bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evolution of the Sheared Magnetic Fields of Two X-Class Flares Observed by Hinode/XRT
Authors: Su Yingna , Golub Leon , Van Ballegooijen Adriaan , DeLuca Edward E. , Reeves Kathy K. , Sakao Taro , Kano Ryouhei , Narukage Noriyuki , Shibasaki Kiyoto 
Published: March 2014

Abstract
We present multi-wavelength observations of the evolution of the sheared magnetic fields in NOAA Active Region 10930, where two X-class flares occurred on 2006 December 13 and December 14, respectively. Observations made with the X-ray Telescope (XRT) and the Solar Optical Telescope (SOT) aboard Hinode suggest that the gradual formation of the sheared magnetic fields in this active region is caused by the rotation and west-to-east motion of an emerging sunspot. In the pre-flare phase of the two flares, XRT shows several highly sheared X-ray loops in the core field region, corresponding to a filament seen in the TRACE EUV observations. XRT observations also show that part of the sheared core field erupted, and another part of the sheared core field stayed behind during the flares, which may explain why a large part of the filament is still seen by TRACE after the flare. About 2–3 hours after the peak of each flare, the core field becomes visible in XRT again, and shows a highly sheared inner and less-sheared outer structure. We also find that the post-flare core field is clearly less sheared than the pre-flare core field, which is consistent with the idea that the energy released during the flares is stored in the highly sheared fields prior to the flare.
Discovery of a Temperature-Dependent Upflow in the Plage Region during a Gradual Phase of the X-Class Flare
Authors: Imada Shinsuke , Hara Hirohisa , Watanabe Tetsuya , Kamio Suguru , Asai Ayumi , Matsuzaki Keiichi , Harra Louise K. , Mariska John T. 
Published: March 2014

Abstract
We present Hinode/EIS raster scan observations of the plage region taken during the gradual phase of the GOES X3.2 flare that occurred on 2006 December 13. The plage region is located 200${}^{\prime\prime}$ east of the flare arcade. The plage region has a small transient coronal hole. The transient coronal hole is strongly affected by an X-class flare, and upflows are observed at its boundary. Multi-wavelength spectral observations allow us to determine velocities from the Doppler shifts at different temperatures. Strong upflows along with stationary plasma have been observed in the Fe XV line 284.2 Å (log$T/$ K $=6.3$) in the plage region. The strong upflows reach almost 150 km s$^{-1}$, which was estimated by a two-component Gaussian fitting. On the other hand, at a lower corona/transition region temperature (He II, 256.3 Å, log$T/$ K $=$ 4.9), very weak upflows, almost stationary, have been observed. We find that these upflow velocities clearly depend on the temperature with the hottest line, Fe XV, showing the fastest upflow velocity and the second-highest line, Fe XIV, showing the second-highest upflow velocity (130 km s$^{-1}$). All velocities are below the sound speed. The trend of the upflow dependence on temperature dramatically changes at 1 MK. These results suggest that heating may have an important role for strong upflow.
Resonant Excitation of Disk Oscillations in Deformed Disks II: A
Model of High-Frequency QPOs
Authors: Kato Shoji 
Published: March 2014

Abstract
The amplification of disk oscillations resulting from nonlinear resonant couplings between the oscillations and a disk deformation is examined. The disk is geometrically thin and general relativistic with a non-rotating central source. A Lagrangian formulation is adopted. The author examined the same problem a few years ago, but here we derive a general stability criterion in a more perspective way. Another distinct point from the previous work is that in addition to the case where the deformation is a warp, the case where the deformation is a one-armed pattern symmetric with respect to the equatorial plane is considered. The results obtained show that in addition to the previous results that the inertial-acoustic mode and g-mode oscillations are amplified by horizontal resonance in warped disks, they also amplified by horizontal resonance in disks deformed by one-armed pattern symmetric with respect to the equatorial plane. If we consider local oscillations that are localized around boundaries of their propagation region, the resonance occurs at $4r_{\rm g}$ , where $r_{\rm g}$ is the Schwarzschild radius. If nonlocal oscillations are considered, frequency ranges of oscillations where oscillations are resonantly amplified are specified.
Mapping Observations of 6.7GHz Methanol Masers with the Japanese VLBI
Network
Authors: Sugiyama Koichiro , Fujisawa Kenta , Doi Akihiro , Honma Mareki , Kobayashi Hideyuki , Bushimata Takeshi , Mochizuki Nanako , Murata Yasuhiro 
Published: March 2014

Abstract
We have observed 13 methanol maser sources associated with massive star-forming regions: W 3(OH), Mon R2, S 255, W 33A, IRAS 18151 $-$ 1208, G 24.78 $+$ 0.08, G 29.95 $-$ 0.02, IRAS 18556 $+$ 0136, W 48, OH 43.8 $-$ 0.1, ON 1, Cep A, and NGC 7538 at 6.7GHz using the Japanese VLBI Network (JVN). Twelve of the thirteen sources were detected at our longest baseline of $\sim$ 50M $\lambda$ , and their images are presented. Seven of them are the first VLBI images at 6.7GHz. The high detection rate and the small fringe spacing of $\sim$ 4 mas suggest that most of the methanol maser sources have compact structures. Given this compactness as well as the known properties of long life and small internal motion, the methanol maser line is suitable for astrometry with VLBI.
Near-Infrared Spectroscopy of Faint Companions around Young Stellar Objects Associated with the Taurus Molecular Cloud
Authors: Itoh Yoichi , Tamura Motohide , Hayashi Masahiko , Oasa Yumiko , Hayashi Saeko S. , Fukagawa Misato , Kudo Tomoyuki , Mayama Satoshi , Ishii Miki , Pyo Tae-Soo , Yamashita Takuya , Morino Junichi 
Published: March 2014

Abstract
We have conducted near-infrared spectroscopy of 26 faint objects around young stellar objects in the Taurus molecular cloud. These objects were detected during a course of near-infrared coronagraphic searches for companions around 72 young stellar objects with the Subaru Telescope and the near-infrared coronagraph CIAO (coronagraphic imager with adaptive optics). A comparison of the Subaru and HST archive images revealed that three central stars and faint companions share common proper motions, suggesting that they are physically associated with each other. None of the 26 sources show deep water absorption bands at near-infrared, except for DH Tau B. This result indicates that all of them, but DH Tau B, have a high photospheric temperature or a large amount of excess from circumstellar materials.
2006 December 17 Long Duration Flare Observed with the Hinode EUV Imaging Spectrometer
Authors: Hara Hirohisa , Watanabe Tetsuya , Matsuzaki Keiichi , Harra Louise K. , Culhane J. Leonard , Cargill Peter , Mariska John T. , Doschek George A. 
Published: March 2014

Abstract
A GOES C-class long-duration flare that occurred near the west limb on 2006 December 17 was observed with the Hinode EUV Imaging Spectrometer (EIS) in raster-scan observations. Cusp-shaped arcades are prominent in the spectroheliogram of the Ca xvii emission line at 192.86$\AA$. Spatial relationships between hot flare loops with a cusp apex and cool post flare loops with various temperatures are clearly shown in the EIS observations. We find an enhanced line broadening above the bright loop-top region in the Ca xvii observation. The Doppler observations of cooling post flare loops with coronal temperatures show both downflows and upflows along the loops, and these are interpreted as a part of siphon flows. Enhanced nonthermal line broadenings are identified at the top of the post flare loops.
A Deep Sky Survey of Edgeworth Kuiper Belt Objects with an Improved Shift-and-Add Method
Authors: Yamamoto Naotaka , Kinoshita Daisuke , Fuse Tetsuharu , Watanabe Jun-ichi , Kawabata Kiyoshi 
Published: March 2014

Abstract
A survey of the minor bodies in the outer regions of our solar system was carried out using the Suprime-Cam attached to the 8.2 m Subaru Telescope on Mauna Kea on 2001 February 22 and 25. Seven areas, covering a total of 1.4 deg$^2$ of the sky, were scanned. Five of them were observed with an $R$-mag limit of approximately 25.0, while the remaining two areas (0.4 deg$^2$ area of the sky) had a much deeper imaging, reaching an $R$-mag limit of 26.0. In order to facilitate our survey, we developed an efficient computer code to detect unknown objects based on an improved shift-and-add method, the validity of which was ascertained from the fact that it could successfully locate the two EKBOs (2001 DM$_{108}$ and 2001 DN$_{108}$) that had been detected in our preliminary analysis. Using our computer code, we discovered three new EKBOs, viz. 2001 DO$_{108}$, 2001 DP$_{108}$, and 2001 DQ$_{108}$, in addition to 2001 DM$_{108}$ and 2001 DN$_{108}$. The present survey succeeded in finding a total of 14 EKBOs (five were discovered, and nine were detected) within the 0.4 deg$^2$ region of the sky observed with an $R$-mag limit of 26.0.
Low-Mass Star-Forming Cores in the GF9 Filament
Authors: Furuya Ray S. , Kitamura Yoshimi , Shinnaga Hiroko 
Published: March 2014

Abstract
We carried out an unbiased mapping survey of dense molecular cloud cores traced by the NH$_3$ (1,1) and (2,2) inversion lines in the GF9 filament, which contains an extremely young low-mass protostar, GF9-2 (2006, ApJ, 653, 1369). The survey was conducted using the Nobeyama 45m telescope over a region of $\sim$1.5D$\times$1$^{\circ}$ with an angular resolution of 73". The large-scale map revealed that the filament contains at least 7 dense cores, as well as 3 possible ones, located at regular intervals of $\sim$0.9pc. Our analysis shows that these cores have kinetic temperatures of $\lesssim$10K and LTE-masses of 1.8-8.2M⊙, which makes them typical sites of low-mass star formation. All of the identified cores are likely to be gravitationally unstable, because their LTE-masses are larger than their virial masses. Since the LTE-masses and separations of the cores are consistent with the Jeans masses and lengths, respectively, for the low-density ambient gas, we argue that the identified cores formed via the gravitational fragmentation of the natal filamentary cloud.
ASTE CO(3-2) Observations of the Southern Barred Spiral Galaxy NGC 986: a Large Gaseous Bar Filled with a Dense Molecular Medium
Authors: Kohno Kotaro , Tosaki Tomoka , Miura Rie , Muraoka Kazuyuki , Sawada Tsuyoshi , Nakanishi Kouichiro , Kuno Nario , Sakai Takeshi , Sorai Kazuo , Kamegai Kazuhisa , Tanaka Kunihiko , Okuda Takeshi , Endo Akira , Hatsukade Bunyo , Sameshima Masahiro , Ezawa Hajime , Sakamoto Seiichi , Kamazaki Takeshi , Yamaguchi Nobuyuki , CortÉs Juan , Tamura Yoichi , Fukuhara Masayuki , Iono Daisuke , Kawabe Ryohei 
Published: March 2014

Abstract
We present CO(3-2) emission observations toward the 3′$\times$3′ (or 20kpc$\times$20kpc at a distance of 23Mpc) region of the southern barred spiral galaxy NGC 986 using the Atacama Submillimeter Telescope Experiment (ASTE). This effort is a part of our on-going extragalactic CO(3-2) imaging project, ADIoS (ASTE Dense gas Imaging of Spiral galaxies). Our CO(3-2) image revealed the presence of a large (the major axis is 14kpc in total length) gaseous bar filled with a dense molecular medium along the dark lanes observed in optical images. This is the largest “dense-gas rich bar” known to date. The dense gas bar, discovered in NGC 986, could be a huge reservoir of possible “fuel” for future starbursts in the central region, and we suggest that star formation in the central region of NGC 986 could still be in a growing phase. We found a good spatial coincidence between the overall distributions of dense molecular gas traced by CO(3-2) and massive star formation depicted by H$\alpha $. The global CO(3-2) luminosity, $L’_{\rm CO(3-2)}$, of NGC 986 was determined to be (5.4$\pm$1.1)$\times$10$^8$Kkms$^{-1}$pc$^2$. The CO(3-2)$/$CO(1-0) integrated intensity ratio was found to be 0.60$\pm$0.13 at a spatial resolution of 44$”$ or 5kpc, and the CO(3-2)$/$CO(2-1) ratio was 0.67$\pm$0.14 at a beam size of $\sim $25$”$ or $\sim $2.8kpc. These line ratios suggest moderate excitation conditions of CO lines ($n_{\rm H_2}$$\sim $10$^{3-4}$cm$^{-3}$) in a few kiloparsec region of central NGC 986.
The 2006 Radio Outbursts of a Microquasar Cygnus X-3: Observations and Data
Authors: Tsuboi Masato , Tosaki Tomoka , Kuno Nario , Nakanishi Kouichiro , Sawada Tsuyoshi , Umemoto Tomofumi , Trushkin Sergei A. , Kotani Taro , Kawai Nobuyuki , Kurono Yasutaka , Handa Toshihiro , Kohno Kotaro , Tsukagoshi Takashi , Kameya Osamu , Kobayashi Hideyuki , Fujisawa Kenta , Doi Akihiro , Omodaka Toshihiro , Takaba Hiroshi , Sudou Hiroshi , Wakamatsu Ken-ichi , Koyama Yasuhiro , Kawai Eiji , Mochizuki Nanako , Murata Yasuhiro 
Published: March 2014

Abstract
We present the results of multi-frequency observations of radio outbursts of the microquasar Cygnus X-3 in 2006 February and March with the Nobeyama 45-m telescope, the Nobeyama Millimeter Array, and the Yamaguchi 32-m telescope. Since the prediction of a flare by RATAN-600, the source was monitored from January 27 (UT) with these radio telescopes. At the eighteenth day after the quench of activity, successive flares exceeding 1Jy were successfully observed. The time scale of the variability in the active phase is presumably shorter in higher frequency bands. We also present the result of a follow-up VLBI observation at 8.4GHz with the Japanese VLBI Network 2.6d after the first rise. A VLBI image exhibits a single core with a size of $&lt;8$ mas (80AU). The observed image is almost stable, although the core shows a rapid variation in the flux density. No jet structure can be seen at a sensitivity of $T_{\rm b}$ (brightness temperature) $=$ 7.5$\times$10$^{5}$K.
Colors and Mass-to-Light Ratios of Bulges and Disks of Nearby Spiral Galaxies
Authors: Yoshino Akira , Ichikawa Takashi 
Published: March 2014

Abstract
We investigated the colors and mass-to-light ($M/L$) ratios of bulges and disks for 28 nearby spiral galaxies with various morphological types of Sab-Scd, using images in optical and near-infrared ($V$, $I$, and $J$) bands as well as published rotation curves. It is shown that the observed colors and $M/L$ values generally agree with the galaxy-formation model with an exponentially declining star-formation rate and a shallow slope initial mass function (e.g., Scalo IMF) for both the bulges and the disks. We find that the bulge $M/L$ is generally higher than the disk $M/L$, and that the galaxies with a larger bulge-to-total luminosity ($B/T$) ratio tend to have a smaller bulge $M/L$. This fact indicates that the luminosity-weighted average age of bulges for early-type spirals is younger than that for later-type spirals. These results support a formation scenario that the bulges of middle-type and early-type spirals produce young stars.
CCD Photometric Study of the W UMa-Type Binary II Canis Majoris in the Field of Berkeley 33
Authors: Liu Liang , Qian Sheng-Bang , Zhu Li-Ying , He Jia-Jia , Yuan Jinzhao , Dai Zhibin , Liao Wenping , Zhang Jia 
Published: March 2014

Abstract
The CCD photometric data of an EW-type binary, IICMa, which is a contact star in the field of the middle-aged open cluster Berkeley 33, are presented. A complete $R$ light curve was obtained. In the present work, using the five CCD epochs of light minimum [three of them were calculated from Mazur et al. (1993 MNRAS, 265, 405)’s data and two from our new data], the orbital period $P$ was revised to 0.22919704 days. The complete $R$ light curve was analyzed by using the 2003 version of W-D (Wilson-Devinney) program. It is found that this is a contact system with a mass ratio of $q=0.9$ and a contact factor of $f=4.1$%. The high mass ratio ($q=0.9$) and the low contact factor ($f=4.1$%) indicate that the system just evolved into the marginal contact stage.
On the Period Variations of BH Virginis
Authors: Tian Yong-Po , Xiang Fu-Yuan , Tao Xia 
Published: March 2014

Abstract
In the present work, 17 new times of the light minimum for BH Vir were derived from observations by Kjurkchieva et al. (2004 , A&A, 424, 993). Combining the new determined eclipse times with others compiled from the literature, the behavior of their $O – C$ variation was investigated. It has been found that the orbital period of BH Vir shows some cyclic variations with three different periods: a long-period variation of 51.7 years, and two short-period variations of 9.2 years and 11.8 years, respectively. The mechanisms that could explain the period changes of the system are discussed.
Excitation of Low-Frequency QPOs in Black-Hole Accretion Flows
Authors: Machida Mami , Matsumoto Ryoji 
Published: March 2014

Abstract
We present the results of global three-dimensional magneto-hydrodynamic simulations of black-hole accretion flows. We focus on the dependence of the numerical results on the gas temperature supplied from the outer region. General-relativistic effects were taken into account using the pseudo-Newtonian potential. We ignored radiative cooling of the accreting gas. The initial state was a torus threaded by a weak azimuthal magnetic field. We found that the mass-accretion rate and the mass-outflow rate strongly depend on the temperature of the initial torus. The ratio of the average Maxwell stress generated by the magneto-rotational instability (MRI) to the gas pressure, $\alpha \equiv \langle B_{\varpi} B_{\varphi}/4 \pi \rangle / \langle P \rangle $, is $\alpha \sim$0.05 in a hot torus and $\alpha \sim$0.01 in a cool torus. In the cool model, a constant angular momentum inner torus is formed around 4-8$r_s$, where $r_s$ is the Schwarzschild radius. This inner torus deforms itself from a circle to a crescent quasi-periodically. During this deformation, the mass-accretion rate, the magnetic energy and the Maxwell stress increase. As the magnetic energy is released, the inner torus returns to a circular shape and starts the next cycle.
The power spectral density (PSD) of the time variation of the mass-accretion rate in the cool model has a low-frequency peak around 10Hz when we assumed a 10$M_{\odot}$ black hole. The mass outflow rate in the low temperature model also shows quasi-periodic oscillation.
Suzaku Observations of the Cluster of Galaxies Abell 2052
Authors: Tamura Takayuki , Mitsuda Kazuhisa , Takei Yoh , Yamasaki Noriko Y. , Itoh Akiharu , Hayashida Kiyoshi , Henry J. Patrick , Kunieda Hideyo , Matsushita Kyoko , Ohashi Takaya 
Published: March 2014

Abstract
The results from Suzaku X-ray Imaging Spectrometer (XIS) observations of relaxed cluster of galaxies, Abell 2052, are presented. Offset pointing data were used to estimate the Galactic foreground emission in the direction of the cluster. Significant soft X-ray excess emission above this foreground, the intracluster medium emission, and other background components was confirmed and resolved both radially and spectroscopically. This excess can be described either by (a) local variations of known Galactic emission components or by (b) an additional thermal component with a temperature of about 0.2 keV, possibly associated with the cluster. The radial temperature and metallicity profiles of the intracluster medium were measured within $\sim\;$20$^\prime$ in radius (about 60% of the virial radius) from the cluster center. The temperature drops radially to 0.5–0.6 of the peak value at a radius of $\sim\;$15$^\prime$. The gas-mass-weighted metal abundance averaged over the observed region was found to be 0.21$\;\pm\;$0.05 times solar.
Non-LTE Calculation for the Be Star Decretion Disk
Authors: Iwamatsu Hidetoshi , Hirata Ryuko 
Published: March 2014

Abstract
The non-LTE state of the hydrogen gas in isothermal transonic decretion disks around a B1V star has been calculated by an iterative method in order to explore the basic physical process in the disk. This dynamical model is characterized by a density law in the equatorial plane of $\rho(R) \propto R^{-3.5}$. The continuous radiation was calculated with the $\Lambda$ iteration in the integral form, while we adopted a single-flight escape probability for lines. We describe the non-LTE state, the radiation flow and conversion in the disk. We conclude that the stellar Balmer continuum plays a key role in the non-LTE state of the disk. An examination of the local energy gain and loss suggests that the disk temperature has double minima along the equatorial plane in the optically thick case: the intermediate region caused by deficient ultraviolet radiation and the outer Lyman $\alpha$ cooling region. We also calculated some observable quantities, such as the spectral energy distribution, the $UBV$ colors, the infrared excess and the Balmer line profiles. Our calculations with a mass-loss rate less than $10^{-10}M_{\odot}\ {\rm yr}^{-1}$ reproduce the observed continuum quantities. However, we could not obtain the large H$\alpha$ emission strength observed in Be stars. We suggest that the density gradient of the Be star disk is slower than that of an isothermal decretion disk.
KASINICS: Near Infrared Camera System for the BOAO 1.8 m Telescope
Authors: Moon Bongkon , Jin Ho , Yuk In-Soo , Lee Sungho , Nam Uk-won , Cha Sang-Mok , Cho Seoung-Hyun , Kyeong Jae-Mann , Park Youngsik , Mock Seungwon , Han Jeong-Yeol , Lee Dea-Hee , Park Jang-Hyun , Han Wonyong , Pak Soojong , Kim Geon-Hee , Kim Yong Ha 
Published: March 2014

Abstract
We developed Korea Astronomy and Space science Institute (KASI) Near Infrared Camera System (KASINICS) to be installed on the 1.8 m telescope of Bohyunsan Optical Astronomy Observatory (BOAO) in Korea. We use a 512$\times$512 InSb array (Aladdin III Quadrant, Raytheon Co.) to enable $L$ band observations as well as $J, H$, and $K_s$ bands. The field-of-view of the array is 3${\rlap{\hskip.75pt{^\prime}}\hskip.75pt.\hskip1pt}$3$\times$3${\rlap{\hskip.75pt{^\prime}}\hskip.75pt.\hskip1pt}$3 with a resolution of 0${\rlap{\hskip.75pt{^{\prime\prime}}}\hskip.75pt.\hskip1.75pt}$39$/$pixel. We adopt an Offner relay optical system, which provides a cold stop to eliminate thermal background emission from the telescope structures. Most parts of the camera, including the mirrors, were manufactured from the same ingot of aluminum alloy to ensure a homologous contraction from room temperature to 80 K. We also developed a readout electronics system for the array detector. Based on preliminary results from test observations, the limiting magnitudes are $J=$ 17.6, $H=$ 17.5, $K_s =$ 16.1, and $L$(narrow) $=$ 10.0 mag at a signal-to-noise ratio of 10 for an integration time of 100 s.