Results for "Motohide Tamura"

total 917took 0.14s
Near-Infrared Polarization Source Catalog of the Northeastern Regions of the Large Magellanic CloudDec 03 2015Dec 08 2015We present a near-infrared band-merged photometric and polarimetric catalog for the 39$\arcmin$ $\times$ 69$\arcmin$ fields on the northeastern part of the Large Magellanic Cloud (LMC), which were observed using SIRPOL, an imaging polarimeter of the InfraRed ... More
Magnetic Field Structure of the HH 1-2 Region: Near-Infrared Polarimetry of Point-Like SourcesNov 11 2009The HH 1-2 region in the L1641 molecular cloud was observed in the near-IR J, H, and Ks bands, and imaging polarimetry was performed. Seventy six point-like sources were detected in all three bands. The near-IR polarizations of these sources seem to be ... More
Planets Around Low-Mass Stars (PALMS). IV. The Outer Architecture of M Dwarf Planetary SystemsNov 13 2014We present results from a high-contrast adaptive optics imaging search for giant planets and brown dwarfs (>1 MJup) around 122 newly identified nearby (<40 pc) young M dwarfs. Half of our targets are younger than 135 Myr and 90% are younger than the Hyades ... More
Magnetic stability of massive star forming clumps in RCW 106Apr 12 2019Apr 16 2019The RCW 106 molecular cloud complex is an active massive star-forming region where a ministarburst is taking place. We examined its magnetic structure by near-IR polarimetric observations with the imaging polarimeter SIRPOL on the IRSF 1.4 m telescope. ... More
Cluster Membership Probability: Polarimetric ApproachDec 31 2012Interstellar polarimetric data of the six open clusters Hogg 15, NGC 6611, NGC 5606, NGC 6231, NGC 5749 and NGC 6250 have been used to estimate the membership probability for the stars within them. For proper-motion member stars, the membership probability ... More
Stellar Imaging Coronagraph and Exoplanet Coronal Spectrometer: Two Additional Instruments for Exoplanet Exploration Onboard The WSO-UV 1.7 Meter Orbital TelescopeOct 17 2018The World Space Observatory for Ultraviolet (WSO-UV) is an orbital optical telescope with a 1.7 m-diameter primary mirror currently under development. The WSO-UV is aimed to operate in the 115-310 nm UV spectral range. Its two major science instruments ... More
YSO search toward the boundary of the Central Molecular Zone with near-infrared polarimetryJun 11 2014We have carried out near-infrared polarimetry toward the boundary of the Central Molecular Zone, in the field of (-1.4 deg $\lesssim l \lesssim$ -0.3 deg and 1.0 deg $\lesssim l \lesssim$ 2.9 deg, $|b|\lesssim$ 0.1 deg), using the near-infrared polarimetric ... More
The Stellar Population of the M31 Spiral Arm Around OB Association A24Mar 02 1999A study of the stellar population of the M31 spiral arm around OB association A24 was carried out based on the photometric data obtained from deep V and JHK imaging. The luminosity function was obtained for -7 <~ Mbol <~ -3.5 by applying the extinction ... More
ALMA Reveals a Misaligned Inner Gas Disk inside the Large Cavity of a Transitional DiskOct 16 2018Pairs of azimuthal intensity decrements at near symmetric locations have been seen in a number of protoplanetary disks. They are most commonly interpreted as the two shadows cast by a highly misaligned inner disk. Direct evidence of such an inner disk, ... More
First Evidence of a Retrograde Orbit of Transiting Exoplanet HAT-P-7bAug 12 2009Aug 27 2009We present the first evidence of a retrograde orbit of the transiting exoplanet HAT-P-7b. The discovery is based on a measurement of the Rossiter-McLaughlin effect with the Subaru HDS during a transit of HAT-P-7b, which occurred on UT 2008 May 30. Our ... More
High Resolution Observations of Dust Continuum Emission at 340 GHz from the Low-mass T Tauri Star FN TauriFeb 12 2010Feb 15 2010FN Tau is a rare example of very low-mass T Tauri stars that exhibits a spatially resolved nebulosity in near-infrared scattering light. To directly derive the parameters of a circumstellar disk around FN Tau, observations of dust continuum emission at ... More
Near-infrared Polarimetry toward the Galactic Center - Magnetic Field Configuration in the Central One Degree Region -Jan 29 2010We present a NIR polarimetric map of the 1deg by 1deg region toward the Galactic center. Comparing Stokes parameters between highly reddened stars and less reddened ones, we have obtained a polarization originating from magnetically aligned dust grains ... More
Detection of Molecular Hydrogen Emission Associated with LkHalpha 264Oct 11 2003We have detected emission of molecular hydrogen from a classical T Tauri star, LkHalpha 264 in the v=1-0 S(1) line at 2.122 micron. The line velocity is coincident with the rest velocity of the star. The line profile is well reproduced by a model in which ... More
Intrinsically Polarized Stars and Implication for Star Formation in the Central Parsec of Our GalaxyOct 11 2013We have carried out adaptive-optics assisted observations at the Subaru telescope, and have found 11 intrinsically polarized sources in the central parsec of our Galaxy. They are selected from 318 point sources with Ks<15.5, and their interstellar polarizations ... More
Red-edge position of habitable exoplanets around M-dwarfsAug 12 2017One of the possible signs of life on distant habitable exoplanets is the red-edge, which is a rise in the reflectivity of planets between visible and near-infrared (NIR) wavelengths. Previous studies suggested the possibility that the red-edge position ... More
A New Concept for Direct Imaging and Spectral Characterization of Exoplanets in Multi-planet SystemsMar 13 2011We present a novel method for direct detection and characterization of exoplanets from space. This method uses four collecting telescopes, combined with phase chopping and a spectrometer, with observations on only a few baselines rather than on a continuously ... More
Completeness of Kozen's Axiomatization for the Modal mu-Calculus: A Simple ProofAug 15 2014Aug 23 2014The modal mu-calculus, introduced by Dexter Kozen, is an extension of modal logic with fixpoint operators. Its axiomatization, Koz, was introduced at the same time and is an extension of the minimal modal logic K with the so-called Park fixpoint induction ... More
Large regular simplices contained in a hypercube with a common barycenterJan 14 2011It has been shown that the $n$-dimensional unit hypercube contains an $n$-dimensional regular simplex of edge length $c\sqrt n$ for arbitrary $c<1/2$ if $n$ is sufficiently large (Maehara, Ruzsa and Tokushige, 2009). We prove the same statement holds ... More
Conductance of telescoped double-walled nanotubes from perturbation calculationsMar 23 2009Aug 06 2010In a telescoped double-walled nanotube (TDWNT), with the inner tube partially extracted from the outer tube, the total current is forced to flow between the layers. Considering the interlayer Hamiltonian as a perturbation, we can obtain an analytic formula ... More
Perturbation calculations on interlayer transmission rates from symmetric to antisymmetric channels in parallel armchair nanotube junctionsJan 07 2019Partially overlapping two parallel armchair nanotubes are investigated theoretically with the $\pi$ orbital tight bonding model. Considering the interlayer Hamiltonian as perturbation, we obtain approximate analytical formulas of the interlayer transmission ... More
Symmetric powers of permutation representations of finite groups and primitive colorings on polyhedronsMar 18 2017In this paper, we define a set which has a finite group action and is generated by a finite color set, a set which has a finite group action, and a subset of the set of non negative integers. we state its properties to apply one of solution of the following ... More
Numerical Evaluation of Generalized Hypergeometric Functions for Degenerated Values of ParametersMar 03 2007In this paper, we give an algorithm to generate connection formulas of generalized hypergeometric functions ${}_p F_{p-1}$ for degenerated values of parameters. We also show that these connection formulas give a fast method for numerical evaluation of ... More
Exterior powers of representations of finite groups and integer-valued charactersMar 16 2017For given representation of finite groups on a finite dimension complex vector space, we can define exterior powers of representations. In 1973, Knutson found one of methods of calculating the character of exterior powers of representations with properties ... More
Sub-Arcsecond Near-Infrared Images of Massive Star Formation Region NGC 6334 VDec 19 2006We present high spatial resolution (0$\farcs$3) polarimetric images in the $H$ and $K$ bands and direct images in the $L'$ and $M'$ bands of the NGC 6334 V infrared nebulae. The images show complex structures including the multi-shells and various knots ... More
Spin-Orbit Alignment of the TrES-4 Transiting Planetary System and Possible Additional Radial Velocity VariationMar 11 2010We report new radial velocities of the TrES-4 transiting planetary system, including observations of a full transit, with the High Dispersion Spectrograph of the Subaru 8.2m telescope. Modeling of the Rossiter-McLaughlin effect indicates that TrES-4b ... More
Substellar Objects in Nearby Young Clusters (SONYC) V: New brown dwarfs in rho OphiuchiOct 07 2011SONYC - Substellar Objects in Nearby Young Clusters - is a survey program to investigate the frequency and properties of substellar objects with masses down to a few times that of Jupiter in nearby star-forming regions. For the ~1Myr old rho Ophiuchi ... More
Interstellar Extinction Law toward the Galactic Center II: V, J, H, and Ks BandsFeb 25 2008We have determined the ratios of total to selective extinction directly from observations in the optical V band and near-infrared J band toward the Galactic center. The OGLE (Optical Gravitational Lensing Experiment) Galactic bulge fields have been observed ... More
Spectroscopically Identified Intermediate Age Stars at 0.5 - 3 pc Distance from Sgr A*Nov 05 2015<Context.> Nuclear star clusters (NSCs) at the dynamical center of galaxies appear to have a complex star formation history. This suggests repeated star formation even in the influence of the strong tidal field from supermassive black holes. <Aim.> In ... More
Isochronal age-mass discrepancy of young stars: SCExAO/CHARIS integral field spectroscopy of the HIP 79124 triple systemNov 26 2018Dec 20 2018We present SCExAO/CHARIS 1.1--2.4 micron integral field direct spectroscopy of the young HIP 79124 triple system. HIP 79124 is a member of the Scorpius-Centaurus association, consisting of an A0V primary with two low-mass companions at a projected separation ... More
First Two-Micron Imaging Polarimetry of Beta PictorisMar 14 2006High-resolution K band imaging polarimetry of the beta Pic dust disk has been conducted with adaptive optics and a coronagraph using the Subaru 8.2-m telescope. Polarization of ~10 % is detected out to r ~ 120 AU with a centro-symmetric vector pattern ... More
Mapping dust column density in dark clouds by using NIR scattered light : Case of the Lupus 3 dark cloudSep 05 2008We present a method of mapping dust column density in dark clouds by using near-infrared scattered light. Our observations of the Lupus 3 dark cloud indicate that there is a well defined relation between (1) the H-Ks color of an individual star behind ... More
Substellar Objects in Nearby Young Clusters (SONYC) VI: The planetary-mass domain of NGC1333Jul 05 2012Aug 16 2012Within the SONYC - Substellar Objects in Nearby Young Clusters - survey, we investigate the frequency of free-floating planetary-mass objects (planemos) in the young cluster NGC1333. Building upon our extensive previous work, we present spectra for 12 ... More
Sequential Formation of Low-Mass Stars in the BRC 14 RegionMay 23 2006We have carried out a deep near-infrared survey of a bright-rimmed molecular cloud, BRC 14 (IC 1848A). The 10 sigma limiting magnitude of the survey is 17.7 mag at the K-band. Seventy-four sources are classified as young stellar object (YSO) candidates ... More
Planets Around Low-Mass Stars (PALMS). II. A Low-Mass Companion to the Young M Dwarf GJ 3629 Separated By 0.2"Jun 14 2012We present the discovery of a 0.2" companion to the young M dwarf GJ 3629 as part of our high contrast adaptive optics imaging search for giant planets around low-mass stars with the Keck-II and Subaru telescopes. Two epochs of imaging confirm the pair ... More
Near-infrared Polarimetry of flares from Sgr A* with Subaru/CIAOJul 31 2009Aug 07 2009We have performed near-infrared monitoring observations of Sgr A*, the Galactic center radio source associated with a supermassive black hole, with the near-infrared camera CIAO and the 36-element adaptive optics system on the Subaru telescope. We observed ... More
Near-Infrared Polarimetry toward the Galactic CenterSep 29 2008Near-infrared polarimetry of point sources reveals the presence of a toroidal magnetic field in the central 20' x 20' region of our Galaxy. Comparing the Stokes parameters between high extinction stars and relatively low extinction ones, we have obtained ... More
Constraining accretion signatures of exoplanets in the TW Hya transitional diskJul 20 2017We present a near-infrared direct imaging search for accretion signatures of possible protoplanets around the young stellar object (YSO) TW Hya, a multi-ring disk exhibiting evidence of planet formation. The Pa$\beta$ line (1.282 $\mu$m) is an indication ... More
Can Ground-based Telescopes Detect The Oxygen 1.27 Micron Absorption Feature as a Biomarker in Exoplanets ?Jun 04 2012Aug 05 2012The oxygen absorption line imprinted in the scattered light from the Earth-like planets has been considered the most promising metabolic biomarker of the exo-life. We examine the feasibility of the detection of the 1.27 micron oxygen band from habitable ... More
Possible Molecular Spiral Arms in the Protoplanetary Disk of AB AurMar 16 2006The circumstellar dust disk of the Herbig Ae star AB Aur has been found to exhibit complex spiral-like structures in the near-IR image obtained with the Subaru Telescope. We present maps of the disk in both 12CO (3-2) and dust continuum at 345 GHz with ... More
The shadow knows: using shadows to investigate the structure of the pretransitional disk of HD 100453Mar 02 2017Apr 08 2017We present GPI polarized intensity imagery of HD 100453 in Y-, J-, and K1 bands which reveals an inner gap ($9 - 18$ au), an outer disk ($18-39$ au) with two prominent spiral arms, and two azimuthally-localized dark features also present in SPHERE total ... More
XO-2b: a Prograde Planet with a Negligible Eccentricity, and an Additional Radial Velocity VariationOct 27 2011We present precise radial velocities of XO-2 taken with the Subaru HDS, covering two transits of XO-2b with an interval of nearly two years. The data suggest that the orbital eccentricity of XO-2b is consistent with zero within 2$\sigma$ ($e=0.045\pm0.024$) ... More
An Infrared Census of Star Formation in the Horsehead NebulaJan 05 2009At ~ 400 pc, the Horsehead Nebula (B33) is the closest radiatively-sculpted pillar to the Sun, but the state and extent of star formation in this structure is not well understood. We present deep near-infrared (IRSF/SIRIUS JHKs) and mid-infrared (Spitzer/IRAC) ... More
Magnetic field structure around cores with very low luminosity objectsNov 04 2014[Abridged] We carried out optical polarimetry of five dense cores, (IRAM 04191, L1521F, L328, L673-7, and L1014) which are found to harbour VeLLO. This study was conducted mainly to understand the role played by the magnetic field in the formation of ... More
The K2-ESPRINT Project III: A Close-in Super-Earth around a Metal-rich Mid-M DwarfNov 26 2015Feb 20 2016We validate a $R_p=2.32\pm 0.24R_\oplus$ planet on a close-in orbit ($P=2.260455\pm 0.000041$ days) around K2-28 (EPIC 206318379), a metal-rich M4-type dwarf in the Campaign 3 field of the K2 mission. Our follow-up observations included multi-band transit ... More
Discovery of an Inner Disk Component around HD 141569 AJan 25 2016Jan 27 2016We report the discovery of a scattering component around the HD 141569 A circumstellar debris system, interior to the previously known inner ring. The discovered inner disk component, obtained in broadband optical light with HST/STIS coronagraphy, was ... More
A Curved Magnetic field in the ring-like shell of bubble N4Mar 08 2017Mar 24 2017We report the detection of a curved magnetic field in the ring-like shell of the bubble N4, derived from near-infrared polarization of reddened diskless stars located behind this bubble. The magnetic field in the shell is curved and parallel to the ring-like ... More
Coeval intermediate-mass star formation in N4WMar 28 2016Protostars are mostly found in star-forming regions, where the natal molecular gas still remains. In about 5' west of the molecular bubble N4, N4W is identified as a star-forming clump hosting three Class II (IRS\,1\,--\,3), and one Class I (IRS\,4) young ... More
Millimeter- and Submillimeter-Wave Observations of the OMC-2/3 Region. III. An Extensive Survey for Molecular OutflowsAug 05 2008Using the ASTE 10 m submillimeter telescope and the 1.4 m Infrared Survey Facility (IRSF), we performed an extensive outflow survey in the Orion Molecular Cloud -2 and -3 region. Our survey, which includes 41 potential star-forming sites, has been newly ... More
IRSF SIRIUS JHKs Simultaneous Transit Photometry of GJ1214bOct 11 2012We report high precision transit photometry of GJ1214b in JHKs bands taken simultaneously with the SIRIUS camera on the IRSF 1.4m telescope at Sutherland, South Africa. Our MCMC analyses show that the observed planet-to-star radius ratios in JHKs bands ... More
Substellar Objects in Nearby Young Clusters (SONYC) IV: A census of very low mass objects in NGC1333Oct 07 2011SONYC -- Substellar Objects in Nearby Young Clusters -- is a program to investigate the frequency and properties of young substellar objects with masses down to a few times that of Jupiter. Here we present a census of very low mass objects in the ~1 Myr ... More
SONYC - Substellar Objects in Nearby Young ClustersDec 29 2010The origin of the lowest mass free-floating objects -- brown dwarfs and planetary-mass objects -- is one of the major unsolved problems in star formation. Establishing a census of young substellar objects is a fundamental prerequisite for distinguishing ... More
The Origin of the Galactic Center Diffuse X-ray Emission Investigated by Near-infrared Imaging and Polarimetric ObservationsJan 26 2014The origin of the Galactic center diffuse X-ray emission (GCDX) is still under intense investigation. We have found a clear excess in a longitudinal GCDX profile over a stellar number density profile in the nuclear bulge region, suggesting a significant ... More
Substellar Objects in Nearby Young Clusters (SONYC) II: The Brown Dwarf Population of Rho OphiuchiOct 27 2010SONYC - Substellar Objects in Nearby Young Clusters - is a survey program to investigate the frequency and properties of brown dwarfs down to masses below the Deuterium burning limit in nearby star forming regions. In this second paper, we present results ... More
Fiber mode scrambler for the Subaru infrared Doppler instrument (IRD)Mar 23 2018We report the results of fiber mode scrambler experiments for the Infra-Red Doppler instrument (IRD) on the Subaru 8.2-m telescope. IRD is a fiber-fed, high precision radial velocity (RV) instrument to search for exoplanets around nearby M dwarfs at near-infrared ... More
Near-Infrared Polarimetric Study of N159/N160 Star-Forming Complex in the Large Magellanic CloudJan 26 2017Feb 20 2017We present near-infrared polarimetric results for N159/N160 star-forming complex, in the Large Magellanic Cloud (LMC) with SIRPOL, the polarimeter of the Infrared Survey Facility (IRSF). We separated foreground sources using their visual extinction derived ... More
Qatar Exoplanet Survey: Qatar-8b, 9b and 10b --- A Hot Saturn and Two Hot JupitersMar 20 2019Apr 15 2019In this paper we present three new extrasolar planets from the Qatar Exoplanet Survey (QES). Qatar-8b is a hot Saturn, with Mpl = 0.37 Mjup and Rpl = 1.3 Rjup, orbiting a solar-like star every Porb = 3.7 days. Qatar-9b is a hot Jupiter with a mass of ... More
The Sizes and Depletions of the Dust and Gas Cavities in the Transitional Disk J160421.7-213028Jan 18 2017Jan 28 2017We report ALMA Cycle 2 observations of 230 GHz (1.3 mm) dust continuum emission, and $^{12}$CO, $^{13}$CO, and C$^{18}$O J = 2-1 line emission, from the Upper Scorpius transitional disk [PZ99] J160421.7-213028, with an angular resolution of ~0".25 (35 ... More
A Possible Tilted Orbit of the Super-Neptune HAT-P-11bSep 28 2010We report the detection of the Rossiter-McLaughlin effect for the eccentric, super-Neptune exoplanet HAT-P-11b, based on radial velocity measurements taken with HDS mounted on the Subaru 8.2m telescope, and simultaneous photometry with the FTN 2.0m telescope, ... More
Multi-Object and Long-Slit Spectroscopy of Very Low Mass Brown Dwarfs in Orion Nebular ClusterOct 30 2013Jan 09 2014We present the results of a H- and K-band multi-object and long-slit spectroscopic survey of substellar mass candidates in the outer regions of the Orion Nebula Cluster. The spectra were obtained using MOIRCS on the 8.2-m Subaru telescope and ISLE on ... More
Polarization in young open cluster NGC 6823Dec 21 2009We present multiwavelength linear polarimetric observations of 104 stars towards the region of young open cluster NGC 6823. The polarization towards NGC 6823 is dominated by foreground dust grains and we found the evidence for the presence of several ... More
Flared Disks and Silicate Emission in Young Brown DwarfsApr 28 2004We present mid-infrared photometry of three very young brown dwarfs located in the $\rho$ Ophiuchi star-forming region -- GY5, GY11 and GY310 --obtained with the Subaru 8-meter telescope. All three sources were detected at 8.6 and 11.7$\mu$m, confirming ... More
Distortion of Magnetic Fields in a Starless Core III: Polarization--Extinction Relationship in FeSt 1-457Mar 22 2018The relationship between dust polarization and extinction was determined for the cold dense starless molecular cloud core FeSt 1-457 based on the background star polarimetry of dichroic extinction at near-infrared wavelengths. Owing to the known (three-dimensional) ... More
Substellar Objects in Nearby Young Clusters (SONYC): The bottom of the Initial Mass Function in NGC1333Jul 13 2009SONYC -- Substellar Objects in Nearby Young Clusters -- is a survey program to investigate the frequency and properties of substellar objects with masses down to a few times that of Jupiter in nearby star-forming regions. Here we present the first results ... More
Interstellar Extinction Law toward the Galactic Center III: J, H, Ks bands in the 2MASS and the MKO systems, and 3.6, 4.5, 5.8, 8.0 micron in the Spitzer/IRAC systemFeb 18 2009We have determined interstellar extinction law toward the Galactic center (GC) at the wavelength from 1.2 to 8.0 micron, using point sources detected in the IRSF/SIRIUS near-infrared survey and those in the 2MASS and Spitzer/IRAC/GLIMPSE II catalogs. ... More
Disks around massive young stellar objects: are they common?Jan 08 2008We present K-band polarimetric images of several massive young stellar objects at resolutions $\sim$ 0.1-0.5 arcsec. The polarization vectors around these sources are nearly centro-symmetric, indicating they are dominating the illumination of each field. ... More
Subaru/SCExAO First-Light Direct Imaging of a Young Debris Disk around HD 36546Jan 09 2017Jan 16 2017We present $H$-band scattered light imaging of a bright debris disk around the A0 star HD 36546 obtained from the Subaru Coronagraphic Extreme Adaptive Optics (SCExAO) system with data recorded by the HiCIAO camera using the vector vortex coronagraph. ... More
Further Observations of the Tilted Planet XO-3: A New Determination of Spin-Orbit Misalignment, and Limits on Differential RotationAug 23 2011Oct 05 2011We report on observations of the Rossiter-McLaughlin (RM) effect for the XO-3 exoplanetary system. The RM effect for the system was previously measured by two different groups, but their results were statistically inconsistent. To obtain a decisive result ... More
Extrasolar Transiting Planet Search with Subaru Suprime-CamMar 14 2006We report the results of a prototype photometric search for transiting extrasolar planets using Subaru Suprime-Cam. Out of about 100,000 stars monitored around the Galactic plane (l=90 degree,b=0 degree), we find that 7,700 (27,000) stars show the photometric ... More
The Distance to the Galactic Center Derived From Infrared Photometry of Bulge Red Clump StarsJul 18 2006On the basis of the near infrared observations of bulge red clump stars near the Galactic center, we have determined the galactocentric distance to be R_0 = 7.52 +- 0.10 (stat) +- 0.35 (sys) kpc. We observed the red clump stars at |l| < 1.0 deg and 0.7 ... More
A Tail Structure Associated with Protoplanetary Disk around SU AurigaeFeb 27 2019We present Atacama Large Millimeter/submillimeter Array (ALMA) observations of the CO ($J$=2--1) line emission from the protoplanetary disk around T-Tauri star SU Aurigae (hereafter SU Aur). Previous observations in optical and near infrared wavelengths ... More
SCExAO/CHARIS Near-Infrared Direct Imaging, Spectroscopy, and Forward-Modeling of kappa And b: A Likely Young, Low-Gravity Superjovian CompanionOct 22 2018We present SCExAO/CHARIS high-contrast imaging/$JHK$ integral field spectroscopy of $\kappa$ And b, a directly-imaged low-mass companion orbiting a nearby B9V star. We detect $\kappa$ And b at a high signal-to-noise and extract high precision spectrophotometry ... More
The Rossiter-McLaughlin Effect of the Transiting Exoplanet XO-4bAug 23 2010We report photometric and radial velocity observations of the XO-4 transiting planetary system, conducted with the FLWO 1.2m telescope and the 8.2m Subaru Telescope. Based on the new light curves, the refined transit ephemeris of XO-4b is $P = 4.1250828 ... More
SUBARU Near-Infrared Multi-Color Images of Class II Young Stellar Object, RNO91Sep 05 2007We conducted sub-arcsecond near-infrared imaging observations of RNO91 with CIAO mounted on the SUBARU 8.2 m telescope. We present our JHK band data along with optical images, which when considered together reveal a complex circumstellar structure. We ... More
Near-Infrared Imaging Polarimetry of the Serpens Cloud Core: Magnetic Field Structure, Outflows, and Inflows in A Cluster Forming ClumpApr 20 2010We made deep NIR imaging polarimetry toward the Serpens cloud core. The polarization vector maps enable us to newly detect 24 small IR reflection nebulae with YSOs. Polarization measurements of NIR point sources indicate an hourglass-shaped magnetic field, ... More
A near-infrared survey of Miras and the distance to the Galactic CentreJul 16 2009We report the results of a near-infrared survey for long-period variables in a field of view of 20 arcmin by 30 arcmin towards the Galactic Centre (GC). We have detected 1364 variables, of which 348 are identified with those reported in Glass et al. (2001). ... More
High-Resolution Transit Spectroscopy of Warm SaturnsDec 06 2018We present high-resolution optical transmission spectroscopy of two sub-Saturn mass transiting exoplanets, HAT-P-12b and WASP-69b. With relatively low densities and high atmospheric scale heights, these planets are particularly well-suited to characterization ... More
Distortion of Magnetic Fields in a Starless Core II: 3D Magnetic Field Structure of FeSt 1-457Sep 13 2017Oct 15 2017Three dimensional (3D) magnetic field information on molecular clouds and cores is important for revealing their kinematical stability (magnetic support) against gravity which is fundamental for studying the initial conditions of star formation. In the ... More
Magnetic stability of massive star forming clumps in RCW 106Apr 12 2019The RCW~106 molecular cloud complex is an active massive star-forming region where a ministarburst is taking place. We examined its magnetic structure by near-IR polarimetric observations with the imaging polarimeter SIRPOL on the IRSF 1.4 m telescope. ... More
Near-Infrared Imaging Polarimetry of S106 Cluster-Forming Region with SIRPOLNov 20 2008We present the results of wide-field JHKs polarimetry toward the HII region S106 using the IRSF (Infrared Survey Facility) telescope. Our polarimetry data revealed an extended (up to ~ 5') polarized nebula over S106. We confirmed the position of the illuminating ... More
Lowest Earth's atmosphere layers probed during a lunar eclipseJun 24 2018Oct 21 2018We report the results of detailed investigation of the Earth's transmission spectra during the lunar eclipse on UT 2011 December 10. The spectra were taken by using the High Dispersion Spectrograph (HDS) mounted on the Subaru 8.2 m telescope with unprecedented ... More
Near-Infrared Spectroscopy of the Cool Brown Dwarf, SDSS 1624+00Dec 28 1999Using the Subaru Telescope, we have obtained multiple near-infrared spectra of the cool brown dwarf, SDSS 1624+00, in search of spectral variability in an 80 minute time span. We have found the suspected variability of water vapor absorption throughout ... More
Imaging Giant Protoplanets with the ELTsMar 13 2019We have now accumulated a wealth of observations of the planet-formation environment and of mature planetary systems. These data allow us to test and refine theories of gas-giant planet formation by placing constraints on the conditions and timescale ... More
Scattering and Trapping of Nonlinear Schroedinger Solitons in External PotentialsJan 20 2004Soliton motion in some external potentials is studied using the nonlinear Schr\"odinger equation. Solitons are scattered by a potential wall. Solitons propagate almost freely or are trapped in a periodic potential. The critical kinetic energy for reflection ... More
Observational Test of Environmental Effects on The Local Group Dwarf Spheroidal GalaxiesSep 01 1999In this paper, we examine whether tidal forces exerted by the Galaxy or M31 have an influence on the Local Group dwarf spheroidal galaxies (dSphs) which are their companions. We focus on the surface brightness profiles of the dSphs, especially their core ... More
Large Deviation Principle for Non-Interacting Boson Random Point ProcessesSep 05 2009Limit theorems, including the large deviation principle, are established for random point processes (fields), which describe the position distributions of the perfect boson gas in the regime of the Bose-Einstein condensation. We compare these results ... More
Quantum Annealing and Quantum Fluctuation Effect in Frustrated Ising SystemsFeb 27 2012Quantum annealing method has been widely attracted attention in statistical physics and information science since it is expected to be a powerful method to obtain the best solution of optimization problem as well as simulated annealing. The quantum annealing ... More
Interlayer-Interaction Dependence of Latent Heat in the Heisenberg Model on a Stacked Triangular Lattice with Competing InteractionsAug 12 2013Nov 21 2013We study the phase transition behavior of a frustrated Heisenberg model on a stacked triangular lattice by Monte Carlo simulations. The model has three types of interactions: the ferromagnetic nearest-neighbor interaction $J_1$ and antiferromagnetic third ... More
Dynamical properties of Potts model with invisible statesDec 20 2010We study dynamic behavior of Potts model with invisible states near the first-order phase transition temperature. We focus on melting process starting from the perfect ordered state. This model is regarded as a standard model to analyze nature of phase ... More
Near-Infrared Imaging Polarimetry of M42: Aperture Polarimetry of Point-like SourcesJul 09 2008We have conducted aperture polarimetry of ~500 stars of the Orion Nebula Cluster (ONC) in M42 based on our wide-field (~8'\times 8') $JHKs$ band polarimetry. Most of the near-infrared (NIR) polarizations are dichroic, with position angles of polarization ... More
Near-Infrared Circular Polarization Survey in Star-Forming Regions: Correlations and TrendsOct 11 2014We have conducted a systematic near-infrared circular polarization (CP) survey in star-forming regions, covering high-mass, intermediate-mass, and low-mass young stellar objects. All the observations were made using the SIRPOL imaging polarimeter on the ... More
MuSCAT: a multicolor simultaneous camera for studying atmospheres of transiting exoplanetsSep 10 2015We report a development of a multi-color simultaneous camera for the 188cm telescope at Okayama Astrophysical Observatory in Japan. The instrument, named MuSCAT, has a capability of 3-color simultaneous imaging in optical wavelength where CCDs are sensitive. ... More
Direct detection and spectral characterization of outer exoplanets with the SPICA coronagraph instrument (SCI)Mar 13 2011The SPICA coronagraph instrument (SCI) provides high-contrast imaging and moderate resolution (R < 200) spectroscopy at the wavelength range from 3.5 to 27 \mu m. Based on the planet evolutional model calculated by Burrows et al. (2003), SCI will search ... More
New Galactic Star Clusters Discovered in the VVV SurveyJun 15 2011VISTA Variables in the V\'{\i}a L\'actea (VVV) is one of the six ESO Public Surveys operating on the new 4-meter Visible and Infrared Survey Telescope for Astronomy (VISTA). VVV is scanning the Milky Way bulge and an adjacent section of the disk, where ... More
H band Image of a Planetary Companion around HR 8799 in 2002Mar 11 2009The discovery of three planetary companions around HR 8799 (Marois et al. 2008) marked a significant epoch in direct imaging of extrasolar planets. Given the importance of this system, we re-analyzed H band images of HR 8799 obtained with the Subaru 36-elements ... More
Planets Around Low-Mass Stars (PALMS). I. A Substellar Companion to the Young M Dwarf 1RXS J235133.3+312720May 09 2012We report the discovery of a brown dwarf companion to the young M dwarf 1RXS J235133.3+312720 as part of a high contrast imaging search for planets around nearby young low-mass stars with Keck-II/NIRC2 and Subaru/HiCIAO. The 2.4" (~120 AU) pair is confirmed ... More
Cepheids and other short-period variables near the Galactic CentreNov 01 2012We report the result of our near-infrared survey of short-period variable stars (P<60d) in a field-of-view of 20'x30' towards the Galactic Centre. Forty-five variables are discovered and we classify the variables based on their light curve shapes and ... More
X-ray Emitting Young Stars in the Carina NebulaMar 02 2006We present a multiwavelength study of the central part of the Carina Nebula, including Trumpler 16 and part of Trumpler 14. Analysis of the Chandra X-ray Observatory archival data led to the identification of nearly 450 X-ray sources. These were then ... More
On-sky speckle nulling demonstration at small angular separation with SCExAOMay 05 2014This paper presents the first on-sky demonstration of speckle nulling, which was achieved at the Subaru Telescope in the context of the Subaru Coronagraphic Extreme Adaptive Optics (SCExAO) Project. Despite the absence of a high-order high-bandwidth closed-loop ... More
Interferometric Observations of the T Tauri Stars in the MBM 12 CloudFeb 24 2003We have carried out a millimeter interferometric continuum survey toward 7 YSOs in the MBM 12 cloud. Thermal emissions associated with 2 YSOs were detected above the 3-$\sigma$ level at 2.1 mm, and one also showed a 1.3 mm thermal emission. Another object ... More
Probable association of T Tauri stars with the L1014 dense coreAug 23 2006Oct 16 2006Using the Wide Field Grism Spectrograph 2 (WFGS2), we have carried out slit-less spectroscopy, g'r'i' photometry, and slit spectroscopy on the L1014 dense core. We detected three Halpha emission line stars. We interpret one as weak-line T Tauri star (WTTS) ... More