Publications (36)
Microlensing Event MOA-2007-BLG-400: Exhuming the Buried Signature of a Cool, Jovian-Mass Planet
Subo Dong, I. A. Bond, A. Gould +55
We report the detection of the cool, Jovian-mass planet MOA-2007-BLG-400Lb. The planet was detected in a high-magnification microlensing event (with peak magnification A_max = 628)…
Microlensig Binaries with Candidate Brown Dwarf Companions
I. -G. Shin, C. Han, A. Gould +152
Brown dwarfs are important objects because they may provide a missing link between stars and planets, two populations that have dramatically different formation history. In this pa…
Discovery and Mass Measurements of a Cold, 10-Earth Mass Planet and Its Host Star
Y. Muraki, C. Han, D. P. Bennett +125
We present the discovery and mass measurement of the cold, low-mass planet MOA-2009-BLG-266Lb, made with the gravitational microlensing method. This planet has a mass of m_p = 10.4…
MOA-2010-BLG-477Lb: constraining the mass of a microlensing planet from microlensing parallax, orbital motion and detection of blended light
E. Bachelet, I. -G. Shin, C. Han +138
Microlensing detections of cool planets are important for the construction of an unbiased sample to estimate the frequency of planets beyond the snow line, which is where giant pla…
Planetary and Other Short Binary Microlensing Events from the MOA Short Event Analysis
D. P. Bennett, T. Sumi, I. A. Bond +22
We present the analysis of four candidate short duration binary microlensing events from the 2006-2007 MOA Project short event analysis. These events were discovered as a byproduct…
Cold atoms probe the magnetic field near a wire
M. P. A. Jones, C. J. Vale, D. Sahagun +6
A microscopic Ioffe-Pritchard trap is formed using a straight, current-carrying wire, together with suitable auxiliary magnetic fields. By measuring the distribution of cold rubidi…
Characterizing Lenses and Lensed Stars of High-Magnification Single-lens Gravitational Microlensing Events With Lenses Passing Over Source Stars
J. -Y. Choi, I. -G. Shin, S. -Y. Park +148
We present the analysis of the light curves of 9 high-magnification single-lens gravitational microlensing events with lenses passing over source stars, including OGLE-2004-BLG-254…
A Low-Mass Planet with a Possible Sub-Stellar-Mass Host in Microlensing Event MOA-2007-BLG-192
D. P. Bennett, I. A. Bond, A. Udalski +44
We report the detection of an extrasolar planet of mass ratio q ~ 2 x 10^(-4) in microlensing event MOA-2007-BLG-192. The best fit microlensing model shows both the microlensing pa…
Microlensing Discovery of a Tight, Low Mass-ratio Planetary-mass Object around an Old, Field Brown Dwarf
C. Han, Y. K. Jung, A. Udalski +67
Observations of accretion disks around young brown dwarfs have led to the speculation that they may form planetary systems similar to normal stars. While there have been several de…
Microlensing Binaries Discovered through High-Magnification Channel
I. -G. Shin, J. -Y. Choi, S. -Y. Park +148
Microlensing can provide a useful tool to probe binary distributions down to low-mass limits of binary companions. In this paper, we analyze the light curves of 8 binary lensing ev…
1 um Excess Sources in the UKIDSS - I. Three T Dwarfs in the SDSS Southern Equatorial Stripe
Y. Matsuoka, B. A. Peterson, K. L. Murata +8
We report the discovery of two field brown dwarfs, ULAS J0128-0041 and ULAS J0321+0051, and the rediscovery of ULAS J0226+0051 (IfA 0230-Z1), in the Sloan Digital Sky Survey (SDSS)…
A Giant Planet beyond the Snow Line in Microlensing Event OGLE-2011-BLG-0251
N. Kains, R. Street, J. -Y. Choi +128
We present the analysis of the gravitational microlensing event OGLE-2011-BLG-0251. This anomalous event was observed by several survey and follow-up collaborations conducting micr…
Interpretation of Strong Short-Term Central Perturbations in the Light Curves of Moderate-Magnification Microlensing Events
C. Han, K. -H. Hwang, D. Kim +87
To improve the planet detection efficiency, current planetary microlensing experiments are focused on high-magnification events searching for planetary signals near the peak of len…
A Cold Neptune-Mass Planet OGLE-2007-BLG-368Lb: Cold Neptunes Are Common
T. Sumi, D. P. Bennett, I. A. Bond +104
We present the discovery of a Neptune-mass planet OGLE-2007-BLG-368Lb with a planet-star mass ratio of q=[9.5 +/- 2.1] x 10^{-5} via gravitational microlensing. The planetary devia…
A New Type of Ambiguity in the Planet and Binary Interpretations of Central Perturbations of High-Magnification Gravitational Microlensing Events
J. -Y. Choi, I. -G. Shin, C. Han +118
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…
OGLE-2008-BLG-355Lb: A Massive Planet around A Late type Star
N. Koshimoto, A. Udalski, T. Sumi +32
We report the discovery of a massive planet OGLE-2008-BLG-355Lb. The light curve analysis indicates a planet:host mass ratio of q = 0.0118 +/- 0.0006 at a separation of 0.877 +/- 0…
Using Orbital Effects to Break the Close/wide Degeneracy in Binary-lens Microlensing Events
I. -G. Shin, T. Sumi, A. Udalski +37
Microlensing can provide an important tool to study binaries, especially those composed of faint or dark objects. However, accurate analysis of binary-lens light curves is often ha…
The Microlensing Event Rate and Optical Depth Toward the Galactic Bulge from MOA-II
T. Sumi, D. P. Bennett, I. A. Bond +19
We present measurements of the microlensing optical depth and event rate toward the Galactic Bulge based on two years of the MOA-II survey. This sample contains ~1000 microlensing…
Mass measurement of a single unseen star and planetary detection efficiency for OGLE 2007-BLG-050
V. Batista, Subo Dong, A. Gould +93
We analyze OGLE-2007-BLG-050, a high magnification microlensing event (A ~ 432) whose peak occurred on 2 May, 2007, with pronounced finite-source and parallax effects. We compute p…
OGLE-2009-BLG-092/MOA-2009-BLG-137: A Dramatic Repeating Event With the Second Perturbation Predicted by Real-Time Analysis
Y. -H. Ryu, C. Han, K. -H. Hwang +105
We report the result of the analysis of a dramatic repeating gravitational microlensing event OGLE-2009-BLG-092/MOA-2009-BLG-137, for which the light curve is characterized by two…
Binary microlensing event OGLE-2009-BLG-020 gives a verifiable mass, distance and orbit predictions
J. Skowron, A. Udalski, A. Gould +99
We present the first example of binary microlensing for which the parameter measurements can be verified (or contradicted) by future Doppler observations. This test is made possibl…
MOA-2010-BLG-523: "Failed Planet" = RS CVn Star
A. Gould, J. C. Yee, I. A. Bond +116
The Galactic bulge source MOA-2010-BLG-523S exhibited short-term deviations from a standard microlensing lightcurve near the peak of an Amax ~ 265 high-magnification microlensing e…
A possible binary system of a stellar remnant in the high magnification gravitational microlensing event OGLE-2007-BLG-514
N. Miyake, A. Udalski, T. Sumi +78
We report the extremely high magnification (A > 1000) binary microlensing event OGLE-2007-BLG-514. We obtained good coverage around the double peak structure in the light curve via…
OGLE-2008-BLG-510: first automated real-time detection of a weak microlensing anomaly - brown dwarf or stellar binary?
V. Bozza, M. Dominik, N. J. Rattenbury +103
The microlensing event OGLE-2008-BLG-510 is characterised by an evident asymmetric shape of the peak, promptly detected by the ARTEMiS system in real time. The skewness of the ligh…
Chemical evolution of the Galactic bulge as traced by microlensed dwarf and subgiant stars. IV. Two bulge populations
T. Bensby, D. Adén, J. Meléndez +21
[ABRIDGED] Based on high-resolution (R~42000 to 48000) and high signal-to-noise (S/N~50 to 150) spectra obtained with UVES/VLT, we present detailed elemental abundances (O, Na, Mg,…
OGLE-2009-BLG-023/MOA-2009-BLG-028: Characterization of a Binary Microlensing Event Based on Survey Data
K. -H. Hwang, C. Han, A. Udalski +37
We report the result of the analysis of the light curve of a caustic-crossing binary-lens microlensing event OGLE-2009-BLG-023/MOA-2009-BLG-028. Even though the event was observed…
Determining the Physical Lens Parameters of the Binary Gravitational Microlensing Event MOA-2009-BLG-016
K. -H. Hwang, C. Han, I. A. Bond +39
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 a…
MOA-2010-BLG-328Lb: a sub-Neptune orbiting very late M dwarf ?
K. Furusawa, A. Udalski, T. Sumi +119
We analyze the planetary microlensing event MOA-2010-BLG-328. The best fit yields host and planetary masses of Mh = 0.11+/-0.01 M_{sun} and Mp = 9.2+/-2.2M_Earth, corresponding to…
Microlensing Discovery of a Population of Very Tight, Very Low-mass Binary Brown Dwarfs
J. -Y. Choi, C. Han, A. Udalski +121
Although many models have been proposed, the physical mechanisms responsible for the formation of low-mass brown dwarfs are poorly understood. The multiplicity properties and minim…
Unbound or Distant Planetary Mass Population Detected by Gravitational Microlensing
T. Sumi, K. Kamiya, A. Udalski +36
Since 1995, more than 500 exoplanets have been detected using different techniques, of which 11 were detected with gravitational microlensing. Most of these are gravitationally bou…
OGLE 2008--BLG--290: An accurate measurement of the limb darkening of a Galactic Bulge K Giant spatially resolved by microlensing
P. Fouque, D. Heyrovsky, S. Dong +115
Gravitational microlensing is not only a successful tool for discovering distant exoplanets, but it also enables characterization of the lens and source stars involved in the lensi…
MOA-2010-BLG-311: A planetary candidate below the threshold of reliable detection
J. C. Yee, L. -W. Hung, I. A. Bond +123
We analyze MOA-2010-BLG-311, a high magnification (A_max>600) microlensing event with complete data coverage over the peak, making it very sensitive to planetary signals. We fit th…
A sub-Saturn Mass Planet, MOA-2009-BLG-319Lb
N. Miyake, T. Sumi, Subo Dong +119
We report the gravitational microlensing discovery of a sub-Saturn mass planet, MOA-2009-BLG-319Lb, orbiting a K or M-dwarf star in the inner Galactic disk or Galactic bulge. The h…
MOA-2008-BLG-379Lb: A Massive Planet from a High Magnification Event with a Faint Source
D. Suzuki, A. Udalski, T. Sumi +31
We report analysis of high microlensing event MOA-2008-BLG-379, which has a strong microlensing anomaly at its peak, due to a massive planet with a mass ratio of q = 6.9 x 10^{-3}.…
Characterizing Low-Mass Binaries From Observation of Long Time-scale Caustic-crossing Gravitational Microlensing Events
I. -G. Shin, C. Han, J. -Y. Choi +119
Despite astrophysical importance of binary star systems, detections are limited to those located in small ranges of separations, distances, and masses and thus it is necessary to u…
MOA-2010-BLG-073L: An M-Dwarf with a Substellar Companion at the Planet/Brown Dwarf Boundary
R. A. Street, J. -Y. Choi, Y. Tsapras +129
We present an analysis of the anomalous microlensing event, MOA-2010-BLG-073, announced by the Microlensing Observations in Astrophysics survey on 2010-03-18. This event was remark…