bluuebunny/crossref_metadata_2025_split huggingface dataset:
First Astronomical Fringe of a Test Correlator for the ALMA: Simultaneous Achievement of Wideband and High Resolution
Authors: Okumura Sachiko K. , Iguchi Satoru , Chikada Yoshihiro , Momose Munetake , Okiura Mahoko 
Published: March 2014

Abstract
The first astronomical fringe of a test correlator for the Atacama Large Millimeter/Submillimeter Array (ALMA) is obtained. The newly-developed test correlator system consists of two 4096-Msps Analog-to-Digital Converters (ADCs) and an FX-type correlator that can divide a 2-GHz correlation signal from one baseline into 131072 frequency channels. A fringe spectrum that contains 20 line features as well as continuum emission at $\sim 86.2 \,\mathrm{GHz}$ was obtained by an interferometric observation of the Orion-KL regions using this test system connected to the Nobeyama Millimeter Array (NMA), demonstrating that the realization of high frequency resolution over a wide bandwidth is technically feasible. The installation of such a correlator system in the ALMA will greatly enhance its capability of multi-line imaging.
Gravitational-Wave Radiation from Magnetized Accretion Disks
Authors: Mineshige Shin , Hosokawa Takashi , Machida Mami , Matsumoto Ryoji 
Published: March 2014

Abstract
The detectability of gravitational-wave (GW) radiation from accretion disks is discussed based on various astrophysical contexts. In order to emit GW radiation, the disk shape should lose axial symmetry. We point out that a significant deformation is plausible in non-radiative hot accretion disks because of enhanced magnetic activity, whereas it is unlikely for standard-type cool disks. We have analyzed the 3D magnetohydrodynamical (MHD) simulation data of magnetized accretion flow, finding non-axisymmetric density patterns. The corresponding ellipticity is $ \epsilon \sim 0.01$. The expected time variations of GW radiation are overall chaotic, but there is a hint of quasi-periodicity. GW radiation has no interesting consequence, however, in the case of close binaries, because of very tiny disk masses. GW radiation is not significant, either, for AGN because of very slow rotation velocities. The most promising case can be found in gamma-ray bursts or supernovae, in which a massive torus (or disk) with a solar mass or so may be formed around a stellar-mass compact object as the result of a merger of compact objects, or by the fallback of exploded material towards the center in a supernova. Although much more intense GW radiation is expected before the formation of the torus, the detection of GW radiation in the subsequent accretion phase is of great importance, since it will provide a good probe to investigating their central engines.
Properties of Spiral-Peculiar Type of Kiso Ultraviolet-Excess Galaxies
Authors: Tomita Akihiko , Maehara Hideo 
Published: March 2014

Abstract
We investigated the optical spectroscopic properties of 44 Kiso Ultraviolet-excess Galaxies (KUG), which is one of the most well-known catalogs of blue galaxies. All of our sample galaxies belong to the spiral-peculiar (Sp) type, the morphological class of spiral galaxy with a peculiar bar and/or a nucleus in KUGs. Since the Sp type is considered to be the most peculiar group among KUGs, and about 45% of the KUGs have the Sp type, a detailed study of the Sp type is crucial to understand the characteristics of the KUG. The sample galaxies have luminosities in the $ B$–band of about $ 10^{8}$ to less than $ 10^{10}$ in solar unit, and a median physical size of 13 kpc. From the nuclear spectra, we determined line excitation sources in 39 galaxies. Among them, we detected four AGNs reliably: two Seyfert 1s, one Seyfert 2, and one LINER. Other sample galaxies show moderately star-forming activity. For this category of ordinary KUG group, the mode of the $ \mathrm{H}\alpha$ equivalent width at the nuclear region is a bin of 40 to 60  Å. Three galaxies have extreme starburst nuclei with an $ \mathrm{H}\alpha$ equivalent width of more than 200  Å. The internal extinction of $ A_{V}$ is about 0.8 mag, which suggests that the star-forming nuclei are not heavily enshrouded by dust.
Observation of the Supernova Remnant Kes 79
Authors: Tsunemi Hiroshi , Enoguchi Hideyuki 
Published: March 2014

Abstract
We report here on an ASCA observation of Kes 79, a possible mixed-morphology (MM) SNR. There are two radio shells: an inner shell and an outer shell. A ROSAT observation revealed an inner ring in X-ray that has been confirmed by the ASCA observation. The X-ray intensity peak is near the inner radio shell. The X-ray spectrum is well-fitted by a single component of the non-equilibrium ionization condition model with about 0.7-times the solar abundance. The plasma age estimated from the ionization parameter is only $ 3.3\times 10^3 \,\mathrm{yr}$. The temperature is uniform ($ \sim 0.7 \,\mathrm{keV}$) while the density profile is approximated by a point symmetric Gaussian function. Comparing the Kes79 results with those of Kes27, a prototypical MM SNR, Kes 79 may not belong to the MM type SNRs.
Detection of Zinc in the Very Metal-Poor Post-AGB Star HR 4049
Authors: Takeda Yoichi , Parthasarathy Mudumba , Aoki Wako , Ita Yoshifusa , Nakada Yoshikazu , Izumiura Hideyuki , Noguchi Kunio , Takada-Hidai Masahide , Sato Bun’ei , Tajitsu Akito , Honda Satoshi , Kawanomoto Satoshi , Ando Hiroyasu , Karoji Hiroshi 
Published: March 2014

Abstract
We report on the detection of two Zn i lines at 4722.15 Å and 4810.53 Å in the high-quality spectrum of the very metal-poor post-AGB star HR 4049, which was obtained with the High Dispersion Spectrograph attached to the Subaru Telescope. The strengths of these lines indicate an appreciable underabundance of Zn by $ \sim-1.3 \,\mathrm{dex}$ relative to the Sun. The fact that this volatile element, similarly to others belonging to the same group (e.g., C, N, O, S), does not conform to the extreme depletion ($ \gt 4 \,\mathrm{dex}$) of refractory metals (e.g., Fe), strongly suggests that grain formation has something to do with the origin of the chemical peculiarity. This (not extremely but significantly) subsolar value of $ \mathrm{[Zn/H]}$ is quantitatively discussed in connection with those of other volatile species, especially with respect to S. We also detected a new Fe ii line at 5159.03 Å along with the already known Fe ii 4923.93 Å line; based on these two lines the Fe abundance of HR 4049 is determined to be $ \sim 2.8$ ($ \mathrm{[Fe/H]} \sim-4.7$).
Activity Cycle of Polar Faculae
Authors: Li Kejun , Irie Makoto , Wang Jingxiu , Xiong Songying , Yun Hongsik , Liang Hongfei , Zhan Lashen , Zhao Haizhuan 
Published: March 2014

Abstract
The data of the polar faculae observed by the National Astronomical Observatory of Japan from the year 1951 through 1991 and the Mount Wilson Observatory from 1906 to 1990 were analysed. We found that the polar facula cycle is in complete antiphase with the sunspot cycle, and highly correlated with the sunspot cycle with a time shift of 51 months into the following sunspot cycle. We also made a quantitative analysis of the hemispheric distribution of polar faculae, and found that hemispheric asymmetry exists, as in solar activity at low latitude. However, the hemispheric asymmetry of polar faculae seems to have little relationship with the asymmetry of solar activity at low latitude.
Log-Normal Distributions in Cygnus X-1: Possible Physical Link with Gamma-Ray Bursts and Blazars
Authors: Negoro Hitoshi , Mineshige Shin 
Published: March 2014

Abstract
Prompted by recent discoveries of log-normal distributions in gamma-ray/X-ray temporal variabilities of gamma-ray bursts (GRBs) and blazars, we re-examine the X-ray variability of Cygnus X-1 in the hard/low state using Ginga data in 1990. It was previously reported that the distributions of the time intervals between X-ray shots (flares) deviated from the Poisson distributions at short time intervals: the occurrence of shots tended to be suppressed for several seconds before and/or after a shot event. Detailed analyses show that this deviation is larger for shots with larger peaks, and that the time-interval distributions for large shots approach log-normal distributions with a peak at the interval of 7–8 s. Furthermore, we also show that the peak-intensity distribution for the shots is consistent with the log-normal distribution, though no typical peak intensity can be seen. This might indicate the presence of a physical link connecting the physics of black hole accretion flow and that of jet/GRB formation.
Lagrangian Statistical Theory of Anisotropic MHD Turbulence
Authors: Nakayama Kunji 
Published: March 2014

Abstract
We construct a Lagrangian statistical theory of spatially uniform, anisotropic, and strong turbulence of an incompressible magneto-fluid with a uniform mean magnetic field. We treat shear Alfvén turbulence; that is, the perturbations of the velocity field and the magnetic field are assumed to be orthogonal to the mean magnetic field. The perturbation energies, however, need not be equiparted; our theory covers non-equipartition turbulence as well as equipartition turbulence. We show that, concerning the relaxation and energy-transfer of inertial-range eddies, the shear Alfvén turbulence has the following fundamental properties: That is, relaxation of inertial-range eddies is dominated by the largest (energy-containing) eddies; energy cascades have spatially a quasi 2-dimensional nature because of the inhibition of cascades parallel to the mean field; thus, inevitably, the $-3/2$ power-law energy-spectra are derived. These properties are independent of whether the turbulence satisfies the energy equipartition. We, therefore, assert that they should be thought of as generic and robust natures of strong MHD turbulence.
Subaru Prime Focus Camera — Suprime-Cam
Authors: Miyazaki Satoshi , Komiyama Yutaka , Sekiguchi Maki , Okamura Sadanori , Doi Mamoru , Furusawa Hisanori , Hamabe Masaru , Imi Katsumi , Kimura Masahiko , Nakata Fumiaki , Okada Norio , Ouchi Masami , Shimasaku Kazuhiro , Yagi Masafumi , Yasuda Naoki 
Published: March 2014

Abstract
We have built an 80-mega pixels ($10240 \times 8192$) mosaic CCD camera, called Suprime-Cam, for the wide-field prime focus of the 8.2 m Subaru telescope. Suprime-Cam covers a field of view $34' \times 27'$, a unique facility among the 8–10 m class telescopes, with a resolution of ${0\rlap {.}{}^{\mathrm {\prime \prime }}202}$ per pixel. The focal plane consists of ten high-resistivity $2\mathrm{k} \times 4\mathrm{k}$ CCDs developed by MIT Lincoln Laboratory, which are cooled by a large Stirling-cycle cooler. The CCD readout electronics was designed to be scalable, which allows the multiple read-out of tens of CCDs. It takes 50 seconds to readout entire arrays. We designed a filter-exchange mechanism of the jukebox type that can hold up to ten large filters ($205\times 170 \times 15 \,\mathrm{mm}^3$). The wide-field corrector is basically a three-lens Wynne-type, but has a new type of atmospheric dispersion corrector. The corrector provides a flat focal plane and an un-vignetted field of view of $30'$ in diameter. The achieved co-planarity of the focal array mosaic is smaller than 30$\,{\mu \mathrm {m}}$ peak-to-peak, which realizes mostly the seeing limited image over the entire field. The median seeing in the $I_\mathrm{c}$-band, measured over one year and a half, is ${0\rlap {.}{}^{\mathrm {\prime \prime }}61}$ . The PSF anisotropy in Suprime-Cam images, estimated by stellar ellipticities, is about 2% under this median seeing condition. At the time of commissioning, Suprime-Cam had the largest survey speed, which is defined as the field of view multiplied by the primary mirror area of the telescope, among those cameras built for sub-arcsecond imaging.
Near-Infrared Coronagraphy of the GG Tauri A Binary System
Authors: Itoh Yoichi , Tamura Motohide , Hayashi Saeko S. , Oasa Yumiko , Fukagawa Misato , Kaifu Norio , Suto Hiroshi , Murakawa Koji , Doi Yoshiyuki , Ebizuka Noboru , Naoi Takahiro , Takami Hideki , Takato Naruhisa , Gaessler Wolfgang , Kanzawa Tomio , Hayano Yutaka , Kamata Yukiko , Saint-Jacques David , Iye Masanori 
Published: March 2014

Abstract
The highest angular resolution near-infrared images of the GG Tau A binary system were obtained with the Coronagraphic Imager with Adaptive Optics (CIAO) mounted on the Subaru Telescope. The images show that its circumbinary disk is smooth and does not have ${0\rlap {.}{}^{\mathrm {\prime \prime }}1}$ scale structures. Asymmetries in the surface brightness as well as a gap are also resolved. Combined with previous measurements of the stellar positions, our data indicate that the central binary is unlikely to have a large eccentricity. The fifth point source toward this double binary system is probably a background star, based on astrometric measurements.
WZ Sge-Type Star V592 Herculis
Authors: Kato Taichi , Uemura Makoto , Matsumoto Katsura , Kinnunen Timo , Garradd Gordon , Masi Gianluca , Yamaoka Hitoshi 
Published: March 2014

Abstract
We observed the entire course of the 1998 outburst of V592 Her, which was originally reported as a nova in 1968. We have been able to construct a full light curve of the outburst, which is characterized by a rapid initial decline ($0.98 \,\mathrm{mag} \,\mathrm{d}^{-1}$), which smoothly developed into a plateau phase with a slower linear decline. We detected superhumps characteristic to SU UMa-type dwarf novae $\sim 7 \,\mathrm{d}$ after the optical maximum. The overall behavior of the light curve and the development of superhumps were characteristic to a WZ Sge-type dwarf nova. Combined with the past literature, we have been able to uniquely determine the superhump period to be 0.05648(2) d. From this period, together with a modern interpretation of the absolute magnitude of the outburst light curve, we conclude that the overall picture of V592 Her is not inconsistent with a lower main-sequence secondary star, in contrast to a previous claim that V592 Her contains a brown dwarf.
Dense Shell around a Young Intermediate-Mass Star: NGC 2264 IRS 1
Authors: Nakano Makoto , Sugitani Koji , Morita Koh-Ichiro 
Published: March 2014

Abstract
The results of $\mathrm{H}{{13\atop} \mathrm{CO}}^{+}$$J = 1 \hbox{--} 0$ line and 93-GHz continuum observations of NGC 2264 IRS 1, a luminous infrared source known as Allen$^\prime$s source, are reported. IRS 1 is a young intermediate-mass star with a surrounding YSO cluster, and is associated with a molecular outflow. High angular resolution interferometric observations were performed using the Nobeyama Millimeter Array, and mapping observations were conducted using a 45-m telescope. The continuum map reveals four sources, three of which correspond to a submillimeter source detected by Ward-Thompson et al. (2000, AAA 73.137.062). Four compact clumps are also observed in the $\mathrm{H}{{13\atop} \mathrm{CO}}^{+}$ map, two of which are associated with these millimeter / submillimeter continuum sources without bipolar outflow. These $\mathrm{H}{{13\atop} \mathrm{CO}}^{+}$ clumps as a whole form an incomplete dense shell of 0.12 pc in diameter around IRS 1, and the outer part of the shell is clearly traced on the single-dish map. The shell, or cavity, structure suggests that the outflow from IRS 1 has evacuated part of the surrounding envelope in $\sim 0.1 \,\mathrm{Myr}$. The kinematic properties can be interpreted as being two clumps of entrained or compressed material derived from steady outflow. It is concluded that the activity of IRS 1 may have triggered the formation of cluster members in the dense surrounding shell.
Three-Dimensional Distribution of the ISM in the Milky Way Galaxy: I. The H i Disk
Authors: Nakanishi Hiroyuki , Sofue Yoshiaki 
Published: March 2014

Abstract
We derived the three-dimensional distribution of H i gas in the Milky Way Galaxy using the latest H i survey data cubes and rotation curves. The distance of the H i gas was determined by the kinematic distance using a rotation curve. We solved the near-far problem in the inner Galaxy by a fitting method which involves introducing a model of vertical H i distribution. In our resultant maps we could trace three prominent arms: the Sagittarius-Carina arm, the Perseus arm, and the Outer arm. These three arms were found to be logarithmic spiral arms. The pitch angles of the Sagittarius–Carina, Perseus, and Outer arms were estimated to be about ${11{}^{\mathrm {\circ }}}$,${18{}^{\mathrm {\circ }}}$, and ${7{}^{\mathrm {\circ }}}$, respectively. The Sun is located in a region rich in H i gas between the Sagittarius–Carina arm and the Perseus arm. The H i disk shows large and asymmetric warping in the outer disk: the H i disk goes up to about 1.5 kpc above the Galactic plane in the northern hemisphere, and down to about 1 kpc in the southern hemisphere, which means asymmetric warping. The inner H i disk is also found to be tilting. The radius of the H i disk is about 17 kpc and the H i mass within this radius is estimated to be $2.5 \times 10^9\,{{{M}_{\odot}}}$, which corresponds to 1.5% of the dynamical mass predicted from the rotation curve. We also found that the H i outskirt is largely swelling in the fourth quadrant, and hence the Galaxy is significantly lopsided. The scale-height of the H i layer increases with the radius, and is correlated with the H i volume density at the centroid of the H i layer.
The Recurrent Nova U Scorpii in the 1999 Outburst: the First Detection of a Significant Orbital-Period Change
Authors: Matsumoto Katsura , Kato Taichi , Hachisu Izumi 
Published: March 2014

Abstract
In this paper we present and discuss our time-resolved photometry of an eclipsing recurrent nova, U Sco, during an outburst in 1999, which was conducted from immediately after the optical maximum to the final fading toward the quiescence. In the first-ever complete light-curve, a few primary and secondary eclipses of the binary system were detected, and the timings of the minima were determined. We found that the eclipses showed no totality during the outburst. The depth of the primary eclipses was 0.4–0.8 mag, much shallower than that in quiescence. In the plateau phase, very little irradiation ($\leq 0.1 \,\mathrm{mag}$) was observed in the orbital light curve, which implies the existence and a large flaring rim of the accretion disk during the outburst. The minima of the eclipses were detected at earlier orbital phases for the predicted ephemerides. Thus, we obtained an orbital period change of the binary system as $\dot{P}/P =-1.7 (\pm 0.7) \times 10^{-6} \,\mathrm{yr}^{-1}$ from the $O-C$. Assuming that this period change is a result of the conservative mass transfer between the component stars, its mass-transfer rate reaches $\dot{M} = 2.4 (\pm 1.0) \times 10^{-6} \,{{{M}_{\odot}}} \,\mathrm{yr}^{-1}$ for a $1.37 \,{{{M}_{\odot}}}$ white dwarf and a $2.0 \,{{{M}_{\odot}}}$ mass-donor companion, which is too high to cause shell flashes, even on a massive white dwarf. Therefore, this large rate of the period change strongly indicates a non-conservative mass transfer in the binary system.
ATCA Monitoring Observations of 202 Compact Radio Sources in Support of the VSOP AGN Survey
Authors: Tingay Steven J. , Jauncey David L. , King Edward A. , Tzioumis Anastasios K. , Lovell James E. J. , Edwards Philip G. 
Published: March 2014

Abstract
The Australia Telescope Compact Array (ATCA) has been used in support of the VLBI Space Observatory Programme (VSOP) space VLBI mission, to monitor the total and polarised flux densities of 202 objects that make up 83% of the VSOP all-sky Survey of compact extragalactic radio sources south of $\delta=+10^{\circ}$. The primary goal of the ATCA observations is to provide information on the total and polarised emission from the compact components in these sources, for correlation with parameters obtained from VSOP imaging observations. These data represent the first high resolution, long timescale flux density monitoring observations of a large number of southern compact radio sources. In the future, comparison of the ATCA and VSOP data will be used to investigate relativistic beaming models and identify similarities or differences between the major classes of extragalactic radio sources. As an illustration of the scientific value of the ATCA data we undertake a comparison of the properties of the gamma-ray loud and gamma-ray quiet AGN in the southern component of the VSOP Survey sample, finding that in a flat-spectrum sub-sample the gamma-ray loud AGN are more variable than the gamma-ray quiet AGN.
On the Stationarity of a Spiral Structure in Disk Galaxies
Authors: Yano Taihei , Kan-ya Yukitoshi , Gouda Naoteru 
Published: March 2014

Abstract
We investigate whether a spiral arm in disk galaxies can possibly be stationary, assuming that the spiral structure is some pattern formed by a density wave. We numerically calculated stellar orbits in assumed galactic potentials with spiral patterns and analyzed the orbital behavior in the potentials to study the criteria for the disk parameters, in which a stationary spiral structure is possible. We found the following results: the spiral potential drives the dynamical evolution, which results in the spiral structure, bar structure, or disappearance of the structure, depending on the form of the assumed spiral pattern. If a stationary spiral structure appears, the only possible pitch angle of the arms is around $5^{\circ}$. Therefore, observed spiral arms in late-type spiral galaxies with large pitch angles cannot be a stationary structure if the arms are induced by a density wave.
Long-Term Orbital Period Variations for EU Hydrae
Authors: Qian Sheng-Bang , Boonrucksar Soonthornthum 
Published: March 2014

Abstract
Long-term period variations of an Algol-type eclipsing binary star, EU Hydrae, are presented based on an analysis of its $O-C$ curve. As in the cases of other Algols studied in recent papers by one of the authors (S.-B. Qian), an alternate period change has discovered to superimpose on a secular period decrease ($dP / dt =-4.8 \times 10^{-8} \,\mathrm{d} \,\mathrm{yr}^{-1}$). By assuming that the alternate variation is cyclic, a period of 26.5 yr and an amplitude of 0.0104 d were determined. A long-term period decrease combined with a semi-detached configuration may indicate that EU Hya is undergoing a secular angular momentum loss. Three possible mechanisms are proposed to explain the alternate period change.