bluuebunny/crossref_metadata_2025 huggingface dataset:
Distance to G14.33–0.64 in the Sagittarius Spiral Arm: H2O Maser Trigonometric Parallax with VERA
Authors: Sato Mayumi , Hirota Tomoya , Reid Mark J. , Honma Mareki , Kobayashi Hideyuki , Iwadate Kenzaburo , Miyaji Takeshi , Shibata Katsunori M.
Published: March 2014

We report on trigonometric parallax measurements for the Galactic star-forming region G14.33$-$0.64 toward the Sagittarius spiral arm. We conducted multi-epoch phase-referencing observations of an H$_2$O maser source in G14.33$-$0.64 with the Japanese VLBI array VERA. We successfully detected a parallax of $\pi =$ 0.893$ \pm $0.101 mas, corresponding to a source distance of $d =$ 1.12$ \pm $0.13 kpc, which is less than half of the kinematic distance for G14.33$-$0.64. Our new distance measurement demonstrates that the Sagittarius arm lies at a closer distance of $\sim$ 1 kpc, instead of the previously assumed $\sim$2–3 kpc from the kinematic distances. The previously suggested deviation of the Sagittarius arm toward the Galactic center from the symmetrically fitted model (Taylor & Cordes 1993, ApJ, 411, 674) is likely due to large errors of the kinematic distances at low galactic longitudes. G14.33$-$0.64 most likely traces the near side of the Sagittarius arm. We attempted to fit the pitch angle of the arm with other parallax measurements along the arm, which yielded two possible pitch angles of $i =$ 34°.7$ \pm $2°.7 and $i =$ 11.D2$ \pm $10.D5. Our proper-motion measurements suggest that G14.33$-$0.64 has no significant peculiar motion relative to the differential rotation of the Galaxy (assumed to be in a circular orbit), indicating that the source motion is in good agreement with the Galactic rotation.
Hydrodynamic Simulations of Merging Galaxy Clusters: Non-Equilibrium Ionization State and Two-Temperature Structure
Authors: Akahori Takuya , Yoshikawa Kohji
Published: March 2014

We investigate a non-equilibrium ionization state and an electron–ion two-temperature structure of the intracluster medium (ICM) in merging galaxy clusters using a series of $N$-body and hydrodynamic simulations. Mergers with various sets of mass ratios and impact parameters are systematically investigated, and it is found that, in most cases, ICM significantly departs from the ionization equilibrium state at the shock layers with a Mach number of $\sim $1.5–2.0 in the outskirts of the clusters, and the shock layers with a Mach number of $\sim $2–4 in front of the ICM cores. Accordingly, the intensity ratio between FeXXV and FeXXVI K$\alpha$ line emissions is significantly altered from that in the ionization equilibrium state. If the effect of the two-temperature structure of ICM is incorporated, the electron temperature is $\sim $10%–20% and $\sim $30%–50% lower than the mean temperature of ICM at the shock layers in the outskirts and in front of the ICM cores, respectively, and the deviation from the ionization equilibrium state becomes larger. We also address the dependence of the intensity ratio on the viewing angle with respect to the merging plane.
VLBI Monitoring of 3C 84 (NGC 1275) in Early Phase of the 2005 Outburst
Authors: Nagai Hiroshi , Suzuki Kenta , Asada Keiichi , Kino Motoki , Kameno Seiji , Doi Akihiro , Inoue Makoto , Kataoka Jun , Bach Uwe , Hirota Tomoya , Matsumoto Naoko , Honma Mareki , Kobayashi Hideyuki , Fujisawa Kenta
Published: March 2014

Multi-epoch Very Long Baseline Interferometry (VLBI) study of a sub-pc scale jet of 3C 84 is presented. We carried out 14-epoch VLBI observations during 2006–2009 with the Japanese VLBI Network and the VLBI Exploration of Radio Astrometry, immediately following a radio outburst that began in 2005. We confirmed that the outburst was associated with the central $\sim1$ pc core, accompanying the emergence of a new component. This is striking evidence of the recurrence of jet activity. The new component became brighter during 2008, in contrast to constant $\gamma$-ray emission that was observed with the Fermi Gamma-ray Space Telescope during the same time. We found that the projected speed of the new component was 0.23$ c$ from 2007/297 (2007 October 24) to 2009/114 (2009 April 24). The direction of movement of this component differs from that of the pre-existing component by $\sim $40$^{\circ}$. This was the first measurement of the kinematics of a sub-pc jet in a $\gamma$-ray active phase. A possible detection of jet deceleration and the jet kinematics in connection with the $\gamma$-ray emission is discussed.
The Effectiveness of Mid IR / Far IR Blind, Wide Area, Spectral Surveys in Breaking the Confusion Limit
Authors: Raymond Gwenifer , Isaak Kate G. , Clements Dave , Rykala Adam , Pearson Chris
Published: March 2014

Source confusion defines a practical depth to which to take large-area extragalactic surveys. 3D imaging spectrometers with positional as well as spectral information, however, potentially provide a means by which to use line emission to break the traditional confusion limit. In this paper we present the results of our investigation into the effectiveness of mid/far infrared, wide-area spectroscopic surveys in breaking the confusion limit. We use SAFARI, a FIR imaging Fourier Transform Spectrometer concept for the proposed JAXA-led SPICA mission, as a test case. We generate artificial skies representative of 100 SAFARI footprints and use a fully-automated redshift determination method to retrieve redshifts for both spatially and spectrally confused sources for bright-end and burst mode galaxy evolution models. We find we are able to retrieve accurate redshifts for 38/54% of the brightest spectrally confused sources, with continuum fluxes as much as an order of magnitude below the 120 $\mu$m photometric confusion limit. In addition we also recover accurate redshifts for 38/29% of the second brightest spectrally confused sources. Our results suggest that deep, spectral line surveys with SAFARI can break the traditional photometric confusion limit, and will also not only resolve, but provide redshifts for, a large number of previously inaccessible galaxies. To conclude we discuss some of the limitations of the technique, as well as further work.
Energetic Relations between the Disappearing Solar Filaments and the Associated Flare Arcades
Authors: Morimoto Taro , Kurokawa Hiroki , Shibata Kazunari , Ishii Takako T.
Published: March 2014

We present the temporal and statistical relations between the mechanical energies of disappearing solar filaments and the thermal energies of the associated flare arcades in soft X-rays. Measuring the 3-D velocity fields of 10 eruptive filaments, we calculated their mechanical energy gain rate, $\epsilon_{\rm mc}$, per unit volume and compared it to the thermal energy release rate per unit volume, $\epsilon_{\rm th}$, derived with Yohkoh/SXT data. For the statistical relation, we found a relation that can be approximated as $\epsilon_{\rm th} \propto \epsilon_{\rm mc}^{1.9}$. This relation can be explained by interpreting the energy input to an arcade via the Poynting flux in the magnetic reconnection process and the acceleration of a filament by the Lorentz force. This explanation is also supported by the strong dependence of the observed increase rates of both the thermal and mechanical energy densities on the mean magnetic field strength of the source region. We also investigated their temporal variations, and found that the start time of increase in the mechanical energy of a filament preceded that of the thermal energy of the coronal arcade in some cases. These relations imply that the basic mechanisms that accelerate a filament and create a hot plasma are different, and both energy increase rates are determined primary by the magnetic field strengths.
Spectral Cross-Calibration of the Konus-Wind, the Suzaku/WAM, and the Swift/BAT Data Using Gamma-Ray Bursts
Authors: Sakamoto Takanori , Pal'SHIN Valentin , Yamaoka Kazutaka , Ohno Masanori , Sato Goro , Aptekar Rafail , Barthelmy Scott D. , Baumgartner Wayne H. , Cummings Jay R. , Fenimore Edward E. , Frederiks Dmitry , Gehrels Neil , Golenetskii Sergey , Krimm Hans A. , Markwardt Craig B. , Onda Kaori , Palmer David M. , Parsons Ann M. , Stamatikos Michael , Sugita Satoshi , Tashiro Makoto , Tueller Jack , Ukwatta Tilan N.
Published: March 2014

We report on the spectral cross-calibration results of the Konus-Wind, the Suzaku/WAM, and the Swift/BAT instruments using simultaneously observed gamma-ray bursts (GRBs). This is the first attempt to use simultaneously observed GRBs as a spectral calibration source to understand systematic problems among the instruments. Based on these joint spectral fits, we find that (1) although a constant factor (a normalization factor) agrees within 20% among the instruments, the BAT constant factor shows a systematically smaller value by 10%–20% compared to that of Konus-Wind, (2) there is a systematic trend that the low-energy photon index becomes steeper by 0.1–0.2 and $E_{\rm peak}$ becomes systematically higher by 10%–20% when including the BAT data in the joint fits, and (3) the high-energy photon index agrees within 0.2 among the instruments. Our results show that cross-calibration based on joint spectral analysis is an important step to understanding the instrumental effects that could be affecting the scientific results from the GRB prompt emission data.
Near- and Mid-Infrared Imaging Study of Young Stellar Objects around LkHα 234
Authors: Kato Eri , Fukagawa Misato , Perrin Marshall D. , Shibai Hiroshi , Itoh Yusuke , Ootsubo Takafumi
Published: March 2014

We present high-resolution (0$''\!\!\!.$2) near-infrared images of the area surrounding the Herbig Be star LkH$\alpha $ 234 taken with the Coronagraphic Imager with Adaptive Optics (CIAO) and the adaptive optics on the Subaru Telescope. The near-infrared ($J$, $H$, $K$, $L'$, and $M'$ bands) images reveal circumstellar structures around LkH$\alpha $ 234 in detail. Eight young stellar object (YSO) candidates (Object B, C, D, E, F, G, NW1, and NW2) were detected at 2$\arcsec$–11$\arcsec$ from LkH$\alpha $ 234. Objects B and C are likely variable stars, which is consistent with a young evolutionary status. Three objects (LkH$\alpha $ 234, NW1, and NW2) were identified in the 11.8$\ \mu$m (SiC) and 17.65$\ \mu$m images obtained with the Long Wavelength Spectrometer (LWS) on the Keck Telescope. NW1 and NW2 are thought to be embedded young stars. We suggest that NW1, and not LkH$\alpha $ 234, is the source illuminating the reflection nebula west of LkH$\alpha $ 234, although Object G may be another candidate. In our images, these objects are located at the center of the 2$\ \mu$m polarization, and NW1 resides at the center of a monopolar cavity. The SED of NW1 suggests that it is a YSO with a spectral type of B6–B7. Object F and G were discovered by our observations at 1$''\!\!\!.$9 and 2$''\!\!\!.$3, respectively, from LkH$\alpha $ 234, and their proximity to LkH$\alpha $ 234 suggests that they may be its lower-mass companions.
Infrared Search for Young Brown Dwarf Companions around Young Stellar Objects in the ρ Ophiuchi and the Serpens Molecular Clouds
Authors: Shirono Chiaki , Itoh Yoichi , Oasa Yumiko
Published: March 2014

We conducted an infrared search for faint companions around 351 young stellar objects in the $\rho$ Ophiuchi molecular cloud and the Serpens molecular cloud. Nine objects in the Spitzer/IRAC archival images were identified as being young stellar companion candidates. They showed an intrinsic infrared excess; one object was extremely red both in the [3.6]$-$[4.5] color and in the [4.5]$-$[5.8] color, and two objects were red in the [4.5]$-$[5.8] color. They were as faint as 15 mag in the [3.6] band. Follow-up $K$-band spectroscopy revealed that the three objects had deep water absorption bands, indicative of low effective temperatures. By comparing their spectra and infrared spectral energy distributions with synthesized spectra of low-temperature objects, we derived the effective temperatures and continuum excesses for these objects. It is very likely that one is a low-mass stellar companion, and two others are young brown dwarf companions associated with young stellar objects.
Detection of Phosphorus Nitride in the Lynds 1157 B1 Shocked Region
Authors: Yamaguchi Takahiro , Takano Shuro , Sakai Nami , Sakai Takeshi , Liu Sheng-Yuan , Su Yu-Nung , Hirano Naomi , Takakuwa Shigehisa , Aikawa Yuri , Nomura Hideko , Yamamoto Satoshi
Published: March 2014

We have observed the $J$$=$ 2–1 rotational emission line of PN toward the low-mass star forming region L 1157 with the Nobeyama 45 m telescope. The PN line has been detected toward the two shocked regions (B1 and B2) caused by the interaction between the blue lobe of the outflow from the protostar IRAS 20386$+$6751 and the ambient gas, whereas it has not been detected toward the protostar position. The fractional abundances of PN relative to H$_2$ are evaluated to be (2–6) $\times$ 10$^{-10}$ and (3–7) $\times$ 10$^{-10}$ toward B1 and B2, respectively. Detection of PN in the B1 and B2 positions indicates that the formation of PN can be triggered by shocks. It seems most likely that PN is formed in the gas phase from PH$_3$ evaporated from grain mantles, as suggested by the existing chemical model.
Propagation of Highly Efficient Star Formation in NGC 7000
Authors: Toujima Hideyuki , Nagayama Takumi , Omodaka Toshihiro , Handa Toshihiro , Koyama Yasuhiro , Kobayashi Hideyuki
Published: March 2014

We surveyed the (1, 1), (2, 2), and (3, 3) lines of NH$_3$ and the H$_2$O maser toward the molecular cloud L935 in the extended H II region NGC 7000 with an angular resolution of 1$'\!\!.$6 using the Kashima 34-m telescope. We found five clumps in the NH$_3$ emission with a size of 0.2–1 pc and mass of 9–452$\ M_{\odot}$. The molecular gas in these clumps has a similar gas kinetic temperature of 11–15 K and a line width of 1–2 km s$^{-1}$. However, they have different star-formation activities, such as the concentration of T-Tauri type stars and the association of H$_2$O maser sources. We found that these star-formation activities are related to the geometry of the H II region. The clump associated with the T-Tauri type star cluster has a high star-formation efficiency of 36%–62%. This clump is located near the boundary of the H II region and molecular cloud. Therefore, we suggest that the star-formation efficiency increases because of the triggered star formation.
Survey of Period Variations of Superhumps in SU UMa-Type Dwarf Novae. III. The Third Year (2010–2011)
Authors: Kato Taichi , Maehara Hiroyuki , Miller Ian , Ohshima Tomohito , de Miguel Enrique , Tanabe Kenji , Imamura Kazuyoshi , Akazawa Hidehiko , Kunitomi Nanae , Takagi Ryosuke , Nose Mikiha , Hambsch Franz-Josef , Kiyota Seiichiro , Pavlenko Elena P. , Baklanov Aleksei V. , Antonyuk Oksana I. , Samsonov Denis , Sosnovskij Aleksei , Antonyuk Kirill , Andreev Maksim V. , Morelle Etienne , Dubovsky Pavol A. , Kudzej Igor , Oksanen Arto , Masi Gianluca , Krajci Thomas , Pickard Roger D. , Sabo Richard , Itoh Hiroshi , Stein William , Dvorak Shawn , Henden Arne , Nakagawa Shinichi , Noguchi Ryo , Iino Eriko , Matsumoto Katsura , Nishitani Hiroki , Aoki Tomoya , Kobayashi Hiroshi , Akasaka Chihiro , Bolt Greg , Shears Jeremy , Ruiz Javier , Shugarov Sergey Yu. , Chochol Drahomir , Parakhin Nikolai A. , Monard Berto , Shiokawa Kazuhiko , Kasai Kiyoshi , Staels Bart , Miyashita Atsushi , Starkey Donn R. , Ögmen Yenal , Littlefield Colin , Katysheva Natalia , Sergey Ivan M. , Denisenko Denis , Tordai Tamas , Fidrich Robert , Goranskij Vitaly P. , Virtanen Jani , Crawford Tim , Pietz Jochen , Koff Robert A. , Boyd David , Brady Steve , James Nick , Goff William N. , Itagaki Koh-ichi , Nishimura Hideo , Nakashima Youichirou , Yoshida Seiichi , Stubbings Rod , Poyner Gary , Maeda Yutaka , Korotkiy Stanislav A. , Sokolovsky Kirill V. , Ueda Seiji
Published: March 2014

Continuing the project described by Kato et al. (2009, PASJ, 61, S395), we collected the times of superhump maxima for 51 SU UMa-type dwarf novae, mainly observed during the 2010–2011 season. Although most of the new data for systems with short superhump periods basically confirmed the findings by Kato et al. (ibid.) and Kato et al. (2010, PASJ, 62, 1525), the long-period system GX Cas showed an exceptionally large positive-period derivative. An analysis of public Kepler data of V344 Lyr and V1504 Cyg yielded less-striking stage transitions. In V344 Lyr, there was a prominent secondary component growing during the late stage of superoutbursts, and this component persisted for at least two more cycles of successive normal outbursts. We also investigated the superoutburst of two conspicuous eclipsing objects: HT Cas and the WZ Sge-type object SDSS J080434.20$+$510349.2. Strong beat phenomena were detected in both objects, and late-stage superhumps in the latter object had an almost constant luminosity during repeated rebrightenings. The WZ Sge-type object SDSS J133941.11$+$484727.5 showed a phase reversal around the rapid fading from the superoutburst. The object showed a prominent beat phenomenon, even after the end of the superoutburst. A pilot study of superhump amplitudes indicated that the amplitude of superhumps is strongly correlated with the orbital period, and the dependence on the inclination is weak in systems with inclinations smaller than 80$^{\circ}$.
A Planetary Companion to the Intermediate-Mass Giant HD 100655
Authors: Omiya Masashi , Han Inwoo , Izumiura Hideyuki , Lee Byeong-Cheol , Sato Bun'ei , Kim Kang-Min , Seog Yoon Tae , Kambe Eiji , Yoshida Michitoshi , Masuda Seiji , Toyota Eri , Urakawa Seitaro , Takada-Hidai Masahide
Published: March 2014

A precise radial-velocity survey conducted by a Korean–Japanese planet search program revealed a planetary companion around the intermediate-mass clump giant HD 100655. The radial velocity of the star exhibits a periodic Keplerian variation with a period, semi-amplitude, and eccentricity of 157.57 d, 35.2 m s$^{-1}$, and 0.085, respectively. Adopting an estimated stellar mass of 2.4$\ M_{\odot}$, we confirmed the presence of a planetary companion with a semi-major axis of 0.76 AU and a minimum mass of 1.7$\ M_{\mathrm{J}}$. The planet is the lowest-mass planet yet discovered around clump giants with masses greater than 1.9$\ M_{\odot}$.
A Study on the Orbital Period Variation of AR Lacertae
Authors: Lu Ye , Xiang Fu-Yuan , Shi Xiao-Min
Published: March 2014

In this paper, we collect all available times of the light minimum of AR Lac from the literature and databases. Through an analysis of the $ O$$-$$ C$ curve by a weighted least-squares method, we found that the orbital period of the system shows a cyclic oscillation with a period of 50.93 yr superimposed on a long-term secular period decrease at a rate of $ dP/dt$$ =$$-$ (2.128 $ \pm$ 0.060) $ \times$ 10$ ^{-9}$ d$ /$ d. Since both components of AR Lac are late-type stars, and show strong Ca H and K emission lines, the orbital period variation may be caused by the magnetic activity of the system.
Constraining Intergalactic Magnetic Field with Fermi-LAT Observation of Cascade Radiation for TeV Blazars
Authors: Yang Jianping , Wang Jiancheng , Yang Jianrong
Published: March 2014

The problem concerning the origin of the Intergalactic Magnetic Field (IGMF) is one of the long-standing problems of astrophysics and cosmology, and direct measurements are difficult. TeV photons emitted by TeV blazars produce electron-positron pairs because of interactions with the extragalactic background light (EBL). These pairs emit secondary cascade gamma-rays via Inverse Compton scattering of the cosmic microwave background (CMB) photons. In this process, the trajectories of the pairs are deviated by the IGMF, and the cascade gamma-ray emission appears as extended emission around TeV source. We used the EBL, synchrotron self-Compton (SSC) model and the observed limits on Lorentz factor of electron-positron pairs to calculate the cascade-radiation spectrum, and then to fit the observed GeV to TeV and multi-waveband spectra of TeV blazars to constrain the IGMF. We obtained the GeV energy spectra of three TeV blazars by analyzing the Fermi-LAT data of the past $ \sim$ 3 yr. The flux upper limits of Fermi-LAT in the 90% significant level of 1ES 0229$ +$ 200 suggests that the IGMF is stronger than 2 $ \times$ 10$ ^{-18}$ G for an engine time of TeV activity with three years. The relationships between the deduced lower limits of IGMF and various engine times for 1ES 0229$ +$ 200 and 1ES 0347$-$ 121 are presented by us.
Suzaku Investigation into the Nature of the Nearest Ultraluminous X-Ray Source, M33 X-8
Authors: Isobe Naoki , Kubota Aya , Sato Hiroshi , Mizuno Tsunefumi
Published: March 2014

The X-ray spectrum of the nearest ultraluminous X-ray source, M 33 X-8, obtained by Suzaku during 2010 January 11–13, was closely analyzed in order to examine its nature. It is, by far, the only data with the highest signal statistic in the 0.4–10 keV range. Despite being able to reproduce the X-ray spectrum, Comptonization of the disk photons failed to give a physically meaningful solution. A modified version of the multi-color disk model, in which the dependence of the disk temperature on the radius is described as $ r^{-p}$ , with $ p$ being a free parameter, can also approximate the spectrum. From this model, the innermost disk temperature and bolometric luminosity were obtained as $ T_{\rm in}$$ =$ 2.00$ _{-0.05}^{+0.06}$ keV and $ L_{\rm disk}$$ =$ 1.36 $ \times$ 10$ ^{39}$ (cos $ i$ )$ ^{-1}$ erg s$ ^{-1}$ , respectively, where $ i$ is the disk inclination. A small temperature gradient of $ p$$ =$ 0.535$ _-0.005^{+0.004}$ , together with the high disk temperature, is regarded as signatures of the slim accretion disk model, suggesting that M 33 X-8 was accreting at a high mass-accretion rate. With a correction factor for the slim-disk taken into account, the innermost disk radius, $ R_{\rm in}$$ =$ 81.9$ _-6.5^{+5.9}$ (cos$ i$ )$ ^{-0.5}$ km, corresponds to a black-hole mass of $ M$$ \sim$ 10 $ M_{\odot}$ (cos $ i$ )$ ^{-0.5}$ . Accordingly, the bolometric disk luminosity is estimated to be about 80(cos $ i$ )$ ^{-0.5}$ % of the Eddington limit. A numerically calculated slim-disk spectrum was found to reach a similar result. Thus, the extremely super-Eddington luminosity is not required to explain the nature of M 33 X-8. This conclusion is utilized to argue for the existence of intermediate-mass black holes with $ M$$ \gtrsim$ 100$ M_{\odot}$ radiating at the sub/trans-Eddington luminosity, among ultraluminous X-ray sources with $ L_{\rm disk}$$ \gtrsim$ 10$ ^{40}$ erg s$ ^{-1}$ .
Fundamental Parameters of the Milky Way Galaxy Based on VLBI Astrometry
Authors: Honma Mareki , Nagayama Takumi , Ando Kazuma , Bushimata Takeshi , Choi Yoon Kyung , Handa Toshihiro , Hirota Tomoya , Imai Hiroshi , Jike Takaaki , Kim Mi Kyoung , Kameya Osamu , Kawaguchi Noriyuki , Kobayashi Hideyuki , Kurayama Tomoharu , Kuji Seisuke , Matsumoto Naoko , Manabe Seiji , Miyaji Takeshi , Motogi Kazuhito , Nakagawa Akiharu , Nakanishi Hiroyuki , Niinuma Kotaro , Oh Chung Sik , Omodaka Toshihiro , Oyama Tomoaki , Sakai Nobuyuki , Sato Katsuhisa , Sato Mayumi , Shibata Katsunori M. , Shiozaki Satoshi , Sunada Kazuyoshi , Tamura Yoshiaki , Ueno Yuji , Yamauchi Aya
Published: March 2014

We present analyses to determine the fundamental parameters of the Galaxy based on VLBI astrometry of 52 Galactic maser sources obtained with VERA, VLBA, and EVN. We model the Galaxy's structure with a set of parameters, including the Galaxy center distance $ R_0$ , the angular rotation velocity at the LSR $ \Omega_0$ , the mean peculiar motion of the sources with respect to Galactic rotation ($ U_{\rm src}$ , $ V_{\rm src}$ , $ W_{\rm src}$ ), the rotation-curve shape index, and the $ V$ component of the Solar peculiar motions, $ V_\odot $ . Based on a Markov chain Monte-Carlo method, we find that the Galaxy center distance is constrained at a 5% level to be $ R_0$$ =$ 8.05 $ \pm$ 0.45 kpc, where the error bar includes both statistical and systematic errors. We also find that the two components of the source peculiar motion $ U_{\rm src}$ and $ W_{\rm src}$ are fairly small compared to the Galactic rotation velocity, being $ U_{\rm src}$$ =$ 1.0 $ \pm$ 1.5 km s$ ^{-1}$ and $ W_{\rm src}$$ =$$-$ 1.4 $ \pm$ 1.2 km s$ ^{-1}$ . Also, the rotation curve shape is found to be basically flat between Galacto-centric radii of 4 and 13 kpc. On the other hand, we find a linear relation between $ V_{\rm src}$ and $ V_\odot $ as $ V_{\rm src}$$ =$$ V_\odot $$-$ 19 ($ \pm$ 2) km s$ ^{-1}$ , suggesting that the value of $ V_{\rm src}$ is fully dependent on the adopted value of $ V_\odot $ . Regarding the rotation speed in the vicinity of the Sun, we also find a strong correlation between $ \Omega_0$ and $ V_\odot $ . We find that the angular velocity of the Sun, $ \Omega_{\odot}$ , which is defined as $ \Omega_\odot$$ \equiv$$ \Omega_0$$ +$$ V_\odot/R_0$ , can be well constrained with the best estimate of $ \Omega_\odot$$ =$ 31.09 $ \pm$ 0.78 km s$ ^{-1}$ kpc$ ^{-1}$ . This corresponds to $ \Theta_0$$ =$ 238 $ \pm$ 14 km s$ ^{-1}$ if one adopts the above value of $ R_0$ and recent determination of $ V_\odot $$ \sim$ 12 km s$ ^{-1}$.
Shear Tensor and Dynamics of Relativistic Accretion Disks around Rotating Black Holes
Authors: Moeen Mahboobe , Ghanbari Jamshid , Ghodsi Ahmad
Published: March 2014

In this paper we solve the hydrodynamical equations of optically thin, steady state accretion disks around Kerr black holes. Here, fully general-relativistic equations are used. We use a new method to calculate the shear tensor in the LNRF (Locally Non-Rotating Frame), BLF (Boyer–Lindquist Frame), and FRF (Fluid Rest Frame). We show that two components of shear tensor in the FRF are nonzero (in previous works only one nonzero component was assumed). We can use these tensors in usual transonic solutions and usual causal viscosity, but we derive solutions analytically by some simplifications. Then, we can calculate the four-velocity and density in all frames, such as the LNRF, BLF, and FRF.
Systematic X-Ray Analysis of Radio Relic Clusters with Suzaku
Authors: Akamatsu Hiroki , Kawahara Hajime
Published: March 2014

We undertook a systematic X-ray analysis of six giant radio relics in four clusters of galaxies using the Suzaku satellite. The sample included CIZA 2242.8$ +$ 5301, Zwcl 2341.1$-$ 0000, the South-East part of A 3667 and previously published results of the North-West part of A 3667 and A 3376. Especially, we first observed the narrow (50 kpc) relic of CIZA 2242.8$ +$ 5301 by the Suzaku satellite, which enabled us to reduce the projection effect. We report on X-ray detections of shocks at the positions of the relics in CIZA 2242.8$ +$ 5301 and A 3667 SE. At the positions of the two relics in ZWCL 2341.1$-$ 0000, we did not detect shocks. From spectroscopic temperature profiles across the relic, we found that the temperature profiles exhibit significant jumps across the relics for CIZA 2242.8$ +$ 5301, A 3376, A 3667 NW, and A 3667 SE. We estimated the Mach number from the X-ray temperature or pressure profile using the Rankine-Hugoniot jump condition, and compared it with the Mach number derived from the radio spectral index. The resulting Mach numbers ($ {\cal M}$$ =$ 1.5–3) are almost consistent with each other, while the Mach number of CIZA 2242.8$ +$ 5301, derived from the X-ray data, tends to be lower than that of the radio observation. These results indicate that the giant radio relics in merging clusters are related to the shock structure, as suggested by previous studies of individual clusters.
The Asteroid Catalog Using AKARI IRC Slow-Scan Observations
Authors: Hasegawa Sunao , Müller Thomas G. , Kuroda Daisuke , Takita Satoshi , Usui Fumihiko
Published: March 2014

We present an asteroidal catalog from the mid-infrared wavelength region using the slow-scan observation mode obtained by the Infrared Camera (IRC) on-board the Japanese infrared satellite AKARI. An archive of IRC slow-scan observations comprising about 1000 images was used to search for serendipitous encounters of known asteroids. We have determined the geometric albedos and diameters for 88 main-belt asteroids, including two asteroids in the Hilda region, and compared these, where possible, with previously published values. Approximately one-third of the acquired data reflects new asteroidal information. Some bodies classified as C or D-type with high albedo were also identified in the catalog.
Paschen α Observations of Be Stars Toward the SMC Cluster NGC 330
Authors: TanabÉ Toshihiko , Motohara Kentaro , Tateuchi Ken , Matsunaga Noriyuki , Ita Yoshifusa , Toshikawa Koji , Konishi Masahiro , Kato Natsuko , Yoshii Yuzuru
Published: March 2014

We made imaging observations of the young SMC cluster NGC 330 in the near-infrared $ J$, $ H$, $ K_{\rm s}$ as well as two narrow-band Pa$ \alpha $ and Pa$ \alpha $-off filters. The observations were carried out at a high-altitude site, 5640 m, where the atmospheric extinction is small enough to make the spectral range around Pa$ \alpha $ transparent. We present the calibration of specially designed narrow-band filters, and the method used to identify Pa$ \alpha $ emission using photometric colors. We have successfully detected Pa$ \alpha $ emission from almost all Be stars within the detection limit of the small telescope and the narrow-band filters. The strength of Pa$ \alpha $ emission well correlates with that of H$ \alpha $, which also confirms the proper detection of Pa$ \alpha $ emission. This was the first systematic detection of the Pa$ \alpha $ emission line from Be stars. We also found new candidates of Pa$ \alpha $ emission-line objects. This work demonstrates that the photometric colors, including the Pa$ \alpha $ band, can be used to detect the Pa$ \alpha $ line when observed from high-altitude sites.
Time Lag in the Intra-Day Variability of Sagittarius A between Light Curves at 90 and 102 GHz
Authors: miyazaki Atsushi , tsuboi Masato , tsutsumi Takahiro
Published: March 2014

We performed observations of the flux densities of Sgr A$ ^\star$ at 90 and 102 GHz in order to detect any time lag between these frequencies using the Nobeyama Millimeter Array, which was previously reported at lower frequencies. We detected a radio flare during the observation period on 2005 April 6, and calculated the z-transformed discrete correlation function between the light curves. No time lag between these frequencies was detected. If the expanding plasma model, which explains a time lag at lower frequencies, is valid, the light curve at 90 GHz would be delayed in respect to that at 102 GHz. This result suggests that plasma blobs ejected close to the Galactic center black hole may be widely diverse, especially in optical thickness. Another possibility is that a major portion of the flux above 100 GHz does not originate in blobs.
Search for Non-Thermal Emissions from an Isolated Magnetic White Dwarf, EUVE J0317 855, with Suzaku
Authors: Harayama Atsushi , Terada Yukikatsu , Ishida Manabu , Hayashi Takayuki , Bamba Aya , Tashiro Makoto S.
Published: March 2014

To search for possible non-thermal emissions from magnetic white dwarfs (WDs), we selected the most suitable candidates from among magnetic cataclysmic variables and isolated WDs. After the magnetic cataclysmic variable AE Aquarii, which emits hard X-ray pulses, the isolated WD EUVE J0317$-$855 is expected to emit the second most powerful magnetic dipole radiation with energies reaching $\sim$1.1 $\times$10$^{29}$ erg s$^{-1}$. EUVE J0317$-$855 was observed with Suzaku from 2009 July 16 to 2009 July 17 for about 60 ks. No significant emissions were detected from the object in the 0.5–10 keV band, and the upper limit of the X-ray flux was estimated to be 1.7 $\times$10$^{-13}$ erg cm$^{-2}$ s$^{-1}$ in the 2–10 keV band. This value corresponds to less than 0.05% of the calculated spin-down energy. It excludes the possibility of explaining soft gamma-ray repeaters and anomalous X-ray pulsars as WDs, but may indicate that the activity in the magnetosphere of WDs is not so different from that occurring in radio pulsars. Curvature radiation, which is one of the suggested mechanism for emissions from the magnetosphere of compact objects, may explain the observed X-ray flux of AE Aquarii, and is consistent with the non-detection of EUVE J0317$-$855.
The Dependence of Particle Acceleration on Initial Locations in Reconnecting Current Sheets
Authors: Yan Li , Winter Henry D. , Murphy Nicholas A. , Jun Lin , Ning Wu
Published: March 2014

Electron and proton acceleration by a super-Dreicer electric field is investigated in a reconnecting current sheet in the presence of a guide field. The electric field is assumed to vary in space. Electrons and protons are accelerated from initial positions randomly distributed over the whole acceleration region. The stability of the energy spectrum is investigated using different numbers of test particles. The energy spectrum eventually obtained is consistent with a power-law spectrum. The spectral index of electrons increases rapidly with increasing guide field, but the index for the protons does not vary significantly. The relation of the final energy to the initial position is also studied. The results indicate that the addition of a guide field not only allows the reconnecting electric field to selectively accelerate electrons and protons from different initial positions, but also increases the number of accelerated electrons and reduces the number of protons. The final position and the pitch angles of the accelerated particles are also investigated. Finally, we also calculate the energy spectrum of particles initially distributed at the boundary of the reconnection inflow.
Particle Acceleration and Emission Processes in Mrk 421
Authors: Cao Gang , Wang Jiancheng
Published: March 2014

We investigated the X-ray and γ-ray flares of Mrk 421 on 2008 June 6–15 using the synchrotron self-Compton- (SSC) model with electron acceleration, in which an evident correlation between the X-ray and γ-ray bands appears, while no significant correlation between the optical and X-ray band was observed. We argue that the emission from Mrk 421 may originate from two different components. One is a steady component from the outer region, which is mainly attributed to the optical band, in which the electrons are accelerated by first-order Fermi acceleration mechanism. We used a steady electron spectrum to produce the SSC emission. The other is a variable component from the inner region, in which the electrons are accelerated by a stochastic acceleration process. We used the timedependent SSC model to produce the emission from the variable component. We suggest that the flares are due to a hardening of the electron spectrum under the process of stochastic acceleration, which leads to a hardening of the observed spectrum in the X-ray and γ-ray bands. Furthermore, we find that the energy densities of electrons and magnetic fields are at near equipartition in both jet regions.
A survey on evacuation planning and its challenges for potential earthquake in Tehran
Authors: Amini Hosseini Kambod , Hosseini Maziar , Hosseinioon Solmaz , O. Izadkhah Yasamin , Shaw Tomoko , Takahashi Ryoji
Published: March 2014

Purpose

– The paper aims to introduce the activities carried out for preparing evacuation plans in Tehran and the challenges observed for involving local communities in earthquake risk mitigation.

Design/methodology/approach

– In order to prepare the evacuation plans, at first the earthquake risk at different scenarios was determined and the potential damages and casualties at neighborhood levels were estimated accordingly. Then, by considering geological and man-made hazards as well as socio-economic parameters, the potential evacuation places were investigated to be equipped with necessary materials for emergency conditions. In addition, some drills were organized at each neighborhood, and the residents were trained about evacuation and other necessary activities at time of crisis.

Findings

– The methodology developed in this research provides practical means for promoting public participation and earthquake risk mitigation. Furthermore, the paper proposes some measures for involving local communities in risk reduction activities.

Research limitations/implications

– Considering the complexities of socio-economic conditions in Tehran, the plan was implemented at two different neighborhoods in 2008. Therefore, similar researches should be conducted in other places to make generalized evacuation plans.

Originality/value

– This paper introduces new methods for promoting preparedness and discusses the impacts of socio-economic conditions on developing risk mitigation plans.
Prioritisation on 5S activities for a semiconductor wafer fabrication: an empirical study
Authors: Chang Yung-Chia , Chen Chuan-Yung
Published: March 2014

Purpose

– Semiconductor wafer fabrication (FAB) is recognized as one of the most complex manufacturing systems. A newly built FAB has to pass various audits from its customer before the customer's wafers are initially produced. 5S audit is one of them. In order to comply with customer (auditor) expectations toward 5S practice, this paper assists wafer fabrication managers in allocating the limited resources to places that are valued most by their customer. The paper aims to discuss these issues.

Design/methodology/approach

– This paper applied Yang's refined Kano model to Ho's 5S checklist to prioritise these checkpoints for a FAB. An empirical study based on Ho's 5S checklist from experienced internal auditors (respondents) to prioritise 5S activities was explored to justify its feasibility for a FAB and importance-satisfaction for customer.

Findings

– An empirical study in a case FAB demonstrated how the refined model prioritised 5S activities based on Ho's 5S checklist. The result of this study further showed that quality attributes possess different identities, which could offer management more framable scopes to implement 5S practice and sustain 5S scene management.

Research limitations/implications

– Since this empirical study was focused on a 300-mm wafer fabrication company, the results and findings may not generally explain other wafer-size fabrications.

Practical implications

– This study was applied to a real-world case of a newly built 300-mm semiconductor fabrication in Taiwan. It is a straightforward bridge to link a methodology in a practical manner to disseminate information to both researchers and practitioners.

Originality/value

– From the adoption of the refined Kano model, specific required check points for 5S practice are transformed from subjective, conceptual and linguistic practice to be identified, quantified and prioritised for semiconductor wafer fabrication under resources constraints to cater customer's 5S expectations and to generate more attention in building-up a much more robust scene management. This paper provided a systemic way to prioritise 5S activities for a semiconductor wafer fabrication.
The influence of a virtual agent on web-users' desire to visit the company
Authors: Etemad-Sajadi Reza
Published: March 2014

Purpose

– The purpose of this study is to measure the perception and the behavioural intention of web-users who interact with a virtual agent on a web site. The author wants to measure the added value of this technology in terms of providing e-service and measure web-users' desire to have a concrete experience with a firm after experiencing its web site.

Design/methodology/approach

– The author integrated a virtual agent on a restaurant's web site and conducted an online survey. The author asked respondents to interact with the virtual agent and then fill in the questionnaire. The author used the expanded version of the technology acceptance model (TAM) for measuring the intention of potential customers to accept a new technology and for evaluating the characteristics of the virtual agent. In order to measure the e-service quality, the author adapted items of WebQual to restaurant industry. As the author had several latent variables, the author used partial least squares (PLS), a variance-based structural equation modeling method.

Findings

– Results show that the utilitarian and hedonic values of the virtual agent increase significantly the desire of potential clients to experiment the restaurant. Hedonic value seems to play a major role. This is a crucial factor for restaurant and hotel industries which can be considered as hedonic industries.

Practical implications

– This research can help firms to manage relationships with current and potential clients through their web site. The nature of the company plays an important role in the success of the virtual agent's implementation. Even if in the case the author applied the virtual agent to a hedonic industry, a lot of companies in other sectors can benefit from having a virtual agent, especially if the company in question is service-oriented (e.g. bank, airline, etc.).

Originality/value

– According to the author's knowledge, virtual agents have never been applied to restaurant/hotel industries before. The results of this research significantly advanced the understanding of the impact of virtual agents, especially in the hospitality industry. Moreover, the author applied the TAM to the characteristics of virtual agent, which is very new for the academic world. Finally, the framework the author presented in this research could be used as a basis of measurement of virtual agent effectiveness.
Warming to the idea: university students' knowledge and attitudes about climate change
Authors: Wachholz Sandra , Artz Nancy , Chene Douglas
Published: March 2014

Purpose

– The literature on climate change knowledge and attitudes has focused on primary and secondary school children. The limited research on college students is dated or narrowly focused. This study aims to contribute to a comprehensive understanding of views about climate change across a wide range of current college students.

Design/methodology/approach

– The authors surveyed college students in a sample of lower- and upper-division courses in three content areas: knowledge and attitudes about climate change, intentions to reduce their personal greenhouse gas emissions, and student satisfaction with the amount of current teaching at the university about climate change and suggestions for improvement.

Findings

– A strong majority of respondents believe that climate change is real and largely human-induced; a majority express concern about climate change. Yet, students in the sample hold misconceptions about the basic causes and consequences of climate change.

Research limitations/implications

– Further research is warranted to understand the college population, so educators can improve and target their educational efforts to the students most in need.

Practical implications

– Higher education needs to expand its educational efforts to ensure that all university graduates understand scientific consensus about climate change and are actively engaged as part of the solution in their public and private roles.

Originality/value

– This paper contributes to the literature by providing a broad portrayal of college student knowledge and engagement with climate change issues, at least for students on one campus. The study is the first to observe noteworthy differences in climate change understanding and concern between college women and men and across academic majors. It is the only study that asks college students how they would like to learn about global warming.
Sustainability capabilities, graduate capabilities, and Australian universities
Authors: Thomas Ian , Day Teresa
Published: March 2014

Purpose

– In the context of universities implementing education for sustainability (EfS), the aim of the research presented here is to review the extent to which capabilities related to sustainability are represented by the capabilities generally sought by employers, and to determine whether these are incorporated in the graduate capability statements of Australian universities.

Design/methodology/approach

– Based on the discussion of graduate capabilities and those associated with sustainability, a web-based survey of university graduate attribute statements was undertaken.

Findings

– Generally, Australian universities have established frameworks of graduate capabilities that relate to the broad needs of employers. Of eight capabilities listed as important by employers, six were identified at some two-thirds of universities. Just under half of the universities' statements contained references to sustainability, while all the literature derived sustainability capabilities, except for “systems/holistic thinking”, are represented to some degree. Those most strongly represented included understanding of social justice and equity; skills in communication and cooperation; and having commitment to social justice and equity.

Practical implications

– Apparently, in Australian universities, the framework for the development of sustainability capabilities is broadly in place, but not all have sustainability capabilities in place. This framework supports the implementation of EfS, but without development of pedagogy to underlie implementation, the authors have little insight about the extent of implementation, and whether graduates leave with sustainability capabilities.

Originality/value

– Uniquely this research identifies the extent to which Australian universities are providing direction in the development of capabilities related to the requirements of employers, and for sustainability.
The reaction against conventional knowledge in higher education
Authors: L. Anderson Gordon
Published: March 2014

Purpose

– Liberal education should consist of a healthy dynamic of mastering and transcending received traditions. This paper aims to discuss this point.

Design/methodology/approach

– This article discusses the inherent tension between the concepts of “liberal” and “education,” where “education” involves imparting conventional knowledge and “liberal” involves freeing the mind from it.

Findings

– With the rise of the social sciences and the maturation of the baby-boomers, higher education in the twentieth century gained a general bias against traditional knowledge. This bias is reflected in higher education becoming more jobs oriented, more ideological, and relativistic in values.

Practical implications

– Higher education should consist of greater integration of historical aspects of education pushed aside in the twentieth-century while continuing its transformation through new scientific research, making twenty-first century education more genuinely liberal.

Originality/value

– The required transformation will be difficult for many baby-boomers now in positions of authority in higher education who rejected conventional knowledge in the 1960s.
Liberal arts in a new era
Authors: B. Jennings Wayne
Published: March 2014

Purpose

– The purpose of this paper is to examine the effectiveness and outcomes of liberal arts in preparing people for adult roles.

Design/methodology/approach

– Review of research and opinions about the liberal arts.

Findings

– Liberal-arts outcomes results have fallen short of expectations though this may be a short coming of higher education generally. A new era of the knowledge society will shrink liberal-arts departments in humanities, literature and philosophy.

Research limitations/implications

– Liberal arts need definition and clarity of expected outcomes.

Practical implications

– Jobs in liberal arts colleges will decrease given its weak effectiveness. Online education for liberal-arts areas will grow explosively.

Originality/value

– Liberal-arts critics have been active for decades. What is different today is world wide access to all information 24/7 and massive open online courses (MOOCs).