bluuebunny/crossref_metadata_2025_split huggingface dataset:
ASCA Observation of Ultra-Luminous X-Ray Sources in the Nearby Spiral Galaxy NGC 2403
Authors: Kotoku Jun'ichi , Mizuno Tsunefumi , Kubota Aya , Makishima Kazuo 
Published: March 2014

Abstract
The spiral galaxy NGC 2403 was observed with ASCA, and three previously known X-ray sources (sources 3, 4, and 5) were detected. Among them, the observed 0.5-10 keV flux of source 3 is 1.4×10−12 erg s−1 cm−2, implying a bolometric luminosity of 3.0×1039 erg s−1. Its spectrum can be explained by emission from an optically thick accretion disk with an inner-disk temperature of 1.1 keV. The spectrum and the high luminosity suggest that source 3 is a mass-accreting black hole binary. The observed properties of source 3 can be interpreted in terms of a black hole of mass ∼ 15 M⊙, accreting at near the Eddington rate.
Resistive Magnetohydrodynamics of Jet Formation and Magnetically Driven Accretion
Authors: Kuwabara Takuhito , Shibata Kazunari , Kudoh Takahiro , Matsumoto Ryoji 
Published: March 2014

Abstract
We carried out 2.5-dimensional resistive magnetohydrodynamic simulations to study the effects of magnetic diffusivity on magnetically driven mass accretion and jet formation. The initial state is a constant angular-momentum torus threaded by large-scale vertical magnetic fields. Since the angular momentum of the torus is extracted due to magnetic braking, the torus medium falls toward the central region. The infalling matter twists the large-scale magnetic fields and drives bipolar jets. We found that (1) when the normalized magnetic diffusivity,$\bar \eta \equiv \eta/(r_0 V_{\textrm {Ko}})$, where VK0 is the Keplerian rotation speed at a reference radius $r=r_0$, is small $(\bar \eta \leq 10^{-3})$, mass accretion and jet formation take place intermittently; (2) when $10^{-3}\leq \bar \eta \leq 10^{-2}$, the system evolves toward a quasi-steady state; and (3) when $\bar \eta \geq 10^{-2}$ the accretion/mass outflow rate decreases with bar $\bar \eta$ and approaches 0. The results of these simulations indicate that in the center of a galaxy which has a super-massive ( ∼ 109M⊙ ) black hole, a massive ( ∼ 108M⊙ ) gas torus and magnetic braking provide a mass accretion rate which is sufficient to explain the activity of AGNs when $\bar \eta \leq 5 \times10^{-2}$
Spiral Structures and Shocks in Accretion Discs in Close Binary Systems: the Role of the Injection Velocity at the Inner Lagrangian Point
Authors: Lanzafame Giuseppe , Maravigna Fabio , Belvedere Gaetano 
Published: March 2014

Abstract
In our previous paper (Lanzafame et al. 2000, PASJ 52, 515) we showed, through 2D SPH simulations, that the stellar mass ratio, $ M_{2}/M_{1}$, of a close binary system (that determines the $ L_{1}$ position and then the initial specific angular momentum at $ L_{1}$) plays a fundamental role in the formation and development of spiral structures and shock fronts in the radial flow of accretion discs. In that work only a quasi-sonic value of the injection velocity at $ L_{1}$ was considered. In the present work we also carried out 2D SPH simulations with the aim to investigate the development of such structures, while keeping constant the mass of the compact primary ($ M_{1} = 1 M_\odot$) and the separation between the two components, and assuming as an initial condition of two different supersonic injection velocities at $ L_{1}$, characterizing two sets of simulations. For each set we considered four values of the secondary to primary mass ratio, $ M_{2}/M_{1}$. We worked out 2D models because the damping effect of the artificial viscosity is too strong in 3D. Furthermore, the 2D environment seems to be the most suitable in order to be evidence of shock fronts in highly compressible gases. Our aim in these two works was to enhance the initial kinematic conditions (from sonic to strongly supersonic) to stress the idea that spiral structures and shock front development are influenced by the initial specific angular momentum at $ L_{1}$. The results show that these structures are more evident with the increasing injection velocity at $ L_{1}$ and the increasing $ L_{1}$ distance from the primary.
Subaru Deep Survey I. Near-Infrared Observations
Authors: Maihara Toshinori , Iwamuro Fumihide , Tanabe Hirohisa , Taguchi Tomoyuki , Hata Ryuji , Oya Shin , Kashikawa Nobunari , Iye Masanori , Miyazaki Satoshi , Karoji Hiroshi , Yoshida Michitoshi , Totani Tomonori , Yoshii Yuzuru , Okamura Sadanori , Shimasaku Kazuhiro , Saito Yoshihiko , Ando Hiroyasu , Goto Miwa , Hayashi Masahiko , Kaifu Norio , Kobayashi Naoto , Kosugi George , Motohara Kentaro , Nishimura Tetsuo , Noumaru Jun’ichi , Ogasawara Ryusuke , Sasaki Toshiyuki , Sekiguchi Kazuhiro , Takata Tadafumi , Terada Hiroshi , Yamashita Takuya , Usuda Tomonori , Tokunaga Alan T. 
Published: March 2014

Abstract
Deep near-infrared images of a blank 2$^{\prime}$$ \times$ 2$ ^{\prime}$ section of sky near the galactic north pole taken by Subaru Telescope are presented. The total integration times of the $ J$ and $ K^{\prime}$ bands were 12.1 hr and 9.7 hr, resulting in 5$ \sigma$ limiting magnitudes of 25.1 and 23.5 mag, respectively. The numbers of sources within these limiting magnitudes found with an automated detection procedure are 385 in the $ J$ band and 350 in $ K^{\prime}$. Based on photometric measurements of these sources, we present number count vs. magnitude relations, color vs. magnitude diagrams, size vs. color relationships, etc. The slope of the galaxy number count plotted against the AB magnitude scale is about 0.23 in the 22 to 26 AB magnitude range of both bands. The spatial number density of galaxies as well as the slopes in the faint-end region given by the Subaru Deep Field (SDF) survey are consistent with those given by HST-NICMOS surveys, as expressed on the AB magnitude diagram. Several sources having very large $ J - K^{\prime}$ color have been found, including a few $ K^{\prime}$ objects without detection at $ J$. In addition, a number of faint galactic stars were also detected, most of which are assigned to M-subdwarfs, together with a few brown dwarf candidates.
ASCA Observations of the BL Lacertae Object OJ 287 in 1997 April and November
Authors: Isobe Naoki , Tashiro Makoto , Sugiho Masahiko , Makishima Kazuo 
Published: March 2014

Abstract
The X-ray properties of the BL Lacertae object OJ 287, observed with ASCA on 1997 April 26 and November 17, are reported. The 0.5–10 keV flux was lower than that obtained in previous X-ray observations, and no evidence of intensity variations was found during each observation. The obtained flux densities at 1 keV, 0.22–0.26 $\mu\mathrm{Jy}$, exceed the extrapolations from lower frequency synchrotron continua, which were measured in nearly the same period as the present ASCA observations. The X-ray spectra acquired with the GIS and SIS were consistently described with a single power-law model modified by the Galactic absorption, and the derived photon indices, 1.5–1.6, are flatter than those observed so far. These results strongly suggest that the X-ray spectra observed in 1997 arise via an inverse Compton process alone. The X-ray spectra obtained in 1994 (Idesawa et al. 1997, AAA 68.159.334), exhibiting a steeper slope than those in 1997, is thought to be contaminated by a “synchrotron soft tail.”
Snapshot VLBI Observations of SiO v=1 and v=2 (J=1-0) Maser Sources
Authors: Imai Hiroshi , Miyoshi Makoto , Ukita Nobuharu , Morimoto Masaki , Iwata Takahiro , Takaba Hiroshi , Kameno Seiji , Matsumoto Kin-ya , Fujisawa Kenta , Kawaguchi Noriyuki 
Published: March 2014

Abstract
We have made snapshot VLBI observations of SiO masers of the $J= 1$−0 transition at two vibrational levels $v=1$ and $v=2$ using the Kashima–Nobeyama Interferometer (KNIFE). Out of 37 sources observed, we detected both of the lines from 16 sources with a typical detection limit of 10 Jy. Most of the SiO masers were significantly spatially resolved with a KNIFE baseline (200 km), indicating extended/complicated structures of the SiO masers with a typical angular size of a few milliarcseconds. Similar fringe-phase profiles along a radial velocity spanning larger than $1.0~\mathrm{km}~\mathrm{s}^{-1}$ between the two lines indicate a similar spatial structure along the velocity spacings. This tendency, shown from 13 SiO maser sources except Orion KL, supports spatial coincidence of the two lines found previously for M-type stars VY CMa and W Hya. The spatial coincidence should enable us to measure group-delays of the SiO masers for stellar astrometry.
SiO Maser Survey of Southern IRAS Sources
Authors: Deguchi Shuji , Nakashima Jun-ichi , Balasubramanyam Ramesh 
Published: March 2014

Abstract
We have surveyed 163 southern IRAS sources in the SiO $J=2$-$1 v=1$ maser line at 86 GHz, obtaining 38 (22 new and 16 previously known) detections. These detections include 6 stars not previously detected in OH 1612 MHz surveys, and 4 sources assigned incorrect OH radial velocities. The distance reachable in this survey turned out to be about 4 kpc. The local velocity dispersion near the Sun were found to be approximately $30~\mathrm{km}~\mathrm{s}^{-1}$ for these IRAS/SiO sources. A relatively high concentration of the SiO detected sources were found at the area $320{{}^{\mathrm{\circ}}} \lt l \lt 340{{}^{\mathrm{\circ}}}$ (toward “Norma tangent”). The estimated distances for these sources suggest that this concentration is spread between 2 and 6 kpc from the Sun, peaking on the Scutum–Crux arm.
A Graph-Theoretical Approach for Quantifying Two-Dimensional Galaxy Distributions and Comparison with Cold Dark Matter Universe
Authors: Ueda Haruhiko , Takeuchi Tsutomu T. , Itoh Makoto 
Published: March 2014

Abstract
With the help of a graph-theoretical approach, we have quantified two-dimensional galaxy distributions in observation and Cold Dark Matter (CDM) simulations. In our analysis, we adopted the Lyon–Meudon Extragalactic Database as a typical two-dimensional observation. To estimate adjacency matrices, we constructed constellation graphs from galaxy distributions, and calculated the distribution functions of the eigenvalues of these matrices. Using the mean absolute deviations, we compared the two-dimensional galaxy distributions in observations with CDM simulations in a statistical way. From our analysis we found that the CDM model with a density parameter of less than one is preferable to reproduce the galaxy distributions in the observations.
X-Ray Microlensing of Bright Quasars
Authors: Takahashi Rohta , Yonehara Atsunori , Mineshige Shin 
Published: March 2014

Abstract
We calculated the expected microlens light curves for several accretion-flow models and compared the results to find what aspects of distinct flow structures can be extracted from the microlens light curves. As for the flow models, we considered the standard disk, optically thin advection-dominated flow, and the disk-corona model by Kawaguchi et al., which can nicely reproduce the observed quasar spectra. The calculated microlens light curves of the disk-corona model exhibit rapid soft X-ray and slow hard X-ray variations. This is because the former is generated by Compton up-scattering of soft (optical–UV) photons from the innermost part of the disk body, while the latter is emitted via bremsstrahlung within the corona at relatively large radii. Furthermore, an inhomogeneous emissivity distribution over the disk produces humps in the microlens light curves because of enhanced microlens amplification of the bright areas. It is hoped that black-hole accretion theory coupled with future multi-wavelength microlens observations will be able to reveal such spatial and temporal behaviors of flows in the vicinity of black holes.
JHK Spectra of the z = 2.39 Radio Galaxy 53W002
Authors: Motohara Kentaro , Yamada Toru , Iwamuro Fumihide , Hata Ryuji , Taguchi Tomoyuki , Harashima Takashi , Maihara Toshinori , Iye Masanori , Simpson Chris , Yoshida Michitoshi 
Published: March 2014

Abstract
We present low-resolution, near-IR JHK spectra of the weak $z=2.39$ radio galaxy 53W002, obtained with the OH-airglow Suppressor spectrograph (OHS) and Cooled Infrared Spectrograph and Camera for OHS (CISCO) on the Subaru Telescope. They cover rest-frame wavelengths of 3400–7200$Å$, and the emission lines of [O II]$\lambda$3727, H$\beta$, [O III]$\lambda\lambda$4959, 5007, H$\alpha$, [N II]$\lambda\lambda$6548, 6583 and [S II]$\lambda\lambda$6716, 6731 were detected. Using the H$\alpha$/H$\beta$ line ratio, we find an extinction of $E(B\hbox{--}V)=0.14$. The emission-line ratios are reproduced by a cloud of electron density $n_{\mathrm{e}}=1\times 10^{3-4}\,\mathrm{cm}^{-3}$ with solar metallicity, ionized by an $\alpha=-0.7$ power-law continuum with ionizing parameter $U=1\times 10^{-3}$. In addition to these emission lines, we make the first spectroscopic confirmation of the Balmer discontinuity in a high-$z$ radio galaxy. Together with rest-frame UV photometry from the literature, we show that at least 1/3 of the present stellar mass was formed in the current starburst. The stellar mass was estimated to be $(1\hbox{--}1.4)\times10^{11}\,{{{M}_{\odot}}}$ by one-component model fitting, which is smaller than that of typical $z\sim 1$ B2/6C radio galaxies. We suggest that 53W002 is currently assembling a large part of its stellar mass through merger events with the surrounding sub-galactic clumps, some of which can be identified with the L$\alpha$ emitters detected in narrow-band imaging. After a few such events over the next few Gyr, 53W002 will evolve into a massive elliptical galaxy.
Radiative Collimation of Electron–Positron Jets
Authors: Fukue Jun , Tojyo Masaharu , Hirai Yasuo 
Published: March 2014

Abstract
We propose a novel mechanism for the collimation of relativistic outflows emanated from accretion disks via the disk radiation field, itself. In general, winds driven by disk radiation fields diverge, due to the effect of rotation and the nature of radiation. If, however, the disk is divided into an optically thin hot inner region and an optically thick luminous outer region, the outflow ejected from the inner disk is accelerated and collimated by radiation fields produced by the outer disk. Since this mechanism effectively works on electron–positron pair plasmas, in accretion disk systems with inner hot advection-dominated regions, electron–positron jets easily form on the disk-rotation axis. For pure electron–positron pair plasmas, the terminal speed of collimated jets is about $0.9c$, which is very close to the jet speed of galactic superluminal sources.
A 168-s X-Ray Pulsar in the Small Magellanic Cloud Observed with ASCA
Authors: Yokogawa Jun , Torii Ken’ichi , Kohmura Takayoshi , Koyama Katsuji 
Published: March 2014

Abstract
We report on the detection of $167.8 \pm 0.2\,\mathrm{s}$ pulsations from AX J0052.9$-$7157 in the Small Magellanic Cloud with ASCA. The pulsations show an energy-independent sinusoidal profile. The X-ray spectrum has been described by an absorbed hard power-law (photon index $\sim 0.7$) with a luminosity of $\sim 8.8 \times 10^{35}\,\mathrm{erg}\,\mathrm{s}^{-1}$ at a distance of $60\,\mathrm{kpc}$. The position is determined to be $\mathrm{(R.A.,~Dec.)}_{\mathrm{J2000}} = (00{}^{\mathrm{h}}52{}^{\rm m}59\rlap{.}{}^{\rm s}2, -71{71{}^{\mathrm{\circ}}57{}^{\mathrm{\prime}}58{}^{\mathrm{\prime\prime}}})$, with an error radius of $\sim {30{}^{\mathrm{\prime\prime}}}$. We have found that a variable Be/X-ray binary RX J0052.9$-$7158 is located within the $30{}^{\mathrm{\prime\prime}}$ error circle, and is also located at the edge of the $10{}^{\mathrm{\prime}}$ error circle of the 169-s pulsar XTE J0054$-$720. We therefore conclude that these are the same source, a Be/X-ray binary pulsar.
Contribution of Supernova Gamma-Rays to the Gamma-Ray Background Emission
Authors: Iwabuchi Kousei , Kumagai Shiomi 
Published: March 2014

Abstract
Diffuse $ \gamma $-ray background emission has been observed by a number of satellites and balloons. The spectrum spreads over a wide range of photon energies, and the emission is almost isotropic. Although the origin of diffuse $ \gamma $-ray background emission is still unclear, some candidates are suggested, such as Seyfert galaxies, blazars, and type-Ia supernovae. The type-Ia supernovae synthesize a large amount of ${{56\atop}\mathrm{Ni}}$, which emit $ \gamma $-ray photons while decaying into ${{56\atop}\mathrm{Co}}$ and then to ${{56\atop}\mathrm{Fe}}$, and thus emit strong $ \gamma $-rays of energy around 1 MeV. We estimate the intensity of the diffuse $ \gamma $-ray background emission from supernovae, and compare the result with the recent observation of COMPTEL. The resultant spectrum is too small to explain the observation, because it is only 10% of the observed flux, implying contributions from other sources.
Eclipsing and Precessional Light Curves of SS 433 with Superdisks
Authors: Hirai Yasuo , Fukue Jun 
Published: March 2014

Abstract
We theoretically calculated light curves of SS 433 during eclipse and precession, under a picture in which SS 433 consists of a geometrically thick superdisk around a compact star and a companion star filling its Roche lobe. The main parameters are the binary mass ratio, the relative thickness of the superdisk, and the surface temperature of the companion. Combinations of eclipsing and precessional light curves impose constraints on the parameter ranges. The favorite values of the parameters are a mass ratio of about 1 to 1.5 (a compact star is a black hole), a relative disk-thickness of about $ {25{}^{\mathrm {\circ }}}$, and a companion surface-temperature of 14000–20000 K.
A Diffuse X-Ray Source, AX J1843.80352: Association with the Radio Complex G28.6-0.1 and Identification of a New Supernova Remnant
Authors: Bamba Aya , Ueno Masaru , Koyama Katsuji , Yamauchi Shigeo 
Published: March 2014

Abstract
ASCA discovered an extended source in the constellation Scutum. The X-ray morphology is an elliptical shape elongated from north to south with a mean diameter of about $ {10{}^{\mathrm {\prime }}}$. The image center is located at $ \mathrm{RA}_{2000}$ = $ {18{}^{\mathrm {h}}43{}^{\mathrm {m}}53{}^{\mathrm {s}}}$, $ \mathrm{DEC}_{2000}$ = $ - {03{}^{\mathrm {\circ }}52{}^{\mathrm {\prime }}55{}^{\mathrm {\prime \prime }}}$ (hereafter, AX J1843.8–0352). The north and south rims of AX J1843.8–0352 are associated with non-thermal radio sources C and F of the G28.6–0.1 complex (Helfand et al. 1989, AAA $ 49.125.029$). The X-ray spectrum was fitted with a model of either a thin thermal plasma in non-equilibrium ionization of a temperature 5.4keV or a power-law of photon index 2.1. The absorption column is $ (2.4$-$ 4.0)\times 10^{22}\mathrm{cm}^{-2}$, which probably places this source in the Scutum arm. With a reasonable distance assumption of about 7kpc, we estimate the mean diameter and X-ray luminosity to be $ \sim 20 \,\mathrm{pc}$ and $ \sim 3 \times 10^{34}\,\mathrm{erg} \,\mathrm{s}^{-1}$, respectively. Although a Sedov solution for a thin thermal plasma model gives parameters of a young shell-like SNR, no strong emission lines are found with the metal abundances being $ \sim$ solar. Thus, a more likely scenario for both the radio and X-ray spectra and the morphologies is that AX J1843.8–0352 is a shell-like SNR which predominantly emits synchrotron X-rays.
A New Look at CO Outflows in the Dark Cloud Complex near IC 5146
Authors: Dobashi Kazuhito , Yonekura Yoshinori , Hayashi Yoshikazu 
Published: March 2014

Abstract
This paper presents the results of a search for CO outflows in a dark cloud complex near IC 5146 carried out using the 45-m telescope at Nobeyama Radio Observatory ($\mathrm{HPBW} = 17^{\prime\prime}$) equipped with the S115Q multi-beam receiver system. A CO outflow was discovered by the present survey toward IRAS 21428$+$4732, whose physical parameters, such as molecular mass, mechanical momentum, and kinetic energy, were derived. In addition to IRAS 21428$+$4732, there are 5 other IRAS point sources accompanied by CO outflows in this cloud complex, which were found by earlier observations with lower angular resolutions ($\mathrm{HPBW} \simeq 1^\prime$). We also made 12 CO ($J = 1-0$), 13CO ($J = 1-0$), and C18O ($J = 1-0$ observations toward the 5 sources with the 45-m telescope in order to obtain new data with higher angular resolutions. CO maps as well as physical parameters of these outflows obtained by the 45-m telescope are also presented.
2 Millimeter Dust around NGC 7538 — IRS 1, 2, and 3: I. Unfilled Structure of Dust Cloud
Authors: Akabane Kenji , Matsuo Hiroshi , Kuno Nario , Sugitani Koji 
Published: March 2014

Abstract
A 2-mm continuum mapping observation around NGC 7538 — IRS 1, 2, and 3 was made by the Nobeyama Bolometer Array (NOBA) with a spatial resolution of 12$^{\prime\prime}$. An extended source of $\sim {32{}^{\mathrm {\prime \prime }}} \times {44{}^{\mathrm {\prime \prime }}}$ ($\Delta\alpha \times \Delta\delta$), having a hardly resolved central core structure, was observed. The core gives a flux density of $3.1 \,\mathrm{Jy} \pm 1 \,\mathrm{Jy}$, and is clearly identified with the free-free emission from the compact H II regions. A smooth and extended source gives an integrated flux density of $5 \,\mathrm{Jy} \pm 1.5 \,\mathrm{Jy}$, and an intensity spectrum of $\nu^{3}$–$\nu^{3.5}$ in the millimeter wave region. The fitting of a gray body function to the observational data shows that an absorption index, $\beta$, of 1.8–2.0, a dust filling factor, $\eta$, of 0.3–0.5, and a dust temperature, $T_\mathrm{d}$, of 34 K–45 K are reasonable parameters for this 2-mm extended dust. Astronomical silicate grains were examined for a dust model. The total dust mass and luminosity were obtained as $M_\mathrm{d} \simeq 0.85 \times 10^{2} \,{{{M}_{\odot}}}$ and $L_\mathrm{d} \simeq 2.2 \times 10^{5} \,{{{L}_{\odot}}}$, respectively. The extent of 2-mm dust emission partly coincides with those of the 100-$/mu$ m map, of the 57-$/mu$ m map, and of the total intensity of the wing parts of the CO ($J = 1-0$) line emission of the region. The absorbing silicate dust layer must be distinct from the extended 2-mm dust, and must arise on smaller scales than the extended 2-mm dust.
When Did the Hubble Sequence Appear?: Morphology, Color, and Number-Density Evolution of the Galaxies in the Hubble Deep Field North
Authors: Kajisawa Masaru , Yamada Toru 
Published: March 2014

Abstract
Using the HST WFPC2/NICMOS archival data of the Hubble Deep Field North, we constructed a nearly complete sample of the $M_{V} \lt-20$ ($\sim L^\ast +1$) galaxies to $z=2$, and investigate when the Hubble sequence appeared, namely, the evolution of the morphology, colors, and the comoving number density of the sample. Even if taking into account the uncertainty of the photometric redshift technique, the number density of relatively bright bulge-dominated galaxies in the HDF-N decreases significantly at $z \gt 1$, and their rest-frame $U-V$ color distribution is wide-spread over $0.5 \lt z \lt 2$. On the other hand, while the number density of both disk-dominated and irregular galaxies does not show a significant change at $0.5 \lt z \lt 2$, their distribution of the rest-frame $U-V$ color alters at $z \sim 1.5$; there is no relatively red (rest $U-V \gtrsim 0.3$) galaxies at $z \gt 1.5$, while a significant fraction of these red disk-dominated or irregular galaxies exist at $z \lt 1.5$. These results suggest that the significant evolution of the Hubble sequence, which is seen in the present Universe, occurs at $1 \lt z \lt2$.