bluuebunny/crossref_metadata_2025_split huggingface dataset:
SiO Maser Sources toward Globular Clusters
Authors: Matsunaga Noriyuki , Deguchi Shuji , Ita Yoshifusa , TanabÉ Toshihiko , Nakada Yoshikazu 
Published: March 2014

Abstract
We report on the detection of SiO masers in Asymptotic Giant Branch variables toward bulge/disk globular clusters. In five out of six cases, the radial velocities are compatible with the optically measured radial velocities of globular clusters in the assessed uncertainty. Two sources, toward Terzan 5 and Terzan 12, lie very close to the cluster centers. The objects toward Pal 6 and Terzan 12 have luminosities appropriate to the AGB tip in globular clusters, while those toward NGC 6171, Pal 10, and Terzan 5 are brighter than expected. It is suggested that the latter three may have evolved from merged binaries, offering a test for binary-evolution scenarios in globular clusters, if the membership is approved.
The Intermediate-Band Dropout Method: A New Method to Search for High-Redshift Galaxies
Authors: Shioya Yasuhiro , Taniguchi Yoshiaki , Ajiki Masaru , Nagao Tohru , Murayama Takashi , Sasaki Shunji , Sumiya Ryoko , Hatakeyama Yuichiro 
Published: March 2014

Abstract
We propose a new method to search for high-redshift galaxies that is based on an intermediate-band dropout technique rather than the usual broad-band dropout one. In this method, we use an intermediate-band filter whose central wavelength is longer than 7000 Å. This new method makes it possible to distinguish both very late-type stars, such as L and T dwarfs, and dusty galaxies at intermediate redshifts from real high-$z$ Lyman break galaxies. The reason for this is that such interlopers do not show strong intermediate-band depression, although they have very red broad-band colors that are indicative of Lyman break galaxies (LBGs). Applying our new method to imaging data sets obtained with Suprime-Cam on the Subaru Telescope, we found a new sample of Lyman break galaxies at $z \simeq 5$.
Time Variation of SiO Masers in VX Sagittarii over an Optically Quiescent Phase
Authors: Kamohara Ryuichi , Deguchi Shuji , Miyoshi Makoto , Shen Zhi-Qiang 
Published: March 2014

Abstract
The time variation of SiO masers in a semi-regular variable, VX Sgr, was investigated in the period between 1994 and 2004 when the optical light curve exhibited an $\sim 6$-yr quiescent phase intercepting a regularly pulsating era. The quiescent period occurred with a delay of several years after a decrease in the SiO maser flux. VLBA observations of SiO masers made during this period showed no drastic spatial variation except for emission features being shifted from south-west to north-east. The SiO maser flux decrease, and a succeeding optical quiescent phase, may indicate that the stellar mass-loss rate diminished over a few years around 1994. A SiO maser flare occurring in 1999 may be a reminiscence of a final gas blow, which resulted in the optically quiescent period.
Momentum Conservation and Mode Classification of the Dipolar Oscillations of Stars
Authors: Takata Masao 
Published: March 2014

Abstract
Despite their apparent simplicity, the dipole modes of stellar oscillations are theoretically less tractable than the other nonradial modes. This is because neglecting the Eulerian perturbation to the gravitational potential (the Cowling approximation), which greatly simplifies the governing equations, is not always very accurate in the case of dipole modes. In this paper, we first derive an integral that is specific to dipole-mode oscillations. It is then shown that the fourth-order differential equation, which governs the nonradial adiabatic oscillations of stars, is reduced to a (linear) second-order equation in the dipole case without assuming the Cowling approximation. Based on this second-order equation, we discuss how to classify the adiabatic dipole modes theoretically. We specifically propose a scheme that allocates a unique index to each of the dipole modes.
Automatic Detection Algorithm for Small Moving Objects
Authors: Yanagisawa Toshifumi , Nakajima Atsushi , Kadota Ken-ichi , Kurosaki Hirohisa , Nakamura Tsuko , Yoshida Fumi , Dermawan Budi , Sato Yusuke 
Published: March 2014

Abstract
We have devised an automatic detection algorithm for unresolved moving objects, such as asteroids and comets. The algorithm uses many CCD images in order to detect very dark moving objects that are invisible on a single CCD image. We carried out a trial observation to investigate its usefulness, using a 35-cm telescope. By using the algorithm, we succeeded to detect asteroids down to about 21 mag. This algorithm will contribute significantly to searches for near-Earth objects and to solar-system astronomy.
A Dynamical Model for the Orbit of the Andromeda Galaxy M31 and the Origin of the Local Group of Galaxies
Authors: Sawa Takeyasu , Fujimoto Mitsuaki 
Published: March 2014

Abstract
We propose a new model for the origin and evolution of the Local Group of Galaxies (LGG) that naturally explains the formation of the Magellanic Clouds and their large orbital angular momenta around the Galaxy. The basic idea is that an off-center hydrodynamical collision occurred some 10 Gyr ago between the primordial Andromeda galaxy (M31) and a similar Galaxy, and compressed the halo gas to form the LGG dwarf galaxies, including the Magellanic Clouds. New-born dwarf galaxies can be expected to locate on the orbital plane of these two massive galaxies. We reexamined the two-dimensional sky distribution of the LGG members, and confirmed an early idea that they align along two similar great circles. The planes of these circles are approximately normal to the line joining the present position of the Sun and the galactic center. We made a distribution map of these objects, and found a well-defined plane of finite thickness. Thus we could determine the orbital elements of M31 relative to the Galaxy by reproducing the well-studied dynamics of the LMC and the SMC around the Galaxy. The expected proper motion of M31 is $(\mu_{l}, \mu_{b}) = (38\pm 16 \,\mu\mathrm{as} \,\mathrm{yr}^{-1},-49 \pm 5 \, \mu\mathrm{as} \,\mathrm{yr}^{-1})$.
An Ultrasoft Transient X-Ray Source in the Norma Region Discovered with Ginga
Authors: Yamauchi Shigeo 
Published: March 2014

Abstract
A new X-ray source was discovered in the Norma region with Ginga in 1988 April. The source position, derived from one-dimensional scan data, and its spectral properties are presented. The X-ray emission was dominant below $\sim 6 \,\mathrm{keV}$ and not found in other observations. Thus, it is thought to be an ultrasoft transient X-ray source. The X-ray spectrum, constructed by a scan fit technique, was well represented by either blackbody, thermal bremsstrahlung, power-law, or multicolor disk models. Although all of the spectral models were acceptable from a statistical point of view, the ultrasoft nature of the spectrum and the transient behavior suggest that this source is a candidate source of black hole binaries.
Large-Scale Clustering of Sloan Digital Sky Survey Quasars: Impact of the Baryon Density and the Cosmological Constant
Authors: Yahata Kazuhiro , Suto Yasushi , Kayo Issha , Matsubara Takahiko , Connolly Andrew J. , Vanden Berk Daniel , Sheth Ravi , Szapudi István , Anderson Scott F. , Bahcall Neta , Brinkmann Jon , Csabai István , Fan Xiaohui , Loveday Jon , Szalay Alexander S. , York Donald 
Published: March 2014

Abstract
We report on the first result from the clustering analysis of SDSS quasars. We computed the two-point correlation function (2PCF) of SDSS quasars in redshift space at $8\,h^{-1} \,\mathrm{Mpc} &lt; s &lt; 500\,h^{-1} \,\mathrm{Mpc}$, with particular attention to its baryonic signature. Our sample consisted of 19986 quasars extracted from the SDSS Data Release 4. The redshift range of the sample is $0.72 \le z \le 2.24$ (the mean redshift is $\overline{z} = 1.46$) and the reddening-corrected $i$-band apparent magnitude range is $15.0 \le m_{i,\mathrm{rc}} \le 19.1$. Due to the relatively low number density of the quasar sample, the bump in the power spectrum due to the baryon density, $\Omega_{\mathrm{b}}$, is not clearly visible. The effect of the baryon density is, however, to distort the overall shape of the 2PCF. The degree of distortion makes it an interesting alternate measure of the baryonic signature. Assuming a scale-independent linear bias and a spatially flat universe, we combined the observed quasar 2PCF and the predicted matter 2PCF to put constraints on $\Omega_{\mathrm{b}}$ and $\Omega_{\Lambda}$ (the cosmological constant). Our result was fitted as $0.80-2.8\Omega_{\mathrm{b}} &lt; \Omega_{\Lambda} &lt; 0.90-1.4\Omega_{\mathrm{b}}$ at the $2 \,\sigma$ confidence level. The “mean” bias parameter of our quasar sample is $1.59 \,{\sigma_8}^{-1}$ (for $\Omega_{\mathrm{b}} = 0.04$ and $\Omega_{\Lambda} = 0.7$), where $\sigma_8$ is the top-hat mass fluctuation amplitude at $8\,h^{-1} \,\mathrm{Mpc}$. We also estimated the corresponding bias parameter of quasars at $z = 0, b_{\mathrm{QSO,Fry}}(0)$, assuming Fry’s bias evolution model. For $\Omega_{\mathrm{b}} = 0.04, \Omega_{\Lambda} = 0.73$, and $\Omega_{\mathrm{d}} = 0.23$, we found $b_{\mathrm{QSO,Fry}}(0) = 0.54 + 0.83 \,{\sigma_8}^{-1}$ which is valid for $0.6 &lt; \sigma_8 &lt; 1.0$.
High Angular Resolution Observations of the (J, K) = (1, 1), (2, 2), and (3, 3) Transitions of Ammonia in NGC 253
Authors: Takano Shuro , Hofner Peter , Winnewisser Gisbert , Nakai Naomasa , Kawaguchi Kentarou 
Published: March 2014

Abstract
The nearby starburst galaxy NGC 253 was mapped in the ammonia $(J, K) = (1, 1), (2, 2)$, and $(3, 3)$ lines in the 23 GHz region with the Very Large Array. The angular resolutions were about $4 {{}^{\prime \prime }} \times 3 {{}^{\prime \prime }}$. The distributions of the three lines were different from one another. The $(1, 1)$ and $(3, 3)$ lines were distributed along the bar mainly at the northeastern and southwestern regions from the center, but the $(2, 2)$ line is distributed mainly at two clumps in the southwestern region from the center. In addition, the $(1, 1)$ line showed absorption at the central region. The obtained rotational temperatures were $&lt;15 \hbox{--} 28 \,\mathrm{K}$ (lower limit), depending on the clumps. The ammonia distributions are generally consistent with estimates from our single-dish results already published. The distributions of ammonia were compared with those of continuum and several other molecular lines.
O i Line Emission in the Quasar PG 1116+215
Authors: Matsuoka Yoshiki , Oyabu Shinki , Tsuzuki Yumihiko , Kawara Kimiaki , Yoshii Yuzuru 
Published: March 2014

Abstract
By observing the near-infrared spectrum of the quasar PG 1116$+$215 at $z = 0.176$ and combining with the HST/FOS spectrum, we obtained the relative strengths of three permitted O i lines ($\lambda$1304, $\lambda$8446, and $\lambda$11287) in a quasar for the first time. The photon flux ratios of the O i lines of the quasar were compared with those previously measured in a Seyfert 1 and six narrow-line Seyfert 1 s. No significant differences were found in the O i line flux ratios between the quasar and the other Seyferts, suggesting that the gas density in the O i and Fe ii line-emitting regions in the quasar is of the same order as those in low-luminosity AGNs. It was also found that the line width of O i$\lambda$11287 is significantly narrower than that of Ly$\alpha$, which is consistent with O i and Fe ii emission occurring in the partly ionized regions at the outermost portion of the broad-line region where velocities are small.
New High-Redshift Galaxies at z = 5.8–6.5 in the Subaru Deep Field
Authors: Shioya Yasuhiro , Taniguchi Yoshiaki , Ajiki Masaru , Nagao Tohru , Murayama Takashi , Sasaki Shunji S. , Sumiya Ryoko , Hatakeyama Yuichiro , Kashikawa Nobunari 
Published: March 2014

Abstract
In order to search for high-redshift galaxies around $z \sim 6$ in the Subaru Deep Field, we have investigated NB816-dropout galaxies where NB816 is the narrow-band filter centered at 815 nm with FWHM of 12.5 nm for Suprime-Cam on the Subaru Telescope. Since the NB816 imaging is so deep, we can detect 10 well-defined NB816-dropout galaxies that are identified as objects at $z = 5.8 \hbox{--} 6.5$. We discuss their observational properties.
Multi-Epoch VERA Observations of H2O Masers in OH 43.8−0.1
Authors: Honma Mareki , Bushimata Takeshi , Choi Yoon Kyung , Fujii Takahiro , Hirota Tomoya , Horiai Koji , Imai Hiroshi , Inomata Noritomo , Ishitsuka Jose , Iwadate Kenzaburo , Jike Takaaki , Kameya Osamu , Kamohara Ryuichi , Kan-ya Yukitoshi , Kawaguchi Noriyuki , Kijima Masachika , Kobayashi Hideyuki , Kuji Seisuke , Kurayama Tomoharu , Manabe Seiji , Miyaji Takeshi , Nakagawa Akiharu , Nakashima Kouichirou , Oh Chung Sik , Omodaka Toshihiro , Oyama Tomoaki , Rioja Maria , Sakai Satoshi , Sato Katsuhisa , Sasao Tetsuo , Shibata Katsunori M. , Shimizu Rie , Sora Kasumi , Suda Hiroshi , Tamura Yoshiaki , Yamashita Kazuyoshi 
Published: March 2014

Abstract
We report on multi-epoch observations of $\mathrm{H}_2\mathrm{O}$ maser emission in the star-forming region OH 43.8$-$0.1, carried out with VLBI Exploration of Radio Astrometry. The large-scale maser distributions obtained by single-beam VLBI mapping reveal new maser spots scattered over the area of ${0\rlap {.}{}^{\mathrm {\prime \prime }}7} \times {1\rlap {.}{}^{\mathrm {\prime \prime }}0}$, in addition to a ‘shell-like’ structure with a scale of ${0\rlap {.}{}^{\mathrm {\prime \prime }}3} \times {0\rlap {.}{}^{\mathrm {\prime \prime }}5}$, which was mapped previously. Proper motions were also obtained for 43 spots based on 5-epoch monitoring with a time span of 281 days. The distributions of the proper motions show a systematic outflow in the north-south direction with an expansion velocity of $\sim 8 \,\mathrm{km} \,\mathrm{s}^{-1}$. The overall distributions of the maser spots as well as the proper motions are better represented by a bipolar flow plus a central maser cluster with a complex structure, rather than a shell with uniform expansion, such as those found in Cep A R5 and W75N VLA2. The distance to OH 43.8$-$0.1 was also estimated based on the statistical parallax, yielding $D = 2.8 \pm 0.5 \,\mathrm{kpc}$. This distance is consistent with a near kinematic distance, and rules out a far kinematic distance ($\sim 9 \,\mathrm{kpc}$). Also, the radial velocity of the OH 43.8$-$0.1 combined with the distance provides a constraint on the flatness of the galactic rotation curve, indicating that there is no systematic difference in the rotation speeds at the Sun and at the position of OH 43.8$-$0.1, which is located at a galacto-centric radius of $\sim 6.3 \,\mathrm{kpc}$.
Search for C2− in Diffuse Clouds
Authors: Civiš Svatopluk , Hosaki Yukio , Kagi Eriko , Izumiura Hideyuki , Yanagisawa Kenshi , Šedivcová Tereza , Kawaguchi Kentarou 
Published: March 2014

Abstract
A search has been carried out for the $\mathrm{C}_2^{-}$ ion in diffuse clouds toward HD 23180, HD 24912, HD 24398, HD 46711, and HD 50064 using the HIDES spectrometer on the Okayama 188-cm telescope. An upper limit of $8.3 \times 10^{10}\hbox{--} 1.8\times 10^{12} \,\mathrm{cm}^{-2}$ was obtained for the $\mathrm{C}_2^{-}$ column density. The upper limit value ($3.8 \times 10^{11} \,\mathrm{cm}^{-2}$) toward HD 23180 is two orders of magnitude smaller than that of the $\mathrm{C}_2$ radical. Possible production mechanisms for $\mathrm{C}_2^{-}$ are discussed.
Infrared Emission from Intracluster Dust Grains and Constraints on Dust Properties
Authors: Yamada Kenkichi , Kitayama Tetsu 
Published: March 2014

Abstract
For 117 clusters of galaxies, we explore the detectability of intracluster dust grains by current and future infrared facilities, taking into account both collisional heating and sputtering of grains by the ambient plasma. If the dust grains are injected into intergalactic space with the amount and size comparable to the Galactic values, the dust-to-gas ratio is typically $10^{-6}$ and the mean dust temperature is $\sim 30 \,\mathrm{K}$ near the cluster center. The predicted infrared intensities lie marginally above the detection thresholds for Spitzer Space Telescope, ASTRO-F, Herschel, and SPICA missions. For some nearby clusters, such as Perseus, A3571, A2319, A3112, and A2204, good detections of intracluster dust signals are expected in the 70$\, {\mu \mathrm {m}}$ band. Given rather tight constraints on the dust temperature from the observed electron density and the temperature, the dust mass can be inferred directly from infrared observations. Further constraints on the size distribution will be obtained once multi-band data are available. They will definitely provide a powerful probe of the dust injection processes and dust-gas interactions in intergalactic space.
Three Spectral States of the Disk X-Ray Emission of the Black-Hole Candidate 4U 1630−47
Authors: Abe Yukiko , Fukazawa Yasushi , Kubota Aya , Kasama Daisuke , Makishima Kazuo 
Published: March 2014

Abstract
We studied a time history of X-ray spectral states of a black-hole candidate, 4U 1630$-$47, utilizing data from a number of monitoring observations with the Rossi X-Ray Timing Explorer over 1996–2004. These observations covered five outbursts of 4U 1630$-$47, and recorded typical features of the high/soft states. The spectra in the high/soft states can be classified into three states. The first state is explained by a concept of the standard accretion disk picture. The second appears in the very high state, where a dominant hard component is seen and the disk radius apparently becomes too small. These phenomena are explained by the effect of inverse Compton scattering of disk photons, as shown by Kubota, Makishima, and Ebisawa (2001, ApJ, 560, L147) for GRO J1655$-$40. The third shows that the disk luminosity varies in proportion to $T_{\mathrm{in}}^2$, rather than $T_{\mathrm{in}}^4$, where $T_{\mathrm{in}}$ is the inner-disk temperature. This state suggests an optically-thick and advection-dominated slim disk, as given by Kubota and Makishima (2004, ApJ, 601, 428) for XTE J1550$-$564. The second and third states appear, with good reproducibility, when $T_{\mathrm{in}}$ and the total X-ray luminosity are higher than 1.2 keV and $\sim 2.5 \times 10^{38} (D/10 \,\mathrm{kpc})^2 [\cos \theta / (1/\sqrt{3})]^{-1} \,\mathrm{erg} \,\mathrm{s}^{-1}$, respectively, where $D$ is the distance to the object and $\theta$ is the inclination angle to the disk. The results suggest that these spectral states commonly appear among black-hole binaries under high accretion rates.
Fourier Phase Analysis of SDSS Galaxies
Authors: Hikage Chiaki , Matsubara Takahiko , Suto Yasushi , Park Changbom , Szalay Alexander S. , Brinkmann Jon 
Published: March 2014

Abstract
We present a first analysis of the clustering of SDSS galaxies using the distribution function of the sum of Fourier phases over three closed wavevectors. Since the Fourier phases are statistically independent of the Fourier amplitudes, the phase statistics plays a complementary role to the conventional two-point statistics of galaxy clustering. We find that the observed distribution functions of the phase sum are in good agreement with the lowest-order approximation from perturbation theory. From comparison of observations with mock catalogs constructed from $N$-body simulations, we find that the observed phase correlations for the galaxies within the range of the absolute magnitude, $-22 &lt; M_r &lt;-18$, agree well with those for $\Lambda$-dominated spatially flat cold dark matter predictions with $\sigma_8 = 0.9$ evolved from the Gaussian initial condition. This agreement implies that the galaxy biasing is approximately linear in redshift space. Instead, assuming that the galaxy biasing is described by a quadratic deterministic function $\delta_{\mathrm{g}} = b_1 \delta_{\mathrm{m}} + (b_2/2)(\delta_{\mathrm{m}}^2-\langle \delta_{\mathrm{m}}^2 \rangle)$ at scale larger than $30 \, h^{-1} \,\mathrm{Mpc}$, we find that the resulting $b_2/b_1$ is well fitted by $b_2/b_1 = 0.54(\pm 0.06)-0.62(\pm 0.08) \,\sigma_8$ and is almost insensitive to the cosmology and luminosity in those ranges. Indeed, $b_2/b_1$ is nearly zero when $\sigma_8 = 0.9$.
Asymmetric Sub-Reflectors for Spherical Antennas and Interferometric Observations with an FPGA-Based Correlator
Authors: Takeuchi Hiroshi , Kuniyoshi Masaya , Daishido Tsuneaki , Asuma Kuniyuki , Matsumura Nobuo , Takefuji Kazuhiro , Niinuma Kotaro , Ichikawa Hajime , Okubo Riki , Sawano Akihiro , Yoshimura Naoya , Fujii Fumiyuki , Mizuno Keiju , Akamine Yukinori 
Published: March 2014

Abstract
The Nasu Radio Interferometer, consisting of eight equally spaced, 20-m diameter fixed spherical antennas, was developed for the purpose of surveying unknown variable radio sources at 1.4 GHz. An asymmetrical Gregorian sub-reflector was designed and installed on each antenna for the purpose of correcting aberrations caused by the spherical reflector. The total collecting area is $2512 \,\mathrm{m}^2$ and the field-of-view of each antenna is $ {0\rlap {.}{}^{\mathrm {\circ }}6} \times {0\rlap {.}{}^{\mathrm {\circ }}6}$. In survey observations a spatial-fast Fourier-transform (FFT)-type multi-beam system will be used. We report on the design of spherical reflectors and a digital back-end system, the basic principle of spatial-FFT image forming, and a result of interferometric observations with an FPGA-based digital correlator.
GRAPE-6A: A Single-Card GRAPE-6 for Parallel PC-GRAPE Cluster Systems
Authors: Fukushige Toshiyuki , Makino Junichiro , Kawai Atsushi 
Published: March 2014

Abstract
In this paper, we describe the design and performance of GRAPE-6A, a special-purpose computer for gravitational many-body simulations. It was designed to be used with a PC cluster, in which each node has one GRAPE-6A. Such a configuration is particularly cost-effective in running parallel tree algorithms. Though the use of parallel tree algorithms was possible with the original GRAPE-6 hardware, it was not very cost-effective since a single GRAPE-6 board was still too fast and too expensive. Therefore, we designed GRAPE-6A as a single PCI card to minimize the reproduction cost and to optimize the computing speed. The peak performance is 130 Gflops for one GRAPE-6A board and 3.1 Tflops for our 24 node cluster. We describe the implementation of the tree, TreePM and individual timestep algorithms on both a single GRAPE-6A system and GRAPE-6A cluster. Using the tree algorithm on our 16-node GRAPE-6A system, we can complete a collisionless simulation with 100 million particles (8000 steps) within 10 days.
Observations of Stellar Maser Sources with No IRAS Counterpart
Authors: Deguchi Shuji , Nakashima Jun-ichi , Miyata Takashi , Ita Yoshifusa 
Published: March 2014

Abstract
We investigated stellar maser sources with no IRAS counterpart at the radio, middle-infrared, and near-infrared wavelengths. A 43 GHz SiO maser search for 120 2MASS/MSX objects, and 10 OH 1612 MHz sources with no or a very faint MSX counterpart, resulted in 43 SiO detections: one OH 1612 MHz source, 2 near-infrared stars, and 40 MSX sources. Additional near-infrared $J$-, $H$-, and $K$-band observations of the OH 1612 MHz sources detected 5 near-infrared counterparts. Furthermore, middle-infrared imaging observations at 8.8, 9.7, 12.4, and 24.5$\, {\mu \mathrm {m}}$ with the Subaru 8.2-m telescope found counterparts for 2 near-infrared stars with SiO masers, and counterparts for 6 OH 1612 MHz sources. However, 4 OH 1612 MHz sources were not detected in the sensitive near- and middle-infrared searches; three of these are relatively strong OH maser sources for which the positions were known accurately. We conclude that one of these (OH 028.286$-$01.801) must be a young object in a star-forming region.