bluuebunny/crossref_metadata_2025_split huggingface dataset:
LMSA and High-Redshift Dusty Starburst Mergers
Authors: Bekki Kenji , Shioya Yasuhiro 
Published: March 2014

Abstract
By using a new numerical code for deriving the spectral energy distributions of galaxies, we have investigated the time evolution of morphological properties, the star formation rate, and the submillimeter flux at 850 μm in high-redshift (z) dusty starburst mergers with mass ratio (m2) of two disks ranging from 0.1 (minor merger) to 1.0 (major one). We found that the maximum star-formation rate, the degree of dust extinction, and the 850 μm flux are larger for mergers with larger m2. The 850 μm flux from mergers at 1.5 ≤ z ≤ 3.0 in the observer frame is found to be a few mJy for major merger cases, and at most ∼ 100 μJy for minor ones. This result suggests that only high-redshift major mergers are now detected by SCUBA with the current 850 μm detection limit of a few mJy. These results imply that LMSA with the expected detection limit of the order of 10 μJy at 850 μm can be used to study high-redshift mergers with variously different m2, and thus provide an important clue to the formation of galaxies in the high-redshift universe.
Stability of Terrestrial Protoplanet Systems and Alignment of Orbital Elements
Authors: Ito Takashi , Tanikawa Kiyotaka 
Published: March 2014

Abstract
The dynamical characteristics of terrestrial protoplanet systems have been investigated. Diagrams which show the instability timescale of terrestrial protoplanet systems as a function of the protoplanet separation (we call them CWB diagrams) were analyzed and interpreted. We have produced CWB diagrams for several different initial parameters, mainly with perturbations from Jupiter and Saturn. One-peakedness of the diagrams for small random velocity cases is interpreted from the viewpoint of orbital alignment in protoplanets. The orbital alignment serves as a stabilizer of the protoplanet system by preventing particles from making close encounters. Terrestrial protoplanet systems appear to be most stable where the tidal force produced by perturbers and mutual gravitational interaction among particles balance; in such cases, orbital alignment is realized. Thus, the terrestrial protoplanet systems turn out to be another example of the so-called secular orbit-orbit resonance frequently found in planet-satellite or satellite-ring systems. Gradual breaking of the orbital alignment invokes an instability in protoplanet systems, which can lead to the collisional evolution of protoplanets into the present planets.
Exploring Galaxy Evolution from Infrared Number Counts and Cosmic Infrared Background
Authors: Takeuchi Tsutomu T. , Ishii Takako T. , Hirashita Hiroyuki , Yoshikawa Kohji , Matsuhara Hideo , Kawara Kimiaki , Okuda Haruyuki 
Published: March 2014

Abstract
Recently reported infrared (IR) galaxy number counts and cosmic infrared background (CIRB) all suggest that galaxies have experienced strong evolution sometime in their lifetime. We statistically estimate the galaxy evolution history from these data. We find that an order-of-magnitude increase of the far-infrared (FIR) luminosity at redshift $ z = 0.5$–$ 1.0$ is necessary to reproduce the very high CIRB intensity at 140 $ \mu m$ reported by Hauser et al. (1998, AAA 070.161.559) and decreases to, even at most, a factor of 10 toward $ z \sim 5$, though many variants are allowed within these constraints. This evolution history also satisfies the constraints from the galaxy number counts obtained by IRAS, ISO and, roughly, SCUBA. The rapid evolution of the comoving IR luminosity density required from the CIRB well reproduces the very steep slope of galaxy number counts obtained by ISO. We also estimate the cosmic star formation history (SFH) from the obtained FIR luminosity density, considering the effect of the metal enrichment in galaxies. The derived SFH increases steeply with redshift in $ 0 \lt z \lt 0.75$, and becomes flat or even declines at $ z \gt 0.75$. This is consistent with the SFH estimated from the reported ultraviolet luminosity density. In addition, we present the performance of the Japanese ASTRO-F FIR galaxy survey. We show the expected number counts in the survey. We also evaluate how large a sky area is necessary to derive secure information of galaxy evolution up to $ z \sim 1$ from the survey, and find that at least $ 50$–$ 300\;\mathrm{deg}^2$ is required.
Substructures Revealed by the Sunyaev–Zel’dovich Effect at 150 GHz in a High-Resolution Map of RX J1347$-$1145
Authors: Komatsu Eiichiro , Matsuo Hiroshi , Kitayama Tetsu , Hattori Makoto , Kawabe Ryohei , Kohno Kotaro , Kuno Nario , Schindler Sabine , Suto Yasushi , Yoshikawa Kohji 
Published: March 2014

Abstract
We report on mapping observations toward the region of the most luminous X-ray cluster, RX J1347$-$1145 ($ z=0.45$), through the Sunyaev–Zel’dovich effect at 21 GHz and 150 GHz with the Nobeyama 45-m telescope. While a low angular resolution image at 21 GHz (beam-size $ \sigma_\mathrm{FWHM}$ of 76$ {}^{\mathrm{\prime\prime}}$) shows a consistent feature with the ROSAT/HRI X-ray image, a higher angular resolution image ($ \sigma_\mathrm{FWHM} =13^{\prime\prime}$) at 150 GHz reveals complex morphological structures of the cluster region, which cannot be simply described by the spherical isothermal $ \beta$-model. If such inhomogeneous morphological features prove to be generic for high-redshift clusters, distance measurements to the clusters based on their Sunyaev–Zel’dovich data with low angular resolution imaging should be interpreted with caution.
The X-Ray Structure of the Supernova Remnant 3C 400.2
Authors: Yoshita Kumi , Tsunemi Hiroshi , Miyata Emi , Mori Koji 
Published: March 2014

Abstract
We present here the results of an X-ray study of the supernova remnant 3C 400.2 (G53.6$-$2.2) using the ASCA data. 3C 400.2 has an unusual morphology at radio wavelengths, suggesting two SNRs superposed along the same line of sight, whereas its X-ray emission is known to be centrally peaked. We investigated the X-ray spectral variation across the remnant using the ASCA GIS and the ROSAT PSPC data. The X-ray spectra can be well fitted by thin thermal plasma models. However, there is no significant variation in the temperature and the ionization parameter across the remnant. We conclude that it is a single SNR rather than two overlapping SNRs. The centrally peaked X-ray morphology and the thin thermal emission with nearly cosmic abundances indicate that 3C 400.2 belongs to a class of “mixed-morphology SNRs”. We found that the physical parameters of 3C 400.2 are similar to those of other mixed-morphology SNRs. The morphology of 3C 400.2 can be explained by a supernova explosion occurring near to the edge of an interstellar cloud.
ASCA Observations of the Twin Supernova Remnants in the Large Magellanic Cloud, DEM L316
Authors: Nishiuchi Mamiko , Yokogawa Jun , Koyama Katsuji , Hughes John P. 
Published: March 2014

Abstract
We report results from an ASCA X-ray study of DEM L316, an emission nebula in the Large Magellanic Cloud (LMC) consisting of two closely-spaced supernova remnants (SNRs). The SIS image shows separate X-ray sources located at the positions of the two radio- and optically-emitting SNR shells, 0547$-$69.7A and 0547$-$69.7B (hereafter, shell A and shell B). The individual X-ray spectrum of each shell is well described by optically-thin thermal emission, although the characteristics of the emission differ in important details between them. Shell A exhibits strong iron L emission, which we attribute to the presence of iron-rich ejecta, leading to the suggestion that this SNR originates from a type Ia SN, an explosion of a moderate mass progenitor. Shell B, on the other hand, has a chemical composition similar to that of the interstellar medium of the LMC, and so its X-ray emission is dominated by swept-up matter. The different spectral features strongly disfavor the hypothesis that the two shells are due to one supernova explosion into an interconnected bubble. We could not obtain evidence which positively supports the collision between two SNRs.
High-Dispersion Spectra of NH2 in the Comet C/1999S4 (LINEAR): Excitation Mechanism of the NH2 Molecule
Authors: Kawakita Hideyo , Watanabe Jun-ichi , Kinoshita Daisuke , Abe Shinsuke , Furusho Reiko , Izumiura Hideyuki , Yanagisawa Kenshi , Masuda Seiji 
Published: March 2014

Abstract
We carried out a high-dispersion spectroscopic observation of the comet C/1999S4 (LINEAR) on 2000 July 8.75 (UT). The $ \mathrm{NH}_2$$ \tilde{\mathrm{A}}(0,10,0)$-$ \tilde{\mathrm{X}}(0,0,0)$ and $ \tilde{\mathrm{A}}(0,9,0)$-$ \tilde{\mathrm{X}}(0,0,0)$ bands were extracted from the observed spectrum and compared with the modeled spectra. We developed a fluorescence equilibrium model for the $ \mathrm{NH}_2$, in which $ \tilde{\mathrm{A}}(0,v_2^{\prime},0)$-$ \tilde{\mathrm{X}}(0,0,0)$ transitions and the radiative relaxation among the rotational levels in $ \tilde{\mathrm{X}}(0,0,0)$ were considered. The rotational structure of the spin doublet ($ F_1$ and $ F_2$ levels) and the Swings effect were considered in the model. The modeled spectra are consistent with the observed spectra of the $ \tilde{\mathrm{A}}(0,10,0)$ and $ \tilde{\mathrm{A}}(0,9,0)$ bands. Our results show that the fluorescence excitation and the radiative relaxation processes are dominant for $ \mathrm{NH}_2$ in a coma of the comet at $ \sim$ 1 AU from the Sun.
The Dense Plasma Torus around the Nucleus of an Active Galaxy NGC1052
Authors: Kameno Seiji , Sawada-Satoh Satoko , Inoue Makoto , Shen Zhi-Qiang , Wajima Kiyoaki 
Published: March 2014

Abstract
A subparsec-scale dense plasma torus around an active galactic nucleus is unveiled. We report on very-long-baseline interferometry (VLBI) observations at 2.3, 8.4, and 15.4 GHz towards the active galaxy NGC1052. The convex spectra of the double-sided jets and the nucleus imply that synchrotron emission is obscured through free–free absorption (FFA) by the foreground cold dense plasma. A trichromatic image was produced to illustrate the distribution of the FFA opacity. We found a central condensation of the plasma which covers about 0.1 pc and 0.7 pc of the approaching and receding jets, respectively. A simple explanation for the asymmetric distribution is the existence of a thick plasma torus perpendicular to the jets. We also found an ambient FFA absorber, whose density profile can be ascribed to a spherical distribution of the isothermal King model. The coexistence of torus-like and spherical distributions of the plasma suggests a transition from radial accretion to rotational accretion around the nucleus.
ASCA Observation of the Superluminal Jet Source GRO J1655–40 in the 1997 Outburst
Authors: Yamaoka Kazutaka , Ueda Yoshihiro , Inoue Hajime , Nagase Fumiaki , Ebisawa Ken , Kotani Taro , Tanaka Yasuo , Zhang Shang Nan 
Published: March 2014

Abstract
We report on the results of an ASCA observation of the Galactic jet source GRO J1655–40 performed from 1997 February 25 to February 28 covering a full orbital period (2.62 d). The averaged 2–10 keV flux was about 1.1 Crab. An absorption line feature centered at 6.8 keV was detected both in the GIS and SIS spectra. We interpret this as a blend of two resonance-absorption $\mathrm{K}\alpha$ lines from H-like and He-like iron ions. We can consistently explain both the ASCA spectra and the simultaneous RXTE/PCA spectrum by a combination of K-absorption lines and K-absorption edges of iron ions. The fact that the absorption line is stably present over the whole orbital phase implies that the distribution of the highly ionized plasma is not affected by the companion star, which is consistent with its presence around the black hole. A curve of growth analysis shows that the plasma contains velocity dispersion along the line-of-sight larger than $300~\mathrm{km}~\mathrm{s}^{-1}$ attributed to bulk motions. It is probably a part of a geometrically thick accretion flow in turbulent motions with velocities of $500$-$1600~\mathrm{km}~\mathrm{s}^{-1}$ at an estimated radius of $\sim10^{10}~\mathrm{cm}$.
Tidal Truncation of Gas Replenishment and Global Suppression of Galactic Star Formation in Distant Clusters
Authors: Bekki Kenji , Couch Warrick J. , Shioya Yasuhiro 
Published: March 2014

Abstract
Recent spectroscopic observations of galaxies in distant clusters have revealed that the rate of star formation in star-forming galaxies is significantly suppressed with respect to their counterparts in the field at a similar redshift. It is, however, highly uncertain which physical processes are responsible for this suppression. We present the results of a numerical investigation of how the global tidal field of a cluster dynamically influences the reservoir of halo gas surrounding a disk galaxy as it falls into the cluster from the surrounding field. We find that the tidal field of the cluster efficiently removes the halo gas from the galaxy, thereby halting its accretion onto the disk, and thus the fueling of star formation within. This effectively truncates the galaxy’s star formation. We also find that this tidal truncation does not depend very strongly on the orbit of the disk with respect to the center of the cluster. These results suggest that the global tidal field of clusters is capable of causing a widespread and uniform suppression of star formation in galaxies accreted by the cluster. In light of these results, we discuss the importance of this tidal truncation of the gas supply in the formation of S0 galaxies in clusters.
X-Ray Probing of the Central Regions of Clusters of Galaxies
Authors: Makishima Kazuo , Ezawa Hajime , Fukazawa Yasushi , Honda Hirohiko , Ikebe Yasushi , Kamae Tuneyoshi , Kikuchi Ken’ich , Matsushita Kyoko , Nakazawa Kazuhiro , Ohashi Takaya , Takahashi Tadayuki , Tamura Takayuki , Xu Haiguang 
Published: March 2014

Abstract
The results on ASCA X-ray study of the central regions of medium-richness clusters of galaxies are summarized, while emphasizing the differences between cD and non-cD clusters. The intra-cluster medium (ICM) is likely to consist of two (hot and cool) phases within $\sim 100$kpc of a cD galaxy, where the ICM metallicity is also enhanced. In contrast, the ICM in non-cD clusters appears to be isothermal with a small metallicity gradient right of the center. The gravitational potential exhibits a hierarchical nesting around cD galaxies, while a total mass-density profile with a central cusp is indicated for a non-cD cluster, Abell 1060. The iron-mass-to-light ratio of the ICM decreases toward the center in both types of clusters, although it is radially constant in peripheral regions. The silicon-to-iron abundance ratio in the ICM increases with the cluster richness, but remains close to the solar ratio around cD galaxies. These overall results are interpreted without appealing to the popular cooling-flow hypothesis. Instead, an emphasis is put on the halo-in-halo structure formed around cD galaxies.
ASCA Temperature Maps of Three Clusters of Galaxies: Abell 1060, AWM 7, and the Centaurus Cluster
Authors: Furusho Tae , Yamasaki Noriko Y. , Ohashi Takaya , Shibata Ryo , Kagei Tomohiro , Ishisaki Yoshitaka , Kikuchi Ken’ichi , Ezawa Hajime , Ikebe Yasushi 
Published: March 2014

Abstract
We present two-dimensional temperature maps of three bright clusters of galaxies (Abell 1060, AWM 7, and the Centaurus cluster), based on multi-pointing observations with the ASCA GIS. The temperatures were derived from hardness ratios by taking into account the XRT response. For the Centaurus cluster, we subtracted the central cool component using the previous ASCA and ROSAT results, and the metallicity gradients observed in AWM 7 and the Centaurus cluster were included in deriving the temperatures. The intracluster medium in Abell 1060 and AWM 7 is almost isothermal from the center to the outer regions with temperatures of 3.3 and $3.9$ keV, respectively. The Centaurus cluster exhibits remarkable hot regions within about ${30{}^{\mathrm {\prime }}}$ from the cluster center, showing a temperature increase of $+0.8$ keV from the surrounding level of 3.5 keV, and the outer cool regions with lower temperatures by $-1.3$ keV. These results imply that a strong merger has occurred in the Centaurus in the recent 2–3 Gyr, and that the central cool component has survived it. In contrast, the gas in Abell 1060 was well-mixed in an early period, which probably has prevented the development of a central cool component. In AWM 7, mixing of the gas should have occurred in a period earlier than the epoch of metal enrichment.
The Radio-to-Submillimeter Flux Density Ratio of Galaxies as a Measure of Redshift
Authors: Rengarajan T. N. , Takeuchi Tsutomu T. 
Published: March 2014

Abstract
We re-examine the technique of determining the redshifts of galaxies from the ratio of the submillimeter-to-radio continuum flux densities based on a recently published catalog of $850\, {\mu \mathrm {m}}$ sources. We derived the expected variation of this ratio as a function of redshift incorporating the expected average luminosity and the spectral energy distribution (SED) of dust emission and the radio continuum. We find that the existing data for most of the high redshift ($z \gtrsim 1$) sources correspond to our new calculation. Amongst the well-identified sources, there is none with an index significantly higher than predicted. Sources which have an index lower than predicted are either within the error zone or much lower, the latter presumably having AGN-dominated radio-continuum emission. We find the median redshift to be $\sim 2$, which is consistent with that deduced by previous work ($\sim 3$) within the error. We also discuss the various systematic effects that can affect the accuracy of the redshift estimate. We examine other methods of redshift estimation, like photometric ratio in the submillimeter and locating the peak of the SED in the rest system of the objects. We conclude that while the various methods are helpful in identifying high-redshift objects and making a crude estimate of the redshift, they are not, at present, accurate enough for a detailed study of redshift distribution of the submillimeter galaxies.
The Spectral Energy Distributions of Blazars and the Connections among XBLs, RBLs, and OVV Quasars
Authors: Xie Guangzhong , Dai Benzhong , Liang Enwei , Ma Li , Jiang Zejun 
Published: March 2014

Abstract
In this paper, we introduce two composite spectral indices, $\alpha_{\mathrm{xox}}=\alpha_{\mathrm{ox}}- \alpha_{\rm {x}}$ and $\alpha_{\mathrm{oro}}=\alpha_{\mathrm{or}}- \alpha_{\mathrm{o}}$. In the composite color–color ($\alpha_{\mathrm{xox}}$–$\alpha_{\mathrm{oro}}$) diagram, there are three regions: (1) For XBLs and XBL-like RBLs, the values of $\alpha_{\mathrm{xox}}$ is in the range of $-1.0$ -$0.0$; (2) For RBLs, $\alpha_{\mathrm{xox}}$ is in 0.0–1.5, and $\alpha_{\mathrm{oro}} \lt -0.75$; (3) For OVV quasars, $\alpha_{\mathrm{xox}}$ is in 0.0–1.5 and the $\alpha_{\mathrm{oro}} \gt-0.75 \alpha_{\mathrm{oro}} \gt-0.75$. Our results support the conclusion that RBLs are intermediate between XBLs and OVV quasars, which has been given by Sambruna et al. (1996, AAA 65.159.120). On the other hand, based on the idea that a group of extragalactic objects which can be regarded as a category with similar physical properties must fit the same relation, using the HST new observational data, we found that there is a strong correlation between the apparent magnitude of the host galaxies and log $z$ for all BL Lac objects (XBLs + RBLs), but OVV quasars lie about 4 magnitude above the Hubble line of 86 BL Lacs. This implies that all XBL-like and XBLs belong to a single category with similar physical properties, while OVV quasars and BL Lacs belong to different populations.
H2 Formation in Low-Metallicity Galaxies
Authors: Kamaya Hideyuki , Hirashita Hiroyuki 
Published: March 2014

Abstract
A possible formation mechanism of hydrogen molecules on a galactic scale is examined. We are interested especially in the role of hydrogen molecules for the formation and evolution of primordial galaxies. Thus, the formation process of hydrogen molecules in a very low-metallicity galaxy (I Zw 18; the most typical metal-deficient galaxy) is studied. Adopting a recent observational result of the absorption lines of hydrogen molecules in I Zw 18, we obtain the upper limit for the ionization degree in the case where hydrogen molecules can form via the $\mathrm{H}^{-}$-process, although they are generally believed to form on the surface of dust grains. Furthermore, we present a critical ionization degree, above which the $\mathrm{H}^{-}$-process can be dominant over the formation process on the surface of grains. Interestingly, this critical ionization degree is comparable to the upper limit of the ionization degree for I Zw 18. For determining the formation process of hydrogen molecules, future observational facilities can be useful. Thus, we examine the detectability in some wavelengths for metal-deficient galaxies. According to our estimate, the near-infrared line emission of hydrogen molecules is observable at the level of $10\,\mu\mathrm{Jy}$, the free–free radio emission is at the level of mJy, and the far-infrared emission from the dust on which hydrogen molecules form can also be detected at the 10-mJy level with its temperature of 16 K. The near-infrared line and the far-infrared continuum are feasible for ASTRO-F observations.
Nucleosynthesis inside Supernova-Driven Supercritical Accretion Disks
Authors: Fujimoto Shin-ichirou , Arai Kenzo , Matsuba Ryuichi , Hashimoto Masa-aki , Koike Osamu , Mineshige Shin 
Published: March 2014

Abstract
We have investigated nucleosynthesis in a supercritical accretion disk around a compact object of $1.4\,{{{M}_{\odot}}}$, using the self-similar solution of an optically thick advection dominated flow. Supercritical accretion is expected to occur in a supernova with fallback material accreting onto a new-born compact object. It has been found that appreciable nuclear reactions take place even for a reasonable value of the viscosity parameter, $\alpha_{\mathrm{vis}} \simeq 0.01$, when the accretion rate $\dot{m} = \dot{M}c^2/(16 L_{\mathrm{Edd}}) \gt 10^5$, where $L_{\mathrm{Edd}}$ is the Eddington luminosity. If $\dot{m} \ge 4 \times 10^6$, all heavy elements are destroyed to ${{4\atop} \mathrm{He}}$ through photodisintegrations at the inner part of the disk. Even ${{4\atop} \mathrm{He}}$ is also disintegrated to protons and neutrons near the inner edge when $\dot{m} \ge 2 \times 10^7$. If the fallback matter of the supernova explosion has the composition of a helium-rich layer of the progenitor, a considerable amount of ${{44\atop} \mathrm{Ti}}$ could be ejected via a jet from the disk.
Kashima 34-m Water Maser Survey of Late-Type Stars
Authors: Takaba Hiroshi , Iwata Takahiro , Miyaji Takeshi , Deguchi Shuji 
Published: March 2014

Abstract
This paper presents new results of a water maser survey of late-type stellar objects at 22.235 GHz with the Kashima 34-m radio telescope. We have detected 179 out of 643 observed sources, including 32 new detections. The sources were selected in terms of the IRAS flux density and colors of late-type stars, involving optically observable Mira/semiregular variables, IRC objects, OH/IR sources and protoplanetary nebulae. We found the highest $\mathrm{H}_{2}\mathrm{O}$ detection rate for the type of stars with a thin dust envelope (Mira/semiregular variables) among other types of sources. This is attributed to the smaller distances to such stars in the sample. The velocity spread of the $\mathrm{H}_{2}\mathrm{O}$ maser profile has an increasing tendency with the IRAS color, though it becomes more difficult to access this color dependence beyond an edge of the transition of the (oxygen-rich) Asymptotic Giant Branch stars to protoplanetary nebulae in the two-color diagram.