bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Discovery of Two Lyman α Emitters beyond Redshift 6 in the Subaru Deep Field,
Authors: Kodaira Keiichi , Taniguchi Yoshiaki , Kashikawa Nobunari , Kaifu Norio , Ando Hiroyasu , Karoji Hiroshi , Ajiki Masaru , Akiyama Masayuki , Aoki Kentaro , Doi Mamoru , Fujita Shinobu S. , Furusawa Hisanori , Hayashino Tomoki , Imanishi Masatoshi , Iwamuro Fumihide , Iye Masanori , Kawabata Koji S. , Kobayashi Naoto , Kodama Tadayuki , Komiyama Yutaka , Kosugi George , Matsuda Yuichi , Miyazaki Satoshi , Mizumoto Yoshihiko , Motohara Kentaro , Murayama Takashi , Nagao Tohru , Nariai Kyoji , Ohta Kouji , Ohyama Youichi , Okamura Sadanori , Ouchi Masami , Sasaki Toshiyuki , Sekiguchi Kazuhiro , Shimasaku Kazuhiro , Shioya Yasunori , Takata Tadafumi , Tamura Hajime , Terada Hiroshi , Umemura Masayuki , Usuda Tomonori , Yagi Masafumi , Yamada Toru , Yasuda Naoki , Yoshida Michitoshi 
Published: March 2014

Abstract
We performed a deep optical imaging survey using a narrow-band filter (NB921) centered at $\lambda = 9196 \,$Å together with $i^\prime$ and $z^\prime$ broadband filters covering an $814 \,\mathrm{arcmin}^2$ area of the Subaru Deep Field. We obtained a sample of 73 strong NB921-excess objects based on the following two color criteria:$z^\prime-\mathit{NB}\,921 \gt 1$$z^\prime-\mathit{NB}\,921 \gt 1$ and $i^\prime-z^\prime \gt 1.3$$i^\prime-z^\prime \gt 1.3$. We then obtained optical spectroscopy of nine objects in our NB921-excess sample, and identified at least two Ly$\alpha$ emitters at $z=6.541 \pm 0.002$ and $z=6.578 \pm 0.002$, each of which shows the characteristic sharp cutoff together with continuum depression at wavelengths shortward of the line peak. The latter object is more distant than HCM-6A at $z=6.56$, which is the most distant known object that has been found so far. These new data allow us to estimate the first meaningful lower limit of the star-formation rate density beyond redshift 6; $\rho_\mathrm{SFR} \sim 5.2 \times 10^{-4} \,{{{M}_{\odot}}} \,\mathrm{yr}^{-1} \,\mathrm{Mpc}^{-3}$. Since it is expected that the actual density is several times higher than this value, our new observation reveals that a moderately high level of star formation activity already occurred at $z \sim 6.6$.
Unusual Phase Reversal of Superhumps in ER Ursae Majoris
Authors: Kato Taichi , Nogami Daisaku , Masuda Seiji 
Published: March 2014

Abstract
We studied the evolution of superhumps in the peculiar SU UMa-type dwarf nova, ER UMa. Contrary to the canonical picture of the SU UMa-type superhump phenomena, the superhumps of ER UMa show an unexpected phase reversal during the very early stage ($\sim 5 \,\mathrm{}$d after the superoutburst maximum). We interpret that a sudden switch to so-called late superhumps occurs during the very early stage of a superoutburst. What had been believed to be (ordinary) superhumps during the superoutburst plateau of ER UMa were actually late superhumps. The implication of this discovery is briefly discussed.
Twin Peaks of the 2002 Leonid Meteor Storm Observed in the Leonid MAC Airborne Mission
Authors: Abe Shinsuke , Yano Hajime , Ebizuka Noboru , Sugimoto Masatoshi , Kasuga Toshihiro , Watanabe Jun-ichi 
Published: March 2014

Abstract
During the Leonid MAC 2002 airborne mission, we carried out a wide-field TV observation of the strong activity of the Leonid meteor shower from 03h30m UT through 11h50m UT on 2002 November 19. Two narrow peaks of the storm activities were observed at around 04h03m UT and 10h49m UT, with peak influx rates ($\mbox{mag} \leq +6.5$ mag$\leq +6.5$) of $1.63 \times 10^{-5} \,\mathrm{km}^{-2} \,\mathrm{s}^{-1}$ and $1.95 \times 10^{-5} \,\mathrm{km}^{-2} \,\mathrm{s}^{-1}$, respectively. Even in the full-Moon condition, the activity level of these twin peaks were comparable to that of the storm observed in 2001 over Japan. The first peak activity generated by the 7-revolution-old dust trail (ejection in 1767) was rich in bright meteors, including the fireball-class, compared to the second peak corresponding to the 4-revolution-old dust trail (ejection in 1866). The magnitude distribution indices ($-2.5 \leq$ mag$\leq +3.5$) were $1.70 \pm 0.10 $ in the first peak (7-rev) and $2.03 \pm 0.05$ in the second peak (4-rev). The correlation between the observed peaks and several theoretical predictions is discussed.
Infant Galaxy Clusters at Low Redshifts?
Authors: Fujita Yutaka 
Published: March 2014

Abstract
The population and population composition of galaxies in galaxy clusters at present reflect the mass of the clusters and the mass growth of the galaxies in the past. We investigated them for six clusters. We showed that galaxies in massive clusters stopped growing at redshifts of $\sim 4$. Moreover, we found that some small galaxy clusters (groups) have too many massive galaxies for their apparent masses. One possibility is that these groups are much more massive and in a phase just before virialization. If this is the case, they should be called ‘infant galaxy clusters’ that will mature in the dynamical time-scale ($\sim 10^9 \,\mathrm{yr}$).
Accretion Rates and the Accretion Efficiency in AGNs
Authors: Bian Wei-Hao , Zhao Yong-Heng 
Published: March 2014

Abstract
We used the standard geometrical-thin accretion theory to obtain the accretion rates in Seyfert 1 galaxies and quasars. Combining the accretion rates with the bolometric luminosity, we obtained the accretion efficiency. We found that most Seyfert 1 galaxies and radio-quiet quasars have lower accretion efficiencies, while most radio-loud quasars possess higher accretion efficiencies. This finding further implies that most of the radio-loud quasars possess Kerr black holes, while Seyfert 1 galaxies and radio-quiet quasars may not possess Kerr black holes. Considering the difference in the accretion efficiency, we found that there is a strong correlation between the accretion rate in units of the Eddington accretion rate and the width of the $\mathrm{H}\beta$ emission line, and that most AGNs are not accreting at super-Eddington rates.
Iron Line Properties of the Seyfert 1 Galaxy MCG $-$ 6-30-15 Observed with ASCA
Authors: Matsumoto Chiho , Inoue Hajime , Fabian Andrew C. , Iwasawa Kazushi 
Published: March 2014

Abstract
We analyzed the data sets of three long observations of the Seyfert 1 galaxy MCG$-$6-30-15 performed with ASCA. We firstly confirmed the common presence of a broad and skewed feature (the so-called disk-line) in the average spectra of the three observations (namely, on a time scale of several times $10^{5} \,\mathrm{s}$). We then investigated the variability of the line flux and the profile on a time scale of $2 \times 10^4 \,\mathrm{s}$, approximating the profile with a double-Gaussian model: a relatively broad line at 5.5 keV (Red line) and a relatively narrow line at 6.4 keV (Blue line). The variability of the Red line is rather larger than that of the continuum flux in some cases; on the other hand, the equivalent width of the Blue line is not rejected to be constant in some cases. No significant correlation between the Red line flux and the Blue line flux is observed. We also evaluated the RMS variability (the standard deviation normalized by the mean) in 15 energy bands on various time-bin-widths using the longest data in 1999. We found that the RMS variability is reduced in the 5.0–6.6 keV band, and that the degree of the depression is more significant on the longer time-bin-width.
ASTRO-F/FIS Observing Simulation: Detection Limits for Point Sources
Authors: Jeong Woong-Seob , Pak Soojong , Lee Hyung Mok , Nakagawa Takao , Sohn Jungjoo , Ahn Insun , Yamamura Issei , Watanabe Masaru , Kawada Mitsunobu , Shibai Hiroshi 
Published: March 2014

Abstract
We describe the observing simulation software FISVI (FIS Virtual Instrument), which was developed for the Far-Infrared Surveyor (FIS) that will be on the Japanese infrared astronomy mission ASTRO-F. The FISVI has two purposes: one is to check the specifications and performances of the ASTRO-F/FIS as a whole; the other is to prepare input data sets for the data analysis softwares prior to launch. In the FISVI, special care was taken by introducing the “Compiled PSF (Point Spread Function)” to optimise inevitable, but time-consuming, convolution processes. With the Compiled PSF, we reduce the computation time by an order of magnitude. The photon and readout noises are included in the simulations. We estimate the detection limits for point sources from the simulation of virtual patches of the sky mostly consisting of distant galaxies. We studied the importance of source confusion for simple power-law models for $N (\gt S)$, the number of sources brighter than $S$. We found that source confusion plays a dominant role in the detection limits only for models with rapid luminosity evolution for the galaxy counts, the evolution of which is suggested by recent observations.
Are Two z ∼ 6 Quasars Gravitationally Lensed?
Authors: Yamada Sanae F. , Shioya Yasuhiro , Taniguchi Yoshiaki , Murayama Takashi , Ajiki Masaru , Nagao Tohru , Fujita Shinobu S. , Umeda Kazuyoshi , Komiyama Yutaka , Karoji Hiroshi , Ando Hiroyasu , Iye Masanori , Kashikawa Nobunari , Kodaira Keiichi 
Published: March 2014

Abstract
Several high-$z$ ($z \gt 5.7$) quasars have been found during the course of Sloan Digital Sky Survey. The presence of such very high-$z$ quasars is expected to put constraints on early structure formation. On one hand, it is suggested that these most luminous objects at high redshift are biased toward highly magnified objects by gravitational lensing. To clarify the effect of gravitational lensing on high-$z$ quasars, we began an imaging survey of intervening lensing galaxies. Indeed, our previous optical image showed that SDSSp J104433.04$+$012502.2 at $z = 5.74$ is gravitationally magnified by a factor of 2. In this paper, we report our new optical imaging of two other high-$z$ quasars, SDSSp J103027.10$+$052455.0 at $z=6.28$ and SDSSp J130608.26$+$035626.3 at $z=5.99$. Since we found neither an intervening galaxy nor a counter image with $i^{\prime} &lt; 25.4 \hbox{--} 25.8$ around each quasar, we conclude that they are not strongly magnified regardless that a lens galaxy is dusty.
The Environment of Passive Spiral Galaxies in the SDSS
Authors: Goto Tomotsugu , Okamura Sadanori , Sekiguchi Maki , Bernardi Mariangela , Brinkmann Jon , GÓmez Percy L. , Harvanek Michael , Kleinman Scot J. , Krzesinski Jurek , Long Dan , Loveday Jon , Miller Christopher J. , Neilsen Eric H. , Newman Peter R. , Nitta Atsuko , Sheth Ravi K. , Snedden Stephanie A. , Yamauchi Chisato 
Published: March 2014

Abstract
In previous work on galaxy clusters, several authors reported the discovery of an unusual population of galaxies, which have spiral morphologies, but do not show any star-formation activity. These galaxies are called “passive spirals”, and have been interesting since it has been difficult to understand the existence of such galaxies. Using a volume-limited sample ($0.05 &lt; z &lt; 0.1$ and $M_{r^{*}} &lt;-20.5$; 25813 galaxies) of the Sloan Digital Sky Survey data, we found 73 ($0.28 \pm 0.03\%$) passive spiral galaxies and studied their environments. It is found that passive spiral galaxies exist in a local galaxy density of $1 \hbox{--} 2 \,\textrm{Mpc}^{-2}$ and have a 1–10 cluster-centric virial radius. Thus, the origins of passive spiral galaxies are likely to be cluster-related. These characteristic environments coincide with a previously reported environment where the galaxy star-formation rate suddenly declines and the so-called morphology-density relation turns. It is likely that the same physical mechanism is responsible for all of these observational results. The existence of passive spiral galaxies suggests that a physical mechanism that works calmly is preferred to dynamical origins such as major merger/interaction since such a mechanism would destroy the spiral-arm structures. Compared with the observed cluster galaxy evolution such as the Butcher-Oemler effect and the morphological Butcher-Oemler effect, passive spiral galaxies are likely to be a key galaxy population in transition between red, elliptical/S0 galaxies in low-redshift clusters and blue, spiral galaxies more numerous in higher-redshift clusters.
Spatial and Temporal Extent of Solar Nanoflares and Their Energy Range
Authors: Katsukawa Yukio 
Published: March 2014

Abstract
Coronal X-ray emission observed with the Yohkoh Soft X-ray Telescope (SXT) fluctuates with an amplitude larger than the Poisson photon noise, as shown in our previous paper (Katsukawa, Tsuneta 2001, ApJ, 557, 343). This fluctuation is attributed to small energy events (“nanoflares”) that cannot be identified as individual bursts. We present here a detailed analysis of the fluctuation, particularly concerning the spatial and temporal extents of the fluctuating sources. A macro-pixel analysis of the intensity fluctuation reveals that the spatial extent of the fluctuation is a few pixels of SXT. The scale size may be due to the point-spread function of SXT, and/or indicates the intrinsic size of the fluctuating source. An auto-correlation analysis gives a loose upper limit of the time scale, 1 minute. Taking into account the spatial and temporal scales, the energy of nanoflares estimated in the previous paper is updated to be $10^{20}$ to $10^{22} \,\mathrm{erg}$.
Sixteen-Color Photometry of Galaxy Cluster Abell 566
Authors: Zhou Xu , Arimoto Nobuo , Tanaka Ichi , Jiang Zhaoji , Chen Jiansheng 
Published: March 2014

Abstract
We present a complete set of 16 color photometric observations in the Beijing-Arizona-Taipei-Connecticut (BATC) filter system for a cluster of galaxy Abell 566 at redshift $z \simeq 0.1$. From $2 \,\mathrm{k} \times 2 \,\mathrm{k}$ CCD images, over 10000 objects have been detected in field of $58' \times 58'$ down to $V \sim 20 \,\mathrm{mag}$ with a good completeness level. By aperture photometric measurements, we obtained spectral energy distributions (SEDs) that cover the wavelengths from 300 nm to 1000 nm of all of the detected objects, including 561 cluster member candidates selected by the method of photometric redshift. The special location of these galaxies in color-color diagrams show a possibility for our method involving member galaxy selection. From the selected member galaxies, we find that the number density of early-type galaxies is much higher in the central region of the cluster than late-type galaxies.
XMM-Newton Observation of the Cluster of Galaxies Abell 1650
Authors: Takahashi Seiji , Yamashita Koujun 
Published: March 2014

Abstract
We present the nonuniform distribution of temperature and abundance in the angular extent of $10 {{}^{\prime }}$ (1.4 Mpc) in A1650 observed by XMM-Newton. Spectral analysis was carried out in 19 systematically-subdivided regions, and in 15 specified regions referred to the hardness ratio ($\mathit{HR}$) map. The value of $\mathit{HR}$, defined as the ratio of counts in the 1.6–10 keV band to those in the 0.8–1.6 keV, is an indicator to investigate the spatial variation of spectral features. The temperature and abundance were obtained to be 4–6 keV and 0.2–0.5 solar value with average values of $5.62^{+0.05}_{-0.07} \,\mathrm{keV}$ and $0.36^{+0.02}_{-0.01}$ solar value within a radius of $5 {{}^{\prime }}$, respectively. The redshift was derived to be $8.01^{+0.02}_{-0.02} \times 10^{-2}$ against an optical value of $8.45\times 10^{-2}$. It turned out that cool regions with a temperature of around 4 keV and a scalelength of a few 100 kpc are patchily distributed in the outer envelope. This temperature structure could be explained by the infalling of groups of galaxies into the cluster main body. More than 30 point sources were found around A1650 in the FOV of $30 {{}^{\prime }}$. The spectrum of the Galactic diffuse emission was obtained in the outskirts of A1650.
Eruptive and Quasi-Eruptive Disappearing Solar Filaments and Their Relationship with Coronal Activities
Authors: Morimoto Taro , Kurokawa Hiroki 
Published: March 2014

Abstract
By measuring the 3-D velocity fields of 35 disappearing filaments (Disparition Brusques: DBs) on the solar disk, we studied the causal relationship between the motions of $\mathrm{H}\alpha$ DBs and the associated coronal phenomena. Using the derived 3-D velocity fields of the DBs, we developed a method to judge whether a DB is ejected into interplanetary space or whether it remains in the solar atmosphere. We compared the DB type thus obtained with the presence of coronal mass ejections (CMEs) and other associated coronal activities. It is inferred that eruptive filaments are always followed by the formation of arcades, while most quasi-eruptive events are followed by localized changes in soft X-rays and the EUV. A close causal relation between eruptive filaments and CMEs was also found: of 15 DBs for which Solar and Heliospheric Observatory Large Angle and Spectrometric Coronagraph data were available, all eight of the eruptive ones were associated with CMEs, while no CMEs were found following any of the 7 quasi-eruptive ones. These observational results indicate that the motions of $\mathrm{H}\alpha$ disappearing filaments are causally related to the associated coronal activities and also to the appearance of CMEs, and that an accurate analysis of their 3-D velocities is important not only for a better understanding of their acceleration and heating mechanisms, but also for predicting the occurrence of CMEs and geomagnetic storms.
On the Symmetric Collinear Four-Body Problem
Authors: Sekiguchi Masayoshi , Tanikawa Kiyotaka 
Published: March 2014

Abstract
The global geometry of the phase structure in a special case of the general Newtonian four-body problem was studied both analytically and numerically in the case of negative energy. Our method consists of blow-up of total collision by McGehee’s coordinates. and representation of orbits by symbol sequences. The analytical study for arbitrary masses clarifies the macroscopic behavior in phase space: escape motion, vortical motion around vertical lines along which the escape motion occurs, and vertical convective flow. We numerically examined a distribution of the symbol sequences on a surface of section in the case of equal masses. The result has clarified that there never exist orbits whose symbol sequences contain special words: un-realizable words. On the other hand, the existence of oscillatory motions are shown under a reasonable assumption. We semi-analytically obtained the initial conditions leading to escape using escape criteria established in the present study. Additionally, we established a way to find the fastest capture-escape orbits, the ejection-collision orbits besides the homothetic solution, the capture-collision orbits, and the ejection-escape orbits. Moreover, quasi-periodic orbits containing a Schubart-like orbit, and unstable periodic orbits were found. The result displays a similarity between the symmetric collinear four-body problem and the collinear three-body problem.
Pre-Processing of Galaxies before Entering a Cluster
Authors: Fujita Yutaka 
Published: March 2014

Abstract
We consider several mechanisms that possibly affect the evolution of disk galaxies in clusters using analytical models based on a hierarchical clustering scenario. We especially focus on the evolution of disk galaxies in subclusters located around a main cluster. We show that ram-pressure stripping cannot be always ignored in subclusters, although their masses are much smaller than that of the main cluster. The star-formation rate of a galaxy may gradually decrease by the stripping of warm gas (‘strangulation’) in a main cluster. However, we find that ram-pressure stripping could start before the strangulation is completed, if a field galaxy directly falls into the main cluster. Since this conflicts with some recent observations, many galaxies might have been affected by some environmental effects when they were in subclusters before they fell into the main cluster (‘pre-processing’). We show that strangulation and evaporation of the cold gas by the surrounding hot ICM in subclusters are the possible candidates. We also show that the observed morphological transformation of disk galaxies at $z\lesssim 1$ is not chiefly due to galaxy mergers.
Wide-Area Mapping of 155 Micron Continuum Emission from the Orion Molecular Cloud Complex
Authors: Arimura Seikoh , Shibai Hiroshi , Teshima Takafumi , Nakagawa Takao , Narita Masanao , Makiuti Shin’itirou , Doi Yasuo , Verma Ram Prakash , Ghosh Swarna Kanti , Rengarajan Thinnian Naganathan , Tanaka Makoto , Okuda Haruyuki 
Published: March 2014

Abstract
We present the results of a wide-area mapping of the far-infrared continuum emission toward the Orion complex by using a Japanese balloon-borne telescope. The 155-$\, {\mu \mathrm {m}}$ continuum emission was detected over a region of $1.5 \,\mathrm{deg}^2$ around the KL nebula with ${3{}^{\mathrm {\prime }}}$ resolution similar to that of the IRAS 100-$\, {\mu \mathrm {m}}$ map. Assuming a single-temperature model of the thermal equilibrium dust, maps of the temperature and the optical thickness were derived from the 155-$\, {\mu \mathrm {m}}$ intensity and the IRAS 100-$\, {\mu \mathrm {m}}$ intensity. The derived dust temperature is 5–15 K lower and the derived dust optical depth is 5–300 times larger than those derived from the IRAS 60 and 100-$\, {\mu \mathrm {m}}$ intensities due to the significant contribution of the statistically heated very small grains to the IRAS 60-$\, {\mu \mathrm {m}}$ intensity. The optical-thickness distribution shows a filamentary dust ridge that has a ${1\rlap {.}{}^{\mathrm {\circ }}5}$ extent in the north-south direction and well resembles the Integral-Shaped Filament (ISF) molecular gas distribution. The gas-to-dust ratio derived from the CO molecular gas distribution along the ISF is in the range 30–200, which may be interpreted as being an effect of CO depletion due to the photodissociation and/or the freezing on dust grains.
Formation of Opposite-Sign Magnetic Helicity by an Erupting Filament in a Coronal Mass Ejection
Authors: Liu Yu , Kurokawa Hiroki 
Published: March 2014

Abstract
It is unclear whether it is possible for magnetic helical fields of opposite signs to co-exist in a coronal mass ejection (CME). During filament eruption with high-cadence observations for the initial stage, evidence is found for the formation of right-handed helical fields in a rising dextral filament that is embedded in a CME with helical fields in a left-handed sense. The data include Mees multi-off-band $\mathrm{H}\alpha$ observations with 16 s cadence and TRACE 1600 Å observations of 2 s cadence. The filament material is ejected outward and is associated with the expanding CME, suggesting that both of the opposite-sign helical fields are injected into interplanetary space. In this paper, we consider the key observational features, including the formation of a coil-like structure (due to barb reconnections) and the alignment of reconnected field lines with the primary axis of the filament. It is found that they are consistent with the predicted changes during filament eruption by the filament model of Martin and McAllister. However, our results do not reject the filament model of Rust and Kumar. Moreover, a model that reconciles both of them seems to be more convenient for understanding the complicated observations. Therefore, the formation of opposite-sign helicity in an eruptive flux rope should be common for such types of filament eruptions.