bluuebunny/crossref_metadata_2025_split huggingface dataset:
Spectral Variation of Hard X-Ray Emission from the Crab Nebula with the Suzaku Hard X-Ray Detector
Authors: Kouzu Tomomi , S. Tashiro Makoto , Terada Yukikatsu , Yamada Shin’ya , Bamba Aya , Enoto Teruaki , Mori Koji , Fukazawa Yasushi , Makishima Kazuo 
Published: March 2014

Abstract
The Crab Nebula is one of the brightest and most stable sources in the X-ray sky. Year-scale flux variation from the object was recently revealed in the hard X-ray band by four satellites. This marked the first detection of year-scale variability from pulsar wind nebulae in the hard X-ray band. The Crab Nebula has been observed at least once a year for calibration purposes with the Suzaku Hard X-ray Detector (HXD) since its launch in 2005. In order to investigate possible spectral changes as well as flux variation, archival data of the HXD were analyzed. The flux variation reported by other instruments was confirmed in the 25–100 keV band by the HXD at a few percent level, but flux above 100 keV did not follow the trend in variation below 100 keV. The hardness ratios produced utilizing the PIN and GSO sensors installed in the HXD exhibit significant scattering, thereby indicating spectral variations in the hard X-ray band. The spectral changes were quantified by spectral fitting with a broken power-law model. The difference between the two photon indexes of the broken power-law model in harder and softer energy bands is in the range of $&lt;$ 2.54. Taking into account a flux variation of 6.3% and a spectral variation time-scale of a few days, multi components of the broken power-law-shaped synchrotron emission with different cooling times are suggested.
Analysis of a Kepler Light Curve of the Novalike Cataclysmic Variable KIC 8751494
Authors: Kato Taichi , Hiroyuki Maehara 
Published: March 2014

AbstractWe analyzed a Kepler light curve of KIC 8751494, a recently recognized novalike cataclysmic variable in the Kepler field. We detected a stable periodicity of 0.114379(1) d, which we identified as being the binary’s orbital period. The stronger photometric period at around 0.12245 d, which had been detected from a ground-based observation, was found to be variable, and we identified this period as the positive-superhump period. This superhump period showed short-term (10–20 d) strong variations in period most unexpectedly when the object entered a slightly faint state. The fractional superhump excess varied by as much large as $\sim$ 30%. The variation of the period very well traced the variation of the brightness of the system. The time-scale of this variation of superhump periods was too slow to be interpreted as a variation caused by a change of the disk radius due to thermal disk instability. We interpreted the cause of the period variation as a varying pressure effect on the period of positive superhumps. This finding suggests that the pressure effect, in at least novalike systems, plays a very important (up to $\sim$ 30% in the precession rate) role in producing the period of positive superhumps. We also described a possible detection of negative superhumps with a varying period of 0.1071–0.1081 d in the Q14 run of the Kepler data, and found that the variation of frequency of negative superhumps followed that of positive superhumps. The relation between the fractional superhump excesses of negative and positive superhumps can be understood if the angular frequency of positive superhumps is decreased by a pressure effect. We also found that the phase of the variation in the velocity of the emission lines reported in the earlier study is compatible with the SW Sex-type classification. Further, we introduced a new two-dimentional period analysis using least absolute shrinkage and selection operator (Lasso), and showed superior advantages of this method.
Clumpy Outflows from Supercritical Accretion Flow
Authors: Takeuchi Shun , Ohsuga Ken , Mineshige Shin 
Published: March 2014

Abstract
A significant amount of matter in supercritical (or super-Eddington) accretion flow is blown away by radiation force, thus forming outflows; however, the properties of such radiation-driven outflows have been poorly understood. We have performed global two-dimensional radiaion-magnetohydrodynamic simulations of supercritical accretion flow onto a black hole with 10 or 10$^{8} M_{\odot}$ in a large simulation box of 514 $r_{\rm S} \times 514 r_{\rm S}$ (with $r_{\rm S}$ being the Schwarzschild radius). We confirm that uncollimated outflows with velocities of 10 percent of the speed of light emerge from the innermost part of the accretion flow at a wide angle of 10$^{\circ}$ –50$^{\circ}$ from the disk rotation axis. Importantly, the outflows exhibit clumpy structures above heights of $\sim 250 r_{\rm S}$. The typical size of the clumps is $\sim 10 r_{\rm S}$, which corresponds to one optical depth, and their shapes are slightly elongated along the outflow direction. Since clumps start to form in the layer above which the (upward) radiation is superior in force to the (downward) gravity, the Rayleigh–Taylor instability seems to be a primary cause. In addition, a radiation-hydrodynamic instability, which arises when radiation funnels through a radiation-pressure-supported atmosphere, may also help to form clumps of one optical depth. A magnetic photon bubble instability does not seem to be essential, since a similar clumpy outflow structure is obtained in nonmagnetic radiation-hydrodynamic simulations. Since the spatial covering factor of the clumps is estimated to be $\sim$ 0.3, and since they are marginally optically thick, they will explain at least some of the rapid light variations of active galactic nuclei. We further discuss a possibility of producing broad-line region clouds by the clumpy outflow.
A New Cluster of Galaxies Towards the Galactic Bulge, Suzaku J1759–3450
Authors: Mori Hideyuki , Maeda Yoshitomo , Furuzawa Akihiro , Haba Yoshito , Ueda Yoshihiro 
Published: March 2014

Abstract
We observed an extended X-ray source, designated as Suzaku J1759–3450, with Suzaku and Chandra observations towards 1RXS J175911.0–344921, which is an unidentified X-ray source listed in the ROSAT Bright Source Catalogue. A conspicuous emission line at 6 keV was also found in the Suzaku J1759–3450 spectrum. Assuming the emission line to be K emission from He-like Fe ions, we inferred Suzaku J1759–3450 to be an extragalactic object located at z = 0.13. The radial profile of the surface brightness in the 0.5–10 keV band was explained well with an isothermal β-model of $r_\textrm c=1{.^\prime}61$ and $\beta=0.78$. The X-ray spectrum was well reproduced by an opticallythin thermal plasma with the electron temperature of $kT_e = 5.3$ keV, attenuated by the photoelectric absorption of $N_\textrm H = 2.3 \times 10^{21} \textrm c\textrm m^{-2}$. The bolometric X-ray luminosity of $L_\textrm X(r &lt; r_{500}) = 4.3 \times 10^{44} \textrm {erg} \textrm s^{-1}$ is consistent with that expected from the L X–T relation of clusters of galaxies. In terms of the spatial extent, the X-ray spectrum, and the bolometric luminosity of the X-ray emitting gas, we concluded that Suzaku J1759–3450 is a new cluster of galaxies.
Observations and Orbital Analysis of the High-Amplitude Delta Scuti Star SZ Lyncis: The Unusual Orbital Precession
Authors: Lin-Jia Li , Sheng-Bang Qian 
Published: March 2014

Abstract
We determined forty-two new times of light maximum from our photometry observations and WASP project, and collected all times of light maximum observed between 1961 and 2013 in order to calculate the orbital elements of the SZ Lyncis system and the secular change of the pulsation period with the classical $O-C$ method. We confirmed the decrease of the longitude of the periastron passage with a rate of $(-1.^{\circ}15 \pm 0. ^{\circ}25 )\textrm {yr}^{-1}$, and discussed the causative mechanism. The results show that the precession of the star's orbit might be due to a close binary system, which means that the companion of SZ Lyncis is actually a binary system. We used the Hipparcos Intermediate Astrometric Data to obtain the complete orbital elements of the SZ Lyncis system, and found that the inclination, i , and parallax, $\pi_{t}$, are $39.^{\circ}5 \pm 17.^{\circ}7$ and $2.^{\circ}61\pm 0.^{\circ}98$ mas (corresponds to $380 \pm 140$), respectively. We reanalyzed the mean radial velocities of SZ Lyncis given by Bardin and Imbert (1984), and noticed a weak variation existing in the residuals from a single-Keplerian fit. We suggest that more detailed high-precision spectroscopic observations are definitely needed in the future to check this short periodic change.
WZ Sge-Type Dwarf Novae with Multiple Rebrightenings: MASTER OT J211258.65+242145.4 and MASTER OT J203749.39+552210.3
Authors: Nakata Chikako , Ohshima Tomohito , Kato Taichi , Nogami Daisaku , Masi Gianluca , de Miguel Enrique , Ulowetz Joseph , Littlefield Colin , Goff William N. , Krajci Thomas , Maehara Hiroyuki , Stein William , Sabo Richard , Noguchi Ryo , Ono Rikako , Kawabata Miho , Furukawa Hisami , Matsumoto Katsura , Ishibashi Takehiro , Dubovsky Pavol A. , Kudzej Igor , Dvorak Shawn , HAMBSCH Franz-Josef , Pickard Roger D. , Morelle Etienne , Muyllaert Eddy , Padovan Stefano , Henden Arne 
Published: March 2014

Abstract
We report on photometric observations of two WZ Sge-type dwarf novae, MASTER OT J211258.65+242145.4 and MASTER OT J203749.39+552210.3, which underwent outbursts in 2012. Early superhumps were recorded in both systems. During the superoutburst plateau, ordinary superhumps with a period of 0.060291(4) d (MASTER J211258) and with 0.061368(11) d (MASTER J203749) on average were observed. MASTERJ211258 and MASTERJ203749 exhibited eight post-superoutburst rebrightenings and more than four, respectively. In the final part of the superoutburst, an increase in superhump period was seen in both systems. We made a survey of WZSge-type dwarf novae with multiple rebrightenings, and confirmed that the superhump periods of WZSge-type dwarf novae with multiple rebrightenings were longer than those of WZSge-type dwarf novae without a rebrightening. Although WZSge-type dwarf novae with multiple rebrightenings have been thought to be likely candidates for period bouncers based on their low mass ratio (q), inferred from the period of fully grown (stage B) superhumps, our new method of using the period of growing superhumps (stage A superhumps), however, implies higher q's than those expected from stage B superhumps. These q values appear to be consistent with the duration of the stage A superoutbursts, which likely reflects the growth time of the 3W1 resonance. We present a working hypothesis that the small fractional superhump excesses for stage B superhumps in these systems may be explained by a gas pressure effect that works more efficiently in these systems than in ordinary SU UMa-type dwarf novae. This result forms a new picture that WZSge-type dwarf novae with multiple rebrightenings and SU UMa-type ones without a rebrightening (they are not period bouncers) are located in the same place on the evolutionary track.
Rotation Curve and Mass Distribution in the Galactic Center —From Black Hole to Entire Galaxy—
Authors: Sofue Yoshiaki 
Published: March 2014

Abstract
Analyzing high-resolution longitude–velocity (LV) diagrams of the Galactic Center observed with the Nobeyama 45-m telescope in the CO and CS line emissions, we obtained a central rotation curve of the Milky Way. We combined it with data for the outer disk, and constructed a logarithmic rotation curve of the entire Galaxy. The new rotation curve covers a wide range of radius from r ∽ 1 pc to several hundred kpc without a gap of data points. It links, for the first time, the kinematical characteristics of the Galaxy from the central black hole to the bulge, disk and dark halo. Using this grand rotation curve, we calculated the radial distribution of the surface mass density in the entire Galaxy, where the radius and derived mass densities vary over a dynamical range with several orders of magnitudes. We show that the galactic bulge is deconvolved into two components: the inner (core) and main bulges. Both of the two bulge components are represented by exponential density profiles, but the de Vaucouleurs law was found to fail to represent the mass profile of the galactic bulge.
Low-Resolution Spectrum of the Diffuse Galactic Light and 3.3μm PAH Emission with the AKARI InfraRed Camera
Authors: Tsumura Kohji , Matsumoto Toshio , Matsuura Shuji , Sakon Itsuki , Tanaka Masahiro , Wada Takehiko 
Published: March 2014

Abstract
We first obtained the spectrum of the diffuse Galactic light (DGL) at general interstellar space in the $1.8-5.3 \mu \textrm m $ wavelength region with the low-resolution prism spectroscopy mode of the AKARI Infra-Red Camera (IRC) NIR channel. The $3.3 \mu \textrm m $ PAH band is detected in the DGL spectrum at Galactic latitude $\mid b \mid \lt 15^{\circ}$, and its correlations with the Galactic dust and gas are confirmed. The correlation between the $3.3 \mu \textrm m $ PAH band and the thermal emission from the Galactic dust is expressed not by a simple linear correlation, but by a relation with extinction. Using this correlation, the spectral shape of DGL at an optically thin region ($5^{\circ} \lt \mid b \mid \lt 15^{\circ}$) was derived as a template spectrum. Assuming that the spectral shape of this template spectrum is uniform at any position, the DGL spectrum can be estimated by scaling this template spectrum using the correlation between the $3.3 \mu \textrm m $ PAH band and the thermal emission from the Galactic dust.
Discovery of an Outstanding Disk in the cD Galaxy of the HydraA Cluster
Authors: Fujita Yutaka , Okabe Nobuhiro , Sato Kosuke , Tamura Takayuki , Matsushita Satoki , Hirashita Hiroyuki , Nakamura Masanori , Matsushita Kyoko , Nakazawa Kazuhiro , Takizawa Motokazu 
Published: March 2014

Abstract
The central cD galaxy of the Hydra A cluster has one of the most powerful active galactic nuclei (AGNs) in the nearby Universe ($z \lesssim 0.2$). We report on the discovery of a dust lane in the cD galaxy using Subaru telescope. The i 0-band image shows the existence of a dark band of the size of $3.\prime \prime 6 \times 0\prime \prime . 7 (4 \textrm {kpc} \times 0.8 \textrm{kpc}),$, which appears to be quite similar to the dust lane observed in Centaurus A. The morphology indicates that the cold disk that seen as the dust lane is almost edge-on and rotates around the AGN. Since the minor axis of the dust lane is nearly parallel to the radio jets emerging from the AGN, the disk is probably feeding its gas into the central black hole. From the absorption, we estimate the hydrogen column density of the lane is $N_{\textrm H} = 2.0 \times 10^{21} \textrm {cm}^{-2}$, and the mass of the disk is $\sim8 \times 10^{7} M \odot$. The column density is consistent with constraints obtained from Chandra X-ray observations. The age of the disk is $\gtrsim 4 \times 10^{7}$ yr. The position angle of the disk and the galaxy's photometric axis are misaligned, which may imply that the cold gas in the disk is brought via galaxy mergers. Our observations may indicate that the supply of cold gas by galaxy mergers is required for the most intensive feedback from AGNs
Long-Period Oscillations of Sunspots by NoRH and SSRT Observations
Authors: Bakunina Irina A. , Abramov-Maximov Vladimir E. , Nakariakov Valery M. , Lesovoy Sergei V. , Soloviev Alexander A. , Tikhomirov Yurii V. , Melnikov Victor F. , Shibasaki Kiyoto , Nagovitsyn Yurii A. , Averina Elena L. 
Published: March 2014

Abstract
Long-term oscillations of microwave emission generated in sunspot magnetospheres are detected with the Nobeyama Radioheliograph (NoRH) at a frequency of 17 GHz, and the Siberian Solar Radio Telescope (SSRT) at 5.7 GHz. Significant periodicities in the range of 22-170 min are found in the variation of the emission intensity, polarisation and the degree of circular polarisation. Periods of the oscillations are not stable: they are different in different sunspots and in the same sunspot on different days. A cross-correlation analysis shows the presence of common significant periods in both NoRH and SSRT data. The cross-correlation coefficients are typically lower than 0.5, which can be attributed to the different heights of the emission formation, and different mechanisms for the emission generation (gyroresonance and thermal bremstrahlung at 17 GHz, and pure gyroresonance at 5.7 GHz). The observational results are consistent with the global sunspot oscillation model.
Systematic Microwave Source Motions along a Flare-Arcade Observed by Nobeyama Radioheliograph and AIA/SDO
Authors: Kim Sujin , Masuda Satoshi , Shibasaki Kiyoto , Bong Su-Chan 
Published: March 2014

Abstract
We found systematic microwave source motions along a flare-arcade using Nobeyama Radioheliograph (NoRH) 17 GHz images. The motions were associated with an X-class disk flare that occurred on 2011 February 15. For this study, we also used EUV images from Atmospheric Imaging Assembly (AIA) and magnetograms from Helioseismic and Magnetic Imager (HMI) onboard Solar Dynamics Observatory, and multi-channel microwave data from Nobeyama Radio Polarimeters (NoRP) and Korean Solar Radio Burst Locator (KSRBL). We traced centroids of the microwave source observed by NoRH 17 GHz during the flare, and found two episodes of the motion based on several facts: (1) The microwave source moved systematically along the flare-arcade, which was observed by the AIA 94 Å channel, in a direction parallel to the neutral line. (2) The period of each episode was 5 min and 14 min, respectively. (3) Estimated parallel speed was 34 km s-1 for the first episode and 22 km s-1 for the second episode. The spectral slope of the microwave flux above 10 GHz obtained by NoRP and KSRBL was negative for both episodes, and for the last phase of the second episodes it was flat with a flux of 150 sfu. The negative spectrum and the flat with high flux indicate that the gyrosynchrotron emission from accelerated electrons was dominant during the source motions. The sequential images from the AIA 304 Å and 94 Å channels revealed that there were successive plasma eruptions, and each eruption was initiated just before the start time of the microwave sources motion. Based on the results, we suggest that the microwave source motion manifests the displacement of the particle acceleration site caused by plasma eruptions.
An Updated View of Solar Eruptive Flares and the Development of Shocks and CMEs: History of the 2006 December 13 GLE-Productive Extreme Event
Authors: Grechnev Victor V. , Kiselev Valentin I. , Uralov Arkadiy M. , Meshalkina Nataliya S. , Kochanov Alexey A. 
Published: March 2014

Abstract
An extreme 2006 December 13 event marked the onset of the Hinode era, being the last major flare in the solar cycle 23 observed with NoRH and NoRP. The event produced a fast CME, strong shock, and a big particle event responsible for GLE70. We endeavor to clarify the relations between the eruptions, shock wave, and flare, and to shed light on a debate over the origin of energetic protons. One concept relates it to flare processes. Another one associates the acceleration of ions with a bow shock driven by a CME at (2-4)R⊙. The latter scenario is favored by a delayed particle release time after the flare. However, our previous studies have established that a shock wave is typically excited by an impulsively erupting magnetic rope (future CME core) during the flare rise, while the outer CME surface evolves from an arcade whose expansion is driven from inside. Observations of the 2006 December 13 event reveal two shocks following each other, whose excitation scenario contradicts the delayed CME-driven bowshock hypothesis. Actually, the shocks developed much earlier, and could accelerate protons still before the flare peak. Then, the two shocks merged into a single stronger one, and only decelerated and dampened long afterwards.
Serum Citrulline as a Biomarker of Gastrointestinal Function During Hematopoietic Cell Transplantation in Children
Authors: Gosselin Kerri B. , Feldman Henry A. , Sonis Andrew L. , Bechard Lori J. , Kellogg Mark D. , Gura Kathleen , Venick Robert , Gordon Catherine M. , Guinan Eva C. , Duggan Christopher 
Published: March 2014

ABSTRACTObjectives:We sought to determine whether serum citrulline (CIT), an amino acid produced by small bowel enterocytes, was associated with clinical and biochemical markers of gastrointestinal function in children undergoing hematopoietic cell transplantation (HCT).Methods:We conducted a multicenter, prospective cohort study of 26 children to define time‐related changes in serum CIT during the course of HCT. Markers of gastrointestinal function including oral energy intake, emesis, stool volume, presence of graft‐versus‐host disease (GVHD), oral mucositis severity, and cytokine and neurohormone levels were measured. Weekly serum CIT concentrations were obtained from 10 days prior until 30 days after HCT.Results:Mean baseline CIT concentration was 22.7 μmol/L (95% confidence interval [CI] 17.7–27.6) on day −10, which decreased to a nadir of 7.5 μmol/L (95% CI 3.1–18.0, P = 0.017) on day 8 following HCT before returning to baseline by day 30. After adjustment for IL‐6 level (1.0% lower CIT per 10% increase in interleukin‐6, P = 0.004), presence of acute GVHD (27% lower CIT, P = 0.025), and oral energy intake (2.1% lower CIT per 10% decrease in energy intake, P = 0.018), the nadir shifted to day 10, when mean CIT concentration was lower in patients with severe oral mucositis (6.7 μmol/L, 95% CI 3.4–13.1) than in those without severe mucositis (11.9 μmol/L, 95% CI 5.8–24.4, P = 0.003). Change in CIT was not correlated with stool volume, C‐reactive protein, tumor necrosis factor‐α, leptin, or ghrelin.Conclusions:In children undergoing HCT, serum CIT correlates with measures of gastrointestinal function (oral mucositis severity, dietary intake, acute GVHD) and may reflect mucosal injury to the gastrointestinal tract.
A FMEA-based approach to prioritize waste reduction in lean implementation
Authors: Victor B. de Souza Ruy , Cesar R. Carpinetti Luiz 
Published: March 2014

Purpose
– This paper presents a proposal of adaptation of the failure mode and effect analysis method to analyze wastes and define priorities for actions aimed at minimizing or eliminating these wastes based on the criteria of severity, occurrence and detection.

Design/methodology/approach
– The proposition was developed in parallel to the implementation of a lean production system of a manufacturing company. A pilot application of the proposal was based on the analysis of a flow of information for order processing.

Findings
– Application of the proposed procedure results in a classification of levels of priority for waste reduction of the analyzed waste modes. Following this procedure, high priority will be given to actions focused on the elimination or minimization of the most common causes of the most severe waste modes.

Originality/value
– Prioritization of actions to minimize waste is essential to sustain lean production systems. However, identifying the wastes most in need of attention is not always straightforward and methods presented in the literature to evaluate leanness do not focus on waste reduction prioritization. Adoption of the proposed technique can certainly aid planning implementation and improvement of lean production programs, and in the end, it can contribute to the effectiveness and sustainability of lean production systems.