bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Possible Mechanism of Flux Cancellation via U-Loop Emergence on the Sun
Authors: Magara Tetsuya 
Published: March 2014

Abstract
We have used a 3-dimensional MHD simulation to investigate a dynamic process producing flux cancellation on the solar surface. Our calculations are fully self-consistent in that any prescribed dynamic process is not applied on the surface, which is self-consistently generated via the emergence of a twisted flux tube. Most of the flux that emerges below the surface is in the form of $\Omega$-loops (concave-down geometry), so that dense photospheric plasma can drain down along the legs of the loop as it rises into the corona. We have found, however, that some U-loops (concave-up geometry) can also emerge. A U-loop geometry implies that a field line has a dip below the surface and a local peak somewhere above the surface on either side of the dip. Although the emergence of U-loops can produce flux cancellation on the surface, loops with such a geometry are not expected to emerge easily, due to the trapping of dense plasma in the dipped portion of the loops. Our results indicate that if one of the peaks is sufficiently low, on the order of the photospheric gravitational scale height above the surface, plasma can drain out of the dipped portion by a siphon-like mechanism, allowing the U-part of the loops to emerge, and resulting in cancellation of the magnetic flux on the surface. However, if both peaks of a U-loop are high compared to the photospheric scale height, dense plasma simply settles in the dip of the loop, preventing the U-part from emerging, rather producing reconnection, which is another possible mechanism of flux cancellation. We also discuss the implications of our results for observations.
Measurements of Antenna Surface for Millimeter-Wave Space Radio Telescope
Authors: Kamegai Kazuhisa , Tsuboi Masato , Doi Akihiro , Sato Eiichi 
Published: March 2014

Abstract
In the construction of a space radio telescope, it is essential to use materials with a low noise factor and high mechanical robustness for the antenna surface. We present the results of measurements of the reflection performance of two candidates for antenna surface materials for use in a radio telescope installed in a new millimeter-wave astronomical satellite, ASTRO-G. To estimate the amount of degradation caused by fluctuations in the thermal environment in the projected orbit of the satellite, a thermal cycle test was carried out for two candidates, namely, copper foil carbon fiber reinforced plastic (CFRP) and aluminum-coated CFRP. At certain points during the thermal cycle test, the reflection loss of the surfaces was measured precisely by using a radiometer in the 41–45 GHz band. In both candidates, cracks appeared on the surface after the thermal cycle test, where the number density of the cracks increased as the thermal cycle progressed. The reflection loss also increased in proportion to the number density of the cracks. Nevertheless, the loss of the copper foil surface met the requirements of ASTRO-G at the end of the equivalent life, whereas that of the aluminum-coated surface exceeded the maximal value in the requirement even before the end of the cycle.
Mid-Infrared Spectroscopy of 11 Main-Belt Asteroids
Authors: Takahashi Jun , Itoh Yoichi , Takahashi Shigeru 
Published: March 2014

Abstract
We present mid-infrared (8–13$\ \mu$m) spectra of 11 main-belt asteroids: 1 Ceres, 3 Juno, 7 Iris, 11 Parthenope, 20 Massalia, 24 Themis, 41 Daphne, 42 Isis, 44 Nysa, 67 Asia, and 88 Thisbe. This paper makes the first report on the mid-infrared spectrum for 5 asteroids. Our observation was conducted with Michelle on UKIRT. The modified Standard Thermal Model (STM) has provided a slightly better fit to the observed spectra than the model without any modification. For 1 Ceres, we detected an emission feature that surpasses the thermal continuum by 6.2$\ \pm\ $1.1%. For the other 10 asteroids, no feature has been detected above their observational errors. However, their $S/N$ ratios are sufficient to only detect 6% emission excess. As the causes of the observed spectral distinction, we examine possible (1) chemical and (2) physical differences on the surfaces of the asteroids: (1) 1 Ceres has silicates with a lower degree of polymerization than do the other asteroids; (2a) the dominant grain size on 1 Ceres is nearer to 200$\ \mu$m, and probably smaller than that on the other asteroids; (2b) In addition, 1 Ceres has very small ($\lt\ $5$\ \mu$m) grains on its surface, while the other asteroids have grains that are moderately small, but larger than on 1 Ceres. In either case, the observed spectral distinctiveness of 1 Ceres, the largest asteroid, suggests that the properties of an asteroid surface may be correlated with the asteroid size.
Observations of Plasma Blob Ejection from a Quiescent Prominence by Hinode Solar Optical Telescope
Authors: Hillier Andrew , Isobe Hiroaki , Watanabe Hiroko 
Published: March 2014

Abstract
We report findings from 0$''\!\!\!.$2 resolution observations of the 2007 October 03 quiescent prominence observed with the Solar Optical Telescope on the Hinode satellite. The observations show clear ejections from the top of the quiescent prominence of plasma blobs. The ejections, originating from the top of prominence threads, are impulsively accelerated to approximately Alfvén velocities and then undergo ballistic motion. The ejections have a characteristic size between $\sim$ 1000–2000 km. These characteristics are similar to downwardly propagating knots (typical size $\sim$ 700 km) that have been observed in prominence threads, we suggest that the plasma blob ejections could be the upward moving counterpart to the downwardly propagating knots. We discuss the tearing instability as a possible mechanism to explain the ejections.
Astrometry of Galactic Star-Forming Region G48.61+0.02 with VERA
Authors: Nagayama Takumi , Omodaka Toshihiro , Handa Toshihiro , Honma Mareki , Kobayashi Hideyuki , Kawaguchi Noriyuki , Ueno Yuji 
Published: March 2014

Abstract
We performed the astrometry of H$_2$O masers in the Galactic star-forming region G48.61$+$0.02 with the VLBI Exploration of Radio Astrometry (VERA). We derived a trigonometric parallax of 199$\ \pm\ $7$\ \mu$as, which corresponds to a distance of 5.03$\ \pm\ $0.19 kpc. The distance to G48.61$+$0.02 is about half of its far kinematic distance, which was often assumed previously. This distance places G48.61$+$0.02 in the Sagittarius–Carina arm, and near to the active star-forming region and the supernova remnant W 51. We also obtained the three-dimensional motion of G48.61$+$0.02, and found that it has a large peculiar motion of 40$\ \pm\ $5 km s$^{-1}$. This peculiar motion would have originated along with multiple supernovae explosions in W 51, or streaming motion across the Sagittarius–Carina arm.
Particle–Particle Particle–Tree: A Direct-Tree Hybrid Scheme for Collisional N-Body Simulations
Authors: Oshino Shoichi , Funato Yoko , Makino Junichiro 
Published: March 2014

Abstract
In this paper, we present a new hybrid algorithm for the time integration of collisional $N$-body systems. In this algorithm, the gravitational force between two particles is divided into short- and long-range terms, using a distance-dependent cutoff function. The long-range interaction is calculated using a tree algorithm, and integrated with a constant-timestep leapfrog integrator. The short-range term is calculated directly and integrated with the high-order Hermite scheme. We can reduce the calculation cost per orbital period from $O$($N^2$) to $O$($N$log$N$), without significantly increasing the long-term integration error. The results of our test simulations show that close encounters are integrated accurately. Long-term errors of the total energy show random-walk behaviour, because they are dominated by the error caused by the tree approximation.
Drastic Spectroscopic Variability of the Be/X-Ray Binary Ariel 0535+262/V725 Tau during and after the 2009 Giant Outburst
Authors: Moritani Yuuki , Nogami Daisaku , Okazaki Atsuo T. , Imada Akira , Kambe Eiji , Honda Satoshi , Hashimoto Osamu , Ichikawa Kohei 
Published: March 2014

Abstract
We report on high-dispersion optical spectroscopic observations of the Be/X-ray binary A 0535$+$262/V725 Tau during a giant outburst in 2009 November/December, and after it. The observed emission line profiles, reflecting the structure of the geometrically thin circumstellar envelope of the Be star (Be disk), show drastic variabilities, and indicate the existence of a warped component. The enhanced blue shoulder seen after periastron passage implies a gas stream from a dense part of the Be disk to the neutron star.
Photographic and Radiometric Observations of the HAYABUSA Re-Entry
Authors: Borovicka Jirí , Abe Shinsuke , ShrbenÝ Lukáš , SpurnÝ Pavel , Bland Philip A. 
Published: March 2014

Abstract
We analyzed photographic observations of the re-entry of the HAYABUSA spacecraft and capsule over Southern Australia on 2010 June 13, 13:52 UT. Radiometric measurements of the brightness of the associated fireball were obtained as well. We derived the trajectories and velocities of the spacecraft, its four fragments, and the capsule. The capsule trajectory was within a few hundred meters of the trajectory predicted by JAXA prior to re-entry. The spacecraft trajectory was about 1 km higher than the capsule trajectory. Two major fragments separated from the spacecraft at a height of about 62 km with a mutual lateral velocity of 250 m s$^{-1}$. The maximum absolute magnitude of the fireball of $-$12.6 was reached at a height of 67 km. The dynamic pressures acting on the spacecraft at the fragmentation points were only 1–50 kPa. No spacecraft fragment was seen to survive below a height of 47 km. The integral luminous efficiency of the event was 1.3%. As expected, the capsule had a very low luminous efficiency and very low ablation coefficient. The ablation coefficients and masses of the major spacecraft fragments are discussed.
Spectroscopic Observation of the Re-Entry Capsule of HAYABUSA Spacecraft
Authors: Ohnishi Kouji , Watanabe Jun-ichi , Sato Mikiya , Ohkawa Takuya , Ebizuka Noboru 
Published: March 2014

Abstract
We performed low-resolution spectroscopic observations of the capsule of the HAYABUSA spacecraft during re-entry into the Earth's atmosphere on 2010 June 13 UT as an artificial meteor. We obtained the photometric magnitude of the HAYABUSA capsule using zeroth-order spectra. The efficiency of the zeroth-order spectra was too low for us to measure the magnitude of the capsule without any saturation at all times. The altitude at the maximal flux of the capsule was at around 56 km (13$^{\rm h}$52$^{\rm m}$19$\!\!\!^{\rm s}$81 UT), which is almost similar to the case GENESIS, i.e., the maximal flux at around 55 km. We examined the change in the spectrum shape of the capsule as a function of its altitude, and investigated the emission from the shock layer and the blackbody radiation from the surface of the capsule. It is found that the shock-layer emission was dominant, and/or on the same order of the blackbody radiation at the early phase of re-entry; also, the emission from blackbody radiation was dominant during the last phase of re-entry. We measured the surface temperature of the capsule along the trajectory; during the last phase before dark flight, we found that the blackbody temperature of the capsule was 3100$\ \pm\ $300 K at an altitude of around 50 km, and 2400$\ \pm\ $300 K at an altitude of around 40 km.
Multiple Outflows Traced by H2O Masers around the Ultra-Compact H II Region G 34.26+0.15
Authors: Imai Hiroshi , Omi Rui , Kurayama Tomoharu , Nagayama Takumi , Hirota Tomoya , Miyaji Takeshi , Omodaka Toshihiro 
Published: March 2014

Abstract
We present the results of VLBI observations of the H$_2$O masers associated with the massive-star forming region G 34.26$+$0.15 with the Very Long Baseline Array (VLBA), the Japanese VLBI Network (JVN), and the VLBI Exploration of Radio Astrometry (VERA) to reveal the whole three-dimensional kinematical structure of the H$_2$O maser region (2$''$$\times$ 5$''$). From the result of one of the astrometric observations with VERA and the revealed maser distribution, we found that, in G 34.26$+$0.15, the H$_2$O masers are likely to be associated with four young stellar objects (YSOs), each of which is traced by at least one of millimeter-continuum and molecular-line emission peaks, rather than by centimeter-continuum peaks that may trace H II regions, including the brightest millimeter- and centimeter-continuum emission peak. We also measured the relative proper motions of 33 H$_2$O masers in the VLBA observations (1996 December–1997 May) and 104 ones in JVN/VERA (2006 March–2008 June). We found that these maser motions indicate large random motion (40–70 km s$^{-1}$), but in at least one region they exhibit radial expansion motions. This suggests the existence of outflows originating from accompanying YSOs. We discuss not only the intrinsic physical properties of multiple YSOs that harbor H$_2$O masers within 0.1 pc but also the implications of the existence of these YSOs. The formation history of the cometary H II region in G 34.26$+$0.15 is also discussed.
Further Observations of the Tilted Planet XO-3: A New Determination of Spin–Orbit Misalignment, and Limits on Differential Rotation
Authors: Hirano Teruyuki , Narita Norio , Sato Bun’ei , Winn Joshua N. , Aoki Wako , Tamura Motohide , Taruya Atsushi , Suto Yasushi 
Published: March 2014

Abstract
We report on observations of the Rossiter–McLaughlin (RM) effect for the XO-3 exoplanetary system. The RM effect for the system was previously measured by two different groups, but their results were statistically inconsistent. To obtain a decisive result, we observed two full transits of XO-3b with the Subaru 8.2-m telescope. By modeling these data with a new and more accurate analytic formula for the RM effect, we found the projected spin–orbit angle to be ${\lambda}$$=$ 37$^\circ\!\!\!.$3$\ \pm\ $3$^\circ\!\!\!.$0, in good agreement with a previous finding by Winn et al. (2009) (2009 ApJ, 700, 302). In addition, an offset of $\sim\ $22 m s$^{-1}$ was observed between the two transit datasets. This offset could be a signal of a third body in the XO-3 system, a possibility that should be checked with future observations. We also attempted to search for a possible signature of the stellar differential rotation in the RM data for the first time, and put weak upper limits on the differential rotation parameters.
X-Ray Study of the Outer Region of Abell 2142 with Suzaku
Authors: Akamatsu Hiroki , Hoshino Akio , Ishisaki Yoshitaka , Ohashi Takaya , Sato Kosuke , Takei Yoh , Ota Naomi 
Published: March 2014

Abstract
We observed outer regions of a bright cluster of galaxies, A 2142, with Suzaku. Temperature and brightness structures were measured out to the virial radius ( $r_{200}$ ) with good sensitivity. We confirmed a temperature drop from 9 keV around the cluster center to about 3.5 keV at $r_{200}$ , with the density profile well approximated by the $\beta$ -model with $\beta$$=$ 0.85. Within 0.4 $r_{200}$ , the entropy profile agrees with $r^{1.1}$ , as predicted by the accretion shock model. The entropy slope becomes flatter in the outer region and negative around $r_{200}$ . These features suggest that the intracluster medium in the outer region is out of thermal equilibrium. Since the relaxation timescale of electron-ion Coulomb collisions is expected to be longer than the elapsed time after shock heating at $r_{200}$ , one plausible reason for the low entropy is a low electron temperature compared to that of ions. Other possible explanations would be gas clumpiness, turbulence and bulk motions of the ICM. We also searched for a warm-hot intergalactic medium around $r_{200}$ , and set an upper limit on the oxygen line intensity. Assuming a line-of-sight depth of 2 Mpc and oxygen abundance of 0.1 solar, the upper limit of an overdensity is calculated to be 280 or 380, depending on the foreground assumption.
Gas Slit Camera (GSC) onboard MAXI on ISS
Authors: Mihara Tatehiro , Nakajima Motoki , Sugizaki Mutsumi , Serino Motoko , Matsuoka Masaru , Kohama Mitsuhiro , Kawasaki Kazuyoshi , Tomida Hiroshi , Ueno Shiro , Kawai Nobuyuki , Kataoka Jun , Morii Mikio , Yoshida Atsumasa , Yamaoka Kazutaka , Nakahira Satoshi , Negoro Hitoshi , Isobe Naoki , Yamauchi Makoto , Sakurai Ikuya 
Published: March 2014

Abstract
The Gas Slit Camera (GSC) is an X-ray instrument on the MAXI (Monitor of All-sky X-ray Image) mission aboard the International Space Station. It is designed to scan the entire sky every 92-minute orbital period in the 2–30 keV band and to achieve the highest sensitivity among the X-ray all-sky monitors ever flown so far. The GSC employs large-area position-sensitive proportional counters with a total detector area of 5350 cm $^2$. The on-board data processor has functions to format telemetry data as well as to control the high voltage of the proportional counters so as to protect them from particle irradiation. This paper describes the instruments, on-board data processing, telemetry data formats, and performance specifications expected from ground calibration tests.
Improvements in Calibration of GSO Scintillators in the Suzaku Hard X-Ray Detector
Authors: Yamada Shin’ya , Makishima Kazuo , Nakazawa Kazuhiro , Kokubun Motohide , Kawaharada Madoka , Kitaguchi Takao , Watanabe Shin , Takahashi Hiromitsu , Noda Hirofumi , Nishioka Hiroyuki , Hiragi Kazuyoshi , Hayashi Katsuhiro , Nakajima Kenta , Tashiro Makoto , Sasano Makoto , Nishino Sho , Torii Shunsuke , Sakurai Soki , Takahashi Tadayuki , Mizuno Tsunefumi , Enoto Teruaki , Yuasa Takayuki , Tanaka Takaaki , Kouzu Tomomi , Nakano Toshio , Fukazawa Yasushi , Terada Yukikatsu , Uchiyama Yasunobu , Iwakiri Wataru 
Published: March 2014

Abstract
Improvements of the in-orbit calibration of GSO scintillators in the Hard X-ray Detector aboard Suzaku are reported. To resolve an apparent change in the energy scale of GSO, which appeared across the launch for unknown reasons, consistent and thorough re-analyses of both pre-launch and in-orbit data have been performed. With laboratory experiments using spare hardware, the pulse-height offset, corresponding to zero energy input, was found to change by $\sim\ $ 0.5% of the full analog voltage scale, depending on the power supply. Furthermore, by carefully calculating all of the light outputs of secondaries from activation lines used in the in-orbit gain determination, their energy deposits in GSO were found to be effectively lower, by several percent, than their nominal energies. Taking both of these effects into account, the in-orbit data agree with the on-ground measurements within $\sim\ $ 5%, without employing the artificial correction introduced in previous work (Kokubun et al. 2007, PASJ, 59, S53). With this knowledge, we updated the data processing, the response, and the auxiliary files of GSO, and reproduced the HXD-PIN and HXD-GSO spectra of the Crab Nebula over 12–300 keV by a broken power-law with a break energy of $\sim\ $ 110 keV.
Nature of the Unidentified TeV Source HESS J1614−518, Revealed by Suzaku and XMM-Newton Observations
Authors: Sakai Michito , Yajima Yukie , Matsumoto Hironori 
Published: March 2014

Abstract
We report on new Suzaku and XMM-Newton results concerning HESS J1614 $-$ 518, which is one of the brightest extended TeV $\gamma$ -ray sources and has two regions with intense $\gamma$ -ray emission. We newly observed the south and center regions of HESS J1614 $-$ 518 with Suzaku, since the north region, including the position of the 1st brightest peak of the TeV $\gamma$ -ray emission, has already been observed. No X-ray counterpart was found at the position of the 2nd brightest peak of the TeV $\gamma$ -ray emission; we estimated the upper limit of the X-ray flux to be 1.6 $\times$ 10 $^{-13}$ erg cm $^{-2}$ s $^{-1}$ in the 2–10 keV band. The soft X-ray source Suzaku J1614 $-$ 5152, which was found at the edge of the field of view in a previous observation, was also detected at the middle of HESS J1614 $-$ 518. Analyzing the XMM-Newton archival data, we revealed that Suzaku J1614 $-$ 5152 consists of multiple point sources. The X-ray spectrum of the brightest point source, XMMU J161406.0 $-$ 515225, can be described by a power-law model with a photon index of $\Gamma$$=$ 5.2 $^{+0.6}_{-0.5}$ , or a blackbody model with temperature $kT$$=$ 0.38 $^{+0.04}_{-0.04}$ keV. In the blackbody model, the hydrogen-equivalent column density is almost the same as that of the hard extended X-ray emission, Suzaku J1614 $-$ 5141, which was found at the 1st peak position. If true, XMMU J161406.0 $-$ 515225 may be physically related to Suzaku J1614 $-$ 5141 and HESS J1614 $-$ 518.
An X-Ray Spectroscopic Study of the Hot Interstellar Medium toward the Galactic Bulge
Authors: Hagihara Toshishige , Yamasaki Noriko Y. , Mitsuda Kazuhisa , Takei Yoh , Sakai Kazuhiro , Yao Yangsen , Wang Q. Daniel , McCammon Dan 
Published: March 2014

Abstract
We present a detailed spectroscopic study of the hot gas toward the galactic bulge along the 4U 1820 $-$ 303 sight line by a combination analysis of emission and absorption spectra. In addition to the absorption lines of O VII K ${\alpha}$ , O VII K ${\beta}$ , O VIII K ${\alpha}$ , and Ne IX K ${\alpha}$ by Chandra LTGS, as shown by previous studies, Suzaku clearly detected the emission lines of O VII, O VIII, Ne IX, and Ne X from the vicinity. We used simplified plasma models with constant temperature and density. An evaluation of the background and foreground emission was carefully performed, including the stellar X-ray contribution based on the recent X-ray observational results and the stellar distribution simulator. If we assume that one plasma component exists in front of 4U 1820 $-$ 303 and the other one at the back, the obtained temperatures are $T$$=$ (1.7 $\ \pm\ $ 0.2) $\times$ 10 $^{6}$ K for the front-side plasma and $T$$=$ (3.9 $^{+0.4}_{-0.3}$ ) $\times$ 10 $^{6}$ K for the back-side. This scheme is consistent with a hot and thick ISM disk, as suggested by extragalactic source observations and an X-ray bulge around the galactic center.
Suzaku Metal Abundance Patterns in the Outflow Region of M 82 and the Importance of Charge Exchange
Authors: Konami Saori , Matsushita Kyoko , Go Tsuru Takeshi , Gandhi Poshak , Tamagawa Toru 
Published: March 2014

Abstract
We performed spectral analysis of Suzaku data of the galactic disk and outflow regions of the starburst galaxy M 82. Thermal modeling of the central disk regions requires at least three temperature components. The Ly $\beta $ line fluxes of O VIII and Ne X exceed those expected from a plasma in collisional ionization equilibrium. The ratios of the Ly $\beta/$ Ly $\alpha$ lines for O VIII and Ne X are higher than those of collisional ionization equilibrium, which may be caused by the process of charge exchange. In the outflow wind region, the spectra are well reproduced with two-temperature thermal models, and we have derived the metal abundances of O, Ne, Mg, and Fe in the outflow. The ratios of O $/$ Fe, Ne $/$ Fe, and Mg $/$ Fe are about 2, 3, and 2, respectively, relative to the solar value determined by Lodders (2003, ApJ, 591, 1220). Since there is no evidence of charge exchange in the outflow region, the metal abundances should be more reliable than those in the central region. This abundance pattern indicates that starburst activity enriches the outflow through SN II metal ejection into intergalactic space.