bluuebunny/crossref_metadata_2025_split huggingface dataset:
Relations between Galaxy Formation and the Environments of Quasars
Authors: Enoki Motohiro , Nagashima Masahiro , Gouda Naoteru 
Published: March 2014

Abstract
We investigate the environments of quasars using a semi-analytic model which includes both galaxy and quasar formations based on a hierarchical clustering scenario. We assume that a supermassive black hole is formed and fueled by the accretion of cold gas during a major merger of galaxies. Our model can reproduce not only the general form of the galaxy luminosity functions in the local Universe, but also the observed relation between a supermassive black hole mass and a spheroid luminosity, the present black hole mass function and the quasar luminosity functions at different redshifts. Using this model, we predict the mean number of quasars per halo, the bias parameter of quasars and the probability distribution of the number of galaxies around quasars. The results of our model show that the spatial distribution of galaxies is different from that of quasars. Furthermore, we found that at $0.2 \lesssim z \lesssim 0.5$ most quasars are likely to reside in galaxy groups. On the other hand, at $1 \lesssim z \lesssim 2$ most quasars seem to reside in environments ranging from small groups of galaxies to clusters of galaxies. Comparing these predictions with observations in the future will enable us to constrain our model of quasar formation.
The Virgo High-Resolution CO Survey: I. CO Atlas
Authors: Sofue Yoshiaki , Koda Jin , Nakanishi Hiroyuki , Onodera Sachiko , Kohno Kotaro , Tomita Akihiko , Okumura Sachiko K. 
Published: March 2014

Abstract
We present the results of the Virgo high-resolution CO survey (ViCS) obtained with the Nobeyama Millimeter-wave Array (NMA). This survey was made during the course of a long-term project at Nobeyama from 1999 December through 2002 April. The objects were selected from Virgo cluster members, while considering the CO richness from the single-dish flux, mild inclination, and a lack of strong tidal perturbations. The central ${1{}^{\mathrm {\prime }}}$ regions ($\sim 4.7 \,\mathrm{kpc}$) of 15 spiral galaxies were observed with resolutions of ${2{}^{\mathrm {\prime \prime }}} \hbox{-} {5{}^{\mathrm {\prime \prime }}}$ and $10 \hbox{-} 20 \,\mathrm{km} \,\mathrm{s}^{-1}$, and sensitivities of $\sim 20 \,\mathrm{mJy} \,\mathrm{beam}^{-1}$ for a $10 \,\mathrm{km} \,\mathrm{s}^{-1}$ channel. The objects lie at the same distance of the Virgo cluster (16.1 Mpc), which is advantageous for comparisons among individual galaxies. We describe the details of observations and data reduction, and present an atlas of integrated CO intensity maps, velocity fields and position–velocity diagrams along the major axes. The molecular gas morphology in the Virgo galaxies shows a wealth of variety, not specifically depending on the Hubble types. Several galaxies show a strong concentration of gas in the central few kpc region, where the CO morphology shows either a “single-peak” or a “twin-peaks”. The morphology of more extended CO components can be classified into “arm-type”, “bar-type”, and “amorphous-type”.
SiO Maser Survey toward the Inner Galactic Disk: ${40{}^{\mathrm {\circ }}} \leq l \leq {70{}^{\mathrm {\circ }}}$ and $\vert b\vert \leq {10{}^{\mathrm {\circ }}}$
Authors: Nakashima Jun-ichi , Deguchi Shuji 
Published: March 2014

Abstract
We present the results of an SiO maser survey for color-selected IRAS sources in the area ${40{}^{\mathrm {\circ }}} &lt; l &lt; {70{}^{\mathrm {\circ }}}$ and $\vert b\vert &lt; {10{}^{\mathrm {\circ }}}$ in the SiO $J = 1\hbox{--}0$, $v = 1$ and 2 transitions ($\sim 43 \,\mathrm{GHz}$). We detected 134 out of 272 observed sources in SiO masers; 127 were new detections. A systematic difference in the detection rates between SiO and OH maser searches was found. Especially, in the color ranges with $\log (F_{25}/F_{12})$ smaller than $-0.1$, the detection rate of the SiO masers is significantly higher than that of OH masers. We found a possible kinematic influence of the Galactic arm on the distribution of SiO maser sources. It was found that the velocity dispersion of SiO maser sources tends to decrease with the galactocentric distance. Using the present and previous data of SiO maser surveys, we found that the local velocity gradient of the rotational velocity of the Galaxy is consistent with the values obtained from other kinds of disk population stars within a statistical uncertainty. The Oort’s constants, A and B, were computed from the gradient of the rotation curve for the present data, and were consistent with the IAU standard values. In addition, in order to check the reliability of IRAS positions, we observed toward the MSX positions for 5 MSX counterparts, which are located more than ${20{}^{\mathrm {\prime \prime }}}$ away (but within ${60{}^{\mathrm {\prime \prime }}}$) from IRAS positions. We detected all of these 5 sources in SiO masers.
Galactic Center Shells and a Recurrent Starburst Model
Authors: Sofue Yoshiaki 
Published: March 2014

Abstract
By applying filtering techniques to remove straight filaments in the 20-cm VLA radio image of the Galactic Center Arc region, we have shown that numerous concentric radio shells of radii 5 to 20 pc are surrounding the Pistol and Sickle region, which we call Galactic Center Shells (GCS). Each shell has thermal energy of the order of $10^{49 \mbox{--} 50} \,\mathrm{erg}$. Several CO-line shells are associated, whose kinetic energies are of the order of $10^{49 \mbox{--} 50} \,\mathrm{erg}$. Summing up the energies of recognized GCSs, the total energy amounts to $\sim 10^{51} \,\mathrm{erg}$. The GCSs show an excellent correlation with the FIR shells observed at 16–26${\mu \mathrm {m}}$ with the MSX. We propose a model in which GCSs were produced by recurrent and/or intermittent starbursts in the Pistol area during the last million years. The most recent burst occurred some $10^5$ years ago, producing an inner round-shaped shell (GCS I); earlier ones a million years ago produced outer shells (GCS II and III), which are more deformed by interactions with the surrounding ISM and Sgr A halo. We argue that recurrent starbursts had also occurred in the past, which produced larger scale hyper-shell structures as well. A burst some million years ago produced the Galactic Center Lobe, and a much stronger one 15 million years ago produced the North Polar Spur.
Chandra X-Ray Spectral Analysis of Cooling Flow Clusters, 2A 0335 $+$ and Abell 2199
Authors: Kawano Naomi , Ohto Akimitsu , Fukazawa Yasushi 
Published: March 2014

Abstract
We report on a spatially resolved analysis of Chandra X-ray data on a nearby typical cooling flow cluster of galaxies 2A 0335$+$096, together with A2199 for a comparison. As recently found in the cores of other clusters, the temperature around the central part of 2A 0335$+$096 is 1.3–1.5 keV, which is higher than that inferred from the cooling flow picture. Furthermore, the absorption column density is almost constant against the radius in 2A 0335$+$096; there is no evidence of excess absorption up to 200–250 kpc. This indicates that no significant amount of cold material, which has cooled down, is present. These properties are similar to those of A2199. Since the cooling time in the central part is much shorter than the age of the clusters, a heating mechanism, which weakens the effect of radiative cooling, is expected to be present in the central part of both clusters of galaxies. Both 2A 0335$+$096 and A 2199 have radio jets associated with their cD galaxy. We discuss the possibility of heating processes caused by these radio jets by considering the thermal conduction and the sound velocity together with the observed disturbance of the ICM temperature and density. We conclude that the observed radio jets can produce local heating and/or cooling, but do not sufficiently reduce the overall radiative cooling. This implies that much more violent jets, whose emission has now decayed, heated up the cooling gas $ \gt 10^9$ years ago.
Near-Infrared Observations of MUSES-C Mission Target
Authors: Ishiguro Masateru , Abe Masanao , Ohba Youhei , Fujiwara Akira , Fuse Tetsuharu , Terada Hiroshi , Goto Miwa , Kobayashi Naoto , Tokunaga Alan T. , Hasegawa Sunao 
Published: March 2014

Abstract
We present near-infrared photometric and spectroscopic observations of the MUSES-C Japanese asteroid sample return mission target (25143) 1998 $\mathrm{SF}_{36}$, which were obtained with the 8-m SUBARU telescope. The near-infrared colors were found to be $J-H = 0.49 \pm 0.04$ and $H-K = 0.02 \pm 0.04$, where $J$, $H$, and $K$ are the magnitudes at the center wavelength of 1.25, 1.63, and 2.12$\, {\mu \mathrm {m}}$, respectively. Comparing these colors to those of known taxonomic type asteroids, we find this asteroid to be S-type. We combined our $M'$-band (4.68$\, {\mu \mathrm {m}}$) photometric data with $N$-band photometric data obtained at the mid-IR wavelength. Using the free beaming parameter thermal model (FBM), the derived size of 1998 $\mathrm{SF}_{36}$, assuming the shape of an ellipsoid, are $a = 620 \pm 140 \,\mathrm{m}$, $b= 280 \pm 60 \,\mathrm{m}$, and $c = 160 \pm 30 \,\mathrm{m}$, and geometric albedo in the $V$-band (0.55$\, {\mu \mathrm {m}}$) is $0.35 \pm 0.11$. The beaming parameter from FBM is found to be 1.1. Our results show that the albedo of 1998 $\mathrm{SF}_{36}$ is high among S-type asteroids, and that the thermal inertia seems to be higher than that of average asteroids. From this we can say that the regolith thickness of this small asteroid is thin, and/or the surface is covered with bare rocks. We also obtained photometric and spectroscopic data in the $L$-band (3.77$\, {\mu \mathrm {m}}$). Since there is no clear absorption band seen around 3$\, {\mu \mathrm {m}}$, we estimate that the water abundance of the surface material is less than 1% in weight.
Meteoroid Clusters in Leonids: Evidence of Fragmentation in Space
Authors: Watanabe Jun-ichi , Tabe Isshi , Hasegawa Hitoshi , Hashimoto Takema , Fuse Tetsuharu , Yoshikawa Makoto , Abe Shinsuke , Suzuki Bunji 
Published: March 2014

Abstract
Three short-duration “outbursts”, in which more than 20–40 meteors appeared in a few seconds, have been reported during a recent Leonid storm. The meteors in these events were extremely localized within a few hundred km, which should be caused by clusters of meteoroids. The existence of such clusters indicates the fragmentation of meteoroids during orbital motion in interplanetary space. Considering the extent of the spatial distribution, the fragmentation should have occurred at around the perihelion passage of the meteoroids just before encountering the Earth. This may cause a possible enhancement of smaller meteoroids, even in old dust trails. A possible example of similar clusters in the past meteor storm of Giacobinids is also noted.
Chandra Observation of the Anomalous X-Ray Pulsar 1E 1841−045
Authors: Morii Mikio , Sato Rie , Kataoka Jun , Kawai Nobuyuki 
Published: March 2014

Abstract
We present the results from a Chandra ACIS CC mode observation of an anomalous X-ray pulsar (AXP) 1E 1841$-$045. This was the first observation in which the pulsar spectrum over a wide energy range was spatially discriminated from the surrounding SNR, Kes 73. Like other AXPs, the phase-integrated spectrum was fitted well with a power-law plus blackbody model. The spectral parameters are $\Gamma = 2.0 \pm 0.3$, $kT_\mathrm{BB} = 0.44 \pm 0.02 \,\mathrm{keV}$, and $N_\mathrm{H} = 2.54^{+0.15}_{-0.13} \times 10^{22} \,\mathrm{cm}^{-2}$. This photon index is the flattest among AXPs, and resembles soft gamma-ray repeaters (SGRs) in a quiescent state. The pulse profile is double-peaked, and we found that the second peak has a significantly hard spectrum. The spectra of all phases are consistent with a power-law plus blackbody model with a constant temperature and photon index. When fitted with a two-blackbody model, we obtained a similarly good fit. These results can be interpreted by saying that there are two emission regions with different energy spectra.
Morphological Butcher–Oemler Effect in the SDSS “Cut and Enhance” Galaxy Cluster Catalog
Authors: Goto Tomotsugu , Okamura Sadanori , Yagi Masafumi , Sheth Ravi K. , Bahcall Neta A. , Zabel Shane A. , Crouch Michael S. , Sekiguchi Maki , Annis James , Bernardi Mariangela , Chong Shang-Shan , GÓmez Percy L. , Hansen Sarah , Kim Rita S. J. , Knudson Adam , Mckay Timothy A. , Miller Christopher J. 
Published: March 2014

Abstract
We investigated the evolution of the fractions of late-type cluster galaxies as a function of redshift using one of the largest, most uniform cluster samples available. The sample consisted of 514 clusters of galaxies in the range of $0.02 \leq z\leq 0.3$ from the Sloan Digital Sky Survey “Cut and Enhance” galaxy cluster catalog. This catalog was created using a single automated cluster-finding algorithm applied to uniform data from a single telescope, with accurate CCD photometry, thus minimizing the selection biases. We used four independent methods to analyze the evolution of the late-type galaxy fraction. Specifically, we selected late-type galaxies based on each of the rest-frame $g-r$ color, the $u-r$ color, galaxy profile fitting, and the concentration index. The first criterion corresponds to that used in classical Butcher–Oemler analyses. The last two criteria are more sensitive to the morphological type of galaxies. In all four cases, we find an increase in the fraction of late-type galaxies with increasing redshift, significant at the 99.9% level. The results confirm that cluster galaxies do change colors with redshift (the Butcher–Oemler effect) and, in addition, they change their morphology to later-type toward a higher redshift — indicating a morphological equivalence of the Butcher–Oemler effect. We also found a tendency of richer clusters to have lower fractions of late-type galaxies. This trend is consistent with a ram-pressure stripping model, where galaxies in richer clusters are affected by stronger ram pressure due to the higher temperature of clusters.
Evolution of Dust-to-Metal Ratio in Galaxies
Authors: Inoue Akio K. 
Published: March 2014

Abstract
This paper investigates the evolution of the dust-to-metal ratio in galaxies based on a simple evolution model for the amount of metal and dust with infall. We take into account grain formation in stellar mass-loss gas, grain growth by the accretion of metallic atoms in a cold dense cloud, and grain destruction by SN shocks. Especially, we propose that the accretion efficiency is independent of the star-formation history. This predicts various evolutionary tracks in the metallicity ($Z$)–dust-to-gas ratio ($\mathcal{D}$) plane depending on the star-formation history. In this framework, the observed linear $Z \hbox{--} \mathcal{D}$ relation of nearby spiral galaxies can be interpreted as a sequence of a constant galactic age. We emphasize that an observational study of the $Z \hbox{--} \mathcal{D}$ relation of galaxies at $z\sim 1$ is very useful to constrain the efficiencies of dust growth and destruction. We also suggest that the Lyman break galaxies at $z\sim 3$ have a very low dust-to-metal ratio, typically $\lesssim 0.1$. Although the effect of infall on the evolutionary tracks in the $Z \hbox{--} \mathcal{D}$ plane is quite small, the dispersion of the infall rate can disturb the $Z \hbox{--} \mathcal{D}$ relation with a constant galactic age.
Where is a Marginally Stable Last Circular Orbit in Super-Critical Accretion Flow?
Authors: Watarai Ken-ya , Mineshige Shin 
Published: March 2014

Abstract
Impressed by a widespread misunderstanding of the issue, we return to the old question concerning the location of the inner edge of the accretion disk around a black hole. We recall the fundamental results obtained in the 1970’s and 1980’s by Warsaw and Kyoto research groups that proved, in particular, that the inner edge does not coincide with the location of the innermost stable Keplerian circular orbit. We give some novel illustrations of this particular point and of some other fundamental results obtained before. To investigate the flow dynamics of the inner edge of an accretion disk, we carefully solved the structure of the transonic flow and plotted the effective potential profile based on the angular-momentum distribution calculated numerically. We showed that the flow does not have a potential minimum for accretion rates, $\dot{M} \gtrsim 10 L_\mathrm{E} / c^2$ (with $L_\mathrm{E}$ being the Eddington luminosity and $c$ being the speed of light). This property is realized even for relatively small viscosity parameters (i.e., $\alpha \sim 0.01$), because of the effect of the pressure gradient. In conclusion, an argument based on the last circular orbit of a test particle cannot give a correct inner boundary of the super-critical flow, and the inner edge should be determined in connection with radiation efficiency. The same argument can apply to optically thin ADAF. The interpretation of the observed QPO frequencies should be re-considered, since the assumption of a Keplerian rotation velocity can grossly over–or underestimate the disk rotation velocity, depending on the magnitude of the viscosity.
Quasar Mesolensing—Direct Probe to Substructures around Galaxies
Authors: Yonehara Atsunori , Umemura Masayuki , Susa Hajime 
Published: March 2014

Abstract
Recently, a “CDM crisis” is being discussed. The main point of this crisis is that the number of substructures presented by cosmological $N$-body simulations based on the CDM scenario for structure formation is much larger than the observed substructures. Therefore, it is crucial for this crisis to discriminate whether the expected number of CDM substructures really exist without detectable radiation, or do not exist. In this paper, we present a new idea to detect such invisible substructures by utilizing gravitational lensing. Here, we consider quasars that are gravitationally lensed by a foreground galaxy. A substructure around a lensing galaxy may superposed on one of the lensed images of such quasars. In this situation, additional image splitting should occur in the image behind the substructure, and additional multiple images are created. From our estimations, the separation and time delay between the additional multiple images are expected to be $1 \hbox{--} 30$ milli-arcsecond and $1 \hbox{--} 10^3$ second, respectively. Furthermore, we evaluate that the optical depth for such events is $\sim 0.1$. Consequently, future fine-resolution imaging and/or high-speed monitoring will unable us to find invisible substructures in one of a few multiple quasars.
Magnetically Arrested Disk: an Energetically Efficient Accretion Flow
Authors: Narayan Ramesh , Igumenshchev Igor V. , Abramowicz Marek A. 
Published: March 2014

Abstract
We consider an accretion flow model originally proposed by Bisnovatyi-Kogan and Ruzmaikin (1974), which has been confirmed in recent 3D MHD simulations. In the model, the accreting gas drags in a strong poloidal magnetic field to the center such that the accumulated field disrupts the axisymmetric accretion flow at a relatively large radius. Inside the disruption radius, the gas accretes as discrete blobs or streams with a velocity much less than the free-fall velocity. Almost the entire rest mass energy of the gas is released as heat, radiation and mechanical/magnetic energy. Even for a non-rotating black hole, the efficiency of converting mass to energy is of order 50% or higher. The model is thus a practical analog of an idealized engine proposed by Geroch and Bekenstein.
Detection of Molecular Hydrogen Emission Associated with LkH$\alpha$ 264
Authors: Itoh Yoichi , Sugitani Koji , Ogura Katsuo , Tamura Motohide 
Published: March 2014

Abstract
We have detected the emission of molecular hydrogen from a classical T Tauri star, LkH$\alpha$ 264 in the $v= 1 \hbox{--} 0$ S(1) line at 2.122$\, {\mu \mathrm {m}}$. The line velocity is coincident with the rest velocity of the star. The line profile is well reproduced by a model in which the line emanates from material in a Keplerian rotating circumstellar disk. Fluorescence by X-ray ionization and shock excitation due to accretion or a low-velocity wind are considered for the emission mechanism of molecular hydrogen.
A Giant Flare on a T Tauri Star Observed at Millimeter Wavelengths
Authors: Furuya Ray S. , Shinnaga Hiroko , Nakanishi Kouichiro , Momose Munetake , Saito Masao 
Published: March 2014

Abstract
We have conducted multi-epoch synthesis imaging of $\lambda = 2$ and 3 millimeter (mm) continuum emission and near-infrared $K$-band (2.2$\, {\mu \mathrm {m}}$) imaging of a flare event in 2003 January that occurred on the young stellar object GMR-A, which is suggested to be a weak-line T Tauri star in the Orion cluster. Our mm data showed that the flare activity lasted for at least over 13 days, whereas the $K$-band magnitude did not change during this event. In addition, we have succeeded in detecting short time variations of flux on time scales of 15 minutes. The total energy of the flare is estimated to be $\sim 10^{35 \hbox{--} 36} \,\mathrm{erg}$, which makes it one of the most energetic flares reported to date. Comparing the mm continuum luminosities with reported X-ray luminosities, we conclude that the mm flare was similar in nature to solar and other stellar flares. Our results will be a crucial step toward understanding magnetically induced stellar surface activities in T Tauri stars.
Exploring Cluster Physics with High-Resolution Sunyaev-Zel’dovich Effect Images and X-Ray Data: The Case of the Most X-Ray-Luminous Galaxy Cluster RX J1347—1145
Authors: Kitayama Tetsu , Komatsu Eiichiro , Ota Naomi , Kuwabara Takeshi , Suto Yasushi , Yoshikawa Kohji , Hattori Makoto , Matsuo Hiroshi 
Published: March 2014

Abstract
Foreseeing the era of high spatial resolution measurements of the Sunyaev–Zel’dovich effect (SZE) in clusters of galaxies, we present a prototype analysis of this sort combined with Chandra X-ray data. It is applied specifically to RX J1347$-$1145 at $z=0.451$, the most X-ray-luminous galaxy cluster known, for which the highest resolution SZE and X-ray images are currently available. We demonstrate that the combined analysis yields a unique probe of complex structures in the intracluster medium, offering determinations of their temperature, density, and line-of-sight extent. For a subclump in RX J1347$-$1145, previously discovered in our SZE map, the temperature inferred after removing the foreground and background components is well in excess of 20 keV, indicating that the cluster has recently undergone a violent merger. Excluding the region around this subclump, the SZE signals in submillimeter to centimeter bands (350, 150, and 21 GHz) are all consistent with those expected from Chandra X-ray observations. We further present a temperature deprojection technique based on the SZE and X-ray images, without any knowledge of spatially resolved X-ray spectroscopy. The methodology presented here will be applicable to a statistical sample of clusters available in the future SZE surveys.