bluuebunny/crossref_metadata_2025 huggingface dataset:
Resonant Excitation of Disk Oscillations in Deformed Disks II: A
Model of High-Frequency QPOs
Authors: Kato Shoji
Published: March 2014

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

We have observed 13 methanol maser sources associated with massive star-forming regions: W 3(OH), Mon R2, S 255, W 33A, IRAS 18151 $-$ 1208, G 24.78 $+$ 0.08, G 29.95 $-$ 0.02, IRAS 18556 $+$ 0136, W 48, OH 43.8 $-$ 0.1, ON 1, Cep A, and NGC 7538 at 6.7GHz using the Japanese VLBI Network (JVN). Twelve of the thirteen sources were detected at our longest baseline of $\sim$ 50M $\lambda$ , and their images are presented. Seven of them are the first VLBI images at 6.7GHz. The high detection rate and the small fringe spacing of $\sim$ 4 mas suggest that most of the methanol maser sources have compact structures. Given this compactness as well as the known properties of long life and small internal motion, the methanol maser line is suitable for astrometry with VLBI.
VLBI Observations of Water Masers in Onsala 1: Massive Binary Star-Forming Site?
Authors: Nagayama Takumi , Nakagawa Akiharu , Imai Hiroshi , Omodaka Toshihiro , Sofue Yoshiaki
Published: March 2014

We present the proper motions of water masers toward the Onsala 1 star-forming region, observed with the Japanese VLBI network at three epochs spanning 290 days. We found that there are two water-maser clusters (WMC 1 and WMC 2) separated from each other by 1.$^{\prime\prime}$6 (2900 AU at a distance of 1.8 kpc). A proper-motion measurement revealed that WMC1 is associated with a bipolar outflow elongated in the east–west direction with an expansion velocity of 69$\pm$11 km s$^{-1}$. WMC1 and WMC2 are associated with two 345 GHz continuum dust emission sources, which are located 2$^{\prime\prime}$ (3600 AU) east from the core of an ultracompact H ii region traced by 8.4 GHz radio continuum emission. This indicates that the star-formation activity of Onsala 1 could move from the west side of the ultracompact H ii region to the east side of two young stellar objects associated with the water masers. We have also found that the WMC1 and UC H ii regions could be gravitationally bound. Their relative velocity along the line of sight is $\sim$3 km s$^{-1}$, and the total mass is $\sim 37 M_\odot$. Onsala 1 seems to harbor a binary star at a different evolutionary stage.
Near-Infrared Spectroscopy of Faint Companions around Young Stellar Objects Associated with the Taurus Molecular Cloud
Authors: Itoh Yoichi , Tamura Motohide , Hayashi Masahiko , Oasa Yumiko , Hayashi Saeko S. , Fukagawa Misato , Kudo Tomoyuki , Mayama Satoshi , Ishii Miki , Pyo Tae-Soo , Yamashita Takuya , Morino Junichi
Published: March 2014

We have conducted near-infrared spectroscopy of 26 faint objects around young stellar objects in the Taurus molecular cloud. These objects were detected during a course of near-infrared coronagraphic searches for companions around 72 young stellar objects with the Subaru Telescope and the near-infrared coronagraph CIAO (coronagraphic imager with adaptive optics). A comparison of the Subaru and HST archive images revealed that three central stars and faint companions share common proper motions, suggesting that they are physically associated with each other. None of the 26 sources show deep water absorption bands at near-infrared, except for DH Tau B. This result indicates that all of them, but DH Tau B, have a high photospheric temperature or a large amount of excess from circumstellar materials.
Role of Compressibility, Turbulent Viscosity, and Mass-Transfer-Rate on Accretion Discs in Close Binaries
Authors: Lanzafame Giuseppe
Published: March 2014

In this work, the roles of both the inflow kinematic conditions at the inner Lagrangian point L1 as an initial boundary condition and the gas compressibility, physical turbulent viscosity on an accretion disc’s dynamics and structure were investigated via simulations of 3D SPH stationary accretion-disc models. Physical viscosity supports accretion-disc development inside the primary gravitational potential well in a close binary system, even for low-compressibility modelling. Currently, an assigned typical turbulent Shakura-Sunyaev parameter, $\alpha \simeq 0.1$, is widely adopted for these structures. Such an investigation was carried out here with the aim of evaluating, in a compressibility-viscosity graph, the most suitable domains where the physical conditions allow a well-bound disc development as a function of the mass-transfer kinematic conditions. Physical, turbulent viscosity is represented by a viscous force contribution, expressed by the divergence of the symmetric viscous stress tensor in the Navier-Stokes equation, while the viscous energy contribution is given by a symmetric combination of the symmetric shear tensor multiplied by the particle velocity. The same binary system parameters-stellar masses and their separation–were adopted throughout, whilst the adopted polytropic index, $\gamma$, is chosen to be in the range between 1-(5$/$3). The results show that in such domains, the lower is the gas compressibility (the higher the polytropic index $\gamma$), the higher is the physical viscosity ($\alpha$) requested. Conclusions, as far as dwarf nova outbursts are concerned, induced by mass-transfer rate variations are also reported.
2006 December 17 Long Duration Flare Observed with the Hinode EUV Imaging Spectrometer
Authors: Hara Hirohisa , Watanabe Tetsuya , Matsuzaki Keiichi , Harra Louise K. , Culhane J. Leonard , Cargill Peter , Mariska John T. , Doschek George A.
Published: March 2014

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

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

Both continuum and emission line flickering are phenomena directly associated with the mass-accretion process. In this work we simulated accretion-disk Doppler maps, including the effects of winds and flickering flares. Synthetic flickering Doppler maps were calculated and the effect of the flickering parameters on the maps was explored. Jets and winds occur in many astrophysical objects where accretion disks are present. Jets are generally absent among the cataclysmic variables (CVs), but there is evidence of mass loss by wind in many objects. CVs are ideal objects to study accretion disks, and consequently to study the wind associated with these disks. We also present simulations of accretion disks, including the presence of a wind with orbital phase resolution. Synthetic H$\alpha$ line profiles in the optical region were obtained and their corresponding Doppler maps were calculated. The effect of the wind simulation parameters on the wind line profiles was also explored. From this study we verified that optically thick lines and/or emission by diffuse material into the primary Roche lobe are necessary to generate single peaked line profiles, often seen in CVs. The future accounting of these effects is suggested for interpreting Doppler tomography reconstructions.
Low-Mass Star-Forming Cores in the GF9 Filament
Authors: Furuya Ray S. , Kitamura Yoshimi , Shinnaga Hiroko
Published: March 2014

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

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

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

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

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

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

We present the results of global three-dimensional magneto-hydrodynamic simulations of black-hole accretion flows. We focus on the dependence of the numerical results on the gas temperature supplied from the outer region. General-relativistic effects were taken into account using the pseudo-Newtonian potential. We ignored radiative cooling of the accreting gas. The initial state was a torus threaded by a weak azimuthal magnetic field. We found that the mass-accretion rate and the mass-outflow rate strongly depend on the temperature of the initial torus. The ratio of the average Maxwell stress generated by the magneto-rotational instability (MRI) to the gas pressure, $\alpha \equiv \langle B_{\varpi} B_{\varphi}/4 \pi \rangle / \langle P \rangle $, is $\alpha \sim$0.05 in a hot torus and $\alpha \sim$0.01 in a cool torus. In the cool model, a constant angular momentum inner torus is formed around 4-8$r_s$, where $r_s$ is the Schwarzschild radius. This inner torus deforms itself from a circle to a crescent quasi-periodically. During this deformation, the mass-accretion rate, the magnetic energy and the Maxwell stress increase. As the magnetic energy is released, the inner torus returns to a circular shape and starts the next cycle.

The power spectral density (PSD) of the time variation of the mass-accretion rate in the cool model has a low-frequency peak around 10Hz when we assumed a 10$M_{\odot}$ black hole. The mass outflow rate in the low temperature model also shows quasi-periodic oscillation.
Suzaku Observations of the Cluster of Galaxies Abell 2052
Authors: Tamura Takayuki , Mitsuda Kazuhisa , Takei Yoh , Yamasaki Noriko Y. , Itoh Akiharu , Hayashida Kiyoshi , Henry J. Patrick , Kunieda Hideyo , Matsushita Kyoko , Ohashi Takaya
Published: March 2014

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

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

We developed Korea Astronomy and Space science Institute (KASI) Near Infrared Camera System (KASINICS) to be installed on the 1.8 m telescope of Bohyunsan Optical Astronomy Observatory (BOAO) in Korea. We use a 512$\times$512 InSb array (Aladdin III Quadrant, Raytheon Co.) to enable $L$ band observations as well as $J, H$, and $K_s$ bands. The field-of-view of the array is 3${\rlap{\hskip.75pt{^\prime}}\hskip.75pt.\hskip1pt}$3$\times$3${\rlap{\hskip.75pt{^\prime}}\hskip.75pt.\hskip1pt}$3 with a resolution of 0${\rlap{\hskip.75pt{^{\prime\prime}}}\hskip.75pt.\hskip1.75pt}$39$/$pixel. We adopt an Offner relay optical system, which provides a cold stop to eliminate thermal background emission from the telescope structures. Most parts of the camera, including the mirrors, were manufactured from the same ingot of aluminum alloy to ensure a homologous contraction from room temperature to 80 K. We also developed a readout electronics system for the array detector. Based on preliminary results from test observations, the limiting magnitudes are $J=$ 17.6, $H=$ 17.5, $K_s =$ 16.1, and $L$(narrow) $=$ 10.0 mag at a signal-to-noise ratio of 10 for an integration time of 100 s.
The Homologousness of Polytropic Gaseous Spheres in the General-Relativistic Case
Authors: Kondo Masa-aki
Published: March 2014

TOV equations in the polytropic case $(P=K\rho^{1+{1/N}})$ are represented by the homologous invariants of $U, V$, and an additional one of $w=P/(\rho c^2)$, where $P$ and $\rho c^2$ are the pressure and the static energy density. The homologous core solutions form a curved surface in the space of $(U,V,w)$, and they are distinguished by the asymptotic surface values of $E(=UV^N)$ and $D(=wV)$. $U, V$, and $w$ lead the invariant variables of $x$ and $\mu$, expressing the radius and the mass function. The solution of $x$ and $\mu$ with a central value of $w_\mathrm{c}$, called the core bundle solution (CB), well describes the extreme general-relativistic state. Core solutions are represented by the usual Emden variables, defined by $\rho=\lambda\theta^N$ and $P=K\lambda^{1+{1/N}}\theta^{N+1}$, as the general-relativistic E-solution (gE), which are determined by the two parameters $\theta_\mathrm{c}$ and $\omega(=K\lambda^{{1/N}})$. However, these two parameters change into each other by a homologous transformation, under the condition of $w_\mathrm{c}=\theta_\mathrm{c}\omega$. Hence, the gE solutions form a continuous group of one-parameter families, one of which is a CB solution corresponding to the gE solution with $\omega=1$, and another of which the general-relativisitic Lane-Emden solutions (gLE), defined by gE solutions with $\theta_\mathrm{c}=1$. A gLE solution changes into a CB solution by homologous transformation between each other. In gLE, three ways of $\lambda=(K^{-1}\omega)^N, \rho_\mathrm{c}$, and $p_\mathrm{c}\omega^{-1}$ render the normalization by $K^{N/2}, \rho_\mathrm{c}^{-1/2}$, and $p_\mathrm{c}^{-1/2}$, respectively, so that three kinds of mass-radius relations, derived from each normalization, weave the mass–radius textile in the $(M,R,\omega)$ space, where it stands up besides the Schwarzschild-radius wall.
Environmental Effect on the Subhalo Abundance—a Solution to the Missing Dwarf Problem
Authors: Ishiyama Tomoaki , Fukushige Toshiyuki , Makino Junichiro
Published: March 2014

Recent high-resolution simulations of the formation of dark-matter halos have shown that the distribution of subhalos is scale-free, in the sense that if scaled by the velocity dispersion of the parent halo, the subhalo velocity distribution functions of galaxy-sized and cluster-sized halos are identical. For cluster-sized halos, the simulation results agreed well with the observations. The simulations, however, predicted far too many subhalos for galaxy-sized halos. Our galaxy has several tens of known dwarf galaxies. On the other hand, simulated dark-matter halos contain thousands of subhalos. We performed a simulation of a single large volume, and measured the abundance of subhalos in all massive halos. We found that the variation of the subhalo abundance is very large, and those with the largest number of subhalos correspond to the simulated halos in previous studies. The subhalo abundance depends strongly on the local density of the background. Halos in high-density regions contain a large number of subhalos. Our Galaxy is in the low-density region. For our simulated halos in low-density regions, the number of subhalos is within a factor of four to that of our Galaxy. We argue that the “missing dwarf problem” is not a real problem, but is caused by biased selections of the initial conditions in previous studies, which were not appropriate for field galaxies.
H2O Maser Outflow from the Red Supergiant Star NML Cygni Observed with Japanese VLBI Network
Authors: Nagayama Takumi , Takeda Koji , Omodaka Toshihiro , Imai Hiroshi , Kameno Seiji , Sofue Yoshiaki , Doi Akihiro , Fujisawa Kenta , Habe Asao , Honma Mareki , Kawaguchi Noriyuki , Kawai Eiji , Kobayashi Hideyuki , Koyama Yasuhiro , Murata Yasuhiro , Sorai Kazuo , Sudou Hiroshi , Takaba Hiroshi , Tamura Sayaka , Wakamatsu Ken-Ichi
Published: March 2014

We present the proper motions of H$_2$O masers in NML Cygni, observed with the Japanese VLBI Network at three epochs spanning 455d. We detected about 15 maser features at each epoch. Overall, 13 features that were detected at least twice were tracked by their radial velocities and proper motions. The three-dimensional kinematics of the maser features indicate the presence of an expanding outflow. The major axis of the outflow is estimated to be at a position angle of $\sim\;$108°, and an inclination angle of $\sim\;$8° with respect to the line of sight. The H$_2$O masers are located between an apparent minimum radius of $\sim\;9.6 \times 10^{12}$m (64AU) and a maximum radius of $\sim\;3.0 \times 10^{13}$m (202AU), where the expansion velocity increases from 12 to 27kms$^{-1}$. A comparison with the distributions of SiO, H$_2$O, and OH masers suggests that the outflow of NML Cygni is expanding outside a radius of $\sim\;$1.5$\times$10$^{13}$m (100AU). This radius corresponds to 6 stellar radii, and is consistent with the radius of the inner boundary for the dust shell.
X-Ray Emission from Supernova Remnants Observed in the ASCA Galactic Plane Survey
Authors: Yamauchi Shigeo , Ueno Masaru , Koyama Katsuji , Bamba Aya
Published: March 2014

X-ray images and spectra of 5 cataloged supernova remnants (SNRs: G12.0$-$0.1, G346.6$-$0.2, G348.5$+$0.1, G348.7$+$0.3, and G355.6$-$0.0) observed in the ASCA galactic plane survey are presented. The sizes of X-ray emission from G12.0$-$0.1, G348.5$+$0.1, G348.7$+$0.3, and G355.6$-$0.0 are comparable to their radio structures, while that of G346.6$-$0.2 is smaller. The X-ray spectra of all the SNRs were heavily absorbed by interstellar matter with $N_{\rm H}/gt10^{22}$cm$^{-2}$. The spectrum of G355.6$-$0.0 exhibited emission lines, indicating that the X-ray emission has a thin thermal plasma origin, and was well represented by a two-temperature thin thermal emission model. On the other hand, no clear emission-line features were found in the spectra of the others, and the spectra could be represented by either a thin thermal emission model or a power-law model.
A Submillimeter Cartridge-Type Receiver: ALMA Band 8 (385--500 GHz) Qualification Model
Authors: Satou Naohisa , Sekimoto Yutaro , Iizuka Yoshizou , Ito Tetsuya , Shan Wen-Lei , Kamba Toshiaki , Kumagai Kazuyoshi , Kamikura Mamoru , Tomimura Yu , Serizawa Yasutaka , Asayama Shin'ichiro , Sugimoto Masahiro
Published: March 2014

We have developed a cartridge-type receiver covering the frequency band of 385-500 GHz as a qualification model of Atacama Large Millimeter/submillimeter Array (ALMA) band 8. It receives two orthogonal polarizations and down-converts the sideband-separated signals to intermediate frequencies (IF) of between 4 and 8 GHz. The cartridge-type receiver consists of cold optics, two feed horns, a wire grid, mirrors, two sideband-separating SIS mixers, cryogenic multipliers of a local oscillator (LO), cryogenic and warm IF amplifiers, a cartridge body, and sensors/wirings. These components were individually tested, and then the cartridge was integrated and tested as a complete assembly. We have also developed equipment for efficiency tests of both the components and the integrated receiver. The single sideband (SSB) noise temperature of this receiver is 100 K at the band center and 300 K at the band edges. The beam pattern and cross-polarization pattern are consistent with a physical optical calculation. The amplitude stability is around $3 \times 10^{-4}$ in 1 s. The phase stability is less than 2.0D on a time scale of 0.1 s to 10 min. These results are promising for a receiver in the ALMA.
New Photometric Data of Old Open Clusters II. A Dataset for 36 Clusters
Authors: Hasegawa Takashi , Sakamoto Tsuyoshi , Malasan Hakim Luthfi
Published: March 2014

We present new photometric data on 36 old open clusters using the 65-cm telescope at Gunma Astronomical Observatory. This dataset is a continuation of photometric data of old open clusters (Hasegawa et al 2004, PASJ, 56, 295) collected mainly in the antigalactic center region. By constructing a color-magnitude diagram, we inspected the main sequence and (if richly populated) red-clump stars to evaluate the cluster parameters, that is, the age, distance, and reddening, by applying an isochrone provided by the Padova group. Now, 49 old clusters have consistently measured parameters (36 clusters in this study and 13 from Hasegawa et al. 2004). The clusters are exclusively older than the Hyades cluster, and the age is distributed in the range 0.6-5.0Gyr. The oldest clusters include Auner 1, Biurakan 12, Berkeley 78, and NGC 2425. Our study includes clusters that are useful in further clarifying the outer disk of the Milky Way, and when inner clusters with galactocentric distances less than 12kpc are compared with outer ones, the latter tends to be less bound to the galactic plane. Nine clusters are found to be cospatial with the northern part of the recently identified stellar overdensity centered in the constellation of Canis Major.
Delay Time Distribution Measurement of Type Ia Supernovae by the Subaru/XMM-Newton Deep Survey and Implications for the Progenitor
Authors: Totani Tomonori , Morokuma Tomoki , Oda Takeshi , Doi Mamoru , Yasuda Naoki
Published: March 2014

The delay time distribution (DTD) of type Ia supernovae (SNe Ia) from star formation is an important clue to reveal the still unknown progenitor system of SNe Ia. Here, we report on a measurement of the SN Ia DTD in a delay time range of $t_{\rm Ia} = $ 0.1-8.0Gyr by using faint variable objects detected in the Subaru/XMM-Newton Deep Survey (SXDS) down to $i'$$\sim$ 25.5. We selected 65 SN candidates showing significant spatial offset from the nuclei of the host galaxies having an old stellar population at $z$$\sim$ 0.4-1.2, out of more than 1000 SXDS variable objects. Although spectroscopic type classification is not available for these, we quantitatively demonstrated that more than $\sim$80% of these should be SNe Ia. The DTD was derived using stellar age estimates of the old galaxies based on 9 band photometries from optical to mid-infrared wavelength. Combined with the observed SN Ia rate in elliptical galaxies at the local universe, the DTD in $t_{\rm Ia}$$\sim$ 0.1-10Gyr is well described by a featureless power-law as $f_{\rm D}$($t_{\rm Ia}$) $\propto$$t_{\rm Ia}^\alpha$ with $\alpha$$\sim$$-$1. The derived DTD is in excellent agreement with a generic prediction of the double-degenerate scenario, giving strong support to this scenario. In the single-degenerate (SD) scenario, although predictions by simple analytic formulations have broad DTD shapes that are similar to the observation, DTD shapes calculated by more detailed binary population synthesis tend to have strong peaks at characteristic time scales, which do not fit the observation. This result thus indicates either that the SD channel is not the major contributor to SNe Ia in an old stellar population, or that an improvement of binary population synthesis theory is required. Various sources of systematic uncertainties were examined and tested, but our main conclusions were not affected significantly.
Clustering of Meter-Wave Luminous Objects toward Monoceros
Authors: Deguchi Shuji , Koike Kazutaka
Published: March 2014

A distribution of the meter-wave luminous objects, which are bright at the frequency 74MHz (a wavelength of 4m), but not detectable at 1.4GHz (21cm) in VLA surveys, shows a notable concentration on a scale of a few degrees in the direction of Monoceros [($l$, $b$) $=$ (225$^{\circ}$, 4$^{\circ}$)]. We argue that it is a part of giant radio relics associated with a nearby cluster of galaxies with $c$z$\sim$ 2400kms$^{-1}$ centered on the spiral galaxy NGC 2377. The angular separation of these objects from the clustering center is consistent with the separation of distant relics from the cluster center if scaled by distance. This fact implies that the concentrations of meter-wave luminous objects can be used as a tracer of the structure of the Local Supercluster and its vicinity.
Measuring the Broad-Band X-Ray Spectrum from 400eV to 40keV in the Southwest Part of the Supernova Remnant RXJ1713.7$-$3946
Authors: Takahashi Tadayuki , Tanaka Takaaki , Uchiyama Yasunobu , Hiraga Junko S. , Nakazawa Kazuhiro , Watanabe Shin , Bamba Aya , Hughes John P. , Katagiri Hideaki , Kataoka Jun , Kokubun Motohide , Koyama Katsuji , Mori Koji , Petre Robert , Takahashi Hiromitsu , Tsuboi Yoko
Published: March 2014

We report on results from Suzaku broadband X-ray observations of the southwest part of the galactic supernova remnant (SNR) RXJ1713.7$-$3946 with an energy coverage of 0.4-40keV. The X-ray spectrum, presumably of synchrotron origin, is known to be completely lineless, making this SNR ideally suited for a detailed study of the X-ray spectral shape formed through efficient particle acceleration at high-speed shocks. With a sensitive hard X-ray measurement from the HXD PIN aboard Suzaku, we determined the hard X-ray spectrum in the 12-40keV range to be described by a power law with photon index of $\Gamma =$ 3.2$\pm$0.2, significantly steeper than the soft X-ray index of $\Gamma =$ 2.4$\pm$0.05 measured previously with ASCA and other missions. We find that a simple power law fails to describe the full spectral range of 0.4-40keV, and instead a power-law with an exponential cutoff with a hard index of $\Gamma =$ 1.50$\pm$0.09 and a high-energy cutoff of $\epsilon_{\rm c} =$ 1.2$\pm$0.3keV formally provides an excellent fit over the full bandpass. If we use the so-called SRCUT model, as an alternative model, it gives a best-fit rolloff energy of $\epsilon_{\rm roll}$$=$ 0.95$\pm$0.04keV. Together with the TeV $\gamma$-ray spectrum, ranging from 0.3 to 100TeV, recently obtained by HESS observations, our Suzaku observations of RXJ1713.7$-$3946 provide stringent constraints on the highest-energy particles accelerated in a supernova shock.
X-Ray Spectroscopy of SN 1006 with Suzaku
Authors: Yamaguchi Hiroya , Koyama Katsuji , Katsuda Satoru , Nakajima Hiroshi , Hughes John P. , Bamba Aya , Hiraga Junko S. , Mori Koji , Ozaki Masanobu , Tsuru Takeshi Go
Published: March 2014

We report on observations of SN 1006 with Suzaku. We firmly detected K-shell emission from Fe, for the first time, and found that the Fe ionization state is quite low. The broad-band spectrum extracted from southeast of the remnant was well-fitted with a model consisting of three optically thin thermal non-equilibrium ionization plasmas and a power-law component. Two of the thermal models are highly overabundant in heavy elements, and hence are likely due to ejecta. These components have different ionization parameters, $n_{\rm e}t \sim 1.4\times 10^{10}$cm$^{-3}$s and $n_{\rm e}t \sim 7.7\times 10^8$cm$^{-3}$s; it is the later one that produces Fe-K emission. This suggests that Fe has been heated by reverse shock more recently than the other elements, consistent with a picture where the ejecta are stratified by composition with Fe in the interior. On the other hand, the third thermal component is assumed to be solar abundance, and we associate it with emission from the interstellar medium. The electron temperature ($kT_{\rm e} \sim$0.5keV) is lower than that expected from the shock velocity, which suggests a lack of collisionless electron heating at the forward shock. The extremely low ionization parameter and extreme non-equilibrium state are due to the low density of the ambient medium.
Suzaku Detection of Extended/Diffuse Hard X-Ray Emission from the Galactic Center
Authors: Yuasa Takayuki , Tamura Ken-ichi , Nakazawa Kazuhiro , Kokubun Motohide , Makishima Kazuo , Bamba Aya , Maeda Yoshitomo , Takahashi Tadayuki , Ebisawa Ken , Senda Atsushi , Hyodo Yoshiaki , Tsuru Takeshi Go , Koyama Katsuji , Yamauchi Shigeo , Takahashi Hiromitsu
Published: March 2014

Five on-plane regions within $\pm$0.8D of the galactic center were observed with the Hard X-ray Detector (HXD) and the X-ray Imaging Spectrometer (XIS) aboard Suzaku. From all regions, significant hard X-ray emission was detected with HXD-PIN up to 40keV, in addition to the extended plasma emission which is dominant in the XIS band. The hard X-ray signals are inferred to come primarily from a spatially extended source, rather than from a small number of bright discrete objects. Contributions to the HXD data from catalogued X-ray sources, typically brighter than 1mCrab, were estimated and removed using information from Suzaku and other satellites. Even after this removal, the hard X-ray signals remained significant, exhibiting a typical 12-40keV surface brightness of 4$\times$10$^{-10}$ergcm$^{-2}$s$^{-1}$deg$^{-2}$ and power-law-like spectra with a photon index of 1.8. Combined fittings to the XIS and HXD-PIN spectra confirm that a separate hard tail component is superposed onto the hot thermal emission, confirming a previous report based on the XIS data. Over the 5-40keV band, the hard tail is spectrally approximated by a power law of photon index $\sim$2, but better by those with somewhat convex shapes. Possible origins of the extended hard X-ray emission are discussed.
Spectral Study of the Galactic Ridge X-Ray Emission with Suzaku
Authors: Ebisawa Ken , Yamauchi Shigeo , Tanaka Yasuo , Koyama Katsuji , Ezoe Yuichiro , Bamba Aya , Kokubun Motohide , Hyodo Yoshiaki , Tsujimoto Masahiro , Takahashi Hiromitsu
Published: March 2014

In order to carry out a precise spectral study of the Galactic Ridge X-ray Emission using Suzaku, we have observed a typical Galactic plane field at $(l,b) =$ (28D46, $-$0D20), which is already deeply observed with Chandra, and known to be devoid of bright X-ray point sources. Thanks to the low background and high spectral resolution of Suzaku, we were able to resolve three narrow iron K-emission lines from low-ionized (6.41keV), helium-like (6.67keV), and hydrogenic ions (7.00keV). The cosmic-ray ion charge-exchange model or the non-equilibrium ionization plasma model are unlikely to explain these line features, since they require either broad emission lines or lines at intermediate ionization states. Collisional ionization equilibrium plasma is the likely origin for the 6.67keV and 7.00keV lines; however, the origin of the 6.41keV line, which is due to fluorescence from cold material, has not been elucidated. We could also precisely measure the absolute X-ray surface brightness in the direction of the Galactic plane. Excluding point sources brighter than $\sim$2 $\times 10^{-13}$ergs$^{-1}$cm$^{-2}$ (2-10keV), the total surface brightness on the Galactic plane is $\sim$6.1 $\times 10^{-11}$ergs$^{-1}$cm$^{-2}$deg$^{-2}$ (2-10keV), including the contribution of the cosmic X-ray background, which is estimated to be $\sim$1.3$\times 10^{-11}$ergs$^{-1}$cm$^{-2}$deg$^{-2}$.
Suzaku Wide-Band X-Ray Spectroscopy of the Seyfert2 AGN in NGC 4945
Authors: Itoh Takeshi , Done Chris , Makishima Kazuo , Madejski Grzegorz , Awaki Hisamitsu , Gandhi Poshak , Isobe Naoki , Dewangan Gulab C. , Griffthis Richard E. , Anabuki Naohisa , Okajima Takashi , Reeves James N. , Takahashi Tadayuki , Ueda Yoshihiro , Eguchi Satohi , Yaqoob Tahir
Published: March 2014

Suzaku observed a nearby Seyfert2 galaxy, NGC 4945, which hosts one of the brightest active galactic nuclei above 20keV. Combining data from the two detectors aboard Suzaku, the AGN intrinsic nuclear emission and its reprocessed signals were observed simultaneously. The intrinsic emission is highly obscured with an absorbing column of $\sim$5$\times 10^{24}$cm$^{-2}$. The spectrum below 10keV is dominated by a reflection continuum and emission lines from neutral/ionized material. Along with a neutral iron K$\alpha$ line, a neutral iron K$\beta$ line and a neutral nickel K$\alpha$ line were detected for the first time from this source. The neutral lines and the cold reflection continuum are consistent with both originating in the same location. The Compton down-scattered shoulder in the neutral Fe-K$\alpha$ line is $\sim 10\%$ in flux of the narrow core, which confirms that the line originates from reflection, rather than transmission. The flux of the intrinsic emission varied by a factor of $\sim 2$ within $\sim 20$ks, which requires the obscuring material to be geometrically thin. Broadband spectral modeling showed that the solid angle of the neutral reflector is less than a few $\times 10^{-2} \times 2\pi$. All of this evidence regarding the reprocessed signals suggests that a disk-like absorber/reflector is viewed from a near edge-on angle.
The Suzaku Observation of NGC3516: Complex Absorption and the Broad and Narrow FeK Lines
Authors: Markowitz Alex , Reeves James N. , Miniutti Giovanni , Serlemitsos Peter , Kunieda Hideyo , Yaqoob Tahir , Fabian Andrew C. , Fukazawa Yasushi , Mushotzky Richard , Okajima Takashi , Gallo Luigi C. , Awaki Hisamitsu , Griffiths Richard E.
Published: March 2014

We present results from a 150ks Suzaku observation of the Seyfert 1.5 NGC3516 in 2005 October. The source was in a relatively highly absorbed state. Our best-fit model is consistent with the presence of a low-ionization absorber having a column density near 5$\times$10$^{22}$cm$^{-2}$ and covering most of the X-ray continuum source (covering fraction 96-100%). A high-ionization absorbing component, which yields a narrow absorption feature consistent with FeXXVIK, is confirmed. A relativistically broadened FeK$\alpha$ line was required in all fits, even after the complex absorption was taken into account; an additional partial-covering component is an inadequate substitute for the continuum curvature associated with the broad Fe line. A narrow FeK$\alpha$ emission line has a velocity width consistent with the Broad Line Region. The low-ionization absorber may be responsible for producing the narrow FeK$\alpha$ line, though a contribution from additional material out of the line of sight is possible. We include in our model soft band emission lines from He- and H-like ions of N, O, Ne, and Mg, consistent with photo-ionization, though a small contribution from collisionally-ionized emission is possible.
Suzaku Observation of HCG 62: Temperature, Abundance, and Extended Hard X-Ray Emission Profiles
Authors: Kazuyo Tokoi , Sato Kosuke , Ishisaki Yoshitaka , Ohashi Takaya , Yamasaki Noriko Y. , Nakazawa Kazuhiro , Matsushita Kyoko , Fukazawa Yasushi , Hoshino Akio , Tamura Takayuki , Egawa Chihiro , Kawano Naomi , Ota Naomi , Isobe Naoki , Kawaharada Madoka , Awaki Hisamitsu , Hughes John P.
Published: March 2014

The compact group of galaxies HCG 62 ($z=$ 0.0145) was observed for 120ks with Suzaku XIS and HXD-PIN. The XIS spectra for four annular regions were fitted with a two-temperature vapec model with variable abundance, combined with the foreground Galactic component. The Galactic component was described by a two-temperature apec model, and constrained to have a common surface brightness among the four annuli. We confirmed the multi-temperature nature of the intra-group medium, as reported previously, with a doughnut-like high temperature ring at radii 3.3'-6.5'. Abundances of Mg, Si, S, and Fe were well-constrained. We examined the possible “high-abundance arc” at $\sim 2'$ southwest from the center; however, Suzaku data did not confirm it. We suspect that it is a misidentification of an excess hot component in this region as the Fe line. Neither XIS (5-12keV) nor HXD-PIN (12-40keV) gave positive detection of the extended hard X-rays previously reported with ASCA, although our upper limit did not exclude the ASCA result. The 5-12keV intensity in the $r <$ 3.3' region turned out to be 70$\pm$19% higher than the nominal CXB level, and Chandra and Suzaku data suggest a concentration of hard X-ray sources with an average photon index of $\Gamma=$ 1.38$\pm$0.06. The cumulative mass of O, Fe, and Mg in the intra-group medium and the metal mass-to-light ratio were compared with those in other groups. The possible role of AGN or galaxy mergers in this group is also discussed.