bluuebunny/crossref_metadata_2025 huggingface dataset:
A Study on Red Asymmetry of Hα Flare Ribbons Using a Narrowband Filtergram in the 2001 April 10 Solar Flare
Authors: Asai Ayumi , Ichimoto Kiyoshi , Kitai Reizaburo , Kurokawa Hiroki , Shibata Kazunari
Published: March 2014

We report on a detailed examination of the “red asymmetry” of the H$\alpha$ emission line seen during the 2001 April 10 solar flare by using a narrowband filtergram. We investigated the temporal evolution and the spatial distribution of the red asymmetry by using H$\alpha$ data taken with the 60-cm Domeless Solar Telescope at Hida Observatory, Kyoto University. We confirmed that the red asymmetry clearly appeared all over the flare ribbons, and the strong red asymmetry is located on the outer narrow edges of the flare ribbons, with a width of about 1$.\!\!\!”$5–3$.\!\!\!”$0 (1000–2000 km), where strong energy releases occur. Moreover, we found that the red asymmetry, which also gives a measure of the Doppler shift of the H$\alpha$ emission line, concentrates on a certain value, not depending on the intensity of the H$\alpha$ kernels. This implies not only that the temporal evolutions of the red asymmetry and those of the intensity are not synchronous in each flare kernel, but also that the peak asymmetry (or velocity of the chromospheric condensation) of individual kernel is not a strong function of their peak intensity.
Kinematics of Red Variables in the Solar Neighborhood I. Basic Data Obtained by an SiO Maser Survey
Authors: Deguchi Shuji , Sakamoto Tsuyoshi , Hasegawa Takashi
Published: March 2014

In order to study the streaming motions of miras in the Solar neighborhood, we newly surveyed 379 red variables in the SiO maser lines at 42.821 and 43.122 GHz with the Nobeyama 45 m radio telescope. Accurate radial velocities were obtained for 229 (220 new) detected stars. The sample was selected from optical variables found by new automated surveys: the Northern Sky Variability Survey and the All Sky Automated Survey. The new sample consists of “bluer” objects compared with those observed in the previous SiO surveys. The distances to the objects were estimated using the period–luminosity relation, and they are mostly less than 3 kpc from the Sun. The longitude–velocity diagram reveals three prominent groups of stars deviant from circular galactic rotation with a flat rotation curve. In addition to the Hercules group of stars, which was studied before, we found two new deviant groups: one toward the Perseus arm and the other toward the Sagittarius arm. These two groups both exhibit anomalous motions toward the galactic center, which seem to be consistent with the noncircular motions of these spiral arms found in recent VLBI proper-motion measurements for maser gas clumps.
Numerical Simulations of Line-Profile Variation beyond a Single-Surface Approximation for Oscillations in roAp Stars
Authors: Nomura Takashi , Naito Jun , Shibahashi Hiromoto
Published: March 2014

Prior to the last decade, most observations of roAp stars have concerned light variations. Recently some new, striking results of spectroscopic observations with high time resolution, high spectral dispersion, and a high signal-to-noise ratio became available. Since the oscillations found in roAp stars are high overtones, the vertical wavelengths of the oscillations are so short that the amplitude and phase of the variation of each spectroscopic line are highly dependent on the level of the line profile. Hence, analyses of the variation of the spectroscopic lines of roAp stars potentially provide us with new information about the vertical structure of the atmosphere of these stars. In order to extract such information, a numerical simulation of the line-profile variation beyond a single-surface approximation is necessary. We carried out a numerical simulation of line-profile variation by taking account of the finite thickness of the line-forming layer. We demonstrated how effective this treatment is, by comparing the simulation with the observed line profiles.
The Jet-Disk Symbiosis in Blazar and Unified Model of FSRQs and BL Lac Objects
Authors: Xie Zhao Hua , Zhang Li
Published: March 2014

Using multi-wave band data for a large sample of 70 blazars, including 38 flat-spectrum radio quasars (FSRQs) and 32 BL Lac Objeces, we studied the correlations for both the flux and luminosity of the broad-line emission ($F_{\rm BLR}$) with the near-infrared flux ($F_{K}$), X-ray flux ($F_{X}$) and radio flux at 5 GHz ($F_{R}$), respectively. We could see that there is always a strong correlation between the broad-line and multi-wave bands for a sample of 70 blazars; also, the slopes of the corresponding linear-regression equations are close to 1, which is consistent with the theoretical results. These results provide some new experimental evidence about coupling of the accretion disk and the jet of blazars. Simultaneously, we also indicated that the relative location of BL Lacs and FSRQs are quite separated, and that the luminosity of the the broad-line emission for BL Lacs is much less for FSRQs, which can prove that FSRQs and BL Lacs could be considered as a single population, or FSRQs and BL Lacs should be regarded as a class. But they are in different evolutionary stages of blazars, and have different types of accretion disks with different line-to-continuum ratios. Finally, the unified model of FSRQs and BL Lacs is also discussed.
Lithium, Sodium, and Potassium Abundances in Sharp-Lined A-Type Stars
Authors: Takeda Yoichi , Kang Dong-Il , Han Inwoo , Lee Byeong-Cheol , Kim Kang-Min , Kawanomoto Satoshi , Ohishi Naoko
Published: March 2014

The abundances of alkali elements (Li, Na, and K) were determined from the Li I 6708, Na I 5682/5688, and K I 7699 lines by taking into account the non-LTE effect for 24 sharp-lined A-type stars ($v _{\rm e}$ sin $i$$\lesssim$ 50 km s$^{-1}$, 7000 K $\lesssim$$T_{\rm eff}$$\lesssim$ 10000 K, many showing Am peculiarities to different degrees), based on high-dispersion and high-$S/N$ spectral data secured at BOAO (Korea) and OAO (Japan). We found a significant trend that $A$(Na) tightly scales with $A$(Fe) irrespective of $T_{\rm eff}$, which means that Na becomes enriched similarly to Fe in accordance with the degree of Am peculiarity. Regarding lithium, $A$(Li) mostly ranges between $\sim$ 3 and $\sim$ 3.5 (i.e., almost the same as or slightly less than the solar system abundance of 3.3) with a weak decreasing tendency with a lowering of $T_{\rm eff}$ at $T_{\rm eff}$$\lesssim$ 8000 K, though several stars exceptionally show distinctly larger depletion. The abundances of potassium also revealed an apparent $T_{\rm eff}$-dependence in the sense that $A$(K) in late-A stars tends to be mildly subsolar [possibly with a weak anti-correlation with $A$(Fe)] systematically decreasing from $\sim$ 5.0 ($T_{\rm eff}$$\sim$ 8500 K) to $\sim$ 4.6 ($T_{\rm eff}$$\sim$ 7500 K), while those for early-A stars remain near-solar around $\sim$ 5.0–5.2. These observational facts may serve as important constraints for any theory aiming to explain chemical anomalies of A-type stars.
Appearance of Jet-Driving Poynting Flux in Hot, Tenuous Accretion Disks Threaded by an Ordered Magnetic Field
Authors: kaburaki Osamu
Published: March 2014

In a series of our previous studies, a model of radiatively inefficient accretion flows (RIAFs) in a global magnetic field (so-called resistive RIAF model) has proved its ability to account for many physical processes taking place in such accretion flows, as realized in the nuclei of galaxies believed to be accreting at a very small fraction of each Eddington accretion rate. Within the present status of this model, however, the model cannot describe the launch of a self-confined bipolar jet from the vicinity of the disk's inner edge, although it allows the existence of a thermal wind widely distributed over the disk surfaces. This is because the electric field (and hence the Poynting flux) vanishes everywhere in the disk, whereas such a jet in a globally ordered magnetic field is most likely to be accelerated electrodynamically. We show in the present paper that this defect can be overcome naturally if we reformulate the problem so as to admit a quasi-stationary change of the magnetic field (and hence the appearance of a non-irrotational electric field), and also restore all of the terms of order $ \epsilon$$ \equiv$ ($ v_r/v_{\varphi}$ )$ ^2$$ \lesssim$ 1 (where $ v_r$ and $ v_{\varphi}$ denote the radial and azimuthal components, respectively, of the fluid velocity), which have been neglected altogether in our previous scheme. The restored effects are the inertial and magnetic draggings on the infalling matter. As an illustrative example, a model solution that is correct up to $ {\cal O}(\epsilon)$ is derived under a set of plausible restrictions. The new solution predicts the appearance of a localized Poynting flux in a region near the disk inner edge, strongly suggesting that a jet is launched from this region. Another interesting prediction is the appearance of a rapid change of the magnetic field, also localized to this region.
Observed Magnitude and Luminous Efficiency of Reentry Capsule of HAYABUSA Spacecraft
Authors: Sato Mikiya , Watanabe Jun-ichi , Tanabe Tsutomu , Ohnishi Kouji , Ohkawa Takuya , Iijima Yutaka , Kagaya Yutaka
Published: March 2014

The brightness variation of the sample capsule of the HAYABUSA spacecraft was observed during reentry into Earth's atmosphere on 2010 June 13 UT. The capsule was observed from 13$^{\rm h}$52$^{\rm m}$01$^{\rm s}$ through 13$^{\rm h}$52$^{\rm m}$38$^{\rm s}$ UT, with three peaks of brightness between 13$^{\rm h}$52$^{\rm m}$19$^{\rm s}$ and 21$^{\rm s}$ UT. The absolute magnitude of the highest peak was $-$5.7($\pm$0.9) at 13$^{\rm h}$52$^{\rm m}$18$.\hskip-1mm^{\rm s}$6 UT. The luminous efficiency reached to the largest value of 0.89% ($+$1.14%, $-$0.50%) at a time corresponding to an altitude of 58.1 km above sea level.
A Particle Simulation for the Pulsar Magnetosphere: Relationship of Polar Cap, Slot Gap, and Outer Gap
Authors: Shinya Yuki , Shinpei Shibata
Published: March 2014

To explain the pulsed emission of the rotation powered pulsars from radio to gamma-ray, polar cap models, slot gap models, and outer gap models are proposed. Recent observations suggest that these models are likely to co-exist in the same magnetosphere. If so, their mutual relation is known to be troublesome (Harding 2009), due to the boundary conditions and the direction of the current, which are properly assumed in each acceleration model. We performed a particle simulation for the global magnetospheric structure. Based on this simulation, we present a new picture of the global structure of the pulsar magnetosphere. It is found that a new dead zone is formed along the current neutral line that separates the oppositely directed current. We shall call this the current-neutral zone. We suggest that the polar cap accelerators and the slot gaps locate above the current-neutral zone, and the outer gap exist between the current neutral zone and the traditional dead zone. We also give an estimate of the super-rotation region.
Relativistic Radiative Transfer in Relativistic Plane–Parallel Flows: Roles of Scattering Effect
Authors: Fukue Jun
Published: March 2014

Relativistic radiative transfer in a relativistic plane–parallel flow has been reexamined under a non-gray treatment, while focusing our attention on the scattering effect. Under the assumption of a constant flow speed and using a variable Eddington factor, we analytically solved the relativistic transfer equations in the comoving frame for several cases, such as radiative equilibrium or local thermodynamical equilibrium, and obtained analytical solutions for the emergent intensity as well as other radiative quantities. In the case of the radiative equilibrium, the scattering effect does not appear, and the solutions are formally the same as those under the gray case, although the frequency-dependent intensity was obtained for the first time. In the case of local thermodynamic equilibrium, on the other hand, the scattering effect is significant in isothermal flow, similar to a static isothermal atmosphere. That is, the source function reduces near to the flow top, and the emergent intensity decreases toward the limb due to scattering. In both cases, when the flow optical depth becomes small, the emergent intensity toward the pole decreases due to the effect of a finite optical depth. In addition, the emergent intensity and other quantities in the fixed (inertial) frame are enhanced due to relativistic effects.
Magnetic Helicity of Solar Active Regions as Revealed by Vector Magnetograms and Coronal X-Ray Images
Authors: Xu Haiqing , Gao Yu , Zhang Hongqi , Sakurai Takashi , Hagino Masaoki , Sokoloff Dmitry , Pevtsov Alexei A.
Published: March 2014

We have used photospheric vector magnetograms of 15 different solar active regions to calculate the current helicity parameter, $ \alpha _{\rm av}$ , and the linear force-free field (LFFF) parameter, $ \alpha _{\rm best}$ , that fits best the observed transverse field. The data were obtained with the Solar Magnetic Field Telescope at the Huairou Solar Observing Station, the National Astronomical Observatories of China, the Solar Flare Telescope of the National Astronomical Observatory of Japan, and the Haleakala Stokes Polarimeter at the Mees Solar Observatory, University of Hawaii, from 1997 to 2000. The agreement in sign of $ \alpha _{\rm av}$ between three vector magnetographs is better than 90%. For $ \alpha _{\rm best}$ , the agreement is 80%–90%. The line-of-sight magnetograms observed with the Michelson–Doppler Imager (MDI) on SOHO and coronal X-ray images observed with the Soft X-ray Telescope (SXT) on Yohkoh have been used to determine the constant $ \alpha _{\rm c}$ of the LFFF in the corona. The value of $ \alpha _{\rm c}$ corresponds to the extrapolated coronal field whose field lines best match, by visual inspection, the structure of coronal loops in X-ray images. It is found that the sign agreement between photospheric $ \alpha _{\rm av}$ or $ \alpha _{\rm best}$ and coronal $ \alpha _{\rm c}$ is lower (60%–85%). We consider the differences in measurements, observing conditions, data reduction methods, and limitation in LFFF extrapolation, and discuss their contributions to the dispersions in the hemispheric sign rule of helicity.
FIBRE-Pac: FMOS Image-Based Reduction Package
Authors: Iwamuro Fumihide , Moritani Yuuki , Yabe Kiyoto , Sumiyoshi Masanao , Kawate Kaori , Tamura Naoyuki , Akiyama Masayuki , Kimura Masahiko , Takato Naruhisa , Tait Philip , Ohta Kouji , Totani Tomonori , Suzuki Yuji , Tonegawa Motonari
Published: March 2014

The FIBRE-pac (FMOS image-based reduction package) is an IRAF-based reduction tool for the fiber multiple-object spectrograph (FMOS) of the Subaru telescope. To reduce FMOS images, a number of special techniques are necessary, because each image contains about 200 separate spectra with airglow emission lines variable in spatial and time domains, and with complicated throughput patterns for airglow masks. In spite of these features, almost all of the reduction processes, except for a few steps, are carried out automatically by scripts in text format, making it easy to check the commands step by step. Wavelength- and flux-calibrated images together with their noise maps are obtained using this reduction package.
Mode Classification of Linear Adiabatic Oscillations of Spherically Symmetric Stars
Authors: Takata Masao
Published: March 2014

We propose a mathematical scheme to classify the eigenmodes of linear adiabatic oscillations of spherically symmetric stars, while fully taking account of the perturbation to the gravitational potential. The scheme allows us to allocate a unique and continuous integral index (the radial order) to each non-degenerate eigenmode with a positive squared eigenfrequency of any stellar structure, whereas a pair of degenerate eigenmodes, if exist, are assigned a unique pair of indices. The indices of the eigenmodes are invariant against any continuous change in the equilibrium structure. Based on these indices, we can unambiguously define the three kinds of eigenmodes of adiabatic stellar oscillations: p-modes, g-modes, and f-modes.
Outburst of LSV+44 17 Observed by MAXI and RXTE, and Discovery of a Dip Structure in the Pulse Profile
Authors: Usui Ryuichi , Morii Mikio , Kawai Nobuyuki , Yamamoto Takayuki , Mihara Tatehiro , Sugizaki Mutsumi , Matsuoka Masaru , Hiroi Kazuo , Ishikawa Masaki , Isobe Naoki , Kimura Masashi , Kitayama Hiroki , Kohama Mitsuhiro , Matsumura Takanori , Nakahira Satoshi , Nakajima Motoki , Negoro Hitoshi , Serino Motoko , Shidatsu Megumi , Sootome Tetsuya , Sugimori Kousuke , Suwa Fumitoshi , Toizumi Takahiro , Tomida Hiroshi , Tsuboi Yoko , Tsunemi Hiroshi , Ueda Yoshihiro , Ueno Shiro , Yamaoka Kazutaka , Yamazaki Kyohei , Yoshida Atsumasa
Published: March 2014

We report on the first observation of an X-ray outburst of a Be/X-ray binary pulsar, LS V $+$44 17/ RX J0440.9$+$4431, and the discovery of an absorption dip structure in the pulse profile. An outburst of this source was discovered by MAXI GSC in 2010 April. It was the first detection of transient activity of LS V $+$44 17 since the source was identified as a Be/X-ray binary in 1997. From the data of a follow-up RXTE observation near the peak of the outburst, we found a narrow dip structure in its pulse profile, which was clearer in the lower-energy bands. The pulse-phase-averaged energy spectra in the 3–100 keV band could be fitted with a continuum model containing a power-law function with an exponential cutoff and a blackbody component, which are modified at low energy by an absorption component. A weak iron K$\alpha$ emission line was also detected in the spectra. From the pulse-phase-resolved spectroscopy we found that the absorption column density at the dip phase was much higher than those in the other phases. The dip was not seen in subsequent RXTE observations at lower flux levels. These results suggest that the dip in the pulse profile originates from the eclipse of the radiation from the neutron star by the accretion column.
Water-Vapor Maser Disk at the Nucleus of the Seyfert 2 Galaxy IC 2560 and its Distance
Authors: Yamauchi Aya , Nakai Naomasa , Ishihara Yuko , Diamond Philip , Sato Naoko
Published: March 2014

We present the results of single-dish and VLBI observations for the water-vapor masers at the nucleus of a Seyfert 2, IC 2560. We monitored the velocities of the maser features with the 45-m telescope of the Nobeyama Radio Observatory. Using data form 1995–2006, the velocity drift rate was detected to be $ \bar{a}$  $ =$  $ +$ 2.57 $ \pm$ 0.04 km s$ ^{-1}$ yr$ ^{-1}$ on the average for 6 systemic features. The Very Long Baseline Array (VLBA) with the Very Large Array (VLA) firstly detected red-shifted and blue-shifted maser features of IC 2560, in addition to systemic maser features and a continuum component. We propose a maser disk in the nuclear region. The systemic and red-shifted features are emitted from a nearly edge-on disk with a position angle of PA  $ =$  $-$ 46$ ^{\circ}$ , which is almost perpendicular to the galactic disk. Assuming Keplerian rotation, the radii of the maser disk are $ r$  $ =$ 0.087–0.335 pc, and the thickness is 2$ H$  $ \leq$ 0.025 pc. The binding mass is 3.5 $ \times$ 10$ ^{6}$  $ M\odot$ at a distance of $ D$  $ =$ 26 Mpc, and the mean volume density within the inner radius is 1.3 $ \times$ 10$ ^{9}M\odot$ pc$ ^{-3}$ , strongly suggesting a massive black hole at the center. A continuum component was detected at 0.2 pc southwest of the disk center, and is considered to be a jet ejected from the nucleus, with an angle of 70$ ^{\circ}$ from the disk. The blue-shifted maser feature is located on the continuum component, being interpreted to be a ``jet maser.'' The distance to IC 2560 was estimated to be $ D$  $ =$ 31$ ^{+12}_{-14}$ Mpc from the geometry of the maser disk and the velocity drift rate.
The 3 mm Spectral Line Survey toward the Lynds 1157 B1 Shocked Region. I. Data
Authors: Takahiro Yamaguchi , Takano Shuro , Watanabe Yoshimasa , Sakai Nami , Sakai Takeshi , Liu Sheng-Yuan , Su Yu-Nung , Hirano Naomi , Takakuwa Shigehisa , Aikawa Yuri , Nomura Hideko , Yamamoto Satoshi
Published: March 2014

We have conducted a spectral line survey of the 3 mm band with the 45 m telescope of Nobeyama Radio Observatory toward the L 1157 B1 shocked region, where the blue-shifted component of the bipolar outflow from the protostar IRAS 20386$ +$ 6751 interacts with the ambient gas. The observed frequency ranges from 78.1 to 115.8 GHz. We have detected 129 spectral lines of 29 molecular species. In addition to various oxygen-bearing organic molecules such as CH$ _3$ CHO, HCOOCH$ _3$ , and HCOOH, we have detected a phosphorus-containing molecule PN, a nitrogen-bearing organic molecule NH$ _2$ CHO, and a carbon-chain molecule CCS in the shocked region. These results clearly indicate that the L 1157 B1 shocked region is chemically rich, which is probably triggered by evaporation of grain mantles.
Multiwavelength Study of the NGC 281 Region
Authors: Sharma Saurabh , Pandey Anil K. , Pandey Jeewan C. , Chauhan Neelam , Ogura Katsuo , Ojha Devandra K. , Borrissova Jura , Mito Hiroyuki , Verdugo Thomas , Bhatt Bhuwan C.
Published: March 2014

We present a multiwavelength study of the NGC 281 complex, which contains the young cluster IC 1590 at the center, using deep wide-field optical $ UBVI_{\rm c}$ photometry, slitless spectroscopy along with archival data sets in the near-infrared (NIR) and X-ray regions. The extent of IC 1590 is estimated to be $ \sim$ 6.5 pc. The cluster region shows a relatively small amount of differential reddening. The majority of the identified young stellar objects (YSOs) are low-mass PMS stars having age $ \lt$ 1–2 Myr and mass 0.5–3.5 $ M_{\odot}$ . The slope ($ \Gamma$ ) of the mass function for IC 1590, in the mass range 2 $ \lt$$ M/M_\odot$$ \le$ 54, is found to be $-$ 1.11 $ \pm$ 0.15. The slope of the $ K$-band luminosity function (0.37 $ \pm$ 0.07) is similar to the average value ($ \sim$ 0.4) reported for young clusters. The distribution of gas and dust obtained from the IRAS, CO, and radio maps indicates clumpy structures around the central cluster. The radial distribution of the young stellar objects, their ages, $ \Delta$ ($ H$$-$$ K$ ) NIR-excess, and the fraction of classical T Tauri stars suggest triggered star formation at the periphery of the cluster region. However, deeper optical, NIR, and MIR observations are needed to have a conclusive view of the star-formation scenario in the region. The properties of the Class 0/I and Class II sources detected by using the Spitzer mid-infrared observations indicate that a majority of the Class II sources are X-ray emitting stars, whereas X-ray emission is absent from the Class 0/I sources. The spatial distribution of Class 0/I and Class II sources reveals the presence of three sub-clusters in the NGC 281 West region.
Do Environmental Conditions Affect the Dust-Induced Fragmentation in Low-Metallicity Clouds? Effect of Pre-Ionization and Far-Ultraviolet/Cosmic-Ray Fields
Authors: Omukai Kazuyuki
Published: March 2014

We study the effects of the fully ionized initial state, or pre-ionization, on the subsequent thermal evolution of low-metallicity clouds under various intensities of external far-ultraviolet (FUV) and cosmic-ray (CR) fields. Pre-ionization significantly affects the thermal and dynamical evolution of metal-free clouds without FUV/CRs by way of efficient HD formation. On the other hand, the pre-ionization effect on thermal evolution is limited in the very low-density regime for more metal-enriched clouds ([Z$ /$ H] $ \gtrsim$$-$ 4), or those under a modest FUV ($ \gtrsim$ 10$ ^{-3}$ ) field or CR field ($ \gtrsim$ 0.1) of the present-day galactic disk levels. In any case, for $ \gtrsim$ 10$ ^{8}$ cm$ ^{-3}$ , neither the initial ionization state nor the irradiating FUV strength affect the thermal evolution. The dust cooling is an important mechanism for making sub-solar mass fragments in low-metallicity gas. Since this fragmentation occurs at the temperature minimum by dust cooling at $ \gtrsim$ 10$ ^{10}$ cm$ ^{-3}$ , this process is not vulnerable either to the initial ionization state or external radiation.
Spatial Distribution of Abundance Patterns in the Starburst Galaxy NGC 3079 Revealed with Chandra and Suzaku
Authors: Konami Saori , Matsushita Kyoko , Gandhi Poshak , Tamagawa Toru
Published: March 2014

We performed simultaneous spectral analyses of Chandra (26.6 ks) and Suzaku (102.3 ks) X-ray data of the starburst galaxy NGC 3079. The spectra were extracted from four regions: 0$ .\!\!'$ 5 (2.25 kpc) circle, an inner 0$ .\!\!'$ 5–1$ '$ (2.25–4.5 kpc) ring, and an outer 1$ '$ –2$ '$ (4.5–9 kpc) ring from Chandra, and 4$ '$ (18 kpc) circle from Suzaku, all centered on the nucleus. Fittings of thermal plasma models yield interstellar medium (ISM) temperatures of 0.65$ ^{+0.05}_{-0.04}$ (0$ .\!\!'$ 5 circle), 0.45$ ^{+0.07}_{-0.06}$ (0$ .\!\!'$ 5–1$ '$ ring), and 0.24$ ^{+0.03}_{-0.02}$ (1$ '$ –2$ '$ ring) keV in the three regions. The combination of Chandra's high angular resolution and Suzaku's high spectral sensitivity enabled us to spatially resolve and measure the abundances of the metals O, Ne, Mg, Si, and Fe within the hot ISM. In particular, the abundance patterns of O$ /$ Fe, Ne$ /$ Fe, Mg$ /$ Fe, and Si$ /$ Fe in the central region ($ \lt$ 4.5 kpc) are consistent with those expected from a supernova (SN) II synthesis. On the other hand, the pattern in the region beyond 4.5 kpc is closer to solar. The central region is also where copious polycyclic aromatic hydrocarbon infrared emission related to the recent starburst activity is known to occur. This suggests that we are seeing starburst-related SN II metal enrichment in the hot X-ray-emitting nuclear ISM. The spatial extent of SN II-like abundance patterns is consistent with that of NGC 3079 being in a relatively-early phase of starburst activity.
Comparative Study of Manufacturing Techniques for Coronagraphic Binary Pupil Masks: Masks on Substrates and Free-Standing Masks
Authors: Enya Keigo , Haze Kanae , Kotani Takayuki , Abe Lyu
Published: March 2014

We present a comparative study of the manufacture of binary pupil masks for coronagraphic observations of exoplanets. A checkerboard mask design, a type of binary pupil mask design, was adopted, and identical patterns of the same size were used for all masks in order that we could compare the differences resulting from the different manufacturing methods. The masks on substrates had aluminum checkerboard patterns with thicknesses of 0.1/0.2/0.4/0.8/1.6 $ \mu$ m, constructed on substrates of BK7 glass, silicon, and germanium using photolithography and chemical processes. Free-standing masks made of copper and nickel with thicknesses of 2/5/10/20 $ \mu$ m were also realized using photolithography and chemical processes, which included careful release from the substrate used as an intermediate step in the manufacture. Coronagraphic experiments using a visible laser were carried out for all masks on BK7 glass substrate and the free-standing masks. The average contrasts were 8.4 $ \times$ 10$ ^{-8}$ , 1.2 $ \times$ 10$ ^{-7}$ , and 1.2 $ \times$ 10$ ^{-7}$ for the masks on BK7 substrates, the free-standing copper masks, and the free-standing nickel masks, respectively. No significant correlation was concluded between the contrast and the mask properties. The high-contrast masks have the potential to cover the needs of coronagraphs for both ground-based and space-borne telescopes over a wide wavelength range. Especially, their application to the infrared space telescope, SPICA, is appropriate.
Electron Impact Excitation of N-like Ca XIV
Authors: Dong Futong , Wang Feilu , Zhong Jiayong , Liang Guiyun , Zhao Gang
Published: March 2014

We present a close-coupling R-matrix calculation of the electron impact excitation of N-like Ca XIV. GRASP (general-purpose relativistic atomic structure package) was used to obtain the target states. Level energies are reported for the 272 levels of the target ion. The oscillator strengths and radiative rates were calculated for E1, E2, M1, and M2 transitions among these levels. In order to determine the collision strength, the lowest 84 levels were used as the target model, together with 40 partial waves included in the R-matrix calculation. The effective collision strengths were obtained by integrating the collision strengths over a Maxwellian electron energies distribution. Comparisons were made with our FAC and the LB results by Landi and Bhatia (2005, At. Data Nucl. Data Tables, 90, 177). Good agreements are shown for level energies, oscillator strengths and radiative rates, respectively. As to the collision strength, a mass of resonances appears in the R-matrix results, which are important in the determination of effective collision strengths. The discrepancies of the effective collision strengths between results from the R-matrix and from FAC are discussed. Finally, the effective collision strengths for transitions among the first 84 levels are reported. To test our results, we also compared the predicted line ratio with the observed values.
Radiative Transfer in Anisotropic Scattering Media
Authors: Fukue Jun
Published: March 2014

Transfer and moment equations in anisotropic scattering media are formulated under a simple linear model using the Eddington approximation. In the transfer equation, a term including the radiative flux appears, and the first moment equation is also modified, while the zeroth moment equation does not change, since the scattering processes exchange momentum, but not energy. Moment equations and transfer equation are solved for several simple cases to clarify the qualitative properties of radiative transfer in anisotropic scattering media. When forward scattering dominates, the radiative intensity is enhanced in some cases, while the gradient of the mean intensity decreases in other cases, depending on the boundary conditions for the problem. These analytic expressions are helpful in studying and understanding the radiative properties of stars with dusty envelopes, interstellar matter, protoplanetary disks and star forming regions, and the dusty universe.
Annual Parallax of the K-Type Star System IRAS 22480+6002 Measured with VERA
Authors: Imai Hiroshi , Sakai Nobuyuki , Nakanishi Hiroyuki , Sakanoue Hirofumi , Honma Mareki , Miyaji Takeshi
Published: March 2014

We present astrometric VLBI observations of H$_2$ O masers associated with IRAS 22480$+$ 6002 ($=$ IRC$+$ 60370, hereafter I22480) with the VLBI Exploration of Radio Astrometry (VERA). The stellar type of I22480 looks unusual in stellar maser sources, and has been debated since the 1970's. We successfully determined that an annual parallax of a group of H$_2$ O maser spots is $\pi$  $=$ 0.400 $\pm$ 0.025 mas, corresponding to a distance to I22480 of $D$  $=$ 2.50$^{+0.17}_{-0.15}$ kpc. This suggests that an estimated bolometric luminosity of I22480 should be revised to 35000 $L_{\odot}$ , preferring a K-type supergiant to an RV Tau-type variable star, previously suggested. Although its spectral type is unusual in stellar maser sources, internal motions of H$_2$ O maser features suggest that the H$_2$ O masers are associated with the circumstellar envelope of this star. We derived a secular proper motion of I22480, ($\mu_{\alpha}$ , $\mu_{\delta}$ ) $=$ ($-$ 2.58 $\pm$ 0.33, $-$ 1.91 $\pm$ 0.17) [mas yr$^{-1}$ ], from a possible stellar motion relative to the maser feature motion. The derived motion of I22480 in the Milky Way has a deviation of $\sim-$ 30 km s$^{-1}$ in the Galactic azimuthal direction from the circular motion, estimated from a galactocentric distance to I22480 and an assumption of a flat Galactic rotation curve. This peculiar motion is still comparable to those typically seen in H$_2$ O maser sources located in the Perseus Arm. Taking into account its peculiar motion and proximity to the Galactic midplane (z  $\simeq$ 60 pc), I22480 may be a member of the Galactic thin disk.
A Common Proper Motion Stellar Companion to HAT-P-7
Authors: Narita Norio , Takahashi Yasuhiro H. , Kuzuhara Masayuki , Hirano Teruyuki , Suenaga Takuya , Kandori Ryo , Kudo Tomoyuki , Sato Bun'ei , Suzuki Ryuji , Ida Shigeru , Nagasawa Makiko , Abe Lyu , Brandner Wolfgang , Brandt Timothy D. , Carson Joseph , Egner Sebastian E. , Feldt Markus , Goto Miwa , Grady Carol A. , Guyon Olivier , Hashimoto Jun , Hayano Yutaka , Hayashi Masahiko , Hayashi Saeko S. , Henning Thomas , Hodapp Klaus W. , Ishii Miki , Iye Masanori , Janson Markus , Knapp Gillian R. , Kusakabe Nobuhiko , Kwon Jungmi , Matsuo Taro , Mayama Satoshi , Mcelwain Michael W. , Miyama Shoken M. , Morino Jun-Ichi , Moro-Martin Amaya , Nishimura Tetsuo , Pyo Tae-Soo , Serabyn Eugene , Suto Hiroshi , Takami Michihiro , Takato Naruhisa , Terada Hiroshi , Thalmann Christian , Tomono Daigo , Turner Edwin L. , Watanabe Makoto , Wisniewski John P. , Yamada Toru , Takami Hideki , Usuda Tomonori , Tamura Motohide
Published: March 2014

We report that HAT-P-7 has a common proper motion stellar companion. The companion is located at $ \sim$ 3$ .\!\!\!''$ 9 to the east and estimated to be an M5.5V dwarf based on its colors. We also confirm the presence of a third companion, which was first reported by Winn et al. (2009, ApJ, 703, L99), based on long-term radial velocity measurements. We revisit the migration mechanism of HAT-P-7b given to the presence of those companions, and propose the sequential Kozai migration as a likely scenario in this system. This scenario may explain the reason for an outlier in the discussion of the spin-orbit alignment timescale for HAT-P-7b by Albrecht et al. (2012, ApJ, 757, 18).
A Fiber Link between the Okayama 188-cm Telescope and the High-Dispersion Spectrograph, HIDES
Authors: Kambe Eiji , Yoshida Michitoshi , Izumiura Hideyuki , Koyano Hisashi , Nagayama Shogo , Shimizu Yasuhiro , Okada Norio , Okita Kiichi , Sakamoto Akihiro , Sato Bun'ei , Yamamuro Tomoyasu
Published: March 2014

We have developed a high-efficiency fiber link (HE mode) connecting Okayama 188-cm telescope to the high-resolution spectrograph, HIDES, in order to improve the throughput of the observing system while keeping its radial-velocity measurement precision. In the HE mode, a multi-mode optical fiber collects stellar light within a 2.7-arcsecond diameter field of view (FOV) at the Cassegrain focus, which is twice as large as that of the typical seeing size at our observing site. An image slicer is used at the other end of the link, just in front of the entrance of HIDES, to keep the proper high spectral resolution for such a wide FOV. We have found that the maximum total throughput of the HE mode observations at around 550 nm reaches as high as 9%. Its practical throughput is also found to be more than twice that of the conventional slit observations. We have also confirmed that its reciprocal resolution is over 50000, as designed. The minimum available wavelength, which is determined from an inter-order gap of the echelle spectrum, is about 440 nm, where the gap becomes as narrow as 5 pixels on the CCD detector for the red cross-disperser of HIDES. From measurements of the rms errors of the radial velocity of some stars over one year, the long-term precision is as good as a few m s$ ^{-1}$. The fiber modal noise that could degrade the observed spectra may not be significant in the HE mode, as long as the signal-to-noise ratio of a spectrum is lower than 1500.
Infrared Spectroscopy of CO Ro-Vibrational Absorption Lines toward the Obscured AGN IRAS 08572+3915
Authors: Shirahata Mai , Nakagawa Takao , Usuda Tomonori , Goto Miwa , Suto Hiroshi , Geballe Thomas R.
Published: March 2014

We present high-resolution spectroscopy of gaseous CO absorption in the fundamental ro-vibrational band toward the heavily obscured active galactic nucleus (AGN) IRAS 08572$ +$ 3915. We have detected absorption lines up to highly excited rotational levels ($ J$$ \leqq$ 17). The velocity profiles reveal three distinct components, the strongest and broadest ($ \Delta v$$ >$ 200 km s$ ^{-1}$ ) of which is due to blueshifted ($-$ 160 km s$ ^{-1}$ ) gas at a temperature of $ \sim$ 270 K absorbing at velocities as high as $-$ 400 km s$ ^{-1}$ . A much weaker but even warmer ($ \sim$ 700 K) component, which is highly redshifted ($ +$ 100 km s$ ^{-1}$ ), is also detected, in addition to a cold ($ \sim$ 20 K) component centered at the systemic velocity of the galaxy. On the assumption of local thermodynamic equilibrium, the column density of CO in the 270 K component is $ N_{\rm {CO}}$$ \sim$ 4.5 $ \times$ 10$ ^{18}$ cm$ ^{-2}$ , which in fully molecular gas corresponds to an H$ _2$ column density of $ N_{\rm {H_2}}$$ \sim$ 2.5 $ \times$ 10$ ^{22}$ cm$ ^{-2}$ . The thermal excitation of CO up to the observed high rotational levels requires a density greater than $ n_{\rm c}$ (H$ _2$ ) $ >$ 2 $ \times$ 10$ ^{7}$ cm$ ^{-3}$ , implying that the thickness of the warm absorbing layer is extremely small ($ \Delta d$$ <$ 4 $ \times$ 10$ ^{-2}$ pc), even if it is highly clumped. The large column densities and high radial velocities associated with these warm components, as well as their temperatures, indicate that they originate in molecular clouds near the central engine of the AGN.
Global Operation of Resistive, Radiation-Inefficient, Accretion Flows in Preparing Jet-Driving Circumstances
Authors: Kaburaki Osamu
Published: March 2014

In our recent paper, we obtained a model solution to the problem of radiation-inefficient accretion flows (RIAFs) in a global magnetic field (so-called, resistive RIAF model), which is asymptotically exact in outer regions of such flows forming accretion disks. When extrapolated inwardly, the model predicts a local enhancement of the vertical Poynting flux within a small radius that may be regarded as the disk inner-edge. This fact has been interpreted as the origin of a power source for the astrophysical jets observationally well-known to be ejected from this type of accretion disks. Since the accuracy of the solution may become rather poor in such inner regions, however, the ground of this assertion may not seem to be so firm. In the present paper, we develop a sophisticated discussion for the appearance of jet-driving circumstances, based on much more firm ground by deriving a global solution in the same situation. Although the new solution still has an approximate nature, it becomes exact in the limits not only of large radius, but also of small radius. The analytic results clarify that the electrodynamic power is gathered by the Poynting flux, from the outer main-disk region to feed the innermost part of an accretion disk. The injected power largely exceeds the local supply of work by the fluid motion.
Catalog of SDSS Quasar Absorption Redshifts Measured from Mg II Absorption Lines. I. For Sources with z
em ≤ 0.8
Authors: Qin Yi-Ping , Chen Zhi-Fu , LÜ Lian-Zhong , Huang Wei-Rong , Li Mu-Sheng , Li Guo-Qiang , Wang Mei-Ping , Zhong Yu-Qing , Wen Sai-Qin , Liao Rong-Hua , Ye Feng
Published: March 2014

We are going to analyze the whole Sloan Digital Sky Survey (SDSS) quasar spectra by visually identifying Mg II absorption line systems one by one. In this paper, we limit our analysis to quasars with $ z_{\rm em}$$ \leq$ 0.8, which leaves 8006 quasars in total. Based on this, we are able to present the first catalog of these redshifts (in the interval of 0.36 $ <$$ z_{\rm abs}$$ <$ 0.81) in our series work (an analysis of higher redshift quasars will be performed later). Our work is based on spectral data previously analyzed by Quider et al. (2011, AJ, 141, 137). These authors identified Mg II absorption-line systems mainly based on search by machine; they found only 394 Mg II absorption lines from these 8006 quasars. However, for the same sample, we identified 4158 Mg II quasar absorption line systems. In our catalog, about 81% (3353/4158) of the absorbers have $ W_{\rm r}\lambda$ 2796 $ \ge$ 0.3 Å, and about 71% (2957/4158) of the absorbers have $ W_{\rm r}\lambda$ 2803 $ \ge$ 0.3 Å, showing that the main portion of our catalog is likely to be occupied by strong absorbers.
VLBI Imagings of a Kilo-Parsec Knot in 3C 380
Authors: Koyama Shoko , Kino Motoki , Nagai Hiroshi , Hada Kazuhiro , Kameno Seiji , Kobayashi Hideyuki
Published: March 2014

We investigated observational properties of a kilo-parsec scale knot in the radio-loud quasar 3C 380 by using two epoch archival data obtained by Very Long Baseline Interferometry (VLBI) at 5 GHz on 1998 July and 2001 April. We succeed to obtain the highest spatial resolution image of the bright knot K1 located at 732 mas, or $ \geqq$ 20 kpc de-projected, downstream from the nucleus three-times better than the previously obtained highest-resolution image by Papageorgiou et al. (2006, MNRAS, 373, 449). Our images reveal, with new clarity, an ``inverted bow-shock'' structure in K1 facing the nucleus; its morphology resembles a conical shock wave. By comparing the two epoch images directly, we explored the kinematics of K1, and obtained the upper limit of the apparent velocity, 0.25 mas yr$ ^{-1}$ or 9.8$ c$ of K1 for the first time. The upper limit of the apparent velocity is marginally smaller than superluminal motions seen in the core region. Further new epoch VLBI observations are necessary to measure the proper motion at K1.
Photosphere and Spectrum of Black-Hole Accretion Flow Near to the Eddington Rate
Authors: Kobayashi Hiroshi , Fukue Jun
Published: March 2014

We examine the observational appearance of optically thick, spherically symmetric accretion onto a black hole at around the critical accretion rate. We find that the apparent photosphere deviates markedly from a sphere, but becomes a parabolic-like shape. In addition, the observed temperature over the apparent photosphere is not uniform, but varies significantly from the center to the limb, which shows a strong limb-darkening effect. As a result, the expected spectrum is not a simple blackbody, but becomes a multi-color-type blackbody.
Phase Variation of Earthshine Polarization Spectra
Authors: Takahashi Jun , Itoh Yoichi , Akitaya Hiroshi , Okazaki Akira , Kawabata Koji , Oasa Yumiko , Isogai Mizuki
Published: March 2014

We present the results of the optical spectropolarimetry of Earthshine on the Moon for Earth phase angles ranging from 49$ ^{\circ}$ to 96$ ^{\circ}$ . The observations were conducted on 2011 March 9–13 (UT) using the spectropolarimeter HBS installed on the 1.88 m telescope at Okayama Astrophysical Observatory. The wavelength coverage was 450–850 nm with a resolution of 6 nm. The observed Earthshine polarization degree spectra exhibit decreasing polarization degree with increasing wavelength at any phase. The overall degree of polarization increases as the Earth approaches a quadrature phase. The phase dependence differs with the wavelengths; the maximum polarization for the $ V$ band occurs at a phase angle of $ \sim $ 90$ ^\circ$ , whereas that for longer wavelengths is reached at larger phase angles. This is interpreted as indicating that Earthshine polarization at shorter wavelengths is dominated by atmospheric Rayleigh scattering, whereas that at longer wavelengths has an increasingly effective contribution from the Earth surface reflection. The wavelength dependence of the phase angle of the maximum polarization appears to be unique among the terrestrial planetary bodies in the Solar System. Therefore, this might constitute important evidence pointing toward a distinctive characteristic of Earth: the planet has a scattering but transparent atmosphere above its surface.
High-Speed Imaging System for Solar-Flare Research at Hida Observatory
Authors: Ishii Takako T. , Kawate Tomoko , Nakatani Yoshikazu , Morita Satoshi , Ichimoto Kiyoshi , Masuda Satoshi
Published: March 2014

A high-speed imaging system for observing solar flares in the continuum and H$ \alpha$ wavelengths was installed on a $ \phi$ 25 cm telescope of the Solar Magnetic Activity Research Telescope (SMART) at Hida observatory of Kyoto University. The aim of this system is to diagnose the spatio-temporal evolution of high-energy particles in solar flares by capturing the explosive evolution of chromospheric and photospheric flare kernels. The system acquires flare images covering a field of view of 344$ ''$$ \times$ 258$ ''$ with a spatial sampling of 0$ \hskip1pt''\!\!\!.\hskip1pt$ 215 pixel$ ^{-1}$ and a frame rate of 25 frames s$ ^{-1}$ . Initial data, including two white-light flares, demonstrate the diffraction-limited performance of the system. Observations have been in regular operation since 2011 November. The system is expected to provide a data set that is highly complementary with Hinode/SOT, SDO/AIA, and other ground-based instruments for upcoming solar-flare research.
Origin of Two Types of X-Ray Outbursts in Be/X-Ray Binaries. I. Accretion Scenarios
Authors: Okazaki Atsuo T. , Hayasaki Kimitake , Moritani Yuki
Published: March 2014

We propose a new scenario for X-ray outbursts in Be/X-ray binaries that normal and giant outbursts are, respectively, caused by radiatively inefficient accretion flows (RIAFs) and Bondi-Hoyle-Lyttleton (BHL) accretion of material transferred from the outermost part of a Be disk misaligned with the binary orbital plane. Based on simulated mass-transfer rates from misaligned Be disks, together with simplified accretion flow models, we show that mass-accretion rates estimated from the luminosity of normal X-ray outbursts are consistent with those obtained with advection-dominated accretion flows, not with the standard, radiative-cooling dominated, accretion. Our RIAF scenario for normal X-ray outbursts resolves problems that have challenged the standard disk picture for these outbursts. When a misaligned Be disk crosses the orbit of a neutron star, e.g., by warping, the neutron star can capture a large amount of mass via BHL-type accretion during the disk transit event. We have numerically shown that such a process can reproduce the X-ray luminosity of giant X-ray outbursts. In the case of a very high Be disk density, the accretion flow associated with the disk transit becomes supercritical, giving rise to a luminosity higher than the Eddington luminosity.
X-Ray Observations of the W 51 Complex with Suzaku
Authors: Hanabata Yoshitaka , Sawada Makoto , Katagiri Hideaki , Bamba Aya , Fukazawa Yasushi
Published: March 2014

We present a detailed analysis of X-ray emission from the middle-aged supernova remnant W 51 C and star-forming region W 51 B with Suzaku. The soft X-ray emission from W 51 C is well-represented by an optically thin thermal plasma in a non-equilibrium ionization state with a temperature of $ \sim$ 0.7 keV. The elemental abundance of Mg is significantly higher than the solar value. We find no significant feature of an over-ionized plasma in W 51 C. The hard X-ray emission is spatially coincident with the molecular clouds associated with W 51 B, overlapping with W 51 C. The spectrum is represented by an optically thin thermal plasma with a temperature of $ \sim$ 5 keV, or a powerlaw model with a photon index of $ \sim$ 2.2. The emission probably has a diffuse nature, since its luminosity of 1 $ \times$ 10$ ^{34}$ erg s$ ^{-1}$ in the 0.5–10 keV band cannot be explained by any emission from point sources in this region. We discuss the possibility that the hard X-ray emission comes from stellar winds of OB stars in W 51 B, or accelerated particles in W 51 C.
New Photometric Models of Four Near-Contact Binaries: EP Cassiopeiae, AK Canis Minoris, FG Geminorum, and DF Puppis
Authors: yang Yuan-Gui , dai Hai-Feng , He Jia-Jia , Zhang Jia , Ding Wei
Published: March 2014

We present new photometric observations of EP Cas, AK CMi, and FG Gem, which were obtained during the period from 2008 October to 2011 March using the 60 cm telescope at the Xinglong station. Several light-minimum times were determined, and orbital periods were revised. By using the 2003-version Wilson–Devinney code, photometric solutions of EP Cas, AK CMi, FG Gem, and DF Pup were deduced from multicolor light curves. The results imply that the four systems are Algol-type near-contact binaries (NCBs), whose less-massive components are filling their Roche lobes. With mass and angular-momentum loss, the separation between both components will decrease, and the primary will finally fill its Roche lobe. Algol-type NCBs of this kind, such as EP Cas, AK CMi, FG Gem, and DF Pup, may evolve into the contact configuration as a progenitor of a W UMa-type binary.