bluuebunny/crossref_metadata_2025_split huggingface dataset:
Propagation of Moreton Waves
Authors: Zhang Yuzong , Kitai Reizaburo , Narukage Noriyuki , Matsumoto Takuma , Ueno Satoru , Shibata Kazunari , Wang Jingxiu 
Published: March 2014

Abstract
With the Flare-Monitoring Telescope (FMT) and Solar Magnetic Activity Research Telescope (SMART) at Hida observatory of Kyoto University, 13 events of Moreton waves were captured at H$\alpha$ center, H$\alpha$ $\pm$0.5 Å, and H$\alpha$ $\pm$0.8 Å wavebands since 1997. With such samples, we have studied the statistical properties of the propagation of Moreton waves. Moreton waves were all restricted in sectorial zones with a mean value of 92$^\circ$. However, their accompanying EIT waves, observed simultaneously with SOHO/EIT at extreme-ultraviolet wavelength, were very isotropic with a quite extended scope of 193$^\circ$. The average propagation speeds of the Moreton waves and the corresponding EIT waves were 664 km s$^{-1}$ and 205 km s$^{-1}$, respectively. Moreton waves propagated either under large-scale close magnetic flux loops, or firstly in the sectorial region where two sets of magnetic loops separated from each other and diverged, and then stopped before the open magnetic flux region. The location swept by Moreton waves had a relatively weak magnetic field as compared to the magnetic fields at their sidewalls. The ratio of the magnetic flux density between the sidewall and the path falls in the range of 1.4 to 3.7 at a height of 0.01 solar radii. Additionally, we roughly estimated the distribution of the fast magnetosonic speed between the propagating path and sidewalls in an event on 1997 November 3, and found a relatively low-fast magnetosonic speed in the path. We also found that the propagating direction of Moreton waves coincided with the direction of filament eruption in a few well-observed events. This favors an interpretation of the “Piston” model, although further studies are necessary for any definitive conclusion.
Beryllium Abundances of Solar-Analog Stars
Authors: Takeda Yoichi , Tajitsu Akito , Honda Satoshi , Kawanomoto Satoshi , Ando Hiroyasu , Sakurai Takashi 
Published: March 2014

Abstract
An extensive Be abundance analysis was conducted for 118 solar analogs (along with 87 FGK standard stars) by applying the spectrum synthesis technique to the near-UV region comprising the Be II line at 3131.066 Å, in an attempt to investigate whether Be suffers any depletion, such as in the case of Li showing a large diversity. We found that, while most of these Sun-like stars are superficially similar in terms of their $A$(Be) (Be abundances) around the solar value within $\sim\pm$0.2 dex, 4 out of 118 samples turned out to be strikingly Be-deficient (by more than $\sim\ $2 dex), and these 4 stars belong to the group of lowest $v_{\rm e}$ sin $i$ (projected rotation velocity). Moreover, even for the other majority showing an apparent similarity in Be, we can recognize a tendency that $A$(Be) gradually increases with an increase in $v_{\rm e}$ sin $i$. These observational facts suggest that any solar analog star (including the Sun) generally suffers some kind of Be depletion during their lives, where the rotational velocity (or the angular momentum) plays an important role in the sense that the depletion tends to be enhanced by slower rotation. Hence, our findings require that the occasionally stated view “G-type dwarfs with $T_{\rm eff}$$\lesssim$ 6000 K are essentially homogeneous in Be with their original composition retained” should be revised. Also, our analysis indicates that the difference of $\sim\ $0.2 dex in $A$(Be) between the solar photosphere and the meteorite really exists, implying that the “UV missing opacity” is irrelevant at least for this Be II line.
Testing Two-Component Jet Models of GRBs with Orphan Afterglows
Authors: Inayoshi Kohei , Tsutsui Ryo 
Published: March 2014

Abstract
In the Swift era, two-component jet models were introduced to explain the complex temporal profiles and the diversity of early afterglows. In this paper, we concentrate on the two-component jet model: the first component is the conventional afterglow, and second is emission due to late internal dissipation, such as late-prompt emission. We suggest herein that the two-component jet model can be probed by the existence of two optical peaks for orphan GRB afterglows. Each peak is caused by its respective jet as its relativistic beaming cone widens to encompass the off-axis line of sight. Typically, the first peak appears at 10$^{4}$–10$^{5}\ $s, and the second at 10$^{5}\ $–10$^{6}\ $s. Furthermore, we expect to observe a single, bright X-ray peak at the same time as the first optical peak. Because orphan afterglows do not have prompt emission, it is necessary to monitor the entire sky every 10$^{4}$s in the X-ray regime. We can test the model with orphan afterglows through the X-ray all-sky survey collaboration, and by using ground-based optical telescopes.
Physical Relation of Source I to IRc2 in the Orion KL Region
Authors: Okumura Shin-ichiro , Yamashita Takuya , Sako Shigeyuki , Miyata Takashi , Honda Mitsuhiko , Kataza Hirokazu , Okamoto Yoshiko K. 
Published: March 2014

Abstract
We present mid-infrared narrow-band images of the Orion BN/KL region, and $N$-band low-resolution spectra of IRc2 and the nearby radio source ``I''. The distributions of the silicate absorption strength and the color temperature have been revealed with a subarcsec resolution. The detailed structure of the 7.8$\ \mu$m$/$12.4$\ \mu$m color temperature distribution was resolved in the vicinity of IRc2. A mid-infrared counterpart to source I has been detected as a large color temperature peak. The color temperature distribution shows an increasing gradient from IRc2 toward source I, and no dominant temperature peak is seen at IRc2. The spectral energy distribution of IRc2 could be fitted by a two-temperature component model, and the ``warmer component'' of the infrared emission from IRc2 could be reproduced by scattering of radiation from source I. IRc2 itself is not self-luminous, but is illuminated and heated by an embedded luminous young stellar object located at source I.
Wind Anisotropy and Angular Momentum Loss in a Massive Rotating Binary System
Authors: Song Han-Feng , Lu Yuan , Wang Jing-Zhou 
Published: March 2014

Abstract
The model of anisotropic loss of the mass and angular momentum is constructed and the non-conservative evolution of the binary system is investigated in this paper. The joint effects of the centrifugal force and tidal force cause the configurations of two components to become triaxial ellipsoids. The high-order disturbing potential, which includes the rotational and tidal distortions, is applied to describe the local gravity in a close binary system. The $g_{\rm eff}$($\theta$, $\varphi$)-effect dominates the mass-loss distribution in the massive O-type star. Both the $g_{\rm eff}$($\theta$, $\varphi$)-effect and the $\kappa$-effect have an important influence on the equatorial ejection, and the Roche lobe overflow and the H-shell burning occur earlier in the rotational models. The rotation and tide can intensify the mass loss before mass overflow, and the rate of stellar wind goes down, resulting from a decrease of the luminosity in the subsequent stages. The high-order disturbing potential and other associated physical factors may significantly affect the Roche lobe and might be possible to drive the non-conservative mass transfer process when the stars approach the break-up rotation. Rotation and tide can allow the primary to shift towards the blue side of the HR diagram and modify the thermal relaxation time-scale in the slow phase of the mass transfer in Case A. The star attempts to attain thermal equilibrium and displays a slightly cyclical expansion and contraction. When stellar wind was taken into consideration in the model, the secondary star accreted less mass than the model without stellar wind.
Hydrodynamic Interaction between the Be Star and the Pulsar in the TeV Binary PSR B1259$-$63/LS 2883
Authors: Okazaki Atsuo T. , Nagataki Shigehiro , Naito Tsuguya , Kawachi Akiko , Hayasaki Kimitake , Owocki Stanley P. , Takata Jumpei 
Published: March 2014

Abstract
We have been studying the interaction between the Be star and the pulsar in the TeV binary PSR B1259$-$63/LS 2883, using 3-D SPH simulations of the tidal and wind interactions in this Be–pulsar system. We first ran a simulation without pulsar wind nor Be wind, while taking into account only the gravitational effect of the pulsar on the Be disk. In this simulation, the gas particles are ejected at a constant rate from the equatorial surface of the Be star, which is tilted in a direction consistent with multi-waveband observations. We ran the simulation until the Be disk was fully developed and started to repeat a regular tidal interaction with the pulsar. Then, we turned on the pulsar wind and the Be wind. We ran two simulations with different wind mass-loss rates for the Be star, one for a B2 V type and the other for a significantly earlier spectral type. Although the global shape of the interaction surface between the pulsar wind and the Be wind agrees with the analytical solution, the effect of the pulsar wind on the Be disk is profound. The pulsar wind strips off an outer part of the Be disk, truncating the disk at a radius significantly smaller than the pulsar orbit. Our results, therefore, rule out the idea that the pulsar passes through the Be disk around periastron, which has been assumed in previous studies. It also turns out that the location of the contact discontinuity can be significantly different between phases when the pulsar wind directly hits the Be disk and those when the pulsar wind collides with the Be wind. It is thus important to adequately take into account the circumstellar environment of the Be star, in order to construct a satisfactory model for this prototypical TeV binary.
Widely Extended [O III] 88μm Line Emission around the 30 Doradus Region Revealed with AKARI FIS-FTS
Authors: Kawada Mitsunobu , Takahashi Ai , Yasuda Akiko , Kiriyama Yuichi , Mori Tatsuya , Mouri Akio , Kaneda Hidehiro , Okada Yoko , Takahashi Hidenori , Murakami Noriko 
Published: March 2014

Abstract
We present a distribution map of the far-infrared [O III] 88 $\mu$m line emission around the 30 Doradus (30 Dor) region in the Large Magellanic Cloud obtained with the Fourier Transform Spectrometer of the Far-Infrared Surveyor on board AKARI. The map reveals that the [O III] emission is widely distributed by more than 10$'$ around the super star cluster R 136, implying that the 30 Dor region is affluent with interstellar radiation field that is hard enough to ionize O$^{2+}$. The observed [O III] line intensities are as high as (1–2) $\times$ 10$^{-6}$ W m$^{-2}$ sr$^{-1}$ on the peripheral regions 4$'$–5$'$ away from the center of 30 Dor, which requires gas densities of 60–100 cm$^{-3}$. However, the observed size of the distribution of the [O III] emission is too large to be explained by massive stars in the 30 Dor region enshrouded by clouds with a constant gas density of 10$^{2}$ cm$^{-3}$. Therefore, the surrounding structure is likely to be highly clumpy. We also find a global correlation between the [O III] and the far-infrared continuum emission, suggesting that the gas and dust are well mixed in the highly ionized region where the dust survives in clumpy dense clouds shielded from energetic photons.
The Effect of Metallicity on the Delay-Time Distribution of Type Ia Supernova
Authors: Meng Xiang Cun , Li Zhong Mu , Yang Wu Ming 
Published: March 2014

Abstract
Measuring the delay-time distribution (DTD) of type Ia supernova (SNe Ia) is an important way to constrain the progenitor nature of SNe Ia. Recently, Strolger et al. (2010, ApJ, 713, 32, hereafter SDR10) obtained a very delayed DTD, which is much different from other measurements. They suggested that metallicity could be the origin of their delayed DTD. In this paper, we show the effect of metallicity on the DTD of SNe Ia from single-degenerate models (including WD $+$ MS and WD $+$ RG channels). Via a binary population synthesis approach, we find that the DTD from a low-metallicity population is significantly delayed compared with that from a high-metallicity one. In addition, we also find that a substantial fraction of SNe Ia have a delay time shorter than 1 Gyr, and the fraction of SNe Ia with short delay times increases with the metallicity, i.e., about 35% for $Z$ $=$ 0.001, while more than 70% for $Z$ $=$ 0.02. These results would help to qualitatively explain the result of SDR10. Furthermore, we noticed that the contribution of the WD $+$ RG channel from the low-metallicity population is higher than that from the high-metallicity one. However, we could not quantitatively obtain a DTD consistent with the results of SDR10 by changing the metallicity. As a consequence, metallicity may partly contribute to the DTD of SNe Ia, and should therefore be carefully checked when one derives the DTD of SNe Ia from observations.
Study of Eclipsing Binary and Multiple Systems in OB Associations. I. Orion OB1a- IM Monocerotis
Authors: Bakis Hicran , Bakis Volkan , Bilir Selçuk , MikulÁšEK Zdenek , Zejda Miloslav , Yaz Esma , Demircan Osman , Bulut Ibrahim 
Published: March 2014

Abstract
All available photometric and spectroscopic observations were collected and used as the basis of a detailed analysis of the close binary IM Mon. The orbital period of the binary was refined to 1$.\!\!\!^{\rm d}$19024249 (0.00000014). The Roche equipotentials, fractional luminosities (in $B$, $V$, and Hp-bands) and fractional radii for the component stars in addition to the mass ratio, $q$, inclination, $i$, of the orbit, and the effective temperature, $T_{\rm eff}$, of the secondary cooler less massive component were obtained by the analysis of light curves. IM Mon is classified to be a detached binary system in contrast to the contact configuration estimations in the literature. The absolute parameters of IM Mon were derived by the simultaneous solutions of light and radial-velocity curves as $M_{1,2}$$=$ 5.50 (0.24)$\ M_{\odot}$ and 3.32 (0.16)$\ M_{\odot}$, $R_{1,2}$$=$ 3.15 (0.04)$\ R_{\odot}$ and 2.36 (0.03)$\ R_{\odot}$, $T_{{\rm eff} 1,2}$$=$ 17500 (350) K and 14500 (550) K implying spectral types of B4 and B6.5 ZAMS stars for the primary and secondary components, respectively. The modelling of the high-resolution spectrum revealed the rotational velocities of the component stars as $V_{{\rm rot}1}$$=$ 147 (15) km s$^{-1}$ and $V_{{\rm rot}2}$$=$ 90 (25) km s$^{-1}$. The photometric distance of 353 (59) pc was found to be more precise and reliable than the Hipparcos distance of 341 (85) pc. An evolutionary age of 11.5 (1.5) Myr was obtained for IM Mon. Kinematical and dynamical analyses support the membership of the young thin-disk population system IM Mon to the Ori OB1a association dynamically. Finally, we derived the distance, age, and metallicity information of Ori OB1a sub-group using information of the IM Mon parameters.
Infrared Spectral Energy Distribution of Galaxies in the AKARI All Sky Survey: Correlations with Galaxy Properties, and Their Physical Origin
Authors: Totani Tomonori , Takeuchi Tsutomu T. , Nagashima Masahiro , Kobayashi Masakazu A. R. , Makiya Ryu 
Published: March 2014

Abstract
We have studied the properties of more than 1600 low-redshift galaxies by utilizing high-quality infrared flux measurements of the AKARI All-Sky Survey and physical quantities based on optical and 21-cm observations. Our goal is to understand the physics determining the infrared spectral energy distribution (SED). The ratio of the total infrared luminosity, $L_{\rm TIR}$, to the star-formation rate (SFR) is tightly correlated by a power-law to specific SFR (SSFR), and $L_{\rm TIR}$ is a good SFR indicator only for galaxies with the largest SSFR. We discovered a tight linear correlation for normal galaxies between the radiation field strength of dust heating, estimated by infrared SED fits ($U_h$), and that of galactic-scale infrared emission ($U_{\rm TIR} \propto L_{\rm TIR}/R^2$), where $R$ is the optical size of a galaxy. The dispersion of $U_h$ along this relation is $\sim $0.3 dex, corresponding to $\sim $13% dispersion in the dust temperature. This scaling and the $U_h/U_{\rm TIR}$ ratio can be explained physically by a thin layer of heating sources embedded in a thicker, optically-thick dust screen. The data also indicate that the heated fraction of the total dust mass is anti-correlated to the dust column density, supporting this interpretation. In the large $U_{\rm TIR}$ limit, the data of circumnuclear starbursts indicate the existence of an upper limit on $U_h$, corresponding to the maximum SFR per gas mass of $\sim $10 Gyr$^{-1}$. We find that the number of galaxies sharply drops when they become optically thin against dust-heating radiation, suggesting that a feedback process to galaxy formation (likely by the photoelectric heating) is working when dust-heating radiation is not self-shielded on a galactic scale. Implications are discussed for the $M_{{\rm H{ I}}}$-size relation, the Kennicutt-Schmidt relation, and galaxy formation in the cosmological context.
H2O Maser Motions and the Distance of the Star-Forming Region G 192.16−3.84
Authors: Shiozaki Satoshi , Imai Hiroshi , Tafoya Daniel , Omodaka Toshihiro , Hirota Tomoya , Honma Mareki , Matsui Makoto , Ueno Yuji 
Published: March 2014

Abstract
We present the results of astrometic observations of H$_{2}$O masers associated with the star-forming region G 192.16$-$3.84 with the VLBI Exploration of Radio Astrometry (VERA). The H$_{2}$O masers seem to be associated with two young stellar objects (YSOs) separated by $\sim\ $1200 AU, as reported in previous observations. In the present observations, we successfully detected an annual parallax of $\pi$$=$ 0.66$\ \pm\ $0.04 mas for the H$_{2}$O masers, which corresponds to a distance to G 192.16$-$3.84 of $D$$=$ 1.52$\ \pm\ $0.08 kpc from the Sun. The determined distance is shorter than the estimated kinematic distance. Using the annual parallax and the estimated parameters of the millimeter continuum emission, we estimate the mass of the disk plus circumstellar cloud in the southern YSO to be 10.0$^{+4.3}_{-3.6}\ M_{\odot}$. We also estimate the galactocentric distance and the peculiar motion of G 192.16$-$3.84, relative to a circular galactic rotation, to be $R_{\ast}$$=$ 9.99$\ \pm\ $0.08 kpc and $Z_{\ast}$$=$$-$0.10$\ \pm\ $0.01 kpc, and ($U_{\ast}$, $V_{\ast}$, $W_{\ast}$) $=$ ($-$2.8$\ \pm\ $1.0, $-$10.5$\ \pm\ $0.3, 4.9$\ \pm\ $2.7) [km s$^{-1}$], respectively. The peculiar motion of G 192.16$-$3.84 is not beyond the range of recent VLBI astrometric results. The angular distribution and three-dimensional velocity field of H$_{2}$O maser features indicate the existence of a bipolar outflow with a major axis along the northeast–southwest direction.
Do Meteoroids Originating from Near-Earth Asteroid (25143) Itokawa Exist?
Authors: Ohtsuka Katsuhito , Abe Shinsuke , Ito Takashi , Nakamura Tomoki , Abe Masanao , Yano Hajime , Watanabe Jun-ichi 
Published: March 2014

Abstract
Making a survey of Itokawids, i.e., meteor(oid)s originating from Apollo-type near-Earth Asteroid (25143) Itokawa, from among the multiple-station optical meteor orbit data, and employing several orbital similarity criteria, we found five Itokawid candidates. Furthermore, we classified the Itokawid candidates in meteorite types according to their physical data. The physical analyses indicate that all of the candidates evidently belong to not cometary, but asteroidal, meteoroids. Especially, the fireball, MORP 172, is the one candidate that is classified among ordinary/carbonaceous chondrites, as against the four other at carbonaceous chondrites. Hence, the classified meteoritic matter of MORP 172 shows more similarities to Itokawa's surface composition of an LL chondrite analogue than those of the other candidates. Therefore, the fireball is considered to be the strongest of the Itokawid candidates.
Enhancement of Terrestrial Diffuse X-Ray Emission Associated with Coronal Mass Ejection and Geomagnetic Storm
Authors: Ezoe Yuichiro , Miyoshi Yoshizumi , Yoshitake Hiroshi , Mitsuda Kazuhisa , Terada Naoki , Oishi Shihoko , Ohashi Takaya 
Published: March 2014

Abstract
We present an analysis of a Suzaku observations taken during the geomagnetic storm of 2005 August 23–24. We found a time variation of diffuse soft X-ray emission when a coronal mass ejection hit Earth and caused a geomagnetic storm. The diffuse emission consisted of fluorescent scattering of solar X-rays and an exospheric solar wind charge exchange. The former is characterized by a neutral oxygen emission line due to strong heating of the upper atmosphere during the storm time, while the latter is dominated by the sum of C V, C VI, N VI, N VII, O VII, and O VIII emission lines due to an enhanced solar wind flux in the vicinity of the exosphere. Using the solar-wind data taken with the ACE and WIND satellites, a time correlation between the solar wind and the strong O VII line flux was investigated. We estimated necessary column densities for the solar X-ray scattering and exospheric SWCX. From these results, we argue that a part of the solar-wind ions enters inside the magnetosphere and causes the SWCX reaction.
X-Ray Observation of Mars at Solar Minimum with Suzaku
Authors: Ishikawa Kumi , Ezoe Yuichiro , Ohashi Takaya , Terada Naoki , Futaana Yoshifumi 
Published: March 2014

Abstract
Mars was observed in X-rays during 2008 April 3–5 for 82 ks with the Japanese Suzaku observatory. Mars has been known to emit X-rays via the scattering of solar X-rays and via charge exchange between neutral atoms in the exosphere and solar-wind ions. Past theoretical studies suggest that the exospheric neutral density may vary by a factor of up to 10 over the solar cycle. To investigate a potential change of the exospheric charge exchange emission, Mars was observed with Suzaku at solar minimum. Significant signals were not detected at the position of Mars in the energy band of 0.2–5 keV. The 2 $\sigma$ upper limit of the O II line flux in 0.5–0.65 keV was 4.3 $\times$ 10 $^{-5}$ photons cm $^{-2}$ s $^{-1}$ . Comparing this upper limit to past Chandra and XMM-Newton observations conducted near solar maximum, it was found that the exospheric density at solar minimum does not exceed that near solar maximum by more than 6–70 times.
X-Ray Study of Rekindled Accretion in the Classical Nova V2491 Cygni
Authors: Takei Dai , Ness Jan-Uwe , Tsujimoto Masahiro , Kitamoto Shunji , Drake Jeremy J. , Osborne Julian P. , Takahashi Hiromitsu , Kinugasa Kenzo 
Published: March 2014

Abstract
We conducted an X-ray spectroscopic study of the classical nova V2491 Cygni using our target-of-opportunity observation data with the Suzaku and XMM-Newton satellites as well as archived data with the Swift satellite. Medium-resolution ( $R$$\sim$ 10–50) spectra were obtained using the X-ray CCD spectrometers at several post-nova epochs on days 9, 29, 40, 50, and 60–150 in addition to a pre-nova interval between days $-$ 322 and $-$ 100, all relative to the time when the classical nova was spotted. We found remarkable changes in the time series of the spectra: (a) In the pre-nova phase and on day 9, the 6.7 keV emission line from Fe XXV was significantly detected. (b) On day 29, no such emission line was found. (c) On day 40, the 6.7 keV emission line emerged again. (d) On days 50 and 60–150, three emission lines at 6.4, 6.7, and 7.0 keV, respectively, from quasi-neutral Fe, Fe XXV, and Fe XXVI were found. Statistically significant changes of the Fe K line intensities were confirmed between days 29 and 50. Based on these phenomena, we conclude that: (1) the post-nova evolution can be divided into two different phases, (2) ejecta is responsible for the X-ray emission in the earlier phase, while rekindled accretion is responsible for the later phase, and (3) the accretion process is considered to be reestablished as early as day 50 when the quasi-neutral Fe emission line emerged, which is a common signature of accretion from magnetic cataclysmic variables.