burgdorf, M., Campbell-White, J., Ciceri, Simona, Evans, D., Figuera Jaimes, R., Fujii, Y., Haikala, L. K., Henning, T., Hinse, T. C., Mancini, L., Peixinho, N., Rahvar, S., Rabus, M., Skottfelt, J., Snodgrass, C., Southworth, J., von Essen, C., Udalski, A., Ryu, Y-H, Sajadian, S., Gould, A., Mroz, P., Poleski, R., Szymanski, M. K., Skowron, J., Soszynski, I, Kozlowski, S., Pietrukowicz, P., Ulaczyk, K., Pawlak, M., Rybicki, K., Iwanek, P., Albrow, M. D., Chung, S-J, Han, C., Hwang, K-H, Jung, Y. K., Shin, I-G, Shvartzvald, Y., Yee, J. C., Zang, W., Zhu, W., Cha, S-M, Kim, D-J, Kim, H-W, Kim, S-L, Lee, C-U, Lee, D-J, Lee, Y., Park, B-G, Pogge, R. W., Bozza, V, Dominik, M., Helling, C., Hundertmark, M., Jorgensen, U. G., Longa-Pena, P., Lowry, S., Burgdorf, M., Campbell-White, J., Ciceri, Simona, Evans, D., Figuera Jaimes, R., Fujii, Y., Haikala, L. K., Henning, T., Hinse, T. C., Mancini, L., Peixinho, N., Rahvar, S., Rabus, M., Skottfelt, J., Snodgrass, C., Southworth, J., and von Essen, C.

Abstract

We report the discovery of a cold Super-Earth planet (m(p) = 4.4 +/- 0.5 M-circle plus) orbiting a low-mass (M = 0.23 +/- 0.03 M-circle dot) M dwarf at projected separation a(perpendicular to) l = 1.18 +/- 0.10 a.u., i.e., about 1.9 times the distance the snow line. The system is quite nearby for a microlensing planet, D-L = 0.86 +/- 0.09 kpc. Indeed, it was the large lens-source relative parallax pi(rel) = 1.0 mas (combined with the low mass M) that gave rise to the large, and thus well-measured, microlens parallax pi(E) proportional to (pi(rel)/M)(1)(/2) that enabled these precise measurements. OGLE-2017-BLG-1434Lb is the eighth microlensing planet with planet-host mass ratio q < 1 x 10(-4). We apply a new planet-detection sensitivity method, which is a variant of V/V-max, to seven of these eight planets to derive the mass-ratio function in this regime. We find dN/ d lnq proportional to q(P) , with p =1.05(-0.68)(+0.78), which confirms the turnover in the mass function found by Suzuki et al. relative to the power law of opposite sign n = -0.93 +/- 0.13 at higher mass ratios q greater than or similar to 2 x 10(-4). We combine our result with that of Suzuki et al. to obtain p = 0.73(-0.34)(+0.42.)

Published
2018
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130. OGLE-2016-BLG-1190Lb : The First Spitzer Bulge Planet Lies Near the Planet/Brown-dwarf Boundary

Author

Ryu, Y. -H., Yee, J. C., Udalski, A., Bond, I. A., Shvartzvald, Y., Zang, W., Jaimes, R. Figuera, Jorgensen, U. G., Zhu, W., Huang, C. X., Jung, Y. K., Albrow, M. D., Chung, S. -J., Gould, A., Han, C., Hwang, K. -H., Shin, I. -G., Cha, S. -M., Kim, D. -J., Kim, H. -W., Kim, S. -L., Lee, C. -U., Lee, D. -J., Lee, Y., Park, B. -G., Pogge, R. W., Novati, S. Calchi, Carey, S., Henderson, C. B., Beichman, C., Gaudi, B. S., Mroz, P., Poleski, R., Skowron, J., Szymanski, M. K., Soszynski, I., Kozlowski, S., Pietrukowicz, P., Ulaczyk, K., Pawlak, M., Abe, F., Asakura, Y., Barry, R., Bennett, D. P., Bhattacharya, A., Donachie, M., Evans, P., Fukui, A., Hirao, Y., Itow, Y., Kawasaki, K., Koshimoto, N., Li, M. C. A., Ling, C. H., Masuda, K., Matsubara, Y., Miyazaki, S., Muraki, Y., Nagakane, M., Ohnishi, K., Ranc, C., Rattenbury, N. J., Saito, To, Sharan, A., Sullivan, D. J., Sumi, T., Suzuki, D., Tristram, P. J., Yamada, T., Yonehara, A., Bryden, G., Howell, S. B., Jacklin, S., Penny, M. T., Mao, S., Fouque, Pascal, Wang, T., Street, R. A., Tsapras, Y., Hundertmark, M., Bachelet, E., Dominik, M., Li, Z., Cross, S., Cassan, A., Horne, K., Schmidt, R., Wambsganss, J., Ment, S. K., Maoz, D., Snodgrass, C., Steele, I. A., Bozza, V., Burgdorf, M. J., Ciceri, Simona, D'Ago, G., Evans, D. F., Hinse, T. C., Kerins, E., Kokotanekova, R., Longa, P., MacKenzie, J., Popovas, A., Rabus, M., Rahvar, S., Sajadian, S., Skottfelt, J., Southworth, J., von Essen, C., Ryu, Y. -H., Yee, J. C., Udalski, A., Bond, I. A., Shvartzvald, Y., Zang, W., Jaimes, R. Figuera, Jorgensen, U. G., Zhu, W., Huang, C. X., Jung, Y. K., Albrow, M. D., Chung, S. -J., Gould, A., Han, C., Hwang, K. -H., Shin, I. -G., Cha, S. -M., Kim, D. -J., Kim, H. -W., Kim, S. -L., Lee, C. -U., Lee, D. -J., Lee, Y., Park, B. -G., Pogge, R. W., Novati, S. Calchi, Carey, S., Henderson, C. B., Beichman, C., Gaudi, B. S., Mroz, P., Poleski, R., Skowron, J., Szymanski, M. K., Soszynski, I., Kozlowski, S., Pietrukowicz, P., Ulaczyk, K., Pawlak, M., Abe, F., Asakura, Y., Barry, R., Bennett, D. P., Bhattacharya, A., Donachie, M., Evans, P., Fukui, A., Hirao, Y., Itow, Y., Kawasaki, K., Koshimoto, N., Li, M. C. A., Ling, C. H., Masuda, K., Matsubara, Y., Miyazaki, S., Muraki, Y., Nagakane, M., Ohnishi, K., Ranc, C., Rattenbury, N. J., Saito, To, Sharan, A., Sullivan, D. J., Sumi, T., Suzuki, D., Tristram, P. J., Yamada, T., Yonehara, A., Bryden, G., Howell, S. B., Jacklin, S., Penny, M. T., Mao, S., Fouque, Pascal, Wang, T., Street, R. A., Tsapras, Y., Hundertmark, M., Bachelet, E., Dominik, M., Li, Z., Cross, S., Cassan, A., Horne, K., Schmidt, R., Wambsganss, J., Ment, S. K., Maoz, D., Snodgrass, C., Steele, I. A., Bozza, V., Burgdorf, M. J., Ciceri, Simona, D'Ago, G., Evans, D. F., Hinse, T. C., Kerins, E., Kokotanekova, R., Longa, P., MacKenzie, J., Popovas, A., Rabus, M., Rahvar, S., Sajadian, S., Skottfelt, J., Southworth, J., and von Essen, C.

Abstract

We report the discovery of OGLE-2016-BLG-1190Lb, which is likely to be the first Spitzer microlensing planet in the Galactic bulge/ bar, an assignation that can be confirmed by two epochs of high-resolution imaging of the combined source-lens baseline object. The planet's mass, M-p = 13.4 +/- 0.9 M-J, places it right at the deuteriumburning limit, i. e., the conventional boundary between planets and brown dwarfs. Its existence raises the question of whether such objects are really planets (formed within the disks of their hosts) or failed stars (lowmass objects formed by gas fragmentation). This question may ultimately be addressed by comparing disk and bulge/bar planets, which is a goal of the Spitzer microlens program. The host is a G dwarf, M-host = 0.89. +/- 0.07 M-circle dot, and the planet has a semimajor axis a similar to 2.0 au. We use Kepler K2 Campaign 9 microlensing data to break the lens-mass degeneracy that generically impacts parallax solutions from Earth-Spitzer observations alone, which is the first successful application of this approach. The microlensing data, derived primarily from near-continuous, ultradense survey observations from OGLE, MOA, and three KMTNet telescopes, contain more orbital information than for any previous microlensing planet, but not quite enough to accurately specify the full orbit. However, these data do permit the first rigorous test of microlensing orbital-motion measurements, which are typically derived from data taken over < 1% of an orbital period.

Published
2018
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131. OGLE-2015-BLG-1459L: The Challenges of Exo-moon Microlensing

Author

Hwang, K.-H., Udalski, A., Bond, I. A., Albrow, M. D., Chung, S.-J., Gould, A., Han, C., Jung, Y. K., Ryu, Y.-H., Shin, I.-G., Yee, J. C., Zhu, W., Cha, S.-M., Kim, D.-J., Kim, H.-W., Kim, S.-L., Lee, C.-U., Lee, D.-J., Lee, Y., Park, B.-G., Pogge, R. W., Pawlak, M., Poleski, R., Szymański, M. K., Skowron, J., Soszyński, I., Mróz, P., Kozłowski, S., Pietrukowicz, P., Ulaczyk, K., Abe, F., Asakura, Y., Barry, R., Bennett, D. P., Bhattacharya, A., Donachie, M., Evans, P., Fukui, A., Hirao, Y., Itow, Y., Kawasaki, K., Koshimoto, N., Li, M. C. A., Ling, C. H., Masuda, K., Matsubara, Y., Miyazaki, S., Muraki, Y., Nagakane, M., Ohnishi, K., Ranc, C., Rattenbury, N. J., Saito, To., Sharan, A., Sullivan, D. J., Sumi, T., Suzuki, Daisuke, Tristram, P. J., Yamada, T., Yonehara, A., Hwang, K.-H., Udalski, A., Bond, I. A., Albrow, M. D., Chung, S.-J., Gould, A., Han, C., Jung, Y. K., Ryu, Y.-H., Shin, I.-G., Yee, J. C., Zhu, W., Cha, S.-M., Kim, D.-J., Kim, H.-W., Kim, S.-L., Lee, C.-U., Lee, D.-J., Lee, Y., Park, B.-G., Pogge, R. W., Pawlak, M., Poleski, R., Szymański, M. K., Skowron, J., Soszyński, I., Mróz, P., Kozłowski, S., Pietrukowicz, P., Ulaczyk, K., Abe, F., Asakura, Y., Barry, R., Bennett, D. P., Bhattacharya, A., Donachie, M., Evans, P., Fukui, A., Hirao, Y., Itow, Y., Kawasaki, K., Koshimoto, N., Li, M. C. A., Ling, C. H., Masuda, K., Matsubara, Y., Miyazaki, S., Muraki, Y., Nagakane, M., Ohnishi, K., Ranc, C., Rattenbury, N. J., Saito, To., Sharan, A., Sullivan, D. J., Sumi, T., Suzuki, Daisuke, Tristram, P. J., Yamada, T., and Yonehara, A.

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

Published
2018

132. OGLE-2017-BLG-0329L:A Microlensing Binary Characterized with Dramatically Enhanced Precision Using Data from Space-based Observations

Author

Han, C., Novati, S. Calchi, Udalski, A., Lee, C. -U., Gould, A., Bozza, V., Mroz, P., Pietrukowicz, P., Skowron, J., Szymanski, M. K., Poleski, R., Soszynski, I., Kozlowski, S., Ulaczyk, K., Pawlak, M., Rybicki, K., Iwanek, P., Albrow, M. D., Chung, S. -J., Hwang, K. -H., Jung, Y. K., Ryu, Y. -H., Shin, I. -G., Shvartzvald, Y., Yee, J. C., Zang, W., Zhu, W., Cha, S. -M., Kim, D. -J., Kim, H. -W., Kim, S. -L., Lee, D. -J., Lee, Y., Park, B. -G., Pogge, R. W., Kim, W. -T., Beichman, C., Bryden, G., Carey, S., Gaudi, B. S., Henderson, C. B., Dominik, M., Helling, C., Hundertmark, M., Jørgensen, Uffe Gråe, Longa-Pena, P., Lowry, S., Sajadian, S., Burgdorf, M. J., Campbell-White, J., Han, C., Novati, S. Calchi, Udalski, A., Lee, C. -U., Gould, A., Bozza, V., Mroz, P., Pietrukowicz, P., Skowron, J., Szymanski, M. K., Poleski, R., Soszynski, I., Kozlowski, S., Ulaczyk, K., Pawlak, M., Rybicki, K., Iwanek, P., Albrow, M. D., Chung, S. -J., Hwang, K. -H., Jung, Y. K., Ryu, Y. -H., Shin, I. -G., Shvartzvald, Y., Yee, J. C., Zang, W., Zhu, W., Cha, S. -M., Kim, D. -J., Kim, H. -W., Kim, S. -L., Lee, D. -J., Lee, Y., Park, B. -G., Pogge, R. W., Kim, W. -T., Beichman, C., Bryden, G., Carey, S., Gaudi, B. S., Henderson, C. B., Dominik, M., Helling, C., Hundertmark, M., Jørgensen, Uffe Gråe, Longa-Pena, P., Lowry, S., Sajadian, S., Burgdorf, M. J., and Campbell-White, J.

Published
2018

133. OGLE-2017-BLG-1434Lb:Eighth q < 1 x 10(-4) Mass-Ratio Microlens Planet Confirms Turnover in Planet Mass-Ratio Function

Author

Udalski, A., Ryu, Y-H, Sajadian, S., Gould, A., Mroz, P., Poleski, R., Szymanski, M. K., Skowron, J., Soszynski, I, Kozlowski, S., Pietrukowicz, P., Ulaczyk, K., Pawlak, M., Rybicki, K., Iwanek, P., Albrow, M. D., Chung, S-J, Han, C., Hwang, K-H, Jung, Y. K., Shin, I-G, Shvartzvald, Y., Yee, J. C., Zang, W., Zhu, W., Cha, S-M, Kim, D-J, Kim, H-W, Kim, S-L, Lee, C-U, Lee, D-J, Lee, Y., Park, B-G, Pogge, R. W., Bozza, V, Dominik, M., Helling, C., Hundertmark, M., Jørgensen, Uffe Gråe, Longa-Pena, P., Lowry, S., Burgdorf, M., Campbell-White, J., Ciceri, S., Evans, D., Jaimes, R. Figuera, Fujii, Yuri, Haikala, L. K., Henning, T., Skottfelt, J., Snodgrass, C., Southworth, J., von Essen, C, Udalski, A., Ryu, Y-H, Sajadian, S., Gould, A., Mroz, P., Poleski, R., Szymanski, M. K., Skowron, J., Soszynski, I, Kozlowski, S., Pietrukowicz, P., Ulaczyk, K., Pawlak, M., Rybicki, K., Iwanek, P., Albrow, M. D., Chung, S-J, Han, C., Hwang, K-H, Jung, Y. K., Shin, I-G, Shvartzvald, Y., Yee, J. C., Zang, W., Zhu, W., Cha, S-M, Kim, D-J, Kim, H-W, Kim, S-L, Lee, C-U, Lee, D-J, Lee, Y., Park, B-G, Pogge, R. W., Bozza, V, Dominik, M., Helling, C., Hundertmark, M., Jørgensen, Uffe Gråe, Longa-Pena, P., Lowry, S., Burgdorf, M., Campbell-White, J., Ciceri, S., Evans, D., Jaimes, R. Figuera, Fujii, Yuri, Haikala, L. K., Henning, T., Skottfelt, J., Snodgrass, C., Southworth, J., and von Essen, C

Published
2018

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

Author

Ryu, Y. -H., Yee, J. C., Udalski, A., Bond, I. A., Shvartzvald, Y., Zang, W., Jaimes, R. Figuera, Jørgensen, U. G., Zhu, W., Huang, C. X., Jung, Y. K., Albrow, M. D., Chung, S. -J., Gould, A., Han, C., Hwang, K. -H., Shin, I. -G., Cha, S. -M., Kim, D. -J., Kim, H. -W., Kim, S. -L., Lee, C. -U., Lee, D. -J., Lee, Y., Park, B. -G., Pogge, R. W., Novati, S. Calchi, Carey, S., Henderson, C. B., Beichman, C., Gaudi, B. S., Maoz, D., Poleski, R., Skowron, J., Szymanski, M. K., Soszynski, I., Kozlowski, S., Pietrukowicz, P., Ulaczyk, K., Pawlak, M., Abe, F., Asakura, Y., Barry, R., Li, M. C. A., Wang, T., Hundertmark, M., Li, Z., Schmidt, R., Popovas, A., Mackenzie, Jacqueline, Skottfelt, J., Jacklin, S., von Essen, C, Ryu, Y. -H., Yee, J. C., Udalski, A., Bond, I. A., Shvartzvald, Y., Zang, W., Jaimes, R. Figuera, Jørgensen, U. G., Zhu, W., Huang, C. X., Jung, Y. K., Albrow, M. D., Chung, S. -J., Gould, A., Han, C., Hwang, K. -H., Shin, I. -G., Cha, S. -M., Kim, D. -J., Kim, H. -W., Kim, S. -L., Lee, C. -U., Lee, D. -J., Lee, Y., Park, B. -G., Pogge, R. W., Novati, S. Calchi, Carey, S., Henderson, C. B., Beichman, C., Gaudi, B. S., Maoz, D., Poleski, R., Skowron, J., Szymanski, M. K., Soszynski, I., Kozlowski, S., Pietrukowicz, P., Ulaczyk, K., Pawlak, M., Abe, F., Asakura, Y., Barry, R., Li, M. C. A., Wang, T., Hundertmark, M., Li, Z., Schmidt, R., Popovas, A., Mackenzie, Jacqueline, Skottfelt, J., Jacklin, S., and von Essen, C

Published
2018

135. Toward a Galactic Distribution of Planets. I. Methodology and Planet Sensitivities of the 2015 High-cadence Spitzer Microlens Sample

Author

Zhu, Wei, Udalski, A., Novati, S. Calchi, Chung, S. -J., Jung, Y. K., Ryu, Y. -H., Shin, I. -G., Gould, A., Lee, C. -U., Albrow, M. D., Yee, J. C., Han, C., Hwang, K. -H., Cha, S. -M., Kim, D. -J., Kim, H. -W., Kim, S. -L., Kim, Y. -H., Lee, Y., Park, B. -G., Pogge, R., Poleski, R., Skowron, J., Mroz, P., Szymanski, M. K., Soszynski, I., Pietrukowicz, P., Kozlowski, S., Ulaczyk, K., Pawlak, M., Beichman, C., Bryden, G., Carey, S., Fausnaugh, M., Gaudi, B. S., Henderson, C., Shvartzvald, Y., and Wibking, B.

Subjects
Physics, 010308 nuclear & particles physics, Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy and Astrophysics, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Planetary system, Mass ratio, Gravitational microlensing, 01 natural sciences, Stars, Space and Planetary Science, Bulge, Planet, 0103 physical sciences, Range (statistics), Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Parallax, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract

We analyze an ensemble of microlensing events from the 2015 Spitzer microlensing campaign, all of which were densely monitored by ground-based high-cadence survey teams. The simultaneous observations from Spitzer and the ground yield measurements of the microlensing parallax vector $\pi_{\rm E}$, from which compact constraints on the microlens properties are derived, including $\lesssim$25\% uncertainties on the lens mass and distance. With the current sample, we demonstrate that the majority of microlenses are indeed in the mass range of M dwarfs. The planet sensitivities of all 41 events in the sample are calculated, from which we provide constraints on the planet distribution function. In particular, assuming a planet distribution function that is uniform in $\log{q}$, where $q$ is the planet-to-star mass ratio, we find a $95\%$ upper limit on the fraction of stars that host typical microlensing planets of 49\%, which is consistent with previous studies. Based on this planet-free sample, we develop the methodology to statistically study the Galactic distribution of planets using microlensing parallax measurements. Under the assumption that the planet distributions are the same in the bulge as in the disk, we predict that $\sim$1/3 of all planet detections from the microlensing campaigns with Spitzer should be in the bulge. This prediction will be tested with a much larger sample, and deviations from it can be used to constrain the abundance of planets in the bulge relative to the disk., Comment: published on Astronomical Journal

Published
2017

139. OGLE-2017-BLG-1130: The First Binary Gravitational Microlens Detected from Spitzer Only

Author

Wang, Tianshu, primary, Calchi Novati, S., additional, Udalski, A., additional, Gould, A., additional, Mao, Shude, additional, Zang, W., additional, Beichman, C., additional, Bryden, G., additional, Carey, S., additional, Gaudi, B. S., additional, Henderson, C. B., additional, Shvartzvald, Y., additional, Yee, J. C., additional, Mróz, P., additional, Poleski, R., additional, Skowron, J., additional, Szymański, M. K., additional, Soszyński, I., additional, Kozłowski, S., additional, Pietrukowicz, P., additional, Ulaczyk, K., additional, Pawlak, M., additional, Albrow, M. D., additional, Chung, S.-J., additional, Han, C., additional, Hwang, K.-H., additional, Jung, Y. K., additional, Ryu, Y.-H., additional, Shin, I.-G., additional, Zhu, W., additional, Cha, S.-M., additional, Kim, D.-J., additional, Kim, H.-W., additional, Kim, S.-L., additional, Lee, C.-U., additional, Lee, D.-J., additional, Lee, Y., additional, Park, B.-G., additional, and Pogge, R. W., additional

Published
2018
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146. Magnetism of ultrathin Fe films on MgO(001).

Author

Yang, Seolun, Park, H.-K., Kim, J.-S., Kim, J.-Y., and Park, B.-G.

Subjects
MAGNETISM, THIN film research, OXIDES, OXIDATION, CIRCULAR dichroism
Abstract

We grow ultrathin (<2-monolayer (ML)) Fe films on MgO(001) at 80 K, limiting oxide formation to the very early stages of Fe growth, and then investigate in situ the magnetism of the films using x-ray magnetic circular dichroism (XMCD). The 0.2-ML-thick Fe film exhibits superparamagnetism, disproving the existence of a magnetically dead layer. For all the films, the spin moments per Fe atom are far less than that of bulk Fe, while anomalously large orbital moments are observed. Those are attributed, respectively, to both the oxidation Fe film at the interface and the existence of some Fe nanoclusters in fcc phase and to the high population of low coordinated atoms, such as Fe at the edges of the nanoclusters. [ABSTRACT FROM AUTHOR]

Published
2011
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147. Temperature dependent phase transition of EuO on MgO(100).

Author

Lee, Hangil, Kim, J.-Y., Rho, K.-J., Park, B.-G., and Park, J.-H.

Subjects
LOW energy electron diffraction, MAGNETIC properties, PHOTOEMISSION, PHASE transitions, EUROPIUM
Abstract

We investigated the changes of magnetic properties and phase transition in EuO films grown on a MgO(100) substrate as a function of temperature. As the temperature was varied, we observed a clear phase transition and polarization change at 69 K using spin resolved photoemission spectroscopy and low energy electron diffraction. We will elucidate the temperature driven changes in the electronic and magnetic properties of EuO films on a MgO(100) substrate. [ABSTRACT FROM AUTHOR]

Published
2007
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148. Temperature dependence of magnetocurrent in a magnetic tunnel transistor.

Author

Park, B. G., Banerjee, T., Min, B. C., Sanderink, J. G. M., Lodder, J. C., and Jansen, R.

Subjects
*JUNCTION transistors, *MAGNETORESISTANCE, *TEMPERATURE, *SEMICONDUCTOR diodes, *ELECTRIC resistance, *FERROMAGNETISM, *PHOTOLITHOGRAPHY, *ELECTRIC potential
Abstract

The temperature dependence of magnetocurrent (MC) and transfer ratio has been investigated in a magnetic tunnel transistor (MTT) with a ferromagnetic (FM) emitter of Co or Ni80Fe20. MTT devices of sizes ranging from 10 to 100 μm in diameter were fabricated using a standard photolithography process and predefined Si substrates. This reduces the edge leakage current across the collector Schottky diode and enables room-temperature operation. For the MTT with both Co and Ni80Fe20 emitter, we obtain a MC of about 80% at room temperature. This corresponds to a tunnel spin polarization of the FM emitter/Al2O3 interface of 29% at 1 V, demonstrating that the tunnel current is still spin-polarized at a high bias voltage. [ABSTRACT FROM AUTHOR]

Published
2005
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150. Interdiffusion in antiferromagnetic/ferromagnetic exchange coupled NiFe/IrMn/CoFe multilayer.

Author

Lee, J. H., Jeong, H. D., Yoon, C. S., Kim, C. K., Park, B. G., and Lee, T. D.

Subjects
DIFFUSION, ELECTRODES, SPECTRUM analysis
Abstract

Auger electron spectroscopy (AES) and Rutherford backscattering spectroscopy (RBS) analysis were carried out in order to study the extent of interdiffusion during thermal treatment of the pinned electrode (Ta/NiFe/Cu/NiFe/IrMn/CoFe) of the magnetic tunneling junction. From the concentration profile results from RBS and AES, a significant amount of Mn–CoFe interdiffusion was observed when the sample was annealed at 200 °C–400 °C under vacuum. The multilayer was completely intermixed at 400 °C, losing the exchange bias interaction between the IrMn and CoFe layers. It was demonstrated that the migration of Mn was enhanced by the preferential oxidation of Mn on the surface. In fact, when a thin layer of Ta for oxidation protection was deposited on top of the electrode, the Mn diffusion was minimal up to 300 °C. Our experiment suggests that in actual magnetic tunneling junctions, the Mn diffusion to the insulation layer could be enhanced by the presence of the free oxygen radicals in the insulation layer produced during the plasma oxidation of the Al layer. © 2002 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Published
2002
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