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Radiation-pressure-driven dust transport to galaxy halos at $z\sim 10$May 14 2019The origin of dust in galaxy halos or in the circum-galactic medium (CGM) is still a mystery. We investigate if the radiation pressure in high-redshift ($z\sim 10$) galaxies can efficiently transport dust to halos. To clarify the first dust enrichment ... More

Revisiting the Cosmic Star Formation History: Caution on the Uncertainties in Dust Correction and Star Formation Rate ConversionAug 02 2012Jan 09 2013The cosmic star formation rate density (CSFRD) has been observationally investigated out to redshift z~10. However, most of theoretical models for galaxy formation underpredict the CSFRD at z>1. Since the theoretical models reproduce the observed luminosity ... More

Effects of dust scattering albedo and 2175 A bump on ultraviolet colours of normal disc galaxiesMay 06 2006We discuss dust properties in the interstellar medium (ISM) of nearby normal galaxies, by comparing observations in the ultraviolet (UV) with simulations by a radiative transfer model. The observed UV colours of nearby galaxies show a reddening relative ... More

Dust formation history of galaxies: a critical role of metallicity for the dust mass growth by accreting materials in the interstellar mediumJun 05 2012This paper investigate what is the main driver of the dust mass growth in the interstellar medium (ISM) by using a chemical evolution model of galaxy with metals (elements heavier than helium) in dust phase in addition to the total amount of metals. We ... More

Imaging of diffuse HI absorption structure in the SSA22 proto-cluster region at z = 3.1Jan 10 2017Using galaxies as background light sources to map intervening Lya absorption is a novel approach to study the interplay among galaxies, the circum-galactic medium (CGM), and the intergalactic medium (IGM). Introducing a new measure of z = 3.1$ HI Lya ... More

Lyman `bump' galaxies - II. A possible signature of massive extremely metal-poor or metal-free stars in z=3.1 Ly-alpha emittersOct 13 2010(Abridged) Deep NB359 imaging with Subaru by Iwata et al. have detected surprisingly strong Lyman continuum (LyC; ~900A in the rest-frame) from some LAEs at z=3.1. However, the redshifts might be misidentified due to a narrow wavelength coverage in previous ... More

Evolution of Dust-to-Metal Ratio in GalaxiesAug 12 2003This paper investigates the evolution of the dust-to-metal ratio in galaxies based on a simple evolution model for the amount of metal and dust with infall. We take into account grain formation in stellar mass-loss gas, grain growth by the accretion of ... More

Competition between dust scattering albedo and 2175 A bump for ultraviolet colours of nearby disc galaxiesMay 06 2006Observed ultraviolet (UV) colours of nearby disc galaxies show a reddening relative to their expected intrinsic colours. Since the 2175 \AA bump found in the Milky Way's dust extinction law blues the UV colours, it might suggest that dust in nearby disc ... More

Star Formation Rate from Dust Infrared EmissionApr 13 2002We examine what types of galaxies the conversion formula from dust infrared (IR) luminosity into the star formation rate (SFR) derived by Kennicutt (1998) is applicable to. The ratio of the observed IR luminosity, $L_{\rm IR}$, to the intrinsic bolometric ... More

Spatial Distribution of Dust Grains within H II RegionsJan 22 2002We discuss the dust distribution within photoionized regions. Assuming a geometry with a central dust cavity, which is strongly suggested by the literature, we can estimate the cavity's radius from the ratio of the infrared and radio fluxes by using a ... More

Lyman Continuum Extinction by Dust in H {\sc ii} Regions of GalaxiesJun 28 2001We examine Lyman continuum extinction (LCE) in H II regions by comparing infrared fluxes of 49 H II regions in the Galaxy, M31, M33, and the LMC with estimated production rates of Lyman continuum photons. A typical fraction of Lyman continuum photons ... More

Lyman "bump" galaxies - I. Spectral energy distribution of galaxies with an escape of nebular Lyman continuumAug 27 2009Sep 18 2009It is essential to know galactic emissivity and spectrum of Lyman continuum (LyC) in order to understand the cosmic reionization. Here we consider an escape of nebular LyC from galaxies and examine the consequent spectral energy distribution. It is usually ... More

A possible signature of primordial stellar populations in $z=3$ Lyman $α$ emittersJun 20 2012Observations with Subaru telescope have detected surprisingly strong Lyman continuum (LyC; $\sim900$ \AA\ in the rest-frame) from some Lyman $\alpha$ emitters (LAEs) at $z=3.1$. We have examined the stellar population which simultaneously accounts for ... More

Attenuation law of normal disc galaxies with clumpy distributions of stars and dustFeb 03 2005We investigate the attenuation law seen through an interstellar medium (ISM) with clumpy spatial distributions of stars and dust. The clumpiness of the dust distribution is introduced by a multi-phase ISM model. We solve a set of radiative transfer equations ... More

The origin of dust in galaxies revisited: the mechanism determining dust contentFeb 14 2012The origin of cosmic dust is a fundamental issue in planetary science. This paper revisits the origin of dust in galaxies, in particular, in the Milky Way, by using a chemical evolution model of a galaxy composed of stars, interstellar medium, metals ... More

Rest-frame ultraviolet-to-optical spectral characteristics of extremely metal-poor and metal-free galaxiesFeb 25 2011Apr 14 2011Finding the first generation of galaxies in the early Universe is the greatest step forward for understanding galaxy formation and evolution. For strategic survey of such galaxies and interpretation of the obtained data, this paper presents an ultraviolet-to-optical ... More

Hubble Space Telescope Wide Field Camera 3 Observations of Escaping Lyman Continuum Radiation from Galaxies and Weak AGN at Redshifts $z$$\,\simeq\,$2.3-4.1Feb 04 2016Dec 21 2017We present observations of escaping Lyman Continuum (LyC) radiation from 34 massive star-forming galaxies and 12 weak AGN with reliably measured spectroscopic redshifts at $z$$\simeq$2.3-4.1. We analyzed Hubble Space Telescope Wide Field Camera 3 (WFC3) ... More

Amount of intergalactic dust: constraints from distant supernovae and thermal history of intergalactic mediumOct 15 2003Jan 30 2004This paper examines the allowed amount of IG (intergalactic) dust, which is constrained by extinction and reddening of distant SNe and thermal history of IGM (intergalactic medium) affected by dust photoelectric heating. Based on the observational cosmic ... More

The Effect of the Remnant Mass in Estimating Stellar Mass of GalaxiesOct 03 2013The definition of the galactic stellar mass estimated from the spectral energy distribution is ambiguous in the literature; whether the stellar mass includes the mass of the stellar remnants, i.e. white dwarfs, neutron stars, and black holes, is not well ... More

A Monte Carlo simulation of the intergalactic absorption and the detectability of the Lyman continuum from distant galaxiesApr 18 2008We have made a Monte Carlo simulation of the intergalactic absorption in order to model the Lyman continuum absorption, which is required to estimate the escape fraction of the Lyman continuum from distant galaxies. To input into the simulation, we derive ... More

Constraint on intergalactic dust from thermal history of intergalactic mediumDec 06 2002Mar 13 2003This Letter investigates the amount of dust in the intergalactic medium (IGM). The dust photoelectric heating can be the most efficient heating mechanism in the IGM where the density is very small and there are a lot of hard ultraviolet photons. Comparing ... More

Disentangling the physical parameters of gaseous nebulae and galaxiesDec 17 2018We present an analysis to disentangle the connection between physical quantities that characterize the conditions of ionized HII regions -- metallicity ($Z$), ionization parameter ($U$), and electron density ($n_\mathrm{e}$) -- and the global stellar ... More

Intergalactic dust and its photoelectric heatingOct 31 2008We have examined the dust photoelectric heating in the intergalactic medium (IGM). The heating rate in a typical radiation field of the IGM is represented by $\Gamma_{\rm pe} = 1.2\times10^{-34}$ erg s$^{-1}$ cm$^{-3}$ $({\cal D}/10^{-4})(n_{\rm H}/10^{-5} ... More

Homogeneous and heterogeneous nucleation of skyrmions in thin layers of cubic helimagnetsMay 14 2018Formation of isolated chiral skyrmions by homogeneous and heterogeneous nucleation has been studied in thin layers of cubic helimagnets via elongation of torons and chiral bobbers, correspondingly. Both torons and bobbers are localized in three dimensions, ... More

The critical radiation intensity for direct collapse black hole formation: dependence on the radiation spectral shapeJul 15 2014It has been proposed that supermassive black holes (SMBHs) are originated from direct-collapse black holes (DCBHs) that are formed at z gtrsim 10 in the primordial gas in the case that H2 cooling is suppressed by strong external radiation. In this work, ... More

Detection of the Far-infrared [O III] and Dust Emission in a Galaxy at Redshift 8.312: Early Metal Enrichment in the Heart of the Reionization EraJun 11 2018Feb 11 2019We present the Atacama Large Millimeter/submillimeter Array (ALMA) detection of the [O III] 88 $\mu$m line and rest-frame 90 $\mu$m dust continuum emission in a Y-dropout Lyman break galaxy (LBG), MACS0416_Y1, lying behind the Frontier Field cluster MACS ... More

SILVERRUSH. V. Census of Lya, [OIII]5007, Ha, and [CII]158um Line Emission with ~1000 LAEs at z=4.9-7.0 Revealed with Subaru/HSCNov 10 2017May 09 2018We investigate Lya, [OIII]5007, Ha, and [CII]158um emission from 1124 galaxies at z=4.9-7.0. Our sample is composed of 1092 Lya emitters (LAEs) at z=4.9, 5.7, 6.6, and 7.0 identified by Subaru/Hyper Suprime-Cam (HSC) narrowband surveys covered by Spitzer ... More

Effects of scattering and dust grain size on the temperature structure of protoplanetary discs: A three-layer approachDec 03 2008The temperature in the optically thick interior of protoplanetary discs is essential for the interpretation of millimeter observations of the discs, for the vertical structure of the discs, for models of the disc evolution and the planet formation, and ... More

Star Formation Efficiency in the Central 1 kpc Region of Early-Type Spiral GalaxiesJul 20 2000It has been reported recently that there are some early-type spiral (Sa--Sab) galaxies having evident star-forming regions which concentrate in their own central 1-kpc. In such central region, is the mechanism of the star formation distinct from that ... More

Near-Infrared Colors of Gamma-Ray Burst Afterglows and Cosmic Reionization HistoryAug 12 2003Oct 06 2003Using the near-infrared (NIR) observations of the afterglows of the high redshift ($5 \la z \la 25$) gamma-ray bursts (GRBs) which will be detected by the {\it Swift} satellite, we discuss a way to study the cosmic reionization history. In principle the ... More

Star formation rate in galaxies from UV, IR, and H-alpha estimatorsAug 29 2003Infrared (IR) luminosity of galaxies originating from dust emission can be used as an indicator of the star formation rate (SFR). Inoue et al. (2000, IHK) have derived a formula for the conversion from IR luminosity to SFR by using the following three ... More

Lyman continuum leaking AGN in the SSA22 fieldApr 01 2016Jun 17 2016Subaru/SuprimeCam narrowband photometry of the SSA22 field reveals the presence of four Lyman continuum (LyC) candidates among a sample of 14 AGN. Two show offsets and likely have stellar LyC in nature or are foreground contaminants. The remaining two ... More

Effect of Dust Extinction on Estimating Star Formation Rate of Galaxies: Lyman Continuum ExtinctionMar 15 2001We re-examine the effect of Lyman continuum ($\lambda \leq 912$ \AA) extinction (LCE) by dust in H {\sc ii} regions in detail and discuss how it affects the estimation of the global star formation rate (SFR) of galaxies. To clarify the first issue, we ... More

Nonmesonic weak decay of light hypernuclei with coherent $Σ$ mixingApr 24 2002Nonmesonic weak decays of the A=4, and 5 hypernuclei are studied. The short range parts of the hyperon-nucleon weak interactions are described by the direct quark (DQ) weak transition potential, while the longer range interactions are given by the $\pi$ ... More

The formation of a Spitzer bubble RCW79 triggered by cloud-cloud collisionSep 07 2017Feb 15 2018Understanding the mechanism of O star formation is one of the most important issues in current astrophysics. It is also an issue of keen interest how O stars affect their surroundings and trigger secondary star formation. An H\,\emissiontype{II} region ... More

Ribbonness of a stable-ribbon surface-link, I. A stably trivial surface-linkApr 08 2018Jun 19 2018There is a question asking whether a handle-irreducible summand of every stable-ribbon surface-link is a unique ribbon surface-link. This question is positively answered for the case of a stably trivial surface-link. That is, a handle-irreducible summand ... More

Elliptic genera, torus orbifolds and multi-fans; IIJan 23 2005Feb 11 2005This article is a continuation of SG/0107014. Some vanishing theorems for orbifold elliptic genus of level N for multi-fans are proved. As an application, complete Q-factorial toric varieties whose canonical divisors are divisible by their dimesion in ... More

Triviality of a surface-link with meridian-based free fundamental groupApr 12 2018It is proved that every disconnected surface-link with meridian-based free fundamental group is a trivial (i.e., an unknotted-unlinked) surface-link. This result is a surface-link version of the author's recent result on smooth unknotting of a surface-knot. ... More

Splitting criteria for a definite 4-manifold with infinite cyclic fundamental groupApr 04 2018Two criteria for a closed connected definite 4-manifold with infinite cyclic fundamental group to be TOP-split are given. One criterion extends a sufficient condition made in a previous paper. The result is equivalent to a purely algebraic result on the ... More

Nebular line emission from z > 7 galaxies in cosmological simulations: rest-frame UV to Optical linesSep 02 2015Jun 11 2016We have performed very large and high resolution cosmological hydrodynamic simulations in order to investigate detectability of nebular lines in the rest-frame ultraviolet (UV) to optical wavelength range from galaxies at $z > 7$. We find that the expected ... More

Effect of Photodesorption on Snow Line at the Surface of Optically Thick Circumstellar Disks around Herbig Ae/Be StarsJan 10 2012We investigate the effect of photodesorption on the snow line position at the surface of a protoplanetary disk around a Herbig Ae/Be star, motivated by the detection of water ice particles at the surface of the disk around HD142527 by Honda et al. For ... More

Escape fraction of ionizing photons from galaxies at z=0--6May 20 2006The escape fraction of ionizing photons from galaxies is a crucial quantity controlling the cosmic ionizing background radiation and the reionization. Various estimates of this parameter can be obtained in the redshift range, z=0--6, either from direct ... More

Observational Possibility of the "Snow Line" on the Surface of Circumstellar Disks with the Scattered LightFeb 07 2008We discuss how we obtain the spatial distribution of ice on the surface of the circumstellar disk around young stars. Ice in the disks plays a very important role in various issues, for instance, on the disk structure, on the planet formation, on the ... More

An updated analytic model for the attenuation by the intergalactic mediumFeb 04 2014May 12 2014We present an updated version of the so-called Madau model for the attenuation by the intergalactic neutral hydrogen against the radiation from distant objects. First, we derive a distribution function of the intergalactic absorbers from the latest observational ... More

Physical Properties of UDF12 Galaxies in Cosmological simulationsOct 01 2013Jan 15 2014We have performed a large cosmological hydrodynamics simulation tailored to the deep survey with the Hubble Space Telescope made in 2012, the so-called UDF12 campaign. After making a light-cone output, we have applied the same color selection criteria ... More

A Suzaku View of Accretion Powered X-ray Pulsar GX 1+4Oct 13 2017Oct 16 2017We present results obtained from a Suzaku observation of the accretion powered X-ray pulsar GX 1+4. Broad-band continuum spectrum of the pulsar was found to be better described by a simple model consisting of a blackbody component and an exponential cutoff ... More

Roles of Quarks in Strong and Weak YN InteractionsNov 10 1998The short range parts of the strong and weak hyperon-nucleon interactions are studied with quark substructure of the baryons taken into account. A summary of the quark cluster model calculations of the baryon-baryon interactions is presented. It is pointed ... More

Upstream reciprocity in heterogeneous networksMay 25 2009May 29 2010Many mechanisms for the emergence and maintenance of altruistic behavior in social dilemma situations have been proposed. Indirect reciprocity is one such mechanism, where other-regarding actions of a player are eventually rewarded by other players with ... More

A refined version of Grothendieck's anabelian conjecture for hyperbolic curves over finite fieldsAug 28 2017In this paper we prove a refined version of a theorem by Tamagawa and Mochizuki on isomorphisms between (tame) arithmetic fundamental groups of hyperbolic curves over finite fields, where one "ignores" the information provided by a "small" set of primes. ... More

Hawking radiation from a collapsing dust sphere and its back reaction at the event horizon -Weak value approach-May 01 2012Mar 16 2013To see the back reaction of the Hawking radiation in a dynamical spacetime of the spherical gravitational collapse, we explicitly calculate the weak value of the energy-momentum tensor of the massless scalar field. The background geometry of a collapsing ... More

Weak Values as Context Dependent Values of Observables and Born's RuleApr 11 2011Sep 08 2011We characterize a value of an observable by a `sum rule' for generally non-commuting observables and a `product rule' when restricted to a maximal commuting subalgebra of observables together with the requirement that the value is unity for the projection ... More

Arithmetic of abelian varieties with constrained torsionFeb 06 2013Let $K$ be a number field. We present several new finiteness results for isomorphism classes of abelian varieties over $K$ whose $\ell$-power torsion fields are arithmetically constrained for some rational prime $\ell$. Such arithmetic constraints are ... More

Cyclic covers and Ihara's QuestionMar 22 2018Let $\ell$ be a rational prime and $k$ a number field. Given a superelliptic curve $C/k$ of $\ell$-power degree, we describe the field generated by the $\ell$-power torsion of the Jacobian variety in terms of the branch set and reduction type of $C$ (and ... More

ASCA PV observations of the Seyfert 1 galaxy MCG-6-30-15 : rapid variability of the warm absorberJun 14 1995We present a detailed re-analysis of the two {\it ASCA} Performance Verification observations of the nearby Seyfert 1 galaxy MCG-6-30-15. Confirming the results of Fabian et al. (1994), we find definite evidence for the {\sc O\,vii} and {\sc O\,viii} ... More

X-ray absorption and rapid variability of the dwarf Seyfert nucleus of NGC4395Jun 29 2000We report the detection of an absorbed central X-ray source and its strong, rapid variability in NGC4395, the least luminous Seyfert nucleus known. The X-ray source exhibits a number of flares with factors of 3-4 flux changes during a half day ASCA observation. ... More

Primordial star clusters at extreme magnificationNov 24 2014Mar 10 2015Gravitationally lensed galaxies with magnification ~10-100 are routinely detected at high redshifts, but magnifications significantly higher than this are hampered by a combination of low probability and large source sizes. Magnifications of ~1000 may ... More

Detections of [OIII] 88 $μ$m in Two Quasars in the Reionization EpochOct 31 2018With the Atacama Large Millimeter/sub-millimeter Array (ALMA), we report detections of the far-infrared (FIR) [OIII] 88 $\mu$m line and the underlying dust continuum in the two quasars in the reionization epoch, J205406.48-000514.8 (hereafter J2054-0005) ... More

Searching for candidates of Lyman continuum sources - revisiting the SSA22 fieldSep 14 2015Oct 14 2016We present the largest to date sample of hydrogen Lyman continuum (LyC) emitting galaxy candidates at any redshift, with 18 Ly$\alpha$ Emitters (LAEs) and 7 Lyman Break Galaxies (LBGs), obtained from the SSA22 field with Subaru/Suprime-Cam. The sample ... More

ALMA will determine the spectroscopic redshift z>8 with FIR [O III] emission linesDec 03 2013We investigate the potential use of nebular emission lines in the rest-frame far-infrared (FIR) for determining spectroscopic redshift of z>8 galaxies with the Atacama Large Millimeter/sub-millimeter Array (ALMA). After making a line emissivity model ... More

Reexamination of the Infrared Excess-Ultraviolet Slope Relation of Local GalaxiesJun 18 2012The relation between the ratio of infrared (IR) and ultraviolet (UV) flux densities (the infrared excess: IRX) and the slope of the UV spectrum (\beta) of galaxies plays a fundamental role in the evaluation of the dust attenuation of star forming galaxies ... More

VLBI Monitoring of 3C 84 in Gamma-ray Active PhaseJun 11 2010We report multi-epoch Very Long Baseline Interferometry (VLBI) study of the innermost jet of 3C 84. We carried out 14-epoch VLBI observations during 2006-2009 with the Japanese VLBI Network (JVN) and the VLBI Exploration of Radio Astrometry (VERA), immediately ... More

Strange Nuclear Physics from QCD on LatticeSep 21 2018We study single-particle potential of Lambda, Sigma, and Xi hyperons in nucleonic matter starting from the fundamental theory of the strong interaction, QCD. First we carry out a lattice QCD numerical simulation, and extract baryon-baryon interactions ... More

Data Augmentation by Pairing Samples for Images ClassificationJan 09 2018Apr 11 2018Data augmentation is a widely used technique in many machine learning tasks, such as image classification, to virtually enlarge the training dataset size and avoid overfitting. Traditional data augmentation techniques for image classification tasks create ... More

General theory of regular biorthogonal pairs and its physical applicationsApr 07 2016Apr 17 2016In this paper we introduce a general theory of regular biorthogonal sequences and its physical applications. Biorthogonal sequences $\{ \phi_{n} \}$ and $\{ \psi_{n} \}$ in a Hilbert space ${\cal H}$ are said to be regular if $Span\; \{ \phi_{n} \}$ and ... More

Expansion of Dirichlet L-function on the critical line in Meixner-Pollaczek polynomialsDec 03 2014We study the expansions of the completed Riemann zeta function and completed Dirichlet L-functions in Meixner-Pollaczek polynomials. We give the proof of the uniform convergence, the multiplicative structure for the coefficients of these expansions, and ... More

Semi-regular biorthogonal pairs and generalized Riesz basesAug 14 2016In this paper we define the notion of semi-regular biorthogonal pairs what is a generalization of regular biorthogonal pairs in Ref. \cite{hiroshi1} and show that if $(\{ \phi_{n} \} , \{ \psi_{n} \})$ is a semi-regular biorthogonal pair, then $\{ \phi_{n} ... More

Bell-Instability-Mediated Spectral Modulation of Hadronic Gamma Rays from a Supernova Remnant Interacting with a Molecular CloudFeb 13 2019Supernova remnants (SNRs) are believed to be the site of galactic cosmic-ray acceleration. However, the details of the cosmic-ray acceleration are still not well understood. Gamma ray observation is a promising method to study cosmic-ray acceleration ... More

Pion-nucleon P_33 and P_11 scatterings in the Lippmann-Schwinger approachOct 16 2007We study the pion-nucleon P_33 and P_11 scattering, where the Delta and the Roper resonances are seen, respectively. We use the Lippmann-Schwinger equation extended to couple to a one-body state, and investigate nature of these resonances by taking and ... More

East Asian VLBI ActivitiesDec 30 2004The VLBI activities in the East Asia region are planning to coordinate among VLBI groups and institutes in China, Japan, and Korea. In these countries, some new projects are going to start or discussed, and some types of collaboration have been already ... More

The Zeta function, Periodic Points and Entropies of the Motzkin ShiftFeb 06 2006Jan 12 2010We discuss a method of calculating the zeta function of subshifts which have a presentation by a finite directed graph labeled by elements of the associated inverse semigroup. This class of subshifts is introduced as a class of property A subshifts(T.Hamachi, ... More

Definition and characterization of supersmooth functions on superspace based on Fréchet-Grassmann algebraOct 20 2009Sep 29 2014Preparing the Fr\'echet-Grassmann (FG-)algebra ${\fR}$ composed with countably infinite Grassmann generators, we introduce the superspace ${\fR}^{m|n}$. After defining Grassmann continuation of smooth functions on ${\euc}^m$ to those on ${\fR}^{m|0}$, ... More

Field Effect Transistor Based on KTaO3 PerovskiteDec 12 2003An n-channel accumulation-type field effect transistor (FET) has been fabricated utilizing a KTaO3 single crystal as an active element and a sputtered amorphous Al2O3 film as a gate insulator. The device demonstrated an ON/OFF ratio of 10^4 and a field ... More

Real-space renormalization group study of the anisotropic antiferromagnetic Heisenberg model of spin S=1 on a honeycomb latticeMar 06 2005Mar 09 2005The real-space RG approach is applied to study critical temperatures of system consisting of interacting spin chains of spin S=1 with an inner antiferromagnetic exchange which form a honeycomb crystal lattice. Using anisotropic Heisenberg model we calculate ... More

Magnetic hysteresis in a molecular Ising ferrimagnet: Glauber dynamics approachJul 08 2009Motivated by recent experimental results reporting giant coercive fields in Co(II)-based molecular magnets we present a theory of hysteresis phenomena based on the Glauber stochastic dynamics. Unusual form of hysteresis loops is similar to those of found ... More

Photonic band structure and eigenmodes of magnetophotonic crystalsJul 06 2009We study photonic band structure of two- and three-dimensional magnetophotonic crystals and the polarization properties of their eigenmodes using a plane wave expansion method. The alteration of the photonic band structure and eigenmodes by magnetization ... More

The Dense Plasma Torus Around the Nucleus of an Active Galaxy NGC 1052Apr 03 2001A subparsec-scale dense plasma torus around an active galactic nucleus (AGN) is unveiled. We report on very-long-baseline interferometry (VLBI) observations at 2.3, 8.4, and 15.4 GHz towards the active galaxy NGC 1052. The convex spectra of the double-sided ... More

A simple model of reactor cores for reactor neutrino flux calculations for the KamLAND experimentJul 13 2006KamLAND is a reactor neutrino oscillation experiment with a very long baseline. This experiment successfully measured oscillation phenomena of reactor antineutrinos coming mainly from 53 reactors in Japan. In order to extract the results, it is necessary ... More

A classical wave-packet approach to shot noise: power spectrum, Fano factor, and effective chargeNov 25 2012The progress in nanofabrication, measurement technology, and mesoscopic transport theory has been expanding the field of shot noise. Although a wave-packet approach to DC shot noise of independent electrons at finite temperature was offered as an intuitive ... More

Adaptive Ensemble Prediction for Deep Neural Networks based on Confidence LevelFeb 27 2017Mar 08 2019Ensembling multiple predictions is a widely used technique for improving the accuracy of various machine learning tasks. One obvious drawback of ensembling is its higher execution cost during inference. In this paper, we first describe our insights on ... More

A two-layer team-assembly model for invention networksJun 21 2012Jul 03 2014Companies are exposed to rigid competition, so they seek how best to improve the capabilities of their innovations. One strategy is to collaborate with other companies in order to speed up their own innovations. Such inter-company collaborations are conducted ... More

Closed-form expression for finite predictor coefficients of vector ARMA processesMay 13 2018May 22 2018We derive a closed-form expression for the finite predictor coefficients $\phi_{n,j}$ of a vector ARMA (autoregressive moving-average) process. This is a new result even for univariate ARMA processes. The significance of the expression is that the sizes ... More

Organizing Volumes of Right-Angled Hyperbolic PolyhedraSep 11 2008This article defines a pair of combinatorial operations on the combinatorial structure of compact right-angled hyperbolic polyhedra in dimension three called decomposition and edge surgery. It is shown that these operations simplify the combinatorics ... More

AR and MA representation of partial autocorrelation functions, with applicationsFeb 22 2007Apr 30 2007We prove a representation of the partial autocorrelation function (PACF), or the Verblunsky coefficients, of a stationary process in terms of the AR and MA coefficients. We apply it to show the asymptotic behaviour of the PACF. We also propose a new definition ... More

Multi-Sample Dropout for Accelerated Training and Better GeneralizationMay 23 2019Dropout is a simple but efficient regularization technique for achieving better generalization of deep neural networks (DNNs); hence it is widely used in tasks based on DNNs. During training, dropout randomly discards a portion of the neurons to avoid ... More

On the knot quandle of a fibered knot, finiteness and equivalence of knot quandlesJul 24 2018We show that the structure of a fibered knot, as a fiber bundle, is reflected in its knot quandle. As an application, we discuss finiteness and equivalence of knot quandles of concrete fibered 2-knots.

Field-Effect Transistor on SrTiO3 with sputtered Al2O3 Gate InsulatorJun 17 2003A field-effect transistor that employs a perovskite-type SrTiO3 single crystal as the semiconducting channel is revealed to function as n-type accumulation-mode device with characteristics similar to that of organic FET's. The device was fabricated at ... More

Magnetization and spin gap in two-dimensional organic ferrimagnet BIPNNBNODec 07 2011A magnetization process in two-dimensional ferrimagnet BIPNNBNO is analyzed. The compound consists of ferrimagnetic (1,1/2) chains coupled by two sorts of antiferromagnetic interactions. Whereas a behavior of the magnetization curve in higher magnetic ... More

High Resolution VSOP Imaging of a Southern Blazar PKS 1921-293 at 1.6 GHzJul 13 1999We present a high resolution 1.6 GHz VSOP image of the southern blazar PKS 1921-293. The image shows a typical core-jet morphology, consistent with ground-based VLBI images. However, the addition of data from the space antenna has greatly improved the ... More

The Cessation of Flickering during Dips in Cygnus X-1Feb 25 1997We report the discovery of the cessation of flickering in dips in the black hole candidate Cygnus X-1, detected for the first time in the ASCA observation of May 9th., 1995. During this observation, particularly deep dipping took place resulting in strong ... More

A Hard Ionizing Spectrum in z=3-4 Ly-alpha Emitters with Intense [OIII] Emission: Analogs of Galaxies in the Reionization Era?Aug 29 2016Sep 22 2016We present Keck/MOSFIRE spectra of the diagnostic nebular emission lines [OIII]5007,4959, [OII]3727, and H-beta for a sample of 15 redshift z=3.1-3.7 Ly-alpha emitters (LAEs) and Lyman break galaxies (LBGs). In conjunction with spectra from other surveys, ... More

Enhancement of HI absorption associated with the $z=3.1$ large-scale proto-cluster and characteristic structures with AGNs sculptured over Gpc scale in the SSA22 fieldJan 31 2019In the SSA22 field which exhibits a large-scale proto-cluster at $z=3.1$, we carried out a spectroscopic survey for Lyman Break Galaxies (LBGs) with the VLT/VIMOS and identified 78 confident LBGs at $z=2.5$--4. We stacked their spectra in the observer's ... More

The IC133 Water Vapor Maser in the Galaxy M33: A Geometric DistanceJul 22 2004We report on the results of a 14 year long VLBI study of proper motions in the IC133 H2O maser source in the galaxy M33. The method of Ordered Motion Parallax was used to model the 3-dimensional structure and dynamics of IC133 and obtain a distance estimate, ... More

Kamland ResultsJul 15 2003The LMA solution of the solar neutrino problem has been explored with the 1,000 ton liquid scinatillator detector, KamLAND. It utilizes nuclear power reactors distributing effectively 180km from the experimental site. Comparing observed neutrino rate ... More

Intermediate psuedoscalar resonance contributions to B->X_s photon photonAug 14 1997We calculate the decay rate B-> X_s photon photon via intermediate psuedoscalar charmonium eta_c. This process is thought to be the main long-distance contribution which dominates the corresponding inclusive rare B decay. We point out that once the momentum ... More

The Intensity Modulation of Fluorescent Line by a Finite Light Speed Effect in Accretion-Powered X-ray PulsarsOct 13 2017Nov 07 2017The X-ray line diagnostic method is a powerful tool for an investigation of plasma around accretion-powered X-ray pulsars. We point out an apparent intensity modulation of emission lines with their rotation period of neutron stars, due to the finite speed ... More

A tropical analogue of Fay's trisecant identity and the ultra-discrete periodic Toda latticeJun 20 2008Feb 23 2009We introduce a tropical analogue of Fay's trisecant identity for a special family of hyperelliptic tropical curves. We apply it to obtain the general solution of the ultra-discrete Toda lattice with periodic boundary conditions in terms of the tropical ... More

Formation of Massive Molecular Cloud Cores by Cloud-cloud CollisionMay 20 2013Aug 19 2013Recent observations of molecular clouds around rich massive star clusters including NGC3603, Westerlund 2, and M20 revealed that the formation of massive stars could be triggered by a cloud-cloud collision. By using three-dimensional, isothermal, magnetohydrodynamics ... More

The 2-components of the 31-stem homotopy groups of the 9 and 10-spheresOct 03 2012Group structures of the 2-primary components of the 31-stem homotopy groups of spheres were studied by Oda in 1979. There are, however, two incompletely determined groups. In this paper, our investigation with Toda's composition method gives structures ... More

Quandle homology and complex volumeDec 14 2010Jul 27 2013We introduce a new homology theory of quandles, called simplicial quandle homology, which is quite different from quandle homology developed by Carter et al. We construct a homomorphism from a quandle homology group to a simplicial quandle homology group. ... More

The UV (GALEX) and FIR (ASTRO-F) All Sky Surveys: the measure of the dust extinction in the local universeSep 12 2002Before the end of 2002 will be launched the GALEX satellite (a NASA/SMEX project) which will observe all the sky in Ultraviolet (UV) through filters at 1500 and 2300 A down to m(AB) 21. In 2004 will be launched the ASTRO-F satellite which will perform ... More