bluuebunny/crossref_metadata_2025_split huggingface dataset:
Suzaku Measurement of Electron and Magnetic Energy Densities in the East Lobe of the Giant Radio Galaxy DA 240
Authors: Isobe Naoki , Seta Hiromi , Tashiro Makoto S. 
Published: March 2014

Abstract
A careful analysis of the Suzaku data of the giant radio galaxy DA 240, of which the size is 1.48 Mpc, revealed diffuse X-ray emission associated with its east lobe. The diffuse X-ray spectrum was described with a simple power-law model with a photon index of $\Gamma$$=$ 1.92 $_{-0.17}^{+0.13}$$_{-0.06}^{+0.04}$ , where the first and second errors represent the statistical and systematic ones. The agreement with the synchrotron radio photon index, $\Gamma_{\rm R}$$=$ 1.95 $\ \pm\ $ 0.01 in 326–608.5 MHz, ensures that any excess X-ray emission is attributed to inverse Compton emission from the synchrotron-radiating electrons, boosting up the cosmic microwave background photons. From the X-ray flux density, 51.5 $\ \pm\ $ 3.9 $_{-5.4}^{+6.2}\ $ nJy at 1 keV, derived with the photon index fixed at $\Gamma_{\rm R}$ , in comparison with the synchrotron radio intensity of 10.30 $\ \pm\ $ 0.12 Jy at 326 MHz, the magnetic and electron energy densities were estimated as $u_{\rm m}$$=$ (3.0 $\ \pm\ $ 0.2 $\ \pm\ $ 0.4) $\times$ 10 $^{-14}\ $ erg cm $^{-3}$ and $u_{\rm e}$$=$ (3.4 $_{-0.2}^{+0.3}$$_{-0.4}^{+0.5}$ ) $\times$ 10 $^{-14}\ $ erg cm $^{-3}$ integrated over the electron Lorentz factor of 10 $^3$ –10 $^5$ , respectively. Thus, the east lobe is found to reside in an equipartition condition between the electrons and magnetic field parametrized as $u_{\rm e}/u_{\rm m}$$=$ 1.1 $_{-0.1}^{+0.2}$$_{-0.2}^{+0.4}$ . The east lobe of DA 240 is indicated to exhibit the lowest value of $u_{\rm e}$ , among all of the X-ray detected lobes of radio galaxies. A comparison of the energetics in the giant radio galaxies with a size of $\sim\ $ 1 Mpc to those in the smaller objects suggests a possibility that radio galaxies lose their jet power as they evolve from $\sim\ $ 100 kpc to $\sim\ $ 1 Mpc.
Suzaku Observations of Iron K-Lines from the Intracluster Medium of the Coma Cluster
Authors: Sato Takuya , Matsushita Kyoko , Ota Naomi , Sato Kosuke , Nakazawa Kazuhiro , Sarazin Craig L. 
Published: March 2014

Abstract
The Coma cluster was observed with the X-ray Imaging Spectrometer (XIS) onboard Suzaku in six pointings, including the central X-ray peak region, 14 $'$ west offset region, 30 $'$ and 34 $'$ north–west offset regions, and 44 $'$ and 60 $'$ south–west offset regions. Owing to its lower background level, Suzaku has better sensitivity to Fe K $\alpha$ lines than other satellites. Using precise Fe line measurements, we studied the temperature structure, possible bulk motions, and iron abundance distributions in the intracluster medium (ICM). The observed spectra were well-represented by a single-temperature model; a two- or three- temperature model did not improve $\chi^2$ substantially. The temperature, derived from K $\alpha$ line ratios of H-like and He-like Fe, agrees with those derived from the single-temperature model. Because the line ratio is a steep function of temperature, the consistency supports the accuracy of temperature measurements conducted with Suzaku. Within the 34 $'$ region, the redshift derived from the central energy of the He-like Fe line is consistent with that from optical observations, within a calibration error of 18 eV or 818 km s $^{-1}$ in the line of sight. This value is smaller than the sound velocity of the ICM, which is 1500 km s $^{-1}$ . The central energy of Fe lines at the 44 $'$ offset region around the NGC 4839 subcluster is also consistent with those within the 34 $'$ region. These results on the temperature and velocity structure suggest that the core of the cluster is in a relaxed state, and non-thermal electrons relevant to the radio halo are accelerated by intracluster turbulence rather than large-scale shocks. The Fe abundance is almost constant at 0.4 solar within the 34 $'$ region, and decreases with radius. This value is slightly lower than those of other clusters, which means that the gas had been mixed well during a past merger associated with the growth of the cluster.
A Spectral Study of the Black Hole Candidate XTE J1752−223 in the High/Soft State with MAXI, Suzaku, and Swift
Authors: Nakahira Satoshi , Koyama Shu , Ueda Yoshihiro , Yamaoka Kazutaka , Sugizaki Mutsumi , Mihara Tatehiro , Matsuoka Masaru , Yoshida Atsumasa , Makishima Kazuo , Ebisawa Ken , Kubota Aya , Yamada Shin'ya , Negoro Hitoshi , Hiroi Kazuo , Ishikawa Masaki , Kawai Nobuyuki , Kimura Masashi , Kitayama Hiroki , Kohama Mitsuhiro , Matsumura Takanori , Morii Mikio , Nakajima Motoki , Serino Motoko , Shidatsu Megumi , Sootome Tetsuya , Sugimori Kousuke , Suwa Fumitoshi , Tomida Hiroshi , Tsuboi Yoko , Tsunemi Hiroshi , Ueno Shiro , Usui Ryuichi , Yamamoto Takayuki , Yamazaki Kyohei , Tashiro Makoto S. , Terada Yukikatsu , Seta Hiromi 
Published: March 2014

Abstract
We report on an X-ray spectral analysis of the black hole candidate XTE J1752$-$223 in the 2009–2010 outburst, utilizing data obtained with the MAXI/Gas Slit Camera (GSC), the Swift/XRT, and Suzaku, which work complementarily. As already reported by Nakahira et al. (2010, PASJ, 62, L27), MAXI monitored the source continuously throughout the entire outburst for about eight months. All of the MAXI/GSC energy spectra in the high/soft state, lasting for 2 months, are well represented by a multi-color disk plus power-law model. The innermost disk temperature changed from $\sim\ $0.7 keV to $\sim\ $0.4 keV and the disk flux decreased by an order of magnitude. Nevertheless, the innermost radius is constant at $\sim\ $41 $D_{3.5}$(cos $i$)$^{-{1}/{2}}\ $km, where $D_{3.5}$ is the source distance in units of 3.5 kpc and $i$ the inclination. The multi-color disk parameters obtained with the MAXI/GSC are consistent with those with the Swift/XRT and Suzaku. The Suzaku data also suggest a possibility that the disk emission is slightly Comptonized, which could account for broad iron-K features reported previously. Assuming that the obtained innermost radius represents the innermost stable circular orbit for a non-rotating black hole, we estimate the mass of the black hole to be 5.51$\ \pm\ $0.28$\ M_{\odot}$$D_{3.5}$(cos $i$)$^{-{1}/{2}}\ $, where the correction for the stress-free inner boundary condition and color hardening factor of 1.7 are taken into account. If the inclination is less than 49$^{\circ}$, as suggested from radio monitoring of transient jets, and the soft-to-hard transition in 2010 April occurred at 1%–4% of Eddignton luminosity, the fitting of the Suzaku spectra with a relativistic accretion-disk model derives constraints on the mass and the distance to be 3.1–55$\ M_{\odot}$ and 2.3–22 kpc, respectively. This confirms that the compact object in XTE J1752$-$223 is a black hole.
Turbulence Effects on Bremsstrahlung Emission in the Turbulent Solar Plasma
Authors: Jung Young-Dae , Kato Daiji 
Published: March 2014

Abstract
Turbulence effects on bremsstrahlung emission due to the electron–ion interaction were investigated in the turbulent solar plasma. The effective interaction potential, taking into account the correction factor to the nonlinear dielectric function due to plasma turbulence, and the impact-parameter method were employed in order to obtain the bremsstrahlung radiation cross section in a turbulent plasma as a function of the impact parameter, diffusion coefficient, radiation photon energy, projectile energy, and plasma parameters. It has been shown that the turbulence effects considerably enhance the bremsstrahlung radiation cross section. In addition, it was found that the turbulence effects of the solar atmosphere on the bremsstrahlung cross section increase with increasing radiation photon energy, but decrease with increasing thermal energy. It can be expected that the Landau damping effect on the bremsstrahlung spectrum from the solar corona is less important than that from the solar chromospheres due to temperature jumps. However, the effect of the plasma turbulence on the bremsstrahlung spectrum from the solar chromosphere would be smaller than that from the solar corona.
Fully Nonadiabatic Analysis of Vibrational Instability of Population III Stars due to the ɛ-Mechanism
Authors: Sonoi Takafumi , Shibahashi Hiromoto 
Published: March 2014

Abstract
A linear nonadiabatic analysis of the vibrational stability of population III main-sequence stars was carried out. It was demonstrated that, in the case of massive stars with $M$$\gtrsim$ 5 $M_\odot$, helium burning (triple alpha reaction) starts during the main-sequence stage and produces $^{12}$C, leading to the activation of a part of the CNO-cycle. It was found that, despite of that, those stars with $M$$\lesssim$ 13 $M_\odot$ become unstable against the dipole g$_1$- and g$_2$-modes due to the $\varepsilon $-mechanism, during the early evolutionary phase at which the pp-chain is still the dominant nuclear energy source. The instability due to the $\varepsilon $-mechanism occurs against g-modes having a large amplitude in the off-centered $^3$He accumulation shell in the deep interior, and the growth time is much shorter than the evolutionary timescale. This instability is therefore likely to induce mixing in the stellar interior, and have a significant influence on the evolution of these stars.
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

Abstract
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

Abstract
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

Abstract
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.
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

Abstract
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.
A Particle Simulation for the Pulsar Magnetosphere: Relationship of Polar Cap, Slot Gap, and Outer Gap
Authors: Shinya Yuki , Shinpei Shibata 
Published: March 2014

Abstract
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.
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

Abstract
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

Abstract
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

Abstract
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.
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

Abstract
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

Abstract
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.