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21 results on '"Abe, F."'

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

Author

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

Subjects
Astrophysics
Abstract

We report the discovery of a binary composed of two brown dwarfs, based on the analysis of the micro lensing event OGLE-2016-BLG-1469. Thanks to the detection of both finite-source and micro lens-parallax effects, we are able to measure both the masses M(sub 1) ~ 0.05 Solar Mass and M(sub 2) ~ 0.01 Solar Mass, and the distance D(sub L) ~ 4.5 kpc, as well as the projected separation a(sub perpendicular) ~ 0.33 au. This is the third brown-dwarf binary detected using the micro lensing method, demonstrating the usefulness of micro lensing in detecting field brown-dwarf binaries with separations of less than 1 au.

Published
2017
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2. The Exoplanet Mass-Ratio Function From the MOA-II Survey: Discovery of a Break and Likely Peak at a Neptune Mass

Author

Suzuki, D, Bennett, D. P, Sumi, T, Bond, I. A, Rogers, L. A, Abe, F, Asakura, Y, Bhattacharya, A, Donachie, M, Freeman, M, Fukui, A, Hirao, Y, Itow, Y, Koshimoto, N, Li, M. C. A, Ling, C. H, Masuda, K, Matsubara, Y, Muraki, Y, Nagakane, M, Onishi, K, Oyokawa, H, Rattenbury, N, Saito, To, and Sharan, A

Subjects
Astrophysics
Abstract

We report the results of the statistical analysis of planetary signals discovered in MOA-II microlensing survey alert system events from 2007 to 2012. We determine the survey sensitivity as a function of planet star mass ratio, q, and projected planet star separation, s, in Einstein radius units. We find that the mass-ratio function is not a single power law, but has a change in slope at q approx.10(exp -4), corresponding to approx. 20 Stellar Mass for the median host-star mass of approx. 0.6 M. We find significant planetary signals in 23 of the 1474 alert events that are well-characterized by the MOA-II survey data alone. Data from other groups are used only to characterize planetary signals that have been identified in the MOA data alone. The distribution of mass ratios and separations of the planets found in our sample are well fit by a broken power-law model. We also combine this analysis with the previous analyses of Gould et al. and Cassan et al., bringing the total sample to 30 planets. The unbroken power-law model is disfavored with a p-value of 0.0022, which corresponds to a Bayes factor of 27 favoring the broken power-law model. These results imply that cold Neptunes are likely to be the most common type of planets beyond the snow line.

Published
2016
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3. Ogle-2012-blg-0724lb: A Saturn Mass Planet Around an M-dwarf

Author

Hirao, Y, Sumi, T, Bennett, D. P, Bond, I. A, Rattenbury, N, Suzuki, D, Koshimoto, N, Abe, F, Asakura, Y, and Bhattacharya, A

Subjects
Astrophysics
Abstract

We report the discovery of a planet by the microlensing method, OGLE-2012-BLG-0724Lb. Although the duration of the planetary signal for this event was one of the shortest seen for a planetary event, the anomaly was well covered thanks to high-cadence observations taken by the survey groups OGLE and MOA. By analyzing the light curve, this planetary system is found to have a mass ratio q = (1.58 +/- 0.15) x 10(exp -3). By conducting a Bayesian analysis, we estimate that the host star is an M dwarf with a mass of M(sub L) = 0.29(+0.33/-0.16) solar mass located at D(sub L) = 6.7(+1.1/-1.2) kpc away from the Earth and the companion's mass is m(sub P) = 0.47(+0.54/-0.26) M(Jup). The projected planet- host separation is a falsum = 1.6(+0.4/-0.3) AU. Because the lens-source relative proper motion is relatively high, future highresolution images would detect the lens host star and determine the lens properties uniquely. This system is likely a Saturn-mass exoplanet around an M dwarf, and such systems are commonly detected by gravitational microlensing. This adds another example of a possible pileup of sub-Jupiters (0.2 less than m(sub P)/M(sub Jup) less than 1) in contrast to a lack of Jupiters (approximately 1-2 M(sub Jup)) around M dwarfs, supporting the prediction by core accretion models that Jupiter-mass or more massive planets are unlikely to form around M dwarfs.

Published
2016
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4. Revisiting the Microlensing Event OGLE 2012-BLG-0026: A Solar Mass Star with Two Cold Giant Planets

Author

Beaulieu, J.-P, Bennett, D. P, Batista, V, Fukui, A, Marquette, J.-B, Brillant, S, Cole, A. A, Rogers, L. A, Sumi, T, and Abe, F

Subjects
Astrophysics
Abstract

Two cold gas giant planets orbiting a G-type main-sequence star in the galactic disk were previously discovered in the high-magnification microlensing event OGLE-2012-BLG-0026. Here, we present revised host star flux measurements and a refined model for the two-planet system using additional light curve data. We performed high angular resolution adaptive optics imaging with the Keck and Subaru telescopes at two epochs while the source star was still amplified. We detected the lens flux, H = 16.39 +/- 0.08. The lens, a disk star, is brighter than predicted from the modeling in the original study. We revisited the light curve modeling using additional photometric data from the B and C telescope in New Zealand and CTIO 1.3 m H-band light curve. We then include the Keck and Subaru adaptive optic observation constraints. The system is composed of an approximately 4-9 Gyr lens star of M(sub lens) = 1.06 +/- 0.05 solar mass at a distance of D(sub lens) = 4.0 +/- 0.3 kpc, orbited by two giant planets of 0.145 +/- 0.008 M(sub Jup) and 0.86 +/- 0.06 M(sub Jup), with projected separations of 4.0 +/- 0.5 au and 4.8 +/- 0.7 au, respectively. Because the lens is brighter than the source star by 16 +/- 8% in H, with no other blend within one arcsec, it will be possible to estimate its metallicity using subsequent IR spectroscopy with 8-10 m class telescopes. By adding a constraint on the metallicity it will be possible to refine the age of the system.

Published
2016
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5. Erratum: “A Detailed Observational Analysis of V1324 Sco, the Most Gamma-Ray-luminous Classical Nova to Date” (2018, ApJ, 852, 108)

Author

Finzell, Thomas, primary, Chomiuk, Laura, additional, Metzger, Brian D., additional, Walter, Frederick M., additional, Linford, Justin D., additional, Mukai, Koji, additional, Nelson, Thomas, additional, Weston, Jennifer H. S., additional, Zheng, Yong, additional, Sokoloski, Jennifer L., additional, Mioduszewski, Amy, additional, Rupen, Michael P., additional, Dong, Subo, additional, Starrfield, Sumner, additional, Cheung, C. C., additional, Woodward, Charles E., additional, Taylor, Gregory B., additional, Bohlsen, Terry, additional, Buil, Christian, additional, Prieto, Jose, additional, Wagner, R. Mark, additional, Bensby, Thomas, additional, Bond, I. A., additional, Sumi, T., additional, Bennett, D. P., additional, Abe, F., additional, Koshimoto, N., additional, Suzuki, D., additional, Tristram, P. J., additional, Christie, Grant W., additional, Natusch, Tim, additional, McCormick, Jennie, additional, Yee, Jennifer, additional, and Gould, Andy, additional

Published
2020
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6. A Detailed Observational Analysis of V1324 Sco, the Most Gamma-Ray-luminous Classical Nova to Date

Author

Finzell, Thomas, primary, Chomiuk, Laura, additional, Metzger, Brian D., additional, Walter, Frederick M., additional, Linford, Justin D., additional, Mukai, Koji, additional, Nelson, Thomas, additional, Weston, Jennifer H. S., additional, Zheng, Yong, additional, Sokoloski, Jennifer L., additional, Mioduszewski, Amy, additional, Rupen, Michael P., additional, Dong, Subo, additional, Starrfield, Sumner, additional, Cheung, C. C., additional, Woodward, Charles E., additional, Taylor, Gregory B., additional, Bohlsen, Terry, additional, Buil, Christian, additional, Prieto, Jose, additional, Wagner, R. Mark, additional, Bensby, Thomas, additional, Bond, I. A., additional, Sumi, T., additional, Bennett, D. P., additional, Abe, F., additional, Koshimoto, N., additional, Suzuki, D., additional, Tristram, P. J., additional, Christie, Grant W., additional, Natusch, Tim, additional, McCormick, Jennie, additional, Yee, Jennifer, additional, and Gould, Andy, additional

Published
2018
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7. DETERMINING THE PHYSICAL LENS PARAMETERS OF THE BINARY GRAVITATIONAL MICROLENSING EVENT MOA-2009-BLG-016

Author

Hwang, K. -H., Han, C., Bond, I. A., Miyake, N., Abe, F., Bennett, D. P., Botzler, C. S., Fukui, A., Furusawa, K., Hayashi, F., Hearnshaw, J. B., Hosaka, S., Itow, Y., Kamiya, K., Kilmartin, P. M., Korpela, A., Lin, W., Ling, C. H., Makita, S., Masuda, K., Matsubara, Y., Muraki, Y., Nishimoto, K., Ohnishi, K., Perrott, Y. C., Rattenbury, N., Saito, To., Sako, T., Skuljan, L., Sullivan, D. J., Sumi, T., Suzuki, D., Sweatman, W. L., Tristram, J., Wada, K., L., P. C. M. Yock D., Depoy, Gaudi, B. S., Gould, A., Lee, C. -U., and Pogge, R. W.

Subjects
Physics, 010504 meteorology & atmospheric sciences, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Light curve, Gravitational microlensing, 01 natural sciences, law.invention, Einstein radius, Lens (optics), Gravitational lens, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, law, 0103 physical sciences, Orbital motion, Astrophysics::Earth and Planetary Astrophysics, Caustic (optics), Parallax, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), 0105 earth and related environmental sciences
Abstract

We report the result of the analysis of the light curve of the microlensing event MOA-2009-BLG-016. The light curve is characterized by a short-duration anomaly near the peak and an overall asymmetry. We find that the peak anomaly is due to a binary companion to the primary lens and the asymmetry of the light curve is explained by the parallax effect caused by the acceleration of the observer over the course of the event due to the orbital motion of the Earth around the Sun. In addition, we detect evidence for the effect of the finite size of the source near the peak of the event, which allows us to measure the angular Einstein radius of the lens system. The Einstein radius combined with the microlens parallax allows us to determine the total mass of the lens and the distance to the lens. We identify three distinct classes of degenerate solutions for the binary lens parameters, where two are manifestations of the previously identified degeneracies of close/wide binaries and positive/negative impact parameters, while the third class is caused by the symmetric cycloid shape of the caustic. We find that, for the best-fit solution, the estimated mass of the lower-mass component of the binary is (0.04 +- 0.01) M_sun, implying a brown-dwarf companion. However, there exists a solution that is worse only by \Delta\chi^2 ~ 3 for which the mass of the secondary is above the hydrogen-burning limit. Unfortunately, resolving these two degenerate solutions will be difficult as the relative lens-source proper motions for both are similar and small (~ 1 mas/yr) and thus the lens will remain blended with the source for the next several decades., Comment: 7 pages, 2 tables, and 5 figures

Published
2010
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8. THE EXTREME MICROLENSING EVENT OGLE-2007-BLG-224: TERRESTRIAL PARALLAX OBSERVATION OF A THICK-DISK BROWN DWARF

Author

Gould, A., Udalski, A., Monard, B., Horne, K., Dong, Subo, Miyake, N., Sahu, K., Bennett, D. P., Wyrzykowski, Ł., Soszyński, I., Szymański, M. K., Kubiak, M., Pietrzyński, G., Szewczyk, O., Ulaczyk, K., Allen, W., Christie, G. W., Depoy, D. L., Gaudi, B. S., Han, C., Lee, C.-U., Mccormick, J., Natusch, T., Park, B.-G., Pogge, R. W., Allan, A., Bode, M. F., Bramich, D. M., Burgdorf, M. J., Dominik, M., Fraser, S. N., Kerins, E., Mottram, C., Snodgrass, C., Steele, I. A., Street, R., Tsapras, Y., Abe, F., Bond, I. A., Botzler, C. S., Fukui, A., Furusawa, K., Hearnshaw, J. B., Itow, Y., Kamiya, K., Kilmartin, P. M., Korpela, A., Lin, W., Ling, C. H., Masuda, K., Matsubara, Y., Muraki, Y., Nagaya, M., Ohnishi, K., Okumura, T., Perrott, Y. C., Rattenbury, N., Saito, To., Sako, T., Skuljan, L., Sullivan, D. J., Sumi, T., Sweatman, W. L., Tristram, P. J., Yock, P. C. M., Albrow, M., Beaulieu, J. P., Coutures, C., Calitz, H., Caldwell, J., Fouqué, P., Martin, Roland, Williams, A., Department of Astronomy (Ohio State University), Ohio State University [Columbus] (OSU), Astrophysics Research Institute [Liverpool] (ARI), Liverpool John Moores University (LJMU), Institut d'Astrophysique de Paris (IAP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Astrophysique de Toulouse-Tarbes (LATT), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), and 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)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Astronomical Objects, Solar System, gravitational lensing, Brown dwarf, FOS: Physical sciences, Astrophysics, Gravitational microlensing, 01 natural sciences, law.invention, stars: low-mass, law, 0103 physical sciences, Thick disk, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Physics, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], 010308 nuclear & particles physics, Astronomy and Astrophysics, [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Astrophysics - Astrophysics of Galaxies, Lens (optics), Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), astrometry, Astrophysics::Earth and Planetary Astrophysics, Parallax, Event (particle physics), brown dwarfs
Abstract

Parallax is the most fundamental technique to measure distances to astronomical objects. Although terrestrial parallax was pioneered over 2000 years ago by Hipparchus (ca. 140 BCE) to measure the distance to the Moon, the baseline of the Earth is so small that terrestrial parallax can generally only be applied to objects in the Solar System. However, there exists a class of extreme gravitational microlensing events in which the effects of terrestrial parallax can be readily detected and so permit the measurement of the distance, mass, and transverse velocity of the lens. Here we report observations of the first such extreme microlensing event OGLE-2007-BLG-224, from which we infer that the lens is a brown dwarf of mass M=0.056 +- 0.004 Msun, with a distance of 525 +- 40 pc and a transverse velocity of 113 +- 21 km/s. The velocity places the lens in the thick disk, making this the lowest-mass thick-disk brown dwarf detected so far. Follow-up observations may allow one to observe the light from the brown dwarf itself, thus serving as an important constraint for evolutionary models of these objects and potentially opening a new window on sub-stellar objects. The low a priori probability of detecting a thick-disk brown dwarf in this event, when combined with additional evidence from other observations, suggests that old substellar objects may be more common than previously assumed., Comment: ApJ Letters, in press, 15 pages including 2 figures

Published
2009
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9. MOA-2008-BLG-379Lb: A Massive Planet from a High Magnification Event with a Faint Source

Author

Suzuki, D, Udalski, A, Sumi, T, Bennett, D. P, Bond, I. A, Abe, F, Botzler, C. S, Freeman, M, Fukagawa, M, Fukui, A, Furusawa, K, Itow, Y, Ling, C. H, Masuda, K, Matsubara, Y, Muraki, Y, Ohnishi, K, Rattenbury, N, Saito, To, Shibai, H, Sullivan, D. J, Suzuki, K, Sweatman, W. L, Takino, S, Tristram, P. J, Wada, K, Yock, P. C. M, MOA Collaboration, Szymański, M. K, Kubiak, M, Soszyński, I, Pietrzyński, G, Poleski, R, Ulaczyk, K, Wyrzykowski, Ł, and OGLE Collaboration

Published
2014

10. Microlensing Discovery of a Population of Very Tight, Very Low Mass Binary Brown Dwarfs

Author

Choi, J.-Y, Han, C, Udalski, A, Sumi, T, Gaudi, B. S, Gould, A, Bennett, D. P, Dominik, M, Beaulieu, J.-P, Tsapras, Y, Bozza, V, Abe, F, Bond, I. A, Botzler, C. S, Chote, P, Freeman, M, Fukui, A, Furusawa, K, Itow, Y, Ling, C. H, Masuda, K, Matsubara, Y, Miyake, N, Muraki, Y, Ohnishi, K, Rattenbury, N. J, Saito, To, Sullivan, D. J, Suzuki, K, Sweatman, W. L, Suzuki, D, Takino, S, Tristram, P. J, Wada, K, Yock, P. C. M, The MOA Collaboration, Szymański, M. K, Kubiak, M, and P

Published
2013

11. MOA-2010-BLG-523: 'Failed Planet' = RS CVn Star

Author

Gould, A, Yee, J. C, Bond, I. A, Udalski, A, Han, C, Jxf8rgensen, U. G, Greenhill, J, Tsapras, Y, Pinsonneault, M. H, Bensby, T, Allen, W, Almeida, L. A, Bos, M, Christie, G. W, DePoy, D. L, Dong, Subo, Gaudi, B. S, Hung, L.-W, Jablonski, F, Lee, C.-U, McCormick, J, Moorhouse, D, Muxf1oz, J. A, Natusch, T, Nola, M, Pogge, R. W, Skowron, J, Thornley, G, The μFUN Collaboration, Abe, F, Bennett, D. P, Botzler, C. S, Chote, P, Freeman, M, Fukui, A, Furusawa, K, Harris, P, and Itow, Y.

Published
2013

12. Microlensing Binaries with Candidate Brown Dwarf Companions

Author

Shin, I.-G, Han, C, Gould, A, Udalski, A, Sumi, T, Dominik, M, Beaulieu, J.-P, Tsapras, Y, Bozza, V, Szymański, M. K, Kubiak, M, Soszyński, I, Pietrzyński, G, Poleski, R, Ulaczyk, K, Pietrukowicz, P, Kozłowski, S, Skowron, J, Wyrzykowski, Ł, The OGLE Collaboration, Abe, F, Bennett, D. P, Bond, I. A, Botzler, C. S, Freeman, M, Fukui, A, Furusawa, K, Hayashi, F, Hearnshaw, J. B, Hosaka, S, Itow, Y, Kamiya, K, Kilmartin, P. M, Kobara, S, Korpela, A, Lin, W, Ling, C. H, and Maki

Published
2012

13. Microlensing Binaries Discovered through High-magnification Channel

Author

Shin, I.-G, Choi, J.-Y, Park, S.-Y, Han, C, Gould, A, Sumi, T, Udalski, A, Beaulieu, J.-P, Dominik, M, Allen, W, Bos, M, Christie, G. W, Depoy, D. L, Dong, S, Drummond, J, Gal-Yam, A, Gaudi, B. S, Hung, L.-W, Janczak, J, Kaspi, S, Lee, C.-U, Mallia, F, Maoz, D, Maury, A, McCormick, J, Monard, L. A. G, Moorhouse, D, Muxf1oz, J. A, Natusch, T, Nelson, C, Park, B.-G, Pogge, R. W, Polishook, D, Shvartzvald, Y, Shporer, A, Thornley, G, Yee, J. C, μFUN Collaboration, Abe, F, and B

Published
2012

14. CAN THE MASSES OF ISOLATED PLANETARY-MASS GRAVITATIONAL LENSES BE MEASURED BY TERRESTRIAL PARALLAX?

Author

Freeman, M., primary, Philpott, L. C., additional, Abe, F., additional, Albrow, M. D., additional, Bennett, D. P., additional, Bond, I. A., additional, Botzler, C. S., additional, Bray, J. C., additional, Cherrie, J. M., additional, Christie, G. W., additional, Dionnet, Z., additional, Gould, A., additional, Han, C., additional, Heyrovský, D., additional, McCormick, J. M., additional, Moorhouse, D. M., additional, Muraki, Y., additional, Natusch, T., additional, Rattenbury, N. J., additional, Skowron, J., additional, Sumi, T., additional, Suzuki, D., additional, Tan, T.-G., additional, Tristram, P. J., additional, and Yock, P. C. M., additional

Published
2015
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15. A NEW TYPE OF AMBIGUITY IN THE PLANET AND BINARY INTERPRETATIONS OF CENTRAL PERTURBATIONS OF HIGH-MAGNIFICATION GRAVITATIONAL MICROLENSING EVENTS

Author

Choi, J.-Y, Shin, I.-G, Han, C., Udalski, A., Sumi, T., Gould, A., Bozza, V., Dominik, M., Fouque´, P., Horne, K., Szyman´ski, M. K., Kubiak, M., Soszyn´ski, I., Pietrzyn´ski, G., Poleski, R., Ulaczyk, K., Pietrukowicz, P., Kozłowski, S., Skowron, J., Wyrzykowski, Ł., OGLE Collaboration, Abe, F., Bennett, D. P., Bond, I. A., Botzler, C. S., Chote, P., Freeman, M., Fukui, A., Furusawa, K., Itow, Y., Kobara, S., Ling, C. H., Masuda, K., Matsubara, Y., Miyake, N., Muraki, Y., Ohmori, K., Ohnishi, K., Rattenbury, N. J., Saito, To, Sullivan, D. J., Suzuki, D., Suzuki, K., Sweatman, W. L., Takino, S., Tristram, P. J., Wada, K., Yock, P. C. M., MOA Collaboration, Bramich, D. M., Snodgrass, C., Steele, I. A., Street, R. A., Tsapras, Y., RoboNet Collaboration, Alsubai, K. A., Browne, P., Burgdorf, M. J., Calchi Novati, S., Dodds, P., Dreizler, S., Fang, X.-S, Grundahl, F., Gu, C.-H, Hardis, S., Harpsøe, K., Hinse, T. C., Hornstrup, Allan, Hundertmark, M., Jessen-Hansen, J., Jørgensen, U. G., Kains, N., Kerins, E., Liebig, C., Lund, M., Lunkkvist, M., Mancini, L., Mathiasen, M., Penny, M. T., Rahvar, S., Ricci, D., Scarpetta, G., Skottfelt, J., Southworth, J., Surdej, J., Tregloan-Reed, J., Wambsganss, J., Wertz, O., Almeida, L. A., Batista, V., Christie, G., DePoy, D. L., Dong, Subo, Gaudi, B. S., Henderson, C., Jablonski, F., Lee, C.-U, McCormick, J., McGregor, D., Moorhouse, D., Natusch, T., Ngan, H., Pogge, R. W., Tan, T.-G, Thornley, G., Yee, J. C., Albrow, M. D., Bachelet, E., Beaulieu, J.-P, Brillant, S., Cassan, A., Cole, A. A., Corrales, E., Coutures, C., Dieters, S., Dominis Prester, D., Donatowicz, J., Greenhill, J., Kubas, D., Marquette, J.-B, Menzies, J. W., Sahu, K. C., and Zub, M.

Subjects
media_common.quotation_subject, FOS: Physical sciences, Binary number, Perturbation (astronomy), gravitational lensing: micro, Astrophysics, Gravitational microlensing, 01 natural sciences, Galaxy: bulge, Settore FIS/05 - Astronomia e Astrofisica, Planet, 0103 physical sciences, 010306 general physics, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), media_common, Earth and Planetary Astrophysics (astro-ph.EP), Physics, Binary Independence Model, Astronomy and Astrophysics, Ambiguity, Light curve, Galaxy: bulge, gravitational lensing: micro, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, Astrophysics::Earth and Planetary Astrophysics, Caustic (optics), Astrophysics - Earth and Planetary Astrophysics
Abstract

High-magnification microlensing events provide an important channel to detect planets. Perturbations near the peak of a high-magnification event can be produced either by a planet or a binary companion. It is known that central perturbations induced by both types of companions can be generally distinguished due to the basically different magnification pattern around caustics. In this paper, we present a case of central perturbations for which it is difficult to distinguish the planetary and binary interpretations. The peak of a lensing light curve affected by this perturbation appears to be blunt and flat. For a planetary case, this perturbation occurs when the source trajectory passes the negative perturbation region behind the back end of an arrowhead-shaped central caustic. For a binary case, a similar perturbation occurs for a source trajectory passing through the negative perturbation region between two cusps of an astroid-shaped caustic. We demonstrate the degeneracy for 2 high-magnification events of OGLE-2011-BLG-0526 and OGLE-2011-BLG-0950/MOA-2011-BLG-336. For OGLE-2011-BLG-0526, the $\chi^2$ difference between the planetary and binary model is $\sim$ 3, implying that the degeneracy is very severe. For OGLE-2011-BLG-0950/MOA-2011-BLG-336, the stellar binary model is formally excluded with $\Delta \chi^2 \sim$ 105 and the planetary model is preferred. However, it is difficult to claim a planet discovery because systematic residuals of data from the planetary model are larger than the difference between the planetary and binary models. Considering that 2 events observed during a single season suffer from such a degeneracy, it is expected that central perturbations experiencing this type of degeneracy is common., Comment: 8 pages, 8 figures

Published
2012
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17. EXTREME MAGNIFICATION MICROLENSING EVENT OGLE-2008-BLG-279: STRONG LIMITS ON PLANETARY COMPANIONS TO THE LENS STAR

Author

Yee, J. C., primary, Udalski, A., additional, Sumi, T., additional, Dong, Subo, additional, Kozłowski, S., additional, Bird, J. C., additional, Cole, A., additional, Higgins, D., additional, McCormick, J., additional, Monard, L. A. G., additional, Polishook, D., additional, Shporer, A., additional, Spector, O., additional, Szymański, M. K., additional, Kubiak, M., additional, Pietrzyński, G., additional, Soszyński, I., additional, Szewczyk, O., additional, Ulaczyk, K., additional, Wyrzykowski, Ł., additional, Poleski, R., additional, Allen, W., additional, Bos, M., additional, Christie, G. W., additional, DePoy, D. L., additional, Eastman, J. D., additional, Gaudi, B. S., additional, Gould, A., additional, Han, C., additional, Kaspi, S., additional, Lee, C. -U., additional, Mallia, F., additional, Maury, A., additional, Maoz, D., additional, Natusch, T., additional, Park, B. -G., additional, Pogge, R. W., additional, Santallo, R., additional, Abe, F., additional, Bond, I. A., additional, Fukui, A., additional, Furusawa, K., additional, Hearnshaw, J. B., additional, Hosaka, S., additional, Itow, Y., additional, Kamiya, K., additional, Korpela, A. V., additional, Kilmartin, P. M., additional, Lin, W., additional, Ling, C. H., additional, Makita, S., additional, Masuda, K., additional, Matsubara, Y., additional, Miyake, N., additional, Muraki, Y., additional, Nagaya, M., additional, Nishimoto, K., additional, Ohnishi, K., additional, Perrott, Y. C., additional, Rattenbury, N. J., additional, Sako, T., additional, Saito, To., additional, Skuljan, L., additional, Sullivan, D. J., additional, Sweatman, W. L., additional, Tristram, P. J., additional, Yock, P. C. M., additional, Albrow, M. D., additional, Batista, V., additional, Fouqué, P., additional, Beaulieu, J. -P., additional, Bennett, D. P., additional, Cassan, A., additional, Comparat, J., additional, Coutures, C., additional, Dieters, S., additional, Greenhill, J., additional, Horne, K., additional, Kains, N., additional, Kubas, D., additional, Martin, R., additional, Menzies, J., additional, Wambsganss, J., additional, Williams, A., additional, and Zub, M., additional

Published
2009
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18. A Low‐Mass Planet with a Possible Sub‐Stellar‐Mass Host in Microlensing Event MOA‐2007‐BLG‐192

Author

Bennett, D. P., primary, Bond, I. A., additional, Udalski, A., additional, Sumi, T., additional, Abe, F., additional, Fukui, A., additional, Furusawa, K., additional, Hearnshaw, J. B., additional, Holderness, S., additional, Itow, Y., additional, Kamiya, K., additional, Korpela, A. V., additional, Kilmartin, P. M., additional, Lin, W., additional, Ling, C. H., additional, Masuda, K., additional, Matsubara, Y., additional, Miyake, N., additional, Muraki, Y., additional, Nagaya, M., additional, Okumura, T., additional, Ohnishi, K., additional, Perrott, Y. C., additional, Rattenbury, N. J., additional, Sako, T., additional, Saito, To., additional, Sato, S., additional, Skuljan, L., additional, Sullivan, D. J., additional, Sweatman, W. L., additional, Tristram, P. J., additional, Yock, P. C. M., additional, Kubiak, M., additional, Szymański, M. K., additional, Pietrzyński, G., additional, Soszyński, I., additional, Szewczyk, O., additional, Wyrzykowski, Ł., additional, Ulaczyk, K., additional, Batista, V., additional, Beaulieu, J. P., additional, Brillant, S., additional, Cassan, A., additional, Fouqué, P., additional, Kervella, P., additional, Kubas, D., additional, and Marquette, J. B., additional

Published
2008
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19. Observation of the First Gravitational Microlensing Event in a Sparse Stellar Field: The Tago Event

Author

Fukui, A., primary, Abe, F., additional, Ayani, K., additional, Fujii, M., additional, Iizuka, R., additional, Itow, Y., additional, Kabumoto, K., additional, Kamiya, K., additional, Kawabata, T., additional, Kawanomoto, S., additional, Kinugasa, K., additional, Koff, R. A., additional, Krajci, T., additional, Naito, H., additional, Nogami, D., additional, Narusawa, S., additional, Ohishi, N., additional, Ohnishi, K., additional, Sumi, T., additional, and Tsumuraya, F., additional

Published
2007
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20. Microlensing Optical Depth toward the Galactic Bulge from Microlensing Observations in Astrophysics Group Observations during 2000 with Difference Image Analysis

Author

Sumi, T., primary, Abe, F., additional, Bond, I. A., additional, Dodd, R. J., additional, Hearnshaw, J. B., additional, Honda, M., additional, Honma, M., additional, Kan‐ya, Y., additional, Kilmartin, P. M., additional, Masuda, K., additional, Matsubara, Y., additional, Muraki, Y., additional, Nakamura, T., additional, Nishi, R., additional, Noda, S., additional, Ohnishi, K., additional, Petterson, O. K. L., additional, Rattenbury, N. J., additional, Reid, M., additional, Saito, To., additional, Saito, Y., additional, Sato, H., additional, Sekiguchi, M., additional, Skuljan, J., additional, Sullivan, D. J., additional, Takeuti, M., additional, Tristram, P. J., additional, Wilkinson, S., additional, Yanagisawa, T., additional, and Yock, P. C. M., additional

Published
2003
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21. On Planetary Companions to the MACHO 98-BLG-35 Microlens Star

Author

Rhie, S. H., Bennett, D. P., Becker, A. C., Peterson, B. A., Fragile, P. C., Johnson, B. R., Quinn, J. L., Crouch, A., Gray, J., King, L., Messenger, B., Thomson, S., Bond, I. A., Abe, F., Carter, B. S., Dodd, R. J., Hearnshaw, J. B., Honda, M., Jugaku, J., Kabe, S., Kilmartin, P. M., Koribalski, B. S., Masuda, K., Matsubara, Y., Muraki, Y., Nakamura, T., Nankivell, G. R., Noda, S., Rattenbury, N. J., Reid, M., Rumsey, N. J., Saito, To., Sato, H., Sato, S., Sekiguchi, M., Sullivan, D. J., Sumi, T., Watase, Y., Yanagisawa, T., Yock, P. C. M., and Yoshizawa, M.

Abstract

We present observations of the microlensing event MACHO 98-BLG-35, which reached a peak magnification factor of almost 80. These observations by the Microlensing Planet Search (MPS) and MOA collaborations place strong constraints on the possible planetary system of the lens star and show intriguing evidence for a low-mass planet with a mass fraction 4 × 10-5? ? 2 × 10-4. A giant planet with = 10-3is excluded from 95% of the region between 0.4 and 2.5 REfrom the lens star, where REis the Einstein ring radius of the lens. This exclusion region is more extensive than the generic "lensing zone," which is 0.6-1.6 RE. For smaller mass planets, we can exclude 57% of the "lensing zone" for = 10-4and 14% of the lensing zone for = 10-5. The mass fraction = 10-5corresponds to an Earth-mass planet for a lensing star of mass ~0.3 M?. A number of similar events will provide statistically significant constraints on the prevalence of Earth-mass planets. In order to put our limits in more familiar terms, we have compared our results to those expected for a solar system clone, averaging over possible lens system distances and orientations. We find that such a system is ruled out at the 90% confidence level. A copy of the solar system with Jupiter replaced by a second Saturn-mass planet can be ruled out at 70% confidence. Our low-mass planetary signal (few Earth masses to Neptune mass) is significant at the 4.5 ? confidence level. If this planetary interpretation is correct, the MACHO 98-BLG-35 lens system constitutes the first detection of a low-mass planet orbiting an ordinary star without gas giant planets.

Published
2000
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