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518 results on '"LING, C. H."'

151. A comparison of numerical results of Arctic Sea ice modeling with satellite images

Author

Ling, C. H and Parkinson, C

Subjects
Oceanography
Abstract

Observations made from 1972 to 1976 with the Electrically Scanning Microwave Radiometer on board the Nimbus 5 Satellite provide sequential synoptic information of the Arctic sea ice cover. This 4 year data set was used to construct a fairly continuous series of 3 day average 19-GHz passive microwave images which has become a valuable source of polar information, yielding many anticipated and unanticipated discoveries of the sea ice canopy observed in its entirety through the clouds and during the polar night. Interpretation of the passive microwave satellite data set was performed by comparing selected sequential images with correspondin microwave profiles and images acquired by the NASA CV-990 airborne laboratory and with various in situ microwave and physical observations.

Published
1983

152. 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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159. MOA-2011-BLG-262Lb: A SUB-EARTH-MASS MOON ORBITING A GAS GIANT PRIMARY OR A HIGH VELOCITY PLANETARY SYSTEM IN THE GALACTIC BULGE.

Author

Bennett, D. P., Batista, V., Bond, I. A., Bennett, C. S., Suzuki, D., Beaulieu, J.-P., Udalski, A., Donatowicz, J., Bozza, V., Abe, F., Botzler, C. S., Freeman, M., Fukunaga, D., Fukui, A., Itow, Y., Koshimoto, N., Ling, C. H., Masuda, K., Matsubara, Y., and Muraki, Y.

Subjects
GRAVITATIONAL lenses, MICROLENSING (Astrophysics), PROTO-planetary nebulae, PLANETARY mass, SPACE exploration
Abstract

We present the first microlensing candidate for a free-floating exoplanet-exomoon system, MOA-2011-BLG-262, with a primary lens mass of Mhost ∼ 4 Jupiter masses hosting a sub-Earth mass moon. The argument for an exomoon hinges on the system being relatively close to the Sun. The data constrain the product MLπrel where ML is the lens system mass and πrel is the lens-source relative parallax. If the lens system is nearby (large πrel), then ML is small (a few Jupiter masses) and the companion is a sub-Earth-mass exomoon. The best-fit solution has a large lens-source relative proper motion, μrel = 19.6 ± 1.6 mas yr–1, which would rule out a distant lens system unless the source star has an unusually high proper motion. However, data from the OGLE collaboration nearly rule out a high source proper motion, so the exoplanet+exomoon model is the favored interpretation for the best fit model. However, there is an alternate solution that has a lower proper motion and fits the data almost as well. This solution is compatible with a distant (so stellar) host. A Bayesian analysis does not favor the exoplanet+exomoon interpretation, so Occam's razor favors a lens system in the bulge with host and companion masses of and , at a projected separation of AU. The existence of this degeneracy is an unlucky accident, so current microlensing experiments are in principle sensitive to exomoons. In some circumstances, it will be possible to definitively establish the mass of such lens systems through the microlensing parallax effect. Future experiments will be sensitive to less extreme exomoons. [ABSTRACT FROM AUTHOR]

Published
2014
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168. MICROLENSING DISCOVERY OF A POPULATION OF VERY TIGHT, VERY LOW MASS BINARY BROWN DWARFS.

Author

CHO, 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., and LING, C. H.

Subjects
MICROLENSING (Astrophysics), BINARY systems (Astronomy), BROWN dwarf stars, STELLAR activity, STELLAR populations
Abstract

Although many models have been proposed, the physical mechanisms responsible for the formation of low-mass brown dwarfs (BDs) are poorly understood. Themultiplicity properties and minimummass of the BD mass function provide critical empirical diagnostics of these mechanisms.We present the discovery via gravitational microlensing of two very low mass, very tight binary systems. These binaries have directly and precisely measured total system masses of 0.025M☉ and 0.034M☉, and projected separations of 0.31 AU and 0.19 AU, making them the lowestmass and tightest field BD binaries known. The discovery of a population of such binaries indicates that BD binaries can robustly form at least down to masses of ~0.02M☉. Future microlensing surveys will measure a mass-selected sample of BD binary systems, which can then be directly compared to similar samples of stellar binaries. [ABSTRACT FROM AUTHOR]

Published
2013
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173. Generation Recombination Noise in the Near Fully Depleted SIMOX SOI n-MOSFET-- Physical Characteristics and Modeling.

Author

Ang, D. S., Lun, Z., and Ling, C. H.

Subjects
COMPLEMENTARY metal oxide semiconductors, NOISE measurement, SILICON-on-insulator technology, SEMICONDUCTORS, SOUND analyzers, ELECTRIC conductivity
Abstract

Noise measurement in the linear regime of the device characteristics shows the evolution of an important Lorentzian-like component in the thin-film SIMOX silicon-on-insulator (SOI) n-MOSFET, during the transition from fully depleted to near fully (or partially) depleted operation. The same noise component co-exists with another Lorentzian-like component commonly observed in the kink region, thus distinguishing it from the latter, which is associated with a shot-noise mechanism. Evidence unambiguously shows that local potential fluctuations, caused by random generation-recombination (G-R) processes at bulk defects in the depleted SOI film, are primarily responsible. Extracted trap energy of ∼0.4-0.45 eV below the silicon conduction band edge confirms the involvement of deep-level electron traps, which are probably linked to the residual oxygen and SiO[sub2] precipitates in the SOI film. A new analytical G-R noise model yields bulk traps with an average density of ∼10[sup16] cm[sup-3], situated at ∼22-32 nm from the front interface. With an area density comparable to that of the front interface states, the proximity of these bulk traps to the conducting channel in thin-film SIMOX SOI devices accounts for the dominance of bulk-trap induced G-R noise over conventional 1/f noise due to near-interface oxide traps. [ABSTRACT FROM AUTHOR]

Published
2003
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174. A Steady State Drain Current Technique for Generation and Recombination Lifetime Measurement in...

Author

Cheng, Zhi-Yuan and Ling, C. H.

Subjects
*METAL oxide semiconductor field-effect transistors, *SILICON-on-insulator technology, *TRANSISTORS
Abstract

Describes a steady state drain current technique for lifetime measurement in the fully depleted silicon-on-insulator (SOI) metal oxide semiconductors field-effect transistors (MOSFET). Significance of generation and recombination lifetimes of free carriers in the floating body of the SOI MOSFET; Results and discussion; Conclusion.

Published
2000
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175. The Role of Electron Traps on the Post-Stress Interface Trap Generation in Hot-Carrier Stressed...

Author

Ang, D.S. and Ling, C. H.

Subjects
*METAL oxide semiconductor field-effect transistors, *HOT carriers
Abstract

Focuses on a study on the role of electron traps on the post-stress interface trap generation in hot-carrier stressed metal oxide semiconductor field-effect transistors (MOSFET). Model involving interaction between inversion holes and hot-carrier-induced electron traps proposed; Experimental results and discussion; Conclusion.

Published
1999
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177. A comparison of hot-carrier degradation in tungsten...

Author

Ang, D. S. and Ling, C. H.

Subjects
*HOT carriers, *METAL oxide semiconductor field-effect transistors, *SCIENTIFIC experimentation
Abstract

Compares the hot-carrier degradation behavior for polycided gate and non-polycided gate p-metal-oxide semiconductor field-effect transistors (MOSFET). Experimental procedure; Gate-to-drain capacitance of MOSFET; Results and discussion of the experiment; Conclusions.

Published
1998
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182. Evidence of Two Distinct Degradation Mechanisms From Temperature Dependence of Negative Bias Stressing of the Ultrathin Gate p-MOSFET.

Author

Ang, D. S., Wang, S., and Ling, C. H.

Subjects
METAL oxide semiconductor field-effect transistors, FIELD-effect transistors, METAL oxide semiconductors, NITRIDES, SEMICONDUCTORS, ELECTRONS, NITROGEN
Abstract

A detailed investigation of the negative-bias temperature instability (NBTI) of the ultrathin nitrided gate p-MOSFET over a wide temperature range reveals two different activation energies, indicating the coexistence of two distinct degradation mechanisms. One mechanism is linked to the incorporation of nitrogen while the other is the classical mechanism responsible for the degradation of conventional SiO2 gate devices. Eliminating the contribution of the former consistently yields an Arrhenius plot that matches excellently with that obtained through direct measurement of SiO2 gate devices. This finding shows that heavy nitridation or, in the extreme case, the adoption of Si3N4/SiO∞ gate stack does not change the nature of the classical NBTI mechanism but introduces a new degradation mechanism of an order-of-magnitude lower activation energy, which dominates over typical operating temperature range. This new mechanism is related to the spontaneous trapping of positive charges at nitrogen-related precursor sites near the Si-SiO2 interface. [ABSTRACT FROM AUTHOR]

Published
2005
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183. Evidence for a Composite Interface State Generation Mode in the CHE-Stressed Deep-Submicrometer n-MOSFET.

Author

Ang, D. S., Liao, H., Phua, T. W. H., and Ling, C. H.

Subjects
METAL oxide semiconductor field-effect transistors, FIELD-effect transistors, METAL oxide semiconductors, ELECTRONS, IONS, GRAPHICAL projection
Abstract

Results from channel hot-electron stressing of 0.18-μm n-MOSFETs indicate that, for typical drain stress voltages ranging from 2-3 V, a significant fraction of the Si-SiO2 interface states is in fact generated by the majority of the less energetic (&les;q Vd < 3 eV) electrons in the channel, as opposed to the usual perception that injection of the more energetic (> 3 eV) high-energy tail (HET) electrons plays a dominant role. The role of the minority HET electrons, however, becomes increasingly dominant as the drain voltage is reduced. On the basis that the HET electrons gain excess energy through secondary means, this composite interface state generation mode may have a significant impact on the accuracy of hot-carrier reliability projection. [ABSTRACT FROM AUTHOR]

Published
2004
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184. Gate-Channel Capacitance Characteristics in the Fully-Depleted SOI MOSFET.

Author

Cheng, Zhi-Yuan and Ling, C. H.

Subjects
*SILICON-on-insulator technology, *METAL oxide semiconductor field-effect transistors, *ELECTRIC capacity
Abstract

Presents a study which proposed a method to determine the gate-channel capacitance characteristics in the silicon-on-insulator metal-oxide-semiconductor field-effect transistors. Details on the steady-state gate-channel capacitance characteristics; Application of gate-channel capacitance; Conclusion.

Published
2001
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186. Close correspondence between forward gated-diode and...

Author

Ling, C. H. and Goh, Y. H.

Subjects
*HOT carriers, *METAL oxide semiconductor field-effect transistors
Abstract

Reports that the gate induced drain leakage (GIDL) current has been used to study hot-carrier induced interface traps, near the drain junction of metal oxide semiconductor field-effect transistor (MOSFET). Experimental details; Results and discussion of the experiment; Conclusions.

Published
1997
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187. Fowler-nordheim stress degradation in gate oxide: Results from gate-to-drain capacitance and...

Author

Ling, C. H. and Goh, Y. H.

Subjects
*METAL oxide semiconductor field-effect transistors
Abstract

Observes the buildup of positive oxide charge and interface trap charge, due to Fowler-Nordheim stress, using the gate-drain overlap region of the Metal Oxide Semiconductor Field-effect Transistor (MOSFET). Analysis on the experiments; Results of the experiments; Performance of the gate-to-drain capacitance and charge pumping current in channel accumulation; Conclusion.

Published
1997
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188. OGLE-2014-BLG-0289: Precise Characterization of a Quintuple-peak Gravitational Microlensing Event

Author

Udalski, A., Han, C., Bozza, V., Gould, A., Bond, I. A., Mróz, P., Skowron, J., Wyrzykowski, Ł., Szymański, M. K., Soszyński, I., Ulaczyk, K., Poleski, R., Pietrukowicz, P., Kozłowski, S., 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., Masuda, K., 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, D., Tristram, P. J., Yamada, T., Yonehara, A., Bachelet, E., Bramich, D. M., DÁgo, G., Dominik, M., Jaimes, R. Figuera, Horne, K., Hundertmark, M., Kains, N., Menzies, J., Schmidt, R., Snodgrass, C., Steele, I. A., Wambsganss, J., Pogge, R. W., Jung, Y. K., Shin, I.-G., Yee, J. C., Kim, W.-T., Beichman, C., Carey, S., Novati, S. Calchi, Zhu, W., Udalski, A., Han, C., Bozza, V., Gould, A., Bond, I. A., Mróz, P., Skowron, J., Wyrzykowski, Ł., Szymański, M. K., Soszyński, I., Ulaczyk, K., Poleski, R., Pietrukowicz, P., Kozłowski, S., 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., Masuda, K., 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, D., Tristram, P. J., Yamada, T., Yonehara, A., Bachelet, E., Bramich, D. M., DÁgo, G., Dominik, M., Jaimes, R. Figuera, Horne, K., Hundertmark, M., Kains, N., Menzies, J., Schmidt, R., Snodgrass, C., Steele, I. A., Wambsganss, J., Pogge, R. W., Jung, Y. K., Shin, I.-G., Yee, J. C., Kim, W.-T., Beichman, C., Carey, S., Novati, S. Calchi, and Zhu, W.

Abstract

We present the analysis of the binary-microlensing event OGLE-2014-BLG-0289. The event light curve exhibits five very unusual peaks, four of which were produced by caustic crossings and the other by a cusp approach. It is found that the quintuple-peak features of the light curve provide tight constraints on the source trajectory, enabling us to precisely and accurately measure the microlensing parallax πE. Furthermore, the three resolved caustics allow us to measure the angular Einstein radius θE. From the combination of πE and θE, the physical lens parameters are uniquely determined. It is found that the lens is a binary composed of two M dwarfs with masses M1 = 0.52 ± 0.04 M⊙ and M2 = 0.42 ± 0.03 M⊙ separated in projection by a⊥ = 6.4 ± 0.5 au. The lens is located in the disk with a distance of DL = 3.3 ± 0.3 kpc. The reason for the absence of a lensing signal in the Spitzer data is that the time of observation corresponds to the flat region of the light curve.

189. Faint-source-star planetary microlensing: the discovery of the cold gas-giant planet OGLE-2014-BLG-0676Lb

Author

Rattenbury, N. J., Bennett, D. P., Sumi, T., Koshimoto, N., Bond, I. A., Udalski, A., Shvartzvald, Y., Maoz, D., Jørgensen, U. G., Dominik, M., Street, R. A., Tsapras, Y., Abe, F., Asakura, Y., Barry, R., Bhattacharya, A., Donachie, M., Evans, P., Freeman, M., Fukui, A., Hirao, Y., Itow, Y., Li, M. C. A., Ling, C. H., Masuda, K., Matsubara, Y., Muraki, Y., Nagakane, M., Ohnishi, K., Oyokawa, H., Saito, To., Sharan, A., Sullivan, D. J., Suzuki, D., Tristram, P. J., Yonehara, A., Poleski, R., Skowron, J., Mróz, P., Szymański, M. K., Soszyński, I., Pietrukowicz, P., Kozłowski, S., Ulaczyk, K., Wyrzykowski, Ł., Friedmann, M., Kaspi, S., Alsubai, K., Browne, P., Andersen, J. M., Bozza, V., Calchi Novati, S., Damerdji, Y., Diehl, C., Dreizler, S., Elyiv, A., Giannini, E., Hardis, S., Harpsøe, K., Hinse, T. C., Liebig, C., Hundertmark, M., Juncher, D., Kains, N., Kerins, E., Korhonen, H., Mancini, L., Martin, R., Mathiasen, M., Rabus, M., Rahvar, S., Scarpetta, G., Skottfelt, J., Snodgrass, C., Surdej, J., Taylor, J., Tregloan-Reed, J., Vilela, C., Wambsganss, J., Williams, A., D'Ago, G., Bachelet, E., Bramich, D. M., Figuera Jaimes, R., Horne, K., Menzies, J., Schmidt, R., Steele, I. A., Rattenbury, N. J., Bennett, D. P., Sumi, T., Koshimoto, N., Bond, I. A., Udalski, A., Shvartzvald, Y., Maoz, D., Jørgensen, U. G., Dominik, M., Street, R. A., Tsapras, Y., Abe, F., Asakura, Y., Barry, R., Bhattacharya, A., Donachie, M., Evans, P., Freeman, M., Fukui, A., Hirao, Y., Itow, Y., Li, M. C. A., Ling, C. H., Masuda, K., Matsubara, Y., Muraki, Y., Nagakane, M., Ohnishi, K., Oyokawa, H., Saito, To., Sharan, A., Sullivan, D. J., Suzuki, D., Tristram, P. J., Yonehara, A., Poleski, R., Skowron, J., Mróz, P., Szymański, M. K., Soszyński, I., Pietrukowicz, P., Kozłowski, S., Ulaczyk, K., Wyrzykowski, Ł., Friedmann, M., Kaspi, S., Alsubai, K., Browne, P., Andersen, J. M., Bozza, V., Calchi Novati, S., Damerdji, Y., Diehl, C., Dreizler, S., Elyiv, A., Giannini, E., Hardis, S., Harpsøe, K., Hinse, T. C., Liebig, C., Hundertmark, M., Juncher, D., Kains, N., Kerins, E., Korhonen, H., Mancini, L., Martin, R., Mathiasen, M., Rabus, M., Rahvar, S., Scarpetta, G., Skottfelt, J., Snodgrass, C., Surdej, J., Taylor, J., Tregloan-Reed, J., Vilela, C., Wambsganss, J., Williams, A., D'Ago, G., Bachelet, E., Bramich, D. M., Figuera Jaimes, R., Horne, K., Menzies, J., Schmidt, R., and Steele, I. A.

Abstract

We report the discovery of a planet – OGLE-2014-BLG-0676Lb– via gravitational microlensing. Observations for the lensing event were made by the following groups: Microlensing Observations in Astrophysics; Optical Gravitational Lensing Experiment; Wise Observatory; RoboNET/Las Cumbres Observatory Global Telescope; Microlensing Network for the Detection of Small Terrestrial Exoplanets; and μ-FUN. All analyses of the light-curve data favour a lens system comprising a planetary mass orbiting a host star. The most-favoured binary lens model has a mass ratio between the two lens masses of (4.78 ± 0.13) × $10^3$. Subject to some important assumptions, a Bayesian probability density analysis suggests the lens system comprises a 3.09 $^{+1.02}_{-1.12}$ MJ planet orbiting a 0.62$^{+0.20}_{-0.22}$ M$_⊙$ host star at a deprojected orbital separation of 4.40$^{+2.16}_{-1.46}$ au. The distance to the lens system is 2.22$^{+0.96}_{-0.83}$ kpc. Planet OGLE-2014-BLG-0676Lb provides additional data to the growing number of cool planets discovered using gravitational microlensing against which planetary formation theories may be tested. Most of the light in the baseline of this event is expected to come from the lens and thus high-resolution imaging observations could confirm our planetary model interpretation.

190. Red noise versus planetary interpretations in the microlensing event OGLE-2013-BLG-446

Author

Bachelet, E., Bramich, D. M., Han, C., Greenhill, J., Street, R. A., Gould, A., D’Ago, G., AlSubai, K., Dominik, M., Jaimes, R. Figuera, Horne, K., Hundertmark, M., Kains, N., Snodgrass, C., Steele, I. A., Tsapras, Y., Albrow, M. D., Batista, V., Beaulieu, J.-P., Bennett, D. P., Brillant, S., Caldwell, J. A. R., Cassan, A., Cole, A., Coutures, C., Dieters, S., Prester, D. Dominis, Donatowicz, J., Fouqué, P., Hill, K., Marquette, J.-B., Menzies, J., Pere, C., Ranc, C., Wambsganss, J., Warren, D., Almeida, L. Andrade de, Choi, J.-Y., DePoy, D. L., Dong, S., Hung, L.-W., Hwang, K.-H., Jablonski, F., Jung, Y. K., Kaspi, S., Klein, N., Lee, C.-U., Maoz, D., Muñoz, J. A., Nataf, D., Park, H., Pogge, R. W., Polishook, D., Shin, I.-G., Shporer, A., Yee, J. C., Abe, F., Bhattacharya, A., Bond, I. A., Botzler, C. S., Freeman, M., Fukui, A., Itow, Y., Koshimoto, N., Ling, C. H., Masuda, K., Matsubara, Y., Muraki, Y., Ohnishi, K., Philpott, L. C., Rattenbury, N., Saito, To., Sullivan, D. J., Sumi, T., Suzuki, D., Tristram, P. J., Yonehara, A., Bozza, V., Calchi Novati, S., Ciceri, S., Galianni, P., Gu, S.-H., Harpsøe, K., Hinse, T. C., Jørgensen, U. G., Juncher, D., Korhonen, H., Mancini, L., Melchiorre, C., Popovas, A., Postiglione, A., Rabus, M., Rahvar, S., Schmidt, R. W., Scarpetta, G., Skottfelt, J., Southworth, John, Stabile, An., Surdej, J., Wang, X.-B., Wertz, O., Bachelet, E., Bramich, D. M., Han, C., Greenhill, J., Street, R. A., Gould, A., D’Ago, G., AlSubai, K., Dominik, M., Jaimes, R. Figuera, Horne, K., Hundertmark, M., Kains, N., Snodgrass, C., Steele, I. A., Tsapras, Y., Albrow, M. D., Batista, V., Beaulieu, J.-P., Bennett, D. P., Brillant, S., Caldwell, J. A. R., Cassan, A., Cole, A., Coutures, C., Dieters, S., Prester, D. Dominis, Donatowicz, J., Fouqué, P., Hill, K., Marquette, J.-B., Menzies, J., Pere, C., Ranc, C., Wambsganss, J., Warren, D., Almeida, L. Andrade de, Choi, J.-Y., DePoy, D. L., Dong, S., Hung, L.-W., Hwang, K.-H., Jablonski, F., Jung, Y. K., Kaspi, S., Klein, N., Lee, C.-U., Maoz, D., Muñoz, J. A., Nataf, D., Park, H., Pogge, R. W., Polishook, D., Shin, I.-G., Shporer, A., Yee, J. C., Abe, F., Bhattacharya, A., Bond, I. A., Botzler, C. S., Freeman, M., Fukui, A., Itow, Y., Koshimoto, N., Ling, C. H., Masuda, K., Matsubara, Y., Muraki, Y., Ohnishi, K., Philpott, L. C., Rattenbury, N., Saito, To., Sullivan, D. J., Sumi, T., Suzuki, D., Tristram, P. J., Yonehara, A., Bozza, V., Calchi Novati, S., Ciceri, S., Galianni, P., Gu, S.-H., Harpsøe, K., Hinse, T. C., Jørgensen, U. G., Juncher, D., Korhonen, H., Mancini, L., Melchiorre, C., Popovas, A., Postiglione, A., Rabus, M., Rahvar, S., Schmidt, R. W., Scarpetta, G., Skottfelt, J., Southworth, John, Stabile, An., Surdej, J., Wang, X.-B., and Wertz, O.

Abstract

For all exoplanet candidates, the reliability of a claimed detection needs to be assessed through a careful study of systematic errors in the data to minimize the false positives rate. We present a method to investigate such systematics in microlensing data sets using the microlensing event OGLE-2013-BLG-0446 as a case study. The event was observed from multiple sites around the world and its high magnification (Amax ~ 3000) allowed us to investigate the effects of terrestrial and annual parallax. Real-time modeling of the event while it was still ongoing suggested the presence of an extremely low-mass companion (~3M⨁) to the lensing star, leading to substantial follow-up coverage of the light curve. We test and compare different models for the light curve and conclude that the data do not favor the planetary interpretation when systematic errors are taken into account.

191. An analysis of binary microlensing event OGLE-2015-BLG-0060

Author

Tsapras, Y, Cassan, A, Ranc, C, Bachelet, E, Street, R, Udalski, A, Hundertmark, M, Bozza, V, Beaulieu, J P, Marquette, J B, Euteneuer, E, Bramich, D M, Dominik, M, Figuera Jaimes, R, Horne, K, Mao, S, Menzies, J, Schmidt, R, Snodgrass, Colin, Steele, I A, Wambsganss, J, Mróz, P, Szymański, M K, Soszyński, I, Skowron, J, Pietrukowicz, P, Kozłowski, S, Poleski, R, Ulaczyk, K, Pawlak, M, Jørgensen, U G, Skottfelt, J, Popovas, A, Ciceri, S, Korhonen, H, Kuffmeier, M, Evans, D F, Peixinho, N, Hinse, T C, Burgdorf, M J, Southworth, J, Tronsgaard, R, Kerins, E, Andersen, M I, Rahvar, S, Wang, Y, Wertz, O, Rabus, M, Novati, S Calchi, D’Ago, G, Scarpetta, G, Mancini, L, Abe, F, Asakura, Y, 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, Muraki, Y, Miyazaki, S, Nagakane, M, Ohnishi, K, Rattenbury, N, Saito, To, Sharan, A, Shibai, H, Sullivan, D J, Sumi, T, Suzuki, D, Tristram, P J, Yamada, T, Yonehara, A, Tsapras, Y, Cassan, A, Ranc, C, Bachelet, E, Street, R, Udalski, A, Hundertmark, M, Bozza, V, Beaulieu, J P, Marquette, J B, Euteneuer, E, Bramich, D M, Dominik, M, Figuera Jaimes, R, Horne, K, Mao, S, Menzies, J, Schmidt, R, Snodgrass, Colin, Steele, I A, Wambsganss, J, Mróz, P, Szymański, M K, Soszyński, I, Skowron, J, Pietrukowicz, P, Kozłowski, S, Poleski, R, Ulaczyk, K, Pawlak, M, Jørgensen, U G, Skottfelt, J, Popovas, A, Ciceri, S, Korhonen, H, Kuffmeier, M, Evans, D F, Peixinho, N, Hinse, T C, Burgdorf, M J, Southworth, J, Tronsgaard, R, Kerins, E, Andersen, M I, Rahvar, S, Wang, Y, Wertz, O, Rabus, M, Novati, S Calchi, D’Ago, G, Scarpetta, G, Mancini, L, Abe, F, Asakura, Y, 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, Muraki, Y, Miyazaki, S, Nagakane, M, Ohnishi, K, Rattenbury, N, Saito, To, Sharan, A, Shibai, H, Sullivan, D J, Sumi, T, Suzuki, D, Tristram, P J, Yamada, T, and Yonehara, A

Abstract

We present the analysis of stellar binary microlensing event OGLE-2015-BLG-0060 based on observations obtained from 13 different telescopes. Intensive coverage of the anomalous parts of the light curve was achieved by automated follow-up observations from the robotic telescopes of the Las Cumbres Observatory. We show that, for the first time, all main features of an anomalous microlensing event are well covered by follow-up data, allowing us to estimate the physical parameters of the lens. The strong detection of second-order effects in the event light curve necessitates the inclusion of longer-baseline survey data in order to constrain the parallax vector. We find that the event was most likely caused by a stellar binary-lens with masses M⋆1=0.87±0.12M⊙ and M⋆2=0.77±0.11M⊙⁠. The distance to the lensing system is 6.41 ± 0.14 kpc and the projected separation between the two components is 13.85 ± 0.16 AU. Alternative interpretations are also considered.

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

Author

Miyazaki, Shota, Sumi, Takahiro, Bennett, David P., Udalski, Andrzej, Shvartzvald, Yossi, Street, Rachel, Bozza, Valerio, Yee, Jennifer C., Bond, Ian A., Rattenbury, Nicholas, Koshimoto, Naoki, Suzuki, Daisuke, Fukui, Akihiko, Abe, F., Bhattacharya, A., Barry, R., Donachie, M., Fujii, H., Hirao, Y., Itow, Y., Kamei, Y., Kondo, I., Li, M. C. A., Ling, C. H., Matsubara, Y., Matsuo, T., Muraki, Y., Nagakane, M., Ohnishi, K., Ranc, C., Saito, T., Sharan, A., Shibai, H., Suematsu, H., Sullivan, D. J., Tristram, P. J., Yamakawa, T., Yonehara, A., Skowron, J., Poleski, R., Mróz, P., Szymański, M. K., Soszyński, I., Pietrukowicz, P., KozŁowski, S., Ulaczyk, K., Wyrzykowski, Ł., Friedmann, Matan, Kaspi, Shai, Maoz, Dan, Albrow, M., Christie, G., DePoy, D. L., Gal-Yam, A., Gould, A., Lee, C.-U., Manulis, I., McCormick, J., Natusch, T., Ngan, H., Pogge, R. W., Porritt, I., Tsapras, Y., Bachelet, E., Hundertmark, M. P. G., Dominik, M., Bramich, D. M., Cassan, A., Jaimes, R. Figuera, Horne, K., Schmidt, R., Snodgrass, C., Wambsganss, J., Steele, I. A., Menzies, J., Mao, S., Jø rgensen, U. G., Burgdorf, M. J., Ciceri, S., Novati, S. Calchi, D’Ago, G., Evans, D. F., Hinse, T. C., Kains, N., Kerins, E., Korhonen, H., Mancini, L., Popovas, A., Rabus, M., Rahvar, S., Scarpetta, G., Skottfelt, J., Southworth, J., Peixinho, N., Verma, P., Miyazaki, Shota, Sumi, Takahiro, Bennett, David P., Udalski, Andrzej, Shvartzvald, Yossi, Street, Rachel, Bozza, Valerio, Yee, Jennifer C., Bond, Ian A., Rattenbury, Nicholas, Koshimoto, Naoki, Suzuki, Daisuke, Fukui, Akihiko, Abe, F., Bhattacharya, A., Barry, R., Donachie, M., Fujii, H., Hirao, Y., Itow, Y., Kamei, Y., Kondo, I., Li, M. C. A., Ling, C. H., Matsubara, Y., Matsuo, T., Muraki, Y., Nagakane, M., Ohnishi, K., Ranc, C., Saito, T., Sharan, A., Shibai, H., Suematsu, H., Sullivan, D. J., Tristram, P. J., Yamakawa, T., Yonehara, A., Skowron, J., Poleski, R., Mróz, P., Szymański, M. K., Soszyński, I., Pietrukowicz, P., KozŁowski, S., Ulaczyk, K., Wyrzykowski, Ł., Friedmann, Matan, Kaspi, Shai, Maoz, Dan, Albrow, M., Christie, G., DePoy, D. L., Gal-Yam, A., Gould, A., Lee, C.-U., Manulis, I., McCormick, J., Natusch, T., Ngan, H., Pogge, R. W., Porritt, I., Tsapras, Y., Bachelet, E., Hundertmark, M. P. G., Dominik, M., Bramich, D. M., Cassan, A., Jaimes, R. Figuera, Horne, K., Schmidt, R., Snodgrass, C., Wambsganss, J., Steele, I. A., Menzies, J., Mao, S., Jø rgensen, U. G., Burgdorf, M. J., Ciceri, S., Novati, S. Calchi, D’Ago, G., Evans, D. F., Hinse, T. C., Kains, N., Kerins, E., Korhonen, H., Mancini, L., Popovas, A., Rabus, M., Rahvar, S., Scarpetta, G., Skottfelt, J., Southworth, J., Peixinho, N., and Verma, P.

Abstract

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

193. The First Simultaneous Microlensing Observations by Two Space Telescopes: Spitzer and Swift Reveal a Brown Dwarf in Event OGLE-2015-BLG-1319

Author

Shvartzvald, Y., Li, Z., Udalski, A., Gould, A., Sumi, T., Street, R. A., Novati, S. Calchi, Hundertmark, M., Bozza, V., Beichman, C., Bryden, G., Carey, S., Drummond, J., Fausnaugh, M., Gaudi, B. S., Henderson, C. B., Tan, T. G., Wibking, B., Pogge, R. W., Yee, J. C., Zhu, W., Tsapras, Y., Bachelet, E., Dominik, M., Bramich, D. M., Cassan, A., Jaimes, R. Figuera, Horne, K., Ranc, C., Schmidt, R., Snodgrass, C., Wambsganss, J., Steele, I. A., Menzies, J., Mao, S., Poleski, R., Pawlak, M., Szymański, M. K., Skowron, J., Mróz, P., Kozłowski, S., Wyrzykowski, Ł., Pietrukowicz, P., Soszyński, I., Ulaczyk, K., Abe, F., Asakura, Y., Barry, R. K., Bennett, D. P., Bhattacharya, A., Bond, I. A., Freeman, M., Hirao, Y., Itow, Y., Koshimoto, N., Li, M. C. A., Ling, C. H., Masuda, K., Fukui, A., Matsubara, Y., Muraki, Y., Nagakane, M., Nishioka, T., Ohnishi, K., Oyokawa, H., Rattenbury, N. J., Saito, To., Sharan, A., Sullivan, D. J., Suzuki, D., Tristram, P. J., Yonehara, A., Jørgensen, U. G., Burgdorf, M. J., Ciceri, S., D’Ago, G., Evans, D. F., Hinse, T. C., Kains, N., Kerins, E., Korhonen, H., Mancini, L., Popovas, A., Rabus, M., Rahvar, S., Scarpetta, G., Skottfelt, J., Southworth, J., Peixinho, N., Verma, P., Sbarufatti, B., Kennea, J. A., Gehrels, N., Shvartzvald, Y., Li, Z., Udalski, A., Gould, A., Sumi, T., Street, R. A., Novati, S. Calchi, Hundertmark, M., Bozza, V., Beichman, C., Bryden, G., Carey, S., Drummond, J., Fausnaugh, M., Gaudi, B. S., Henderson, C. B., Tan, T. G., Wibking, B., Pogge, R. W., Yee, J. C., Zhu, W., Tsapras, Y., Bachelet, E., Dominik, M., Bramich, D. M., Cassan, A., Jaimes, R. Figuera, Horne, K., Ranc, C., Schmidt, R., Snodgrass, C., Wambsganss, J., Steele, I. A., Menzies, J., Mao, S., Poleski, R., Pawlak, M., Szymański, M. K., Skowron, J., Mróz, P., Kozłowski, S., Wyrzykowski, Ł., Pietrukowicz, P., Soszyński, I., Ulaczyk, K., Abe, F., Asakura, Y., Barry, R. K., Bennett, D. P., Bhattacharya, A., Bond, I. A., Freeman, M., Hirao, Y., Itow, Y., Koshimoto, N., Li, M. C. A., Ling, C. H., Masuda, K., Fukui, A., Matsubara, Y., Muraki, Y., Nagakane, M., Nishioka, T., Ohnishi, K., Oyokawa, H., Rattenbury, N. J., Saito, To., Sharan, A., Sullivan, D. J., Suzuki, D., Tristram, P. J., Yonehara, A., Jørgensen, U. G., Burgdorf, M. J., Ciceri, S., D’Ago, G., Evans, D. F., Hinse, T. C., Kains, N., Kerins, E., Korhonen, H., Mancini, L., Popovas, A., Rabus, M., Rahvar, S., Scarpetta, G., Skottfelt, J., Southworth, J., Peixinho, N., Verma, P., Sbarufatti, B., Kennea, J. A., and Gehrels, N.

Abstract

Simultaneous observations of microlensing events from multiple locations allow for the breaking of degeneracies between the physical properties of the lensing system, specifically by exploring different regions of the lens plane and by directly measuring the “microlens parallax.” We report the discovery of a 30–65MJ brown dwarf orbiting a K dwarf in the microlensing event OGLE-2015-BLG-1319. The system is located at a distance of ∼5 kpc toward the Galactic Bulge. The event was observed by several ground-based groups as well as by Spitzer and Swift, allowing a measurement of the physical properties. However, the event is still subject to an eight-fold degeneracy, in particular the well-known close-wide degeneracy, and thus the projected separation between the two lens components is either ∼0.25 au or ∼45 au. This is the first microlensing event observed by Swift, with the UVOT camera. We study the region of microlensing parameter space to which Swift is sensitive, finding that though Swift could not measure the microlens parallax with respect to ground-based observations for this event, it can be important for other events. Specifically, it is important for detecting nearby brown dwarfs and free-floating planets in high magnification events.

194. Discovery of a Gas Giant Planet in Microlensing Event OGLE-2014-BLG-1760

Author

Bhattacharya, A., Bennett, D. P., Bond, I. A., Sumi, T., Udalski, A., Street, R., Tsapras, Y., Abe, F., 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., Rattenbury, N., Saito, T., Sharan, A., Sullivan, D. J., Suzuki, D., Tristram, P. J., Skowron, J., Szymański, M. K., Soszyński, I., Poleski, R., Mróz, P., Kozlowski, S., Pietrukowicz, P., Ulaczyk, K., Wyrzykowski, L., Bachelet, E., Bramich, D. M., D’Ago, G., Dominik, M., Figuera Jaimes, R., Horne, K., Hundertmark, M., Kains, N., Menzies, J., Schmidt, R., Snodgrass, C., Steele, I. A., Wambsganss, J., Bhattacharya, A., Bennett, D. P., Bond, I. A., Sumi, T., Udalski, A., Street, R., Tsapras, Y., Abe, F., 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., Rattenbury, N., Saito, T., Sharan, A., Sullivan, D. J., Suzuki, D., Tristram, P. J., Skowron, J., Szymański, M. K., Soszyński, I., Poleski, R., Mróz, P., Kozlowski, S., Pietrukowicz, P., Ulaczyk, K., Wyrzykowski, L., Bachelet, E., Bramich, D. M., D’Ago, G., Dominik, M., Figuera Jaimes, R., Horne, K., Hundertmark, M., Kains, N., Menzies, J., Schmidt, R., Snodgrass, C., Steele, I. A., and Wambsganss, J.

Abstract

We present the analysis of the planetary microlensing event OGLE-2014-BLG-1760, which shows a strong light-curve signal due to the presence of a Jupiter mass ratio planet. One unusual feature of this event is that the source star is quite blue, with $V-I=1.48\pm 0.08$. This is marginally consistent with a source star in the Galactic bulge, but it could possibly indicate a young source star on the far side of the disk. Assuming a bulge source, we perform a Bayesian analysis assuming a standard Galactic model, and this indicates that the planetary system resides in or near the Galactic bulge at ${D}_{L}=6.9\pm 1.1\,\mathrm{kpc}$. It also indicates a host-star mass of ${M}_{* }={0.51}_{-0.28}^{+0.44}{M}_{\odot }$, a planet mass of ${m}_{{\rm{p}}}={0.56}_{-0.26}^{+0.34}{M}_{J}$, and a projected star–planet separation of ${a}_{\perp }={1.75}_{-0.33}^{+0.34}$ au. The lens–source relative proper motion is ${\mu }_{\mathrm{rel}}$=6.5 ± 1.1 mas yr$^{-1}$. The lens (and stellar host star) is estimated to be very faint compared to the source star, so it is most likely that it can be detected only when the lens and source stars start to separate. Due to the relatively high relative proper motion, the lens and source will be resolved to about ~46 mas in 6–8 yr after the peak magnification. So, by 2020–2022, we can hope to detect the lens star with deep, high-resolution images.

195. Ground-based Parallax Confirmed by Spitzer: Binary Microlensing Event MOA-2015-BLG-02

Author

Wang, Tianshu, Zhu, Wei, Mao, Shude, Bond, I. A., Gould, A., Udalski, A., Sumi, T., Bozza, V., Ranc, C., Cassan, A., Yee, J. C., Han, C., 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., Rattenbury, N., Saito, To., Sharan, A., Shibai, H., Sullivan, D. J., Suzuki, D., Tristram, P. J., Yamada, T., Yonehara, A., KozŁowski, S., Mróz, P., Pawlak, M., Pietrukowicz, P., Poleski, R., Skowron, J., Soszyński, I., Szymański, M. K., Ulaczyk, K., Beichman, C., Bryden, G., Calchi Novati, S., Carey, S., Fausnaugh, M., Gaudi, B. S., Henderson, C. B., Shvartzvald, Y., Wibking, B., Albrow, M. D., Chung, S.-J., 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, C.-U., Lee, Y., Park, B.-G., Pogge, R. W., Street, R. A., Tsapras, Y., Hundertmark, M., Bachelet, E., Dominik, M., Horne, K., Jaimes, R. Figuera, Wambsganss, J., Bramich, D. M., Schmidt, R., Snodgrass, C., Steele, I. A., Menzies, J., Wang, Tianshu, Zhu, Wei, Mao, Shude, Bond, I. A., Gould, A., Udalski, A., Sumi, T., Bozza, V., Ranc, C., Cassan, A., Yee, J. C., Han, C., 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., Rattenbury, N., Saito, To., Sharan, A., Shibai, H., Sullivan, D. J., Suzuki, D., Tristram, P. J., Yamada, T., Yonehara, A., KozŁowski, S., Mróz, P., Pawlak, M., Pietrukowicz, P., Poleski, R., Skowron, J., Soszyński, I., Szymański, M. K., Ulaczyk, K., Beichman, C., Bryden, G., Calchi Novati, S., Carey, S., Fausnaugh, M., Gaudi, B. S., Henderson, C. B., Shvartzvald, Y., Wibking, B., Albrow, M. D., Chung, S.-J., 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, C.-U., Lee, Y., Park, B.-G., Pogge, R. W., Street, R. A., Tsapras, Y., Hundertmark, M., Bachelet, E., Dominik, M., Horne, K., Jaimes, R. Figuera, Wambsganss, J., Bramich, D. M., Schmidt, R., Snodgrass, C., Steele, I. A., and Menzies, J.

Abstract

e present the analysis of the binary gravitational microlensing event MOA-2015-BLG-020. The event has a fairly long timescale (˜63 days) and thus the light curve deviates significantly from the lensing model that is based on the rectilinear lens-source relative motion. This enables us to measure the microlensing parallax through the annual parallax effect. The microlensing parallax parameters constrained by the ground-based data are confirmed by the Spitzer observations through the satellite parallax method. By additionally measuring the angular Einstein radius from the analysis of the resolved caustic crossing, the physical parameters of the lens are determined. It is found that the binary lens is composed of two dwarf stars with masses {M}1=0.606+/- 0.028 {M}⊙ and {M}2=0.125 +/- 0.006 {M}⊙ in the Galactic disk. Assuming that the source star is at the same distance as the bulge red clump stars, we find the lens is at a distance {D}L=2.44+/- 0.10 {kpc}. We also provide a summary and short discussion of all of the published microlensing events in which the annual parallax effect is confirmed by other independent observations.

196. 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., Mróz, P., Poleski, R., Skowron, J., Szymański, M. K., Soszyński, I., Kozłowski, 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., Fouqué, 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, S., 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, 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., Mróz, P., Poleski, R., Skowron, J., Szymański, M. K., Soszyński, I., Kozłowski, 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., Fouqué, 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, S., 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, Mp = 13.4 ± 0.9 MJ , places it right at the deuterium-burning 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" (low-mass 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, Mhost = 0.89 ± 0.07 M ⊙, and the planet has a semimajor axis a ~ 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.

197. MOA-2016-BLG-227Lb: A Massive Planet Characterized by Combining Light-curve Analysis and Keck AO Imaging

Author

Koshimoto, N., Shvartzvald, Y., Bennett, D. P., Penny, M. T., Hundertmark, M., Bond, I. A., Zang, W. C., Henderson, C. B., Suzuki, D., Rattenbury, N. J., Sumi, T., Abe, F., Asakura, Y., Bhattacharya, A., Donachie, M., Evans, P., Fukui, A., Hirao, Y., Itow, Y., Li, M. C. A., Ling, C. H., Masuda, K., Matsubara, Y., Matsuo, T., Muraki, Y., Nagakane, M., Ohnishi, K., Ranc, C., Saito, To., Sharan, A., Shibai, H., Sullivan, D. J., Tristram, P. J., Yamada, T., Yonehara, A., Gelino, C. R., Beichman, C., Beaulieu, J.-P., Marquette, J.-B., Batista, V., Friedmann, M., Hallakoun, N., Kaspi, S., Maoz, D., Bryden, G., Novati, S. Calchi, Howell, S. B., Wang, T. S., Mao, S., Fouqué, P., Korhonen, H., Jørgensen, U. G., Street, R., Tsapras, Y., Dominik, M., Kerins, E., Cassan, A., Snodgrass, C., Bachelet, E., Bozza, V., Bramich, D. M., Koshimoto, N., Shvartzvald, Y., Bennett, D. P., Penny, M. T., Hundertmark, M., Bond, I. A., Zang, W. C., Henderson, C. B., Suzuki, D., Rattenbury, N. J., Sumi, T., Abe, F., Asakura, Y., Bhattacharya, A., Donachie, M., Evans, P., Fukui, A., Hirao, Y., Itow, Y., Li, M. C. A., Ling, C. H., Masuda, K., Matsubara, Y., Matsuo, T., Muraki, Y., Nagakane, M., Ohnishi, K., Ranc, C., Saito, To., Sharan, A., Shibai, H., Sullivan, D. J., Tristram, P. J., Yamada, T., Yonehara, A., Gelino, C. R., Beichman, C., Beaulieu, J.-P., Marquette, J.-B., Batista, V., Friedmann, M., Hallakoun, N., Kaspi, S., Maoz, D., Bryden, G., Novati, S. Calchi, Howell, S. B., Wang, T. S., Mao, S., Fouqué, P., Korhonen, H., Jørgensen, U. G., Street, R., Tsapras, Y., Dominik, M., Kerins, E., Cassan, A., Snodgrass, C., Bachelet, E., Bozza, V., and Bramich, D. M.

Abstract

We report the discovery of a microlensing planet—MOA-2016-BLG-227Lb—with a large planet/host mass ratio of q ≃ 9 × 10−3. This event was located near the K2 Campaign 9 field that was observed by a large number of telescopes. As a result, the event was in the microlensing survey area of a number of these telescopes, and this enabled good coverage of the planetary light-curve signal. High angular resolution adaptive optics images from the Keck telescope reveal excess flux at the position of the source above the flux of the source star, as indicated by the light-curve model. This excess flux could be due to the lens star, but it could also be due to a companion to the source or lens star, or even an unrelated star. We consider all these possibilities in a Bayesian analysis in the context of a standard Galactic model. Our analysis indicates that it is unlikely that a large fraction of the excess flux comes from the lens, unless solar-type stars are much more likely to host planets of this mass ratio than lower mass stars. We recommend that a method similar to the one developed in this paper be used for other events with high angular resolution follow-up observations when the follow-up observations are insufficient to measure the lens–source relative proper motion.

198. MOA-2011-BLG-028Lb: A Neptune-Mass Microlensing Planet in the Galactic Bulge

Author

Skowron, J., Udalski, A., Poleski, R., Kozłowski, S., Szymański, M. K., Wyrzykowski, Ł., Ulaczyk, K., Pietrukowicz, P., Pietrzyński, G., Soszyński, I., Abe, F., Bennett, D. P., Bhattacharya, A., Bond, I. A., Freeman, M., Fukui, A., Hirao, Y., Itow, Y., Koshimoto, N., Ling, C. H., Masuda, K., Matsubara, Y., Muraki, Y., Nagakane, M., Ohnishi, K., Rattenbury, N., Saito, To., Sullivan, D. J., Sumi, T., Suzuki, D., Tristram, P. J., Yonehara, A., Dominik, M., Jørgensen, U. G., Bozza, V., Harpsøe, K., Hundertmark, M., Skottfelt, J., Skowron, J., Udalski, A., Poleski, R., Kozłowski, S., Szymański, M. K., Wyrzykowski, Ł., Ulaczyk, K., Pietrukowicz, P., Pietrzyński, G., Soszyński, I., Abe, F., Bennett, D. P., Bhattacharya, A., Bond, I. A., Freeman, M., Fukui, A., Hirao, Y., Itow, Y., Koshimoto, N., Ling, C. H., Masuda, K., Matsubara, Y., Muraki, Y., Nagakane, M., Ohnishi, K., Rattenbury, N., Saito, To., Sullivan, D. J., Sumi, T., Suzuki, D., Tristram, P. J., Yonehara, A., Dominik, M., Jørgensen, U. G., Bozza, V., Harpsøe, K., Hundertmark, M., and Skottfelt, J.

Abstract

We present the discovery of a Neptune-mass planet orbiting a $0.8\pm 0.3M_{\odot}$ star in the Galactic bulge. The planet manifested itself during the microlensing event MOA-2011-BLG-028/OGLE-2011-BLG-0203 as a low-mass companion to the lens star. The analysis of the light curve provides the measurement of the mass ratio $(1.2 \pm 0.2) \times 10^{-4}$, which indicates that the mass of the planet is 12–60 Earth masses. The lensing system is located at 7.3 ± 0.7 kpc away from the Earth near the direction of Baade's Window. The projected separation of the planet at the time of the microlensing event was 3.1–5.2 au. Although the microlens parallax effect is not detected in the light curve of this event, preventing the actual mass measurement, the uncertainties of mass and distance estimation are narrowed by the measurement of the source star proper motion on the OGLE-III images spanning eight years, and by the low amount of blended light seen, proving that the host star cannot be too bright and massive. We also discuss the inclusion of undetected parallax and orbital motion effects into the models and their influence onto the final physical parameters estimates.

199. An analysis of binary microlensing event OGLE-2015-BLG-0060

Author

Tsapras, Y, Cassan, A, Ranc, C, Bachelet, E, Street, R, Udalski, A, Hundertmark, M, Bozza, V, Beaulieu, J P, Marquette, J B, Euteneuer, E, Bramich, D M, Dominik, M, Figuera Jaimes, R, Horne, K, Mao, S, Menzies, J, Schmidt, R, Snodgrass, Colin, Steele, I A, Wambsganss, J, Mróz, P, Szymański, M K, Soszyński, I, Skowron, J, Pietrukowicz, P, Kozłowski, S, Poleski, R, Ulaczyk, K, Pawlak, M, Jørgensen, U G, Skottfelt, J, Popovas, A, Ciceri, S, Korhonen, H, Kuffmeier, M, Evans, D F, Peixinho, N, Hinse, T C, Burgdorf, M J, Southworth, J, Tronsgaard, R, Kerins, E, Andersen, M I, Rahvar, S, Wang, Y, Wertz, O, Rabus, M, Novati, S Calchi, D’Ago, G, Scarpetta, G, Mancini, L, Abe, F, Asakura, Y, 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, Muraki, Y, Miyazaki, S, Nagakane, M, Ohnishi, K, Rattenbury, N, Saito, To, Sharan, A, Shibai, H, Sullivan, D J, Sumi, T, Suzuki, D, Tristram, P J, Yamada, T, Yonehara, A, Tsapras, Y, Cassan, A, Ranc, C, Bachelet, E, Street, R, Udalski, A, Hundertmark, M, Bozza, V, Beaulieu, J P, Marquette, J B, Euteneuer, E, Bramich, D M, Dominik, M, Figuera Jaimes, R, Horne, K, Mao, S, Menzies, J, Schmidt, R, Snodgrass, Colin, Steele, I A, Wambsganss, J, Mróz, P, Szymański, M K, Soszyński, I, Skowron, J, Pietrukowicz, P, Kozłowski, S, Poleski, R, Ulaczyk, K, Pawlak, M, Jørgensen, U G, Skottfelt, J, Popovas, A, Ciceri, S, Korhonen, H, Kuffmeier, M, Evans, D F, Peixinho, N, Hinse, T C, Burgdorf, M J, Southworth, J, Tronsgaard, R, Kerins, E, Andersen, M I, Rahvar, S, Wang, Y, Wertz, O, Rabus, M, Novati, S Calchi, D’Ago, G, Scarpetta, G, Mancini, L, Abe, F, Asakura, Y, 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, Muraki, Y, Miyazaki, S, Nagakane, M, Ohnishi, K, Rattenbury, N, Saito, To, Sharan, A, Shibai, H, Sullivan, D J, Sumi, T, Suzuki, D, Tristram, P J, Yamada, T, and Yonehara, A

Abstract

We present the analysis of stellar binary microlensing event OGLE-2015-BLG-0060 based on observations obtained from 13 different telescopes. Intensive coverage of the anomalous parts of the light curve was achieved by automated follow-up observations from the robotic telescopes of the Las Cumbres Observatory. We show that, for the first time, all main features of an anomalous microlensing event are well covered by follow-up data, allowing us to estimate the physical parameters of the lens. The strong detection of second-order effects in the event light curve necessitates the inclusion of longer-baseline survey data in order to constrain the parallax vector. We find that the event was most likely caused by a stellar binary-lens with masses M⋆1=0.87±0.12M⊙ and M⋆2=0.77±0.11M⊙⁠. The distance to the lensing system is 6.41 ± 0.14 kpc and the projected separation between the two components is 13.85 ± 0.16 AU. Alternative interpretations are also considered.

200. Ground-based Parallax Confirmed by Spitzer: Binary Microlensing Event MOA-2015-BLG-02

Author

Wang, Tianshu, Zhu, Wei, Mao, Shude, Bond, I. A., Gould, A., Udalski, A., Sumi, T., Bozza, V., Ranc, C., Cassan, A., Yee, J. C., Han, C., 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., Rattenbury, N., Saito, To., Sharan, A., Shibai, H., Sullivan, D. J., Suzuki, D., Tristram, P. J., Yamada, T., Yonehara, A., KozŁowski, S., Mróz, P., Pawlak, M., Pietrukowicz, P., Poleski, R., Skowron, J., Soszyński, I., Szymański, M. K., Ulaczyk, K., Beichman, C., Bryden, G., Calchi Novati, S., Carey, S., Fausnaugh, M., Gaudi, B. S., Henderson, C. B., Shvartzvald, Y., Wibking, B., Albrow, M. D., Chung, S.-J., 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, C.-U., Lee, Y., Park, B.-G., Pogge, R. W., Street, R. A., Tsapras, Y., Hundertmark, M., Bachelet, E., Dominik, M., Horne, K., Jaimes, R. Figuera, Wambsganss, J., Bramich, D. M., Schmidt, R., Snodgrass, C., Steele, I. A., Menzies, J., Wang, Tianshu, Zhu, Wei, Mao, Shude, Bond, I. A., Gould, A., Udalski, A., Sumi, T., Bozza, V., Ranc, C., Cassan, A., Yee, J. C., Han, C., 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., Rattenbury, N., Saito, To., Sharan, A., Shibai, H., Sullivan, D. J., Suzuki, D., Tristram, P. J., Yamada, T., Yonehara, A., KozŁowski, S., Mróz, P., Pawlak, M., Pietrukowicz, P., Poleski, R., Skowron, J., Soszyński, I., Szymański, M. K., Ulaczyk, K., Beichman, C., Bryden, G., Calchi Novati, S., Carey, S., Fausnaugh, M., Gaudi, B. S., Henderson, C. B., Shvartzvald, Y., Wibking, B., Albrow, M. D., Chung, S.-J., 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, C.-U., Lee, Y., Park, B.-G., Pogge, R. W., Street, R. A., Tsapras, Y., Hundertmark, M., Bachelet, E., Dominik, M., Horne, K., Jaimes, R. Figuera, Wambsganss, J., Bramich, D. M., Schmidt, R., Snodgrass, C., Steele, I. A., and Menzies, J.

Abstract

e present the analysis of the binary gravitational microlensing event MOA-2015-BLG-020. The event has a fairly long timescale (˜63 days) and thus the light curve deviates significantly from the lensing model that is based on the rectilinear lens-source relative motion. This enables us to measure the microlensing parallax through the annual parallax effect. The microlensing parallax parameters constrained by the ground-based data are confirmed by the Spitzer observations through the satellite parallax method. By additionally measuring the angular Einstein radius from the analysis of the resolved caustic crossing, the physical parameters of the lens are determined. It is found that the binary lens is composed of two dwarf stars with masses {M}1=0.606+/- 0.028 {M}⊙ and {M}2=0.125 +/- 0.006 {M}⊙ in the Galactic disk. Assuming that the source star is at the same distance as the bulge red clump stars, we find the lens is at a distance {D}L=2.44+/- 0.10 {kpc}. We also provide a summary and short discussion of all of the published microlensing events in which the annual parallax effect is confirmed by other independent observations.

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