bluuebunny/crossref_metadata_2025 huggingface dataset:
Probable Association of T Tauri Stars with the L 1014 Dense Core
Authors: Morita Atsuko , Watanabe Makoto , Sugitani Koji , Itoh Yoichi , Uehara Mariko , Nagashima Chie , Ebizuka Noboru , Hasegawa Takashi , Kinugasa Kenzo , Tamura Motohide
Published: March 2014

Using the Wide Field Grism Spectrograph 2 (WFGS2), we carried out slit-less spectroscopy, $g'r'i'$ photometry, and slit spectroscopy on the L 1014 dense core. We detected three $\mathrm{H}\alpha$ emission-line stars. We interpret one as being a weak-line T Tauri star (WTTS) and the others as classical T Tauri stars (CTTS). Since their $g'-i'$ colors and/or classified spectral types are consistent with those of T Tauri stars and two of them show less extinction than the cloud, these three stars are likely to be T Tauri stars associated with L 1014. Adopting an age range for T Tauri stars, 1–10 Myr, the color–magnitude diagram suggests a distance of $\sim 400 \hbox{--} 900 \,\mathrm{pc}$, rather than the previously assumed distance, 200 pc. This could strongly affect the mass estimate of L 1014-IRS, which is thought to be either a very young protostar or proto-brown dwarf.
Radio Polarization of BL Lacertae Objects
Authors: Fan Jun-Hui , Hua Tong-Xu , Yuan Yu-Hai , Wang Yong-Xiang , Liu Yi , Su Jiang-Bo , Zhang Yong-Wei , Yang Jiang-He , Huang Yong
Published: March 2014

In the present work, using the data base of the University of Michigan Radio Astronomy Observatory (UMRAO) at three radio frequencies (4.8 GHz, 8GHZ, and 14.5 GHz), we studied the polarization properties for 47 BL Lacertae objects: 38 radio selected BL Lac objects, 7 X-ray selected BL Lac objects, and two inter-middle objects (Mkn 421 and Mkn 501), and found that: (1) the polarizations at higher radio frequency is higher than those at lower frequency, (2) the variability of polarization at higher radio frequency is higher than those at lower frequency, (3) the polarization is correlated with the radio spectral index, (4) the polarization is correlated with the core-dominance parameter for those objects with known core-dominance parameters, suggesting that relativistic beaming could explain the polarization characteristic of BL Lacs.
CO (3–2) and CO (2–1) Detections in a z = 1.3 Hyper-Luminous Starburst Galaxy
Authors: Iono Daisuke , Tamura Yoichi , Nakanishi Kouichiro , Kawabe Ryohei , Kohno Kotaro , Okuda Takeshi , Yamada Kenkichi , Hatsukade Bunyo , Sameshima Masahiro
Published: March 2014

We present an $\sim 2^{\prime\prime}$ resolution image of the CO (2–1) emission and an $\sim 4^{\prime\prime}$ resolution image of the CO (3–2) emission in the $z=1.3$ hyper-luminous starburst galaxy MIPS J142824.0$+$352619, obtained at the Nobeyama Radio Observatory. Our new CO (3–2) and CO (2–1) emission detections yield $L'_{\mathrm{CO}\,(3 \hbox{--} 2)} = 1.4 \; (\pm 0.5) \times 10^{11}$ and $L'_{\mathrm{CO}\,(2 \hbox{--}1)} = 1.2 \; (\pm 0.3) \times 10^{11} \,\mathrm{K} \,\mathrm{km} \,\mathrm{s}^{-1} \,\mathrm{pc}^2$, which translate to a molecular gas mass of $\sim 10^{11} \,{{{M}_{\odot}}}$, assuming a CO to $\mathrm{H}_2$ conversion factor appropriate for ULIRGs. The derived high CO luminosities place this source as being one of the brightest galaxies detected in CO to date. The CO (3–2) and CO (2–1) derived redshifts are $1.3248 \pm 0.0002$ and $1.3250 \pm 0.0002$. If the bulk of the molecular gas traced in these lines is completely thermalized, as suggested by $L'_{\mathrm{CO}\,(3 \hbox{--} 2)} / L'_{\mathrm{CO}\,(2 \hbox{--}1)} \sim 1$, a constraint to the gas density of $n \gtrsim 10^3 \,\mathrm{cm}^{-3}$ is obtained from our Large Velocity Gradient (LVG) analysis. If a significant fraction of the bright FIR luminosity of $L_{\mathrm{FIR}} = (3.2 \pm 0.7) \times 10^{13} \,{{{L}_{\odot}}}$ arises from starburst activity, then the Star Formation Efficiency (SFE) is $320 \,{{{L}_{\odot}}} \,M_{ {\odot }}^{-1}$. The size constraint of ${1\rlap {.}{}^{\mathrm {\prime \prime }}3}$ given by the CO (2–1) map provides an upper limit to the lensing magnification factor of $\mu \lesssim 8$, which further supports the earlier claim that the magnification of this source is only modest.
Nobeyama CO Atlas of Nearby Spiral Galaxies: Distribution of Molecular Gas in Barred and Nonbarred Spiral Galaxies
Authors: Kuno Nario , Sato Naoko , Nakanishi Hiroyuki , Hirota Akihiko , Tosaki Tomoka , Shioya Yasuhiro , Sorai Kazuo , Nakai Naomasa , Nishiyama Kota , Vila-VilarÓ Baltsar
Published: March 2014

The data from a CO ($J$ = 1–0) mapping survey of 40 nearby spiral galaxies, performed with the Nobeyama 45 m telescope, are presented. The criteria of the sample selection were: (1) RC3 morphological type ranging from Sa to Scd, (2) distance of less than 25 Mpc, (3) inclination angle less than 79$^{\circ}$ (RC3), (4) flux at 100$\mu$m higher than $\sim$ 10 Jy, and (5) spiral structure not destroyed by any interaction. The maps of CO cover most of the optical disk of the galaxies. We investigated the influence of bars on the distribution of molecular gas in spiral galaxies using these data. We confirmed that the degree of the central concentration is higher in barred spirals than in nonbarred spirals, as shown by previous studies. Furthermore, we present observational evidence that bars are efficient in driving molecular gas that lies within the bar length toward the center, while the role in bringing gas in from the outer parts of the disks is small. The transported gas accounts for about half of the molecular gas within the central region in barred spiral galaxies. We found a correlation between the degree of central concentration and the bar strength. Galaxies with stronger bars tend to have a higher central concentration. The correlation implies that stronger bars accumulate molecular gas toward the center more efficiently. These results are consistent with long-lived bars.
Relativistic Effects on the Observed AGN Luminosity Distribution
Authors: Liu Yuan , Zhang Shuang Nan , Zhang Xiao Ling
Published: March 2014

Recently, Zhang (2005 ApJ, 618, L79) has proposed a model to account for the well-established effect that the fraction of type-II AGNs is anti-correlated with the observed X-ray luminosity; the model consists of an X-ray emitting accretion disk coaligned to the dusty torus within the standard AGN unification model. In this paper the model is refined by including relativistic effects of the observed X-ray radiation from the vicinity of the supermassive black hole in an AGN. The relativistic corrections improve the combined fitting results of the observed luminosity distribution and the type-II AGN fraction, though the improvement is not significant. The type-II AGN fraction prefers non–or mildly spinning black hole cases, and rules out the extremely spinning case.
Age Sequence in Small Clusters Associated with Bright-Rimmed Clouds
Authors: Ogura Katsuo , Chauhan Neelam , Pandey Anil K. , Bhatt Bhuwan C. , Ojha Devendra , Itoh Yoichi
Published: March 2014

Bright-rimmed clouds (BRCs) found in HII regions are probable sites of triggered star formation due to compression by ionization/shock fronts, and it is hypothesized that star formation proceeds from the exciting star(s) side outward of the HII region (“small-scale sequential star formation”). In order to quantitatively test this hypothesis we undertook $BVI_\mathrm{c}$ photometry of four BRC aggregates. The amounts of interstellar extinction and reddening for each star were estimated by using $JHK_\mathrm{s}$ photometry. We then constructed reddening-corrected $V/V-I_\mathrm{c}$ color-magnitude diagrams, where the age of each star was derived. All of the stars turned out to be a few tenths to a few Myr old. Although the scatters were large and the numbers of the sample stars are small, we found a clear trend that the stars inside or in the immediate vicinity of the bright rim are younger than those outside it in all four aggregates, confirming the hypothesis in question.
Subarcsecond Near-Infrared Images of Massive Star Formation Region NGC 6334 V
Authors: Hashimoto Jun , Tamura Motohide , Suto Hiroshi , Abe Lyu , Ishii Miki , Kudo Tomoyuki , Mayama Satoshi
Published: March 2014

We present high spatial resolution (0$\rlap{.}^{\prime\prime}3$) polarimetric images in the $H$ and $K$ bands and direct images in the $L'$ and $M'$ bands of the NGC 6334 V infrared nebulae. The images show complex structures including the multishells and various knots in the nebulae. The appearances and colors of the eastern and western nebulae differ considerably. Our polarization images also show differences between the illuminating sources of the nebulae: the eastern nebula is illuminated by a deeply embedded mid-infrared source, KDJ 4, and the western nebula by our newly detected near-infrared source, WN-A1. The degree of polarization of the nebulae is very large, up to 70% at $K$ and 60% at $H$, which is consistent with a single scattering of near-infrared radiation from each source at the walls of the mass outflows.
Physical Conditions of Molecular Gas in the Galactic Center
Authors: Nagai Makoto , Tanaka Kunihiko , Kamegai Kazuhisa , Oka Tomoharu
Published: March 2014

We estimated the physical conditions of molecular gas in the central molecular zone (CMZ) of the Galaxy, using our CO $J = 3-2$ data obtained with the Atacama Submillimeter Telescope Experiment (ASTE) in conjunction with J = 1–0 $^{12}$CO and $^{13}$CO data previously observed with the Nobeyama Radio Observatory (NRO) 45 m telescope. The large velocity gradient (LVG) approximation was employed. The distributions of gas density, kinetic temperature, and CO column density were derived as functions of the position and the velocity for the entire coverage of the CO $J = 3-2$ data. We fairly determined the physical conditions for 69% of data points in the CMZ with $\geq 1 \hskip2pt\sigma$ CO detections. The kinetic temperature was found to be roughly uniform in the CMZ, while the gas density was higher in the 120 pc star-forming ring than in the outer dust lanes. The physical conditions of high $J = 3-2/J = 1-0$ features are also discussed.
ASTE Observations of Nearby Galaxies: A Tight Correlation between CO J = 3–2 Emission and H$\alpha$
Authors: Komugi Shinya , Kohno Kotaro , Tosaki Tomoka , Nakanishi Hiroyuki , Onodera Sachiko , Egusa Fumi , Sofue Yoshiaki
Published: March 2014

Star formation rates (SFRs) obtained via extinction-corrected H$\alpha$ are compared to dense gas, as traced by $^{12}{\rm CO}$ (J = 3–2) emission at the centers of nearby galaxies, observed with the ASTE telescope. It is found that, although many of the observed positions are dusty, and therefore heavily absorbed at H$\alpha$, the SFR shows a striking correlation with dense gas in the form of the Schmidt law with an index of 1.0. The correlation is also compared between gas traced by $^{12}{\rm CO}$ (J = 1–0) and the application of an H$\alpha$ extinction correction. We find that dense gas produces a far-better correlation with SFR in view of the surface density values.
ASTE 12CO (J = 3–2) Survey of Elliptical Galaxies
Authors: Nakanishi Hiroyuki , Tosaki Tomoka , Kohno Kotaro , Sofue Yoshiaki , Kuno Nario
Published: March 2014

We report on $^{12}$CO ($J$ = 3–2) observations of 15 nearby elliptical galaxies, carried out with the ASTE telescope. Thirteen were selected without regard to the presence of other tracers of cold interstellar matter. CO emission was detected from three of the galaxies, two of which were undetected by IRAS at 100 $\mu$m. The molecular gas masses range from $2.2 \times 10^6$ to $4.3 \times 10^8 M_\odot$. The ratio of the CO (3–2) and (1–0) lines, $R_{31}$, has a lower value for elliptical galaxies than for spiral galaxies, except for NGC 855, for which the value is close to the mean for spirals. The molecular gas in NGC 855 has a mean density in the range of 300–1000 cm$^{-3}$, adopting a temperature range of 15–100 K.
A Search for CO (J = 3–2) Emission from the Host Galaxy of GRB 980425 with the Atacama Submillimeter Telescope Experiment
Authors: Hatsukade Bunyo , Kohno Kotaro , Endo Akira , Tosaki Tomoka , Ohta Kouji , Sakamoto Seiichi , Kawai Nobuyuki , CortÉs Juan R. , Nakanishi Kouichiro , Okuda Takeshi , Muraoka Kazuyuki , Sakai Takeshi , Vreeswijk Paul M. , Ezawa Hajime , Yamaguchi Nobuyuki , Kamegai Kazuhisa , Kawabe Ryohei
Published: March 2014

We report on a deep search for $^{12}$CO ($J$=3–2) line emission from the host galaxy of GRB 980425 with the Atacama Submillimeter Telescope Experiment (ASTE). We observed five points of the galaxy, covering the entire region. After combining all of the spectra, we obtained a global spectrum with a rms noise level of 3.3 mK in the $T_{\mathrm{mb}}$ scale at a velocity resolution of 10 $\mathrm{km\ s^{-1}}$. No significant emission was detected, though we found a marginal emission feature in the velocity range corresponding to the redshift of the galaxy. We derived 3 $\sigma$ upper limits on the global properties: the velocity-integrated CO (3–2) intensity of $I_{\mathrm{CO}}$(3–2) $< 0.26\ \mathrm{K\ km\ s^{-1}}$, by adopting a velocity width of $67\ \mathrm{km\ s^{-1}}$; an H$_2$ column density of $N(\mathrm{H_2}) < 3 \times 10^{20} \mathrm{cm^{-2}}$; a molecular gas mass of $M(\mathrm{H_2}) < 3 \times 10^8\ M_{\odot}$, by assuming a CO line luminosity to H$_2$ molecular gas mass conversion factor of $X_{\mathrm{CO}}=5.0\times10^{20}\ \mathrm{cm^{-2}\ (K\ km\ s^{-1})^{-1}}$; and a star-formation rate of SFR $< 0.1\ M_{\odot}\ \mathrm{yr}^{-1}$, based on the Schmidt law. The SFR is consistent with the previous results of H$\alpha$ and mid-IR observations, thereby suggesting that there is no significant obscured star formation in the host galaxy of GRB 980425. This result implies that there is a variety of GRB hosts with regard to the presence of obscured star formation.
X-Ray Study of Temperature and Abundance Profiles of the Cluster of Galaxies Abell 1060 with Suzaku
Authors: Sato Kosuke , Yamasaki Noriko Y. , Ishida Manabu , Ishisaki Yoshitaka , Ohashi Takaya , Kawahara Hajime , Kitaguchi Takao , Kawaharada Madoka , Kokubun Motohide , Makishima Kazuo , Ota Naomi , Nakazawa Kazuhiro , Tamura Takayuki , Matsushita Kyoko , Kawano Naomi , Fukazawa Yasushi , Hughes John P.
Published: March 2014

We carried out observations of the central and 20$'$ east offset regions of the cluster of galaxies Abell 1060 with Suzaku. Spatially resolved X-ray spectral analysis has revealed temperature and abundance profiles of Abell 1060 out to 27$'\simeq 380\; h_{70}^{-1}$ kpc, which corresponds to $\sim$ 0.25 $r_{180}$. Temperature decrease of the intra-cluster medium from 3.4 keV at the center to 2.2 keV in the outskirt region was clearly observed. The abundances of Si, S, and Fe also decrease by more than 50% from the center to the outer region, while Mg shows a fairly constant abundance distribution at $\sim 0.7$ solar within $r \lesssim 17'$. O shows a lower abundance of $\sim 0.3$ solar in the central region ($r \lesssim 6'$), and indicates a similar feature with Mg; however, it is sensitive to the estimated contribution of the Galactic components of $kT_1 \sim$ 0.15 keV and $kT_2 \sim$ 0.7 keV in the outer annuli ($r \gtrsim 13'$). Systematic effects due to the point-spread function tails, contamination on the XIS filters, instrumental background, cosmic and/or Galactic X-ray background, and the assumed solar abundance tables were carefully examined. The results on the temperature and abundances of Si, S, and Fe are consistent with those derived by XMM-Newton at $r \lesssim$ 13$'$. The formation and metal-enrichment process of the cluster are discussed based on the present results.
Triaxial Analytical Potential-Density Pairs for Galaxies
Authors: Vogt Daniel , Letelier Patricio S.
Published: March 2014

We present two triaxial analytical potential-density pairs that can be viewed as generalized versions of the axisymmetric Miyamoto-Nagai and Satoh galactic models. These potential-density pairs may be useful models for galaxies with box-shaped bulges. The resulting mass-density distributions are everywhere non-negative and free from singularities. Also, a few numerically calculated orbits for the Miyamoto-Nagai-like triaxial potential are presented.
High-Resolution Mappings of the $l=1{\rlap{.}{^\circ}}3$ Complex in Molecular Lines: Discovery of a Proto-Superbubble
Authors: Tanaka Kunihiko , Kamegai Kazuhisa , Nagai Makoto , Oka Tomoharu
Published: March 2014

We report on the results of molecular line observations toward the $l=1{\rlap{\hskip.75pt{^\circ}}\hskip.75pt.\hskip1pt}3$ complex, an anomalous cloud complex in the central molecular zone of the Galaxy. The CO $J$=$3$–$2$ survey recently performed with the Atacama Submillimeter Telescope Experiment (ASTE) 10 m telescope has found that the complex has an enhanced CO $J$=$3$–$2$/$J$=$1$–$0$ intensity ratio. We have made high-resolution maps of the CO $J$=$1$–$0$, HCN $J$=$1$–$0, {\rm HCO^{+}} J$=$1$–$0$, SiO $J$=$1$–$0$, and $J$=$2$–$1$ lines with the Nobeyama 45 m telescope. The complex is found to be rich in shells and arcs of dense molecular gas. We identified 9 expanding shells in HCN maps and compact SiO features associated with the shells. The intensity ratios of HCN/CO, ${\rm HCO^{+}}$/CO, and CO $J$=$3$–$2$/$J$=$1$–$0$ are coherently enhanced by a factor of a few in gas with an LSR velocity higher than $110\ {\rm kms^{-1}}$. The high-velocity gas has a high density (${n_{\rm H}}\sim10^{4.5}\ {\rm cm^{-3}}$) and high SiO/$^{13}{\rm CO}$ intensity ratio, indicating that the gas was shocked. The typical HCN/${\rm HCO^{+}}$ intensity ratio is found to be 2.3, being higher by a factor of a few than those in the Galactic disk clouds. The typical kinetic energy and expansion time of the shells are estimated to be $10^{50.9\mbox{-}52.5}$ erg and $10^{4.6\mbox{-}5.3}$ yr, respectively. The kinetic energy could be furnished by multiple supernova and/or hypernova explosions at a rate of $10^{-3\mbox{-}-4}$ yr$^{-1}$. These estimates suggest that the expanding shells as a whole may be in the early stage of superbubble formation. This proto-superbubble may have originated in a massive cluster formation that took place $10^{6.8\mbox{-}7.6}\ {\rm yr}$ ago.
Fundamental Parameters and Elemental Abundances of 160 F–G–K Stars Based on OAO Spectrum Database
Authors: Takeda Yoichi
Published: March 2014

The properties of 160 F, G, and K disk dwarfs/subgiants (including 27 planet-host stars) mostly within $-0.6 \lesssim$ [Fe/H] $\lesssim +0.4$, the Okayama Astrophysical Observatory spectrum collection of which had been made open to the public recently, were extensively investigated with particular attention to determining (1) the mass and the age with the help of theoretical stellar evolution calculations, (2) the kinematic parameters of orbital motions in the Galaxy, and (3) the abundances of 15 elements (Na, Mg, Al, Si, S, Ca, Sc, Ti, V, Cr, Mn, Co, Ni, Cu, and Zn) by analyzing the spectra in this database. The resulting characteristics are discussed in terms of several relevant topics of interest, such as a validity check for assuming LTE, the [X/Fe] vs. [Fe/H] diagram containing information on the chemical evolution of the Galactic disk, the age–metallicity–kinematics relation, and the difference/similarity between stars with and without planets.
Microwave Spectral Evolution of Solar Flares
Authors: Ning Zongjun , Ding Mingde
Published: March 2014

We analyze the time evolution of microwave spectral indices for 103 solar flares observed by Nobeyama Radio Polarimeters (NoRP) between 1998 and 2005. The microwave spectral index, $\gamma(t)$, is derived from the flux spectral index, $\delta(t)$. We assume a flux frequency dependence of the form $S(\nu,t) = F_0\nu^{\delta(t)}$ in the optically thin part, i.e., above the turnover frequency, $f_{\max}$. Here, $f_{\max}$ is defined as the frequency with the maximum flux among six discrete frequencies (i.e., 1, 2, 3.75, 9.4, 17, and 35 GHz). Based on NoRP observations, we find two typical types of solar flares with various microwave spectral behavior. Type I displays a soft–hard–soft pattern, while the type II flare follows a soft–hard–harder behavior in the rise–peak–decay phases at 35 GHz. Our statistical results of microwave flares confirm previous findings. Most microwave flares appear to be of type II (91 out of the present samples), which is different from the hard X-ray flares dominated by the soft–hard–soft property. Such a difference is an observational constraint for electron acceleration and transport theories in flare models.
Observations of Fragments Split from Nucleus B of Comet 73P/Schwassmann-Wachmann 3 with Subaru Telescope
Authors: Fuse Tetsuharu , Yamamoto Naotaka , Kinoshita Daisuke , Furusawa Hisanori , Watanabe Jun-ichi
Published: March 2014

We observed the nucleus B of Comet 73P/Schwassmann-Wachmann 3 on 2006 May 3, UT with a wide-field camera Suprime-Cam of the Subaru Telescope just before the closest approach to the Earth on 2006 May 12, UT. Since the fragmentation of nucleus B was reported in April of 2006, fresh fragments were expected to be detected. A total of 54 fragments were discovered within a 1$'$.60 $\times$ 1$'$.13 region, southwest of nucleus B. Carrying out aperture photometry for the fragments, we obtained the power-law index of the cumulative luminosity function, $\alpha=0.222$. If we assume that the CCD flux of a fragment is proportional to the cross section, the equation $q = 5\alpha + 1$ can be derived, where $q$ is the power-law index of the cumulative size distribution, and therefore $q$ = 2.1. Due to the large FOV of the camera ($34' \times 27'$), we might also be able to find fragments split from nucleus B before the perihelion passage in 2006. Upon searching for such fragments in the image, no object was found; since the approximate limiting magnitude is 24.2 mag, a bare nucleus (i.e., non-active comet) with 13.3 m in radius could be detected in the image; however, the real detection limit should be less than a radius of 13.3 m, because a comet at the same heliocentric distance as nucleus B of 1.1 AU would be active, and an active comet whose magnitude is 24.2 mag has a smaller nucleus than 13.3 m in radius due to the brightness of the dust coma.
Development of a Near-Infrared Echelle Spectrograph “NICE”
Authors: Yamamuro Tomoyasu , Kawabata Hironobu , Nedachi Ko , Nishimaki Yuichiro , Motohara Kentaro , Miyata Takashi , Pyo Tae-Soo , Takeyama Norihide , Tanaka Masuo
Published: March 2014

We developed a Near-Infrared Cross-dispersed Echelle spectrograph, “NICE”, which covers the wavelength range from 0.9$\mu$m to 2.4$\mu$m with four exposures, and has a wavelength resolution of $\lambda/\delta\lambda\sim2600$. These capabilities enable us to simultaneously evaluate the continuum level and intensity of various lines of a spectrum with high accuracy over a wide wavelength range. Since NICE is designed to be compact, by adopting a “white pupil” configuration and fully refractive lenses, we can carry out observations with small telescopes.
New Analytical Formulae for Optically Thin Accretion Flows
Authors: Watarai Ken-ya
Published: March 2014

In a previous paper, we described new analytic formulae for optically thick supercritical accretion flows (Watarai 2006, hereafter paper 1). Here, we present analytic formulae for optically thin one-temperature accretion flows including the advection-dominated regime, using the “semi-iterative” method, described in paper 1. Our analytic formulae have two real solutions. The first solution corresponds to advection-dominated accretion flow (ADAF), and the second solution corresponds to radiation-dominated accretion flow, described by Shapiro, Lightman, and Eardley (the so-called SLE model). Both solutions are given by a cubic equation for the advection parameter, $f$, which is the ratio of the advection cooling rate, $Q_{\rm adv}$, to the viscous heating rate, $Q_{\rm vis}$, i.e., $f=Q_{\rm adv}/Q_{\rm vis}$. Most previous studies assumed that $f$ is constant ($f \sim 1$ for the ADAF). However, it is clear that $f$ should be a function of the physical parameters of the radiative-cooling dominated regime. We found that the ratio $f$ can be written as a function of the radius, mass-accretion rate, and viscous parameter, $\alpha$. Using this formula, we can estimate the transition radius from the inner optically thin ADAF to the outer optically thick standard disk, which can be measured using observations of the quiescent state in black hole X-ray binaries.
Frequency Correlations of QPOs Based on a Disk Oscillation Model in Warped Disks
Authors: Kato Shoji
Published: March 2014

In previous papers, we proposed a model that high-frequency quasi-periodic oscillations (QPOs) observed in black-hole and neutron-star X-ray binaries are disk oscillations (inertial-acoustic and/or g-mode oscillations) resonantly excited on warped disks. In this paper we examine whether time variations of the QPOs and their frequency correlations observed in neutron-star X-ray binaries can be accounted for by this disk-oscillation model. By assuming that a warp has a time-dependent precession, we can well describe the observed frequency correlations among kHz QPOs and low-frequency QPOs over a wide range of frequencies.
Near-Infrared Polarimetry of the Eagle Nebula (M 16)
Authors: Sugitani Koji , Watanabe Makoto , Tamura Motohide , Kandori Ryo , Hough James H. , Nishiyama Shogo , Nakajima Yasushi , Kusakabe Nobuhiko , Hashimoto Jun , Nagayama Takahiro , Nagashima Chie , Kato Daisuke , Fukuda Naoya
Published: March 2014

We carried out deep and wide ($\sim$8$^{\prime}\times ^{\prime}$8) $JHK_{\rm s}$ imaging polarimetry in the southern region of the Eagle Nebula (M 16). The polarization intensity map reveals that two YSOs with near-IR reflection nebulae are located at the tips of two famous molecular pillars (Pillars 1 and 2) facing toward the exciting stars of M 16. The centrosymmetric polarization pattern are consistent with those around Class I objects having circumstellar envelopes, confirming that star formation is now taking place at the two tips of the pillars under the influence of UV radiation from the exciting stars. Polarization measurements of point sources show that magnetic fields are aligned along some of the pillars, but in a direction that is quite different to the global structure in M 16.
CO Observations of a FeLoBAL Quasar with an Hα $\alpha$ Absorption Line at z = 2.3
Authors: Ohta Kouji , Gaku Kiuchi , Kouichiro Nakanishi , Kentaro Aoki , Ikuru Iwata , Masayuki Akiyama , Naoyuki Tamura , Masataka Ando
Published: March 2014

SDSS J083942.11+380526.3 is an Iron Low-ionization Broad Absorption Line (FeLoBAL) quasar at $z=2.3$, and Aoki et al. (2006) recently found the presence of an H$\alpha$ absorption line in the broad H$\alpha$ emission line. Motivated by an idea that this quasar may be a huge molecular gas reservoir in the early phase of quasar evolution, we made CO($J=3$–$2$) observations of it using the Nobeyama Millimeter Array. No significant CO emission was detected; although an emission-like feature ($2.5\sigma$) was seen close ($\sim 2^{\prime\prime}$) to the quasar, we regard it as noise. The obtained 3$\sigma$ upper limit on the CO luminosity is $L^{\prime}_{{\rm CO}(J=3\mbox{-}2)} = 4.5 \times 10^{10}$ K km s$^{-1}$ pc$^2$, which corresponds to $M({\rm H}_2) = 3.6 \times 10^{10} M_{\odot}$ if we adopt CO-to-H$_2$ conversion factor of 0.8 $M_{\odot}$ (K km s$^{-1}$ pc$^2)^{-1}$. This upper limit is comparable to $L^{\prime}_{{\rm CO}(J=3\mbox{-}2)}$ (and thus the molecular gas mass) detected in quasars and BAL quasars at $z=1$-3, and no sign of the presence of the huge amount of molecular gas in this FeLoBAL quasar was obtained.
X-Ray Study of Discrete Sources in NGC 1808 with Chandra
Authors: Heike Kazunori , Awaki Hisamitsu
Published: March 2014

We analyzed discrete sources in a typical starburst galaxy, NGC 1808, with Chandra in order to study the relation between X-ray and star-forming activities. We detected thirty-eight X-ray sources with an X-ray luminosity ($L_{\rm X}$) of $\gt$ 10$^{37}$ erg s$^{-1}$ in the central 5$^{\prime}\times$5$^{\prime}$ (13.4 kpc $\times$ 13.4 kpc) region. About 90% of the hard X-rays previously detected with ASCA came from these discrete sources. Among the detected sources, sixteen sources had an $L_{\rm X}$ of $\gt$ 10$^{38}$ erg s$^{-1}$. The number of luminous sources is nearly equal to that of M 82, although their concentration into the central star-forming region is lower than that of M 82. There are several soft X-ray sources with a temperature of 0.6 keV in the central star-forming region. The X-ray properties of the soft sources are similar to those of a H II region, or a supernova remnant. The existence of both luminous sources and soft X-ray sources indicates the star-forming activity of NGC 1808. However, we detected only a few candidates of high-mass X-ray binaries that would be produced by enhanced star-forming activity. This may be due to the starburst age of NGC 1808.
The IRSF Magellanic Clouds Point Source Catalog
Authors: Kato Daisuke , Nagashima Chie , Nagayama Takahiro , Kurita Mikio , Koerwer Joel F. , Kawai Toshihide , Yamamuro Tomoyasu , Zenno Takahiro , Nishiyama Shogo , Baba Daisuke , Kadowaki Ryota , Haba Yasuaki , Hatano Hirofumi , Shimizu Hideyuki , Nishimura Mamiko , Nagata Tetsuya , Sato Shuji , Murai Yuka , Kawazu Takahiro , Nakajima Yasushi , Nakaya Hidehiko , Kandori Ryo , Kusakabe Nobuhiko , Ishihara Akika , Kaneyasu Nagisa , Hashimoto Jun , Tamura Motohide , Tanabé Toshihiko , Ita Yoshifusa , Matsunaga Noriyuki , Nakada Yoshikazu , Sugitani Koji , Wakamatsu Ken-ichi , Glass Ian S. , Feast Michael W. , Menzies John W. , Whitelock Patricia A. , Fourie Pieter , Stoffels John , Evans Geoff P. , Hasegawa Tetsuo
Published: March 2014

We present a near-infrared ($JHK_{\rm s}$) photometric catalog, including 14811185 point sources for a 40 deg$^2$ area of the Large Magellanic Cloud, 2769682 sources for an 11 deg$^2$ area of the Small Magellanic Cloud, and 434145 sources for a 4 deg$^2$ area of the Magellanic Bridge. The 10$\sigma$ limiting magnitudes are 18.8, 17.8, and 16.6 mag at $J, H$, and $K_{\rm s}$, respectively. The photometric and astrometric accuracies for bright sources are 0.03–0.04 mag and 0$\rlap {.}{^{\prime\prime}}$1, respectively. Based on the catalog, we also present (1) spatial distributions, (2) luminosity functions, (3) color–color diagrams, and (4) color–magnitude diagrams for point sources toward the Magellanic Clouds.
A Suggested Arrangement of Grooves for Enhancing the Return Loss Performance Characteristics of Submillimeter-Wave Corrugated Horns
Authors: Matsunaga Mayumi , Matsunaga Toshiaki
Published: March 2014

A new arrangement of grooves by which the return loss performance characteristics of submillimeter-wave corrugated horns have been greatly improved is presented. Corrugated horns equipped with grooves arranged as per the way introduced in this paper each have been found to be capable of radiating a field with return losses of $-$28 or less dB, while maintaining maximum cross-polarization levels of $-$45 or less dB within a frequency range of 385 GHz to 500 GHz. This is a performance level greater than the goal set for feed horns for radio telescopes. The reason for this enhancement of the return losses is because the part often referred to as the “mode-transforming section” has been formed differently, that is to say the grooves are arranged differently in this part than in the conventional mode-transforming section. Specifically, the number of grooves provided in this new mode-transforming section has been decreased vis-à-vis that of those in the conventional mode-transforming section, and these grooves are arranged with their depths varied in accordance with the angles of the section’s flares. Further, the structure of each groove has been so simplified that it is a parallelogram in cross section, and the part outside the mode-transforming section is provided with grooves that are in uniform depth and width being arranged at a regular interval. Despite the simplicity of the grooves, the return losses of submillimeter-wave corrugated horns have been greatly enhanced while their cross-polar radiation fields are maintained at low levels.
Absolute Proper Motions of H2O Masers Away from the Galactic Plane Measured with VERA in the “Superbubble” Region NGC 281
Authors: Sato Mayumi , Hirota Tomoya , Honma Mareki , Kobayashi Hideyuki , Sasao Tetsuo , Bushimata Takeshi , Choi Yoon Kyung , Imai Hiroshi , Iwadate Kenzaburo , Jike Takaaki , Kameno Seiji , Kameya Osamu , Kamohara Ryuichi , Kan-ya Yukitoshi , Kawaguchi Noriyuki , Kijima Masachika , Kim Mi Kyoung , Kuji Seisuke , Kurayama Tomoharu , Manabe Seiji , Maruyama Kenta , Matsui Makoto , Matsumoto Naoko , Miyaji Takeshi , Nagayama Takumi , Nakagawa Akiharu , Nakamura Kayoko , Oh Chung Sik , Omodaka Toshihiro , Oyama Tomoaki , Sakai Satoshi , Sato Katsuhisa , Shibata Katsunori M. , Shintani Motonobu , Tamura Yoshiaki , Tsushima Miyuki , Yamashita Kazuyoshi
Published: March 2014

We report on absolute proper-motion measurements of an H2O maser source in the NGC 281 West molecular cloud, which is located $\sim$ 320 pc above the Galactic plane and is associated with an H I loop extending from the Galactic plane. We conducted multi-epoch phase-referencing observations of the maser source with VERA (VLBI Exploration of Radio Astrometry) over a monitoring period of 6 months, since 2006 May. We find that the H2O maser features in NGC 281 West are systematically moving toward the southwest and further away from the Galactic plane with a vertical velocity of 20–30 km s$^{-1}$ at its estimated distance of 2.2–3.5 kpc. Our new results provide the most direct evidence that the gas in the NGC 281 region on the H I loop was blown out from the Galactic plane, most likely in a superbubble driven by multiple or sequential supernova explosions in the Galactic plane.
Relativistic Radiation Hydrodynamical Accretion-Disk Winds
Authors: Fukue Jun , Akizuki Chizuru
Published: March 2014

Accretion-disk winds blowing off perpendicular to a luminous disk are examined within the framework of fully special relativistic radiation hydrodynamics. The wind is assumed to be steady, vertical, and isothermal. Using a velocity-dependent variable Eddington factor, we can solve the rigorous equations of relativistic radiative hydrodynamics, and can obtain radiatively driven winds accelerated up to relativistic speeds. For less-luminous cases, disk winds are transonic types passing through saddle-type critical points, and the final speeds of the winds increase as the disk flux and/or the isothermal sound speed increase. For luminous cases, on the other hand, disk winds are always supersonic, since the critical points disappear due to the characteristic nature of the disk gravitational fields. The boundary between the transonic and supersonic types is located at around $\hat{F}_{\rm c} \sim 0.1 (\varepsilon+p)/(\rho c^2)/\gamma_{\rm c}$, where $\hat{F}_{\rm c}$ is the radiative flux at the critical point normalized by the local Eddington luminosity, $(\varepsilon+p)/(\rho c^2)$ is the enthalpy of the gas divided by the rest-mass energy, and $\gamma_{\rm c}$ is the Lorentz factor of the wind velocity at the critical point. In transonic winds, the final speed becomes 0.4–0.8$c$ for typical parameters, while it can reach $\sim c$ in supersonic winds.
Characteristic Scales of Baryon Acoustic Oscillations from Perturbation Theory: Nonlinearity and Redshift-Space Distortion Effects
Authors: Takahiro Nishimichi , Ohmuro Hiroshi , Nakamichi Masashi , Taruya Atsushi , Yahata Kazuhiro , Shirata Akihito , Saito Shun , Nomura Hidenori , Yamamoto Kazuhiro , Suto Yasushi
Published: March 2014

An acoustic oscillation of the primeval photon-baryon fluid around the decoupling time imprints a characteristic scale in the galaxy distribution today, known as the baryon acoustic oscillation (BAO) scale. Several ongoing and/or future galaxy surveys aim to detect and precisely determine the BAO scale so as to trace the expansion history of the universe. We consider nonlinear and redshift-space distortion effects on the shifts of the BAO scale in $k$-space using perturbation theory. The resulting shifts are indeed sensitive to different choices for the definition of the BAO scale, which needs to be kept in mind in the data analysis. We present a toy model to explain the physical behavior of the shifts. We find that the BAO scale defined as in Percival et al. (2007, ApJ, 657, 51) indeed shows very small shifts ($\lesssim$1%) relative to the prediction in linear theory in real space. The shifts can be predicted accurately for scales where perturbation theory is reliable.
Is the Evolutionary Outcome of Algol-Type Systems T Leonis Minoris and RW Monocerotis the W UMa Systems?
Authors: Li Li-Fang , Jiang Tian-Yu , Zhang Feng-Hui , Han Zhan-Wen , Jiang Deng-Kai
Published: March 2014

The variations of the orbital periods of two Algol-type eclipsing binaries, T LMi and RW Mon, are presented through a detailed analysis of $(O-C)$ diagrams. It is found that, apart from a secular decrease, several sudden jumps have occurred in the orbital periods of both binary systems. The period decrease rate was derived to be $-1.12\times10^{-8}$d/cycle and $-$1.456$\times$10$^{-9}$d/cycle for T LMi and RW Mon, respectively. Such a large rate is impossibly explained by angular momentum loss and mass loss due to magnetic stellar winds. The sudden jumps in the orbital periods of both stars might be caused by a rapid mass exchange between the circumstellar matter and binaries. At last, the evolutionary trend of the two Algol-type systems, whose periods decreased continuously, is discussed. Their evolutionary outcome might be W UMa stars.
Effects of Compton Scattering on the Gamma-Ray Spectra of Solar Flares
Authors: Kotoku Jun’ichi , Makishima Kazuo , Matsumoto Yukari , Kohama Mitsuhiro , Terada Yukikatsu , Tamagawa Toru
Published: March 2014

Using the fully relativistic GEANT4 simulation toolkit, Monte Carlo simulation was applied to the transport of energetic electrons generated in solar flares, and resultant bremsstrahlung gamma-ray spectra were calculated. The solar atmosphere was approximated by 10 vertically stacked zones. The simulation took into account two important physical processes: that the bremsstrahlung photons emitted by precipitating relativistic electrons are strongly forward beamed toward the photosphere, and that the majority of these gamma-rays must be Compton backscattered by the solar atmosphere in order to reach the observer. Then, the Compton degradation was found to make the observable gamma-ray spectra much softer than predicted by simple analytic calculations. The gamma-ray signals were found to be enhanced by several conditions, including a broad pitch-angle distribution of the electrons, a near-limb flare longitude, and a significant tilt in the magnetic field lines if the flare longitude is rather small. These results successfully explain several important flare properties observed in the range of hard X-ray to gamma-ray, in particular including those obtained with Yohkoh. A comparison of the Yohkoh spectrum, from a GOES X3.7 class limb flare on 1998 November 22, with a simulation assuming a broad electron pitch-angle distribution suggests that gamma-rays from this particular solar flare were a mixture of direct bremsstrahlung photons and their Comptonization.
Apparent Photosphere of Massive Accretion-Disk Winds
Authors: Nishiyama Shinji , Watarai Ken-ya , Fukue Jun
Published: March 2014

We examined the observational appearance of highly optically thick winds from supercritical accretion disks, while especially focusing on the shape of a “photosphere” of the wind. When a massive wind blows from an accretion disk, the optical depth of the wind may exceed unity in the place, which is higher than the scale height of the disk. If such a wind is realized, the observed light may have originated from the photosphere of the wind, rather than from the disk surface. We calculated the apparent surface of the photosphere, where the observed optical depth is unity, and compared it with the geometry of the accretion disk. We found that the wind photosphere can expand over the disk scale-height for super-Eddington mass-loss rates, but the location and appearance of the photosphere strongly depend on the inclination angle as well as the mass-loss rate. This fact may affect on the interpretation of light curves in galactic eclipsing binaries and recently well-observed ultraluminous X-ray sources.
The X-Ray Observatory Suzaku
Authors: Mitsuda Kazuhisa , Bautz Mark , Inoue Hajime , Kelley Richard L. , Koyama Katsuji , Kunieda Hideyo , Makishima Kazuo , Ogawara Yoshiaki , Petre Robert , Takahashi Tadayuki , Tsunemi Hiroshi , White Nicholas E. , Anabuki Naohisa , Angelini Lorella , Arnaud Keith , Awaki Hisamitsu , Bamba Aya , Boyce Kevin , Brown Gregory V. , Chan Kai-Wing , Cottam Jean , Dotani Tadayasu , Doty John , Ebisawa Ken , Ezoe Yuichiro , Fabian Andrew C. , Figueroa Enectali , Fujimoto Ryuichi , Fukazawa Yasushi , Furusho Tae , Furuzawa Akihiro , Gendreau Keith , Griffiths Richard E. , Haba Yoshito , Hamaguchi Kenji , Harrus Ilana , Hasinger Günther , Hatsukade Isamu , Hayashida Kiyoshi , Henry Patrick J. , Hiraga Junko S. , Holt Stephen S. , Hornschemeier Ann , Hughes John P. , Hwang Una , Ishida Manabu , Ishisaki Yoshitaka , Isobe Naoki , Itoh Masayuki , Iyomoto Naoko , Kahn Steven M. , Kamae Tuneyoshi , Katagiri Hideaki , Kataoka Jun , Katayama Haruyoshi , Kawai Nobuyuki , Kilbourne Caroline , Kinugasa Kenzo , Kissel Steve , Kitamoto Shunji , Kohama Mitsuhiro , Kohmura Takayoshi , Kokubun Motohide , Kotani Taro , Kotoku Jun’ichi , Kubota Aya , Madejski Greg M. , Maeda Yoshitomo , Makino Fumiyoshi , Markowitz Alex , Matsumoto Chiho , Matsumoto Hironori , Matsuoka Masaru , Matsushita Kyoko , McCammon Dan , Mihara Tatehiko , Misaki Kazutami , Miyata Emi , Mizuno Tsunefumi , Mori Koji , Mori Hideyuki , Morii Mikio , Moseley Harvey , Mukai Koji , Murakami Hiroshi , Murakami Toshio , Mushotzky Richard , Nagase Fumiaki , Namiki Masaaki , Negoro Hitoshi , Nakazawa Kazuhiro , Nousek John A. , Okajima Takashi , ogasaka yasushi , Ohashi Takaya , Oshima Tai , Ota Naomi , Ozaki Masanobu , Ozawa Hideki , Parmar Arvind N. , Pence William D. , Porter F. Scott , Reeves James N. , Ricker George R. , Sakurai Ikuya , Sanders Wilton T. , Senda Atsushi , Serlemitsos Peter , Shibata Ryo , Soong Yang , Smith Randall , Suzuki Motoko , Szymkowiak Andrew E. , Takahashi Hiromitsu , Tamagawa Toru , Tamura Keisuke , Tamura Takayuki , Tanaka Yasuo , Tashiro Makoto , Tawara Yuzuru , Terada Yukikatsu , Terashima Yuichi , Tomida Hiroshi , Torii Ken’ichi , Tsuboi Yohko , Tsujimoto Masahiro , Tsuru Takeshi Go , Turner Martin J. L. , Ueda Yoshihiro , Ueno Shiro , Ueno Masaru , Uno Shin’ichiro , Urata Yuji , Watanabe Shin , Yamamoto Norimasa , Yamaoka Kazutaka , Yamasaki Noriko Y. , Yamashita Koujun , Yamauchi Makoto , Yamauchi Shigeo , Yaqoob Tahir , Yonetoku Daisuke , Yoshida Atsumasa
Published: March 2014

High-sensitivity wide-band X-ray spectroscopy is the key feature of the Suzaku X-ray observatory, launched on 2005 July 10. This paper summarizes the spacecraft, in-orbit performance, operations, and data processing that are related to observations. The scientific instruments, the high-throughput X-ray telescopes, X-ray CCD cameras, non-imaging hard X-ray detector are also described.
Monte Carlo Simulator and Ancillary Response Generator of Suzaku XRT/XIS System for Spatially Extended Source Analysis
Authors: Ishisaki Yoshitaka , Maeda Yoshitomo , Fujimoto Ryuichi , Ozaki Masanobu , Ebisawa Ken , Takahashi Tadayuki , Ueda Yoshihiro , Ogasaka Yasushi , Ptak Andrew , Mukai Koji , Hamaguchi Kenji , Hirayama Masaharu , Kotani Taro , Kubo Hidetoshi , Shibata Ryo , Ebara Masatoshi , Furuzawa Akihiro , Iizuka Ryo , Inoue Hirohiko , Mori Hideyuki , Okada Shunsaku , Yokoyama Yushi , Matsumoto Hironori , Nakajima Hiroshi , Yamaguchi Hiroya , Anabuki Naohisa , Tawa Noriaki , Nagai Masaaki , Katsuda Satoru , Hayashida Kiyoshi , Bamba Aya , Miller Eric D. , Sato Kosuke , Yamasaki Noriko Y.
Published: March 2014

We have developed a framework for the Monte Carlo simulations of X-Ray Telescope (XRT) and X-ray Imaging Spectrometer (XIS) on board Suzaku, mainly for the scientific analysis of spatially and spectroscopically complex celestial sources. A photon-by-photon instrumental simulator is built on the ANL platform, which has been successfully used in ASCA data analysis. The simulator has a modular structure, in which the XRT simulation is based on a ray-tracing library, while the XIS simulation utilizes a spectral “Redistribution Matrix File” (RMF), generated separately by other tools. Instrumental characteristics and calibration results [e.g., XRT geometry, reflectivity, mutual alignments, thermal shield transmission, build-up of the contamination on the XIS optical blocking filters (OBF)] are incorporated as completely as possible. Most of this information is available in the form of FITS (Flexible Image Transport System) files in the standard calibration database (CALDB). This simulator can also be utilized to generate an “Ancillary Response File” (ARF), which describes the XRT response and the amount of OBF contamination. An ARF is dependent on the spatial distribution of the celestial target and the photon accumulation region on the detector, as well as the observing conditions, such as the observation date and satellite attitude. We describe the principles of the simulator and the ARF generator, and demonstrate their performance compared with in-flight data.
A Suzaku Observation of the Low-Ionization Fe-Line Emission from RCW 86
Authors: Ueno Masaru , Sato Rie , Kataoka Jun , Bamba Aya , Harrus Ilana , Hiraga Junko , Hughes John P. , Kilbourne Caroline A. , Koyama Katsuji , Kokubun Motohide , Nakajima Hiroshi , Ozaki Masanobu , Petre Robert , Takahashi Tadayuki , Tanaka Takaaki , Tomida Hiroshi , Yamaguchi Hiroya
Published: March 2014

The newly operational X-ray satellite Suzaku observed the southwestern quadrant of the supernova remnant RCW 86 in 2006 February to study the nature of the 6.4 keV emission line first detected with the Advanced Satellite for Cosmology and Astronomy (ASCA). The new data confirm the existence of the line, localizing it for the first time; most of the line emission is adjacent and interior to the forward shock, and not at the locus of the continuum hard emission. We also report the first detection of a 7.1 keV line, which we interpret as $\mathrm{K}\beta$ emission from low-ionization iron. The Fe K line features are consistent with a non-equilibrium plasma of Fe-rich ejecta with $n_{\mathrm{e}} \, t \lesssim 10^{9} \,\mathrm{cm}^{-3} \,\mathrm{s}$ and $kT_{\mathrm{e}} \sim 5 \,\mathrm{keV}$. This combination of low $n_{\mathrm{e}} \, t$ and high $k T_{\mathrm{e}}$ suggests collisionless electron heating in an SNR shock. The Fe $\mathrm{K}\alpha$ line shows evidence for intrinsic broadening, with a width of 47 (34–59) eV (99% error region). The difference in the spatial distributions of the hard continuum above 3 keV and the Fe K line emission supports a synchrotron origin for the hard continuum.
An Apparent Hard X-Ray Decline of CH Cygni
Authors: Mukai Koji , Ishida Manabu , Kilbourne Caroline , Mori Hideyuki , Terada Yukikatsu , Chan Kai-Wing , Soong Yang
Published: March 2014

CH Cygni is a symbiotic star consisting of an M giant and an accreting white dwarf, which is known to be a highly variable X-ray source with a complex, two-component, spectra. Here, we report on two Suzaku observations of CH Cyg, taken in 2006 January and May, during which the system was seen to be in a soft X-ray bright, hard X-ray faint state. Based on the extraordinary strength of the 6.4 keV fluorescent Fe $\mathrm{K}\alpha$ line, we show that the hard X-rays observed with Suzaku are dominated by scattering.