Publications (72)
Solar neutrino measurements using the full data period of Super-Kamiokande-IV
Kamiokande Collaboration, K. Abe, C. Bronner +322
An analysis of solar neutrino data from the fourth phase of Super-Kamiokande~(SK-IV) from October 2008 to May 2018 is performed and the results are presented. The observation time…
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…
A Sub-Earth-Mass Moon Orbiting a Gas Giant Primary or a High Velocity Planetary System in the Galactic Bulge
D. P. Bennett, V. Batista, I. A. Bond +90
We present the first microlensing candidate for a free-floating exoplanet-exomoon system, MOA-2011-BLG-262, with a primary lens mass of M_host ~ 4 Jupiter masses hosting a sub-Eart…
Luminous, pc-scale CO 6-5 emission in the obscured nucleus of NGC1377
S. Aalto, S. Muller, F. Costagliola +13
High resolution submm observations are important in probing the morphology, column density and dynamics of obscured active galactic nuclei (AGNs). With high resolution (0.06 x 0.05…
Development of a data overflow protection system for Super-Kamiokande to maximize data from nearby supernovae
M. Mori, K. Abe, Y. Hayato +252
Neutrinos from very nearby supernovae, such as Betelgeuse, are expected to generate more than ten million events over 10\,s in Super-Kamokande (SK). At such large event rates, the…
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}.…
On the disappearance of a cold molecular torus around the low-luminosity active galactic nucleus of NGC 1097
T. Izumi, K. Kohno, K. Fathi +15
We used the Atacama Large Millimeter/submillimeter Array (ALMA) to map the CO(3-2) and the underlying continuum emissions around the type 1 low-luminosity active galactic nucleus (…
OGLE-2012-BLG-0455/MOA-2012-BLG-206: Microlensing event with ambiguity in planetary interpretations caused by incomplete coverage of planetary signal
H. Park, C. Han, A. Gould +55
Characterizing a microlensing planet is done from modeling an observed lensing light curve. In this process, it is often confronted that solutions of different lensing parameters r…
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…
The Galaxy Activity, Torus and Outflow Survey (GATOS) I. ALMA images of dusty molecular tori in Seyfert galaxies
S. GarcÃa-Burillo, A. Alonso-Herrero, C. Ramos Almeida +32
We present the first results of the Galaxy Activity, Torus and Outflow Survey (GATOS), a project aimed at understanding the properties of the dusty molecular tori and their connect…
Molecular Hydrogen in Damped Ly-alpha Systems: Spatial Distribution
H. Hirashita, A. Ferrara, K. Wada +1
To interpret H_2 quasar absorption line observations in Damped Ly-alpha clouds (DLAs), we model the H_2 spatial distribution within a DLA. Based on numerical simulations of disk st…
Dynamical Susceptibility in KDP-type Crysals above and below Tc II
S. Yoshida, N. Ihara, K. Wada
The path probability method (PPM) in the tetrahedron-cactus approximation is applied to the Slater-Takagi model with dipole-dipole interaction for KH2PO4-type hydrogen-bonded ferro…
Time-resolved infrared emission from radiation-driven central obscuring structures in Active Galactic Nuclei
M. Schartmann, K. Wada, M. A. Prieto +2
The central engines of Seyfert galaxies are thought to be enshrouded by geometrically thick gas and dust structures. In this article, we derive observable properties for a self-con…
Search for supernova bursts in Super-Kamiokande IV
Kamiokande collaboration, M. Mori, K. Abe +242
Super-Kamiokande has been searching for neutrino bursts characteristic of core-collapse supernovae continuously, in real time, since the start of operations in 1996. The present wo…
ALMA resolves the remarkable molecular jet and rotating wind in the extremely radio-quiet galaxy NGC 1377
S. Aalto, N. Falstad, S. Muller +14
Submillimetre and millimetre observations are important in probing the properties of the molecular gas and dust around obscured active galactic nuclei (AGNs) and their feedback. Wi…
MOA-2013-BLG-220Lb: Massive Planetary Companion to Galactic-Disk Host
J. C. Yee, C. Han, A. Gould +70
We report the discovery of MOA-2013-BLG-220Lb, which has a super-Jupiter mass ratio relative to its host. The proper motion, $μ=12.5\pm 1\, {\rm mas…
A Super-Jupiter orbiting a late-type star: A refined analysis of microlensing event OGLE-2012-BLG-0406
Y. Tsapras, J. -Y. Choi, R. A. Street +122
We present a detailed analysis of survey and follow-up observations of microlensing event OGLE-2012-BLG-0406 based on data obtained from 10 different observatories. Intensive cover…
Search for astrophysical electron antineutrinos in Super-Kamiokande with 0.01wt% gadolinium-loaded water
M. Harada, K. Abe, C. Bronner +238
We report the first search result for the flux of astrophysical electron antineutrinos for energies O(10) MeV in the gadolinium-loaded Super-Kamiokande (SK) detector. In June 2020,…
220 fs Er-Yb:glass laser mode-locked by a broadband low-loss Si/Ge saturable absorber
F. J. Grawert, S. Akiyama, F. O. Ilday +7
We demonstrate femtosecond performance of an ultra-broadband high-index-contrast saturable Bragg reflector consisting of a silicon/silicon-dioxide/germanium structure that is fully…
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…
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…
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…
Neutron multiplicity measurement in muon capture on oxygen nuclei in the Gd-loaded Super-Kamiokande detector
Kamiokande Collaboration, S. Miki, K. Abe +282
In recent neutrino detectors, neutrons produced in neutrino reactions play an important role. Muon capture on oxygen nuclei is one of the processes that produce neutrons in water C…
Testing Non-Standard Interactions Between Solar Neutrinos and Quarks with Super-Kamiokande
Kamiokande Collaboration, P. Weatherly, K. Abe +268
Non-Standard Interactions (NSI) between neutrinos and matter affect the neutrino flavor oscillations. Due to the high matter density in the core of the Sun, solar neutrinos are sui…
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…
Search for proton decay via in 0.37 megaton-years exposure of Super-Kamiokande
Kamiokande Collaboration, R. Matsumoto, K. Abe +229
We searched for proton decay via in 0.37\,Mtonyears of data collected between 1996 and 2018 from the Super-Kamiokande water Cherenkov experiment. The selection…
The Galaxy Activity, Torus and Outflow Survey (GATOS): II. Torus and polar dust emission in nearby Seyfert galaxies
A. Alonso-Herrero, S. GarcÃa-Burillo, S. F. Hoenig +30
We compare mid-IR and ALMA far-IR images of 12 nearby Seyferts selected from GATOS. The mid-IR unresolved emission contributes more than 60% of the nuclear emission in most galaxie…
MOA-2011-BLG-322Lb: a "second generation survey" microlensing planet
Y. Shvartzvald, D. Maoz, S. Kaspi +37
Global "second-generation" microlensing surveys aim to discover and characterize extrasolar planets and their frequency, by means of round-the-clock high-cadence monitoring of a la…
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…
Measurement of the cosmogenic neutron yield in Super-Kamiokande with gadolinium loaded water
Kamiokande Collaboration, M. Shinoki, K. Abe +238
Cosmic-ray muons that enter the Super-Kamiokande detector cause hadronic showers due to spallation in water, producing neutrons and radioactive isotopes. Those are a major backgrou…
Updated Analysis of a "Dark" Galaxy and its Blue Companion in the Virgo Cloud HI 1225+01
Y. Matsuoka, N. Ienaka, S. Oyabu +2
HI 1225+01 is an intergalactic gas cloud located on the outskirts of Virgo cluster. Its main components are two large clumps of comparable HI masses (M_HI ~ 10^9 Msun) separated by…
Nuclear Bar, Star Formation and Gas Fueling in the Active Galaxy NGC 4303
L. Colina, K. Wada
A combination of Hubble Space Telescope (HST) WFPC2 and NICMOS images are used to investigate the gas/dust and stellar structure inside the central 300 pc of the nearby active gala…
The dynamics of spiral arms in pure stellar disks
M. S. Fujii, J. Baba, T. R. Saitoh +3
It has been believed that spirals in pure stellar disks, especially the ones spontaneously formed, decay in several galactic rotations due to the increase of stellar velocity dispe…
Measurements of the charge ratio and polarization of cosmic-ray muons with the Super-Kamiokande detector
H. Kitagawa, T. Tada, K. Abe +253
We present the results of the charge ratio () and polarization () measurements using the decay electron events collected from 2008 September to 2022 June by the Super-…
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…
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…
Interpretation of a Short-Term Anomaly in the Gravitational Microlensing Event MOA-2012-BLG-486
K. -H. Hwang, J. -Y. Choi, I. A. Bond +78
A planetary microlensing signal is generally characterized by a short-term perturbation to the standard single lensing light curve. A subset of binary-source events can produce per…
Reanalyses of Anomalous Gravitational Microlensing Events in the OGLE-III Early Warning System Database with Combined Data
J. Jeong, H. Park, C. Han +95
We reanalyze microlensing events in the published list of anomalous events that were observed from the OGLE lensing survey conducted during 2004-2008 period. In order to check the…
Pre-Supernova Alert System for Super-Kamiokande
Kamiokande Collaboration, L. N. Machado, K. Abe +223
In 2020, the Super-Kamiokande (SK) experiment moved to a new stage (SK-Gd) in which gadolinium (Gd) sulfate octahydrate was added to the water in the detector, enhancing the effici…
Laser cooling of positronium
K. Shu, Y. Tajima, R. Uozumi +16
When laser radiation is skilfully applied, atoms and molecules can be cooled allowing precise measurements and control of quantum systems. This is essential in fundamental studies…
Multi-Phase Gas Dynamics in a Weak Barred Potential
K. Wada, J. Koda
The structure of the interstellar medium in the central kpc region of a galaxy with a weak bar-like potential is investigated taking into account realistic cooling and heating proc…
A precessing molecular jet signaling an obscured, growing supermassive black hole in NGC1377?
S. Aalto, F. Costagliola, S. Muller +11
With high resolution (0."25 x 0."18) ALMA CO 3-2 observations of the nearby (D=21 Mpc, 1"=102 pc), extremely radio-quiet galaxy NGC1377, we have discovered a high-velocity, very co…
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…
Search for Cosmic-ray Boosted Sub-GeV Dark Matter using Recoil Protons at Super-Kamiokande
Kamiokande Collaboration, K. Abe, Y. Hayato +218
We report a search for cosmic-ray boosted dark matter with protons using the 0.37 megatonyears data collected at Super-Kamiokande experiment during the 1996-2018 period (SK…
OGLE-2013-BLG-0102LA,B: Microlensing binary with components at star/brown-dwarf and brown-dwarf/planet boundaries
Y. K. Jung, A. Udalski, T. Sumi +51
We present the analysis of the gravitational microlensing event OGLE-2013-BLG-0102. The light curve of the event is characterized by a strong short-term anomaly superposed on a smo…
Hydrogen embrittlement susceptibility of additively manufactured 316L stainless steel: influence of post-processing, printing direction, temperature and pre-straining
G. Ãlvarez, Z. Harris, K. Wada +2
The influence of post-build processing on the hydrogen embrittlement behavior of additively manufactured (AM) 316L stainless steel fabricated using laser powder bed fusion was asse…
A Terrestrial Planet in a ~1 AU Orbit Around One Member of a ~15 AU Binary
A. Gould, A. Udalski, I. -G. Shin +61
We detect a cold, terrestrial planet in a binary-star system using gravitational microlensing. The planet has low mass (2 Earth masses) and lies projected at ~ 0.8 a…
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…
Asynchronous Gathering Algorithms for Autonomous Mobile Robots with Lights
R. Nakai, Y. Sudo, K. Wada
We consider a Gathering problem for n autonomous mobile robots with persistent memory called light in an asynchronous scheduler (ASYNC). It is well known that Gathering is impossib…
Application of the Cluster Variation Method to Spin Ice Systems on the Pyrochlore Lattice
S. Yoshida, K. Nemoto, K. Wada
The cactus approximation in the cluster variation method is applied to the spin ice system with nearest neighbor ferromagnetic coupling. The temperature dependences of the entropy…
Candidate Gravitational Microlensing Events for Future Direct Lens Imaging
C. B. Henderson, H. Park, T. Sumi +76
The mass of the lenses giving rise to Galactic microlensing events can be constrained by measuring the relative lens-source proper motion and lens flux. The flux of the lens can be…
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…
Searching for neutrinos from solar flares across solar cycles 23 and 24 with the Super-Kamiokande detector
K. Okamoto, K. Abe, Y. Hayato +242
Neutrinos associated with solar flares (solar-flare neutrinos) provide information on particle acceleration mechanisms during the impulsive phase of solar flares. We searched using…
On Phase Transition of -Type Crystals by Cluster Variation Method
N. Ihara, S. Yoshida, K. Wada
The Cluster Variation Method (CVM) is applied to the Ishibashi model for ammonium dihydrogen phosphate () of a typical hydrogen bonded anti-ferroelectric cry…
Effect of projectile shape and interior structure on crater size in strength regime
T. Kadono, M. Arakawa, S. Tsujido +9
Experiments on crater formation in the strength regime were conducted using projectiles of various shapes with an aspect ratio of ~1, including both solid and hollow interiors. The…
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…
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…
Search for proton decay via and with a 0.37 Mton-year exposure of Super-Kamiokande
Kamiokande Collaboration, N. Taniuchi, K. Abe +288
A search for proton decay into and a meson has been performed using data from a 0.373 Mtonyear exposure (6050.3 live days) of Super-Kamiokande. Compared to p…
Feedback From the First Supernovae in Protogalaxies:The Fate of the Generated Metals
K. Wada, A. Venkatesan
We investigate the chemo-dynamical effects of multiple supernova explosions in the central region of primordial galaxies using three-dimensional hydrodynamical simulations of the i…
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…
On the origin of the Tully-Fisher relation
J. Koda, Y. Sofue, K. Wada
We discuss the origin of the Tully-Fisher (TF) relation using the -body/SPH method, which includes cooling, star formation and stellar feedback of energy, mass and metals. We co…
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,…
The life cycle of starbursting circumnuclear gas discs
M. Schartmann, J. Mould, K. Wada +5
High-resolution observations from the sub-mm to the optical wavelength regime resolve the central few 100pc region of nearby galaxies in great detail. They reveal a large diversity…