bluuebunny/crossref_metadata_2025 huggingface dataset:
Log-Normal Distributions in Cygnus X-1: Possible Physical Link with Gamma-Ray Bursts and Blazars
Authors: Negoro Hitoshi , Mineshige Shin
Published: March 2014

Prompted by recent discoveries of log-normal distributions in gamma-ray/X-ray temporal variabilities of gamma-ray bursts (GRBs) and blazars, we re-examine the X-ray variability of Cygnus X-1 in the hard/low state using Ginga data in 1990. It was previously reported that the distributions of the time intervals between X-ray shots (flares) deviated from the Poisson distributions at short time intervals: the occurrence of shots tended to be suppressed for several seconds before and/or after a shot event. Detailed analyses show that this deviation is larger for shots with larger peaks, and that the time-interval distributions for large shots approach log-normal distributions with a peak at the interval of 7–8 s. Furthermore, we also show that the peak-intensity distribution for the shots is consistent with the log-normal distribution, though no typical peak intensity can be seen. This might indicate the presence of a physical link connecting the physics of black hole accretion flow and that of jet/GRB formation.
Lagrangian Statistical Theory of Anisotropic MHD Turbulence
Authors: Nakayama Kunji
Published: March 2014

We construct a Lagrangian statistical theory of spatially uniform, anisotropic, and strong turbulence of an incompressible magneto-fluid with a uniform mean magnetic field. We treat shear Alfvén turbulence; that is, the perturbations of the velocity field and the magnetic field are assumed to be orthogonal to the mean magnetic field. The perturbation energies, however, need not be equiparted; our theory covers non-equipartition turbulence as well as equipartition turbulence. We show that, concerning the relaxation and energy-transfer of inertial-range eddies, the shear Alfvén turbulence has the following fundamental properties: That is, relaxation of inertial-range eddies is dominated by the largest (energy-containing) eddies; energy cascades have spatially a quasi 2-dimensional nature because of the inhibition of cascades parallel to the mean field; thus, inevitably, the $-3/2$ power-law energy-spectra are derived. These properties are independent of whether the turbulence satisfies the energy equipartition. We, therefore, assert that they should be thought of as generic and robust natures of strong MHD turbulence.
Approximate Orbits of Ancient and Medieval Comets
Authors: Hasegawa Ichiro
Published: March 2014

This is one of our reports in a continuing series of papers providing orbital elements for ancient and medieval comets recorded in histories. Newly determined orbital elements and calculated paths of comets with translated records are presented for ten comets found in East Asian histories. The distributions of the small perihelion distance and the close geocentric distance of bright naked-eye comets are discussed. Those orbital characteristics given in this paper are fundamentals, and will be useful for further studies of comets.
Subaru Prime Focus Camera — Suprime-Cam
Authors: Miyazaki Satoshi , Komiyama Yutaka , Sekiguchi Maki , Okamura Sadanori , Doi Mamoru , Furusawa Hisanori , Hamabe Masaru , Imi Katsumi , Kimura Masahiko , Nakata Fumiaki , Okada Norio , Ouchi Masami , Shimasaku Kazuhiro , Yagi Masafumi , Yasuda Naoki
Published: March 2014

We have built an 80-mega pixels ($10240 \times 8192$) mosaic CCD camera, called Suprime-Cam, for the wide-field prime focus of the 8.2 m Subaru telescope. Suprime-Cam covers a field of view $34' \times 27'$, a unique facility among the 8–10 m class telescopes, with a resolution of ${0\rlap {.}{}^{\mathrm {\prime \prime }}202}$ per pixel. The focal plane consists of ten high-resistivity $2\mathrm{k} \times 4\mathrm{k}$ CCDs developed by MIT Lincoln Laboratory, which are cooled by a large Stirling-cycle cooler. The CCD readout electronics was designed to be scalable, which allows the multiple read-out of tens of CCDs. It takes 50 seconds to readout entire arrays. We designed a filter-exchange mechanism of the jukebox type that can hold up to ten large filters ($205\times 170 \times 15 \,\mathrm{mm}^3$). The wide-field corrector is basically a three-lens Wynne-type, but has a new type of atmospheric dispersion corrector. The corrector provides a flat focal plane and an un-vignetted field of view of $30'$ in diameter. The achieved co-planarity of the focal array mosaic is smaller than 30$\,{\mu \mathrm {m}}$ peak-to-peak, which realizes mostly the seeing limited image over the entire field. The median seeing in the $I_\mathrm{c}$-band, measured over one year and a half, is ${0\rlap {.}{}^{\mathrm {\prime \prime }}61}$ . The PSF anisotropy in Suprime-Cam images, estimated by stellar ellipticities, is about 2% under this median seeing condition. At the time of commissioning, Suprime-Cam had the largest survey speed, which is defined as the field of view multiplied by the primary mirror area of the telescope, among those cameras built for sub-arcsecond imaging.
Near-Infrared Coronagraphy of the GG Tauri A Binary System
Authors: Itoh Yoichi , Tamura Motohide , Hayashi Saeko S. , Oasa Yumiko , Fukagawa Misato , Kaifu Norio , Suto Hiroshi , Murakawa Koji , Doi Yoshiyuki , Ebizuka Noboru , Naoi Takahiro , Takami Hideki , Takato Naruhisa , Gaessler Wolfgang , Kanzawa Tomio , Hayano Yutaka , Kamata Yukiko , Saint-Jacques David , Iye Masanori
Published: March 2014

The highest angular resolution near-infrared images of the GG Tau A binary system were obtained with the Coronagraphic Imager with Adaptive Optics (CIAO) mounted on the Subaru Telescope. The images show that its circumbinary disk is smooth and does not have ${0\rlap {.}{}^{\mathrm {\prime \prime }}1}$ scale structures. Asymmetries in the surface brightness as well as a gap are also resolved. Combined with previous measurements of the stellar positions, our data indicate that the central binary is unlikely to have a large eccentricity. The fifth point source toward this double binary system is probably a background star, based on astrometric measurements.
WZ Sge-Type Star V592 Herculis
Authors: Kato Taichi , Uemura Makoto , Matsumoto Katsura , Kinnunen Timo , Garradd Gordon , Masi Gianluca , Yamaoka Hitoshi
Published: March 2014

We observed the entire course of the 1998 outburst of V592 Her, which was originally reported as a nova in 1968. We have been able to construct a full light curve of the outburst, which is characterized by a rapid initial decline ($0.98 \,\mathrm{mag} \,\mathrm{d}^{-1}$), which smoothly developed into a plateau phase with a slower linear decline. We detected superhumps characteristic to SU UMa-type dwarf novae $\sim 7 \,\mathrm{d}$ after the optical maximum. The overall behavior of the light curve and the development of superhumps were characteristic to a WZ Sge-type dwarf nova. Combined with the past literature, we have been able to uniquely determine the superhump period to be 0.05648(2) d. From this period, together with a modern interpretation of the absolute magnitude of the outburst light curve, we conclude that the overall picture of V592 Her is not inconsistent with a lower main-sequence secondary star, in contrast to a previous claim that V592 Her contains a brown dwarf.
Dense Shell around a Young Intermediate-Mass Star: NGC 2264 IRS 1
Authors: Nakano Makoto , Sugitani Koji , Morita Koh-Ichiro
Published: March 2014

The results of $\mathrm{H}{{13\atop} \mathrm{CO}}^{+}$$J = 1 \hbox{--} 0$ line and 93-GHz continuum observations of NGC 2264 IRS 1, a luminous infrared source known as Allen$^\prime$s source, are reported. IRS 1 is a young intermediate-mass star with a surrounding YSO cluster, and is associated with a molecular outflow. High angular resolution interferometric observations were performed using the Nobeyama Millimeter Array, and mapping observations were conducted using a 45-m telescope. The continuum map reveals four sources, three of which correspond to a submillimeter source detected by Ward-Thompson et al. (2000, AAA 73.137.062). Four compact clumps are also observed in the $\mathrm{H}{{13\atop} \mathrm{CO}}^{+}$ map, two of which are associated with these millimeter / submillimeter continuum sources without bipolar outflow. These $\mathrm{H}{{13\atop} \mathrm{CO}}^{+}$ clumps as a whole form an incomplete dense shell of 0.12 pc in diameter around IRS 1, and the outer part of the shell is clearly traced on the single-dish map. The shell, or cavity, structure suggests that the outflow from IRS 1 has evacuated part of the surrounding envelope in $\sim 0.1 \,\mathrm{Myr}$. The kinematic properties can be interpreted as being two clumps of entrained or compressed material derived from steady outflow. It is concluded that the activity of IRS 1 may have triggered the formation of cluster members in the dense surrounding shell.
Three-Dimensional Distribution of the ISM in the Milky Way Galaxy: I. The H i Disk
Authors: Nakanishi Hiroyuki , Sofue Yoshiaki
Published: March 2014

We derived the three-dimensional distribution of H i gas in the Milky Way Galaxy using the latest H i survey data cubes and rotation curves. The distance of the H i gas was determined by the kinematic distance using a rotation curve. We solved the near-far problem in the inner Galaxy by a fitting method which involves introducing a model of vertical H i distribution. In our resultant maps we could trace three prominent arms: the Sagittarius-Carina arm, the Perseus arm, and the Outer arm. These three arms were found to be logarithmic spiral arms. The pitch angles of the Sagittarius–Carina, Perseus, and Outer arms were estimated to be about ${11{}^{\mathrm {\circ }}}$,${18{}^{\mathrm {\circ }}}$, and ${7{}^{\mathrm {\circ }}}$, respectively. The Sun is located in a region rich in H i gas between the Sagittarius–Carina arm and the Perseus arm. The H i disk shows large and asymmetric warping in the outer disk: the H i disk goes up to about 1.5 kpc above the Galactic plane in the northern hemisphere, and down to about 1 kpc in the southern hemisphere, which means asymmetric warping. The inner H i disk is also found to be tilting. The radius of the H i disk is about 17 kpc and the H i mass within this radius is estimated to be $2.5 \times 10^9\,{{{M}_{\odot}}}$, which corresponds to 1.5% of the dynamical mass predicted from the rotation curve. We also found that the H i outskirt is largely swelling in the fourth quadrant, and hence the Galaxy is significantly lopsided. The scale-height of the H i layer increases with the radius, and is correlated with the H i volume density at the centroid of the H i layer.
The Recurrent Nova U Scorpii in the 1999 Outburst: the First Detection of a Significant Orbital-Period Change
Authors: Matsumoto Katsura , Kato Taichi , Hachisu Izumi
Published: March 2014

In this paper we present and discuss our time-resolved photometry of an eclipsing recurrent nova, U Sco, during an outburst in 1999, which was conducted from immediately after the optical maximum to the final fading toward the quiescence. In the first-ever complete light-curve, a few primary and secondary eclipses of the binary system were detected, and the timings of the minima were determined. We found that the eclipses showed no totality during the outburst. The depth of the primary eclipses was 0.4–0.8 mag, much shallower than that in quiescence. In the plateau phase, very little irradiation ($\leq 0.1 \,\mathrm{mag}$) was observed in the orbital light curve, which implies the existence and a large flaring rim of the accretion disk during the outburst. The minima of the eclipses were detected at earlier orbital phases for the predicted ephemerides. Thus, we obtained an orbital period change of the binary system as $\dot{P}/P =-1.7 (\pm 0.7) \times 10^{-6} \,\mathrm{yr}^{-1}$ from the $O-C$. Assuming that this period change is a result of the conservative mass transfer between the component stars, its mass-transfer rate reaches $\dot{M} = 2.4 (\pm 1.0) \times 10^{-6} \,{{{M}_{\odot}}} \,\mathrm{yr}^{-1}$ for a $1.37 \,{{{M}_{\odot}}}$ white dwarf and a $2.0 \,{{{M}_{\odot}}}$ mass-donor companion, which is too high to cause shell flashes, even on a massive white dwarf. Therefore, this large rate of the period change strongly indicates a non-conservative mass transfer in the binary system.
ATCA Monitoring Observations of 202 Compact Radio Sources in Support of the VSOP AGN Survey
Authors: Tingay Steven J. , Jauncey David L. , King Edward A. , Tzioumis Anastasios K. , Lovell James E. J. , Edwards Philip G.
Published: March 2014

The Australia Telescope Compact Array (ATCA) has been used in support of the VLBI Space Observatory Programme (VSOP) space VLBI mission, to monitor the total and polarised flux densities of 202 objects that make up 83% of the VSOP all-sky Survey of compact extragalactic radio sources south of $\delta=+10^{\circ}$. The primary goal of the ATCA observations is to provide information on the total and polarised emission from the compact components in these sources, for correlation with parameters obtained from VSOP imaging observations. These data represent the first high resolution, long timescale flux density monitoring observations of a large number of southern compact radio sources. In the future, comparison of the ATCA and VSOP data will be used to investigate relativistic beaming models and identify similarities or differences between the major classes of extragalactic radio sources. As an illustration of the scientific value of the ATCA data we undertake a comparison of the properties of the gamma-ray loud and gamma-ray quiet AGN in the southern component of the VSOP Survey sample, finding that in a flat-spectrum sub-sample the gamma-ray loud AGN are more variable than the gamma-ray quiet AGN.
On the Stationarity of a Spiral Structure in Disk Galaxies
Authors: Yano Taihei , Kan-ya Yukitoshi , Gouda Naoteru
Published: March 2014

We investigate whether a spiral arm in disk galaxies can possibly be stationary, assuming that the spiral structure is some pattern formed by a density wave. We numerically calculated stellar orbits in assumed galactic potentials with spiral patterns and analyzed the orbital behavior in the potentials to study the criteria for the disk parameters, in which a stationary spiral structure is possible. We found the following results: the spiral potential drives the dynamical evolution, which results in the spiral structure, bar structure, or disappearance of the structure, depending on the form of the assumed spiral pattern. If a stationary spiral structure appears, the only possible pitch angle of the arms is around $5^{\circ}$. Therefore, observed spiral arms in late-type spiral galaxies with large pitch angles cannot be a stationary structure if the arms are induced by a density wave.
Long-Term Orbital Period Variations for EU Hydrae
Authors: Qian Sheng-Bang , Boonrucksar Soonthornthum
Published: March 2014

Long-term period variations of an Algol-type eclipsing binary star, EU Hydrae, are presented based on an analysis of its $O-C$ curve. As in the cases of other Algols studied in recent papers by one of the authors (S.-B. Qian), an alternate period change has discovered to superimpose on a secular period decrease ($dP / dt =-4.8 \times 10^{-8} \,\mathrm{d} \,\mathrm{yr}^{-1}$). By assuming that the alternate variation is cyclic, a period of 26.5 yr and an amplitude of 0.0104 d were determined. A long-term period decrease combined with a semi-detached configuration may indicate that EU Hya is undergoing a secular angular momentum loss. Three possible mechanisms are proposed to explain the alternate period change.
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

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

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

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

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

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

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

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

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 $i^{\prime} < 25.4 \hbox{--} 25.8$ 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

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 ($0.05 < z < 0.1$ and $M_{r^{*}} <-20.5$; 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

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

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

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

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 Totality of the Eclipse in AD 628 in the Nihongi
Authors: Tanikawa Kiyotaka , Sôma Mitsuru
Published: March 2014

It is widely accepted that the solar eclipse on AD 628 April 10 (the reign of Empress Suiko, 36th year, 3rd month, 2nd day) recorded in the Nihongi (日本書紀) was not total, but partial at the site of observation, though it is written as an exhausted eclipse. A contemporary Japanese occultation observation on AD 681 November 3 is also suspected as being a missing of Mars in the glaring light of the Moon. We suggest in this paper that both records in the Nihongi may be true. Several reasonings are put forward. We then point out the possibility that the value of $\Delta T$ at around AD 600 is about 2000 s which is far less than 4500 s, the value adopted by Stephenson (1997, Historical Eclipses and Earth’s Rotation). Lunar grazing occultation data are found to be very useful.
On the Symmetric Collinear Four-Body Problem
Authors: Sekiguchi Masayoshi , Tanikawa Kiyotaka
Published: March 2014

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

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

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.
Radio Observations of the Afterglow of GRB 030329
Authors: Kuno Nario , Sato Naoko , Nakanishi Hiroyuki , Yamauchi Aya , Nakai Naomasa , Kawai Nobuyuki
Published: March 2014

We present results of the radio observations of the afterglow of GRB 030329 with the Nobeyama 45-m telescope. The observations were made at 23.5 GHz, 43 GHz, and 90 GHz. The light curves show a steep decline after a constant phase. The start time of the decline depends on the frequency. Namely, the decline started earlier at a higher frequency. The spectrum has a peak in the mm wavelength range. The peak frequency and the peak flux decreased with time. These results are consistent with the expectation from the fireball model.
A Photometric Analysis and Spot Activity of BH Virginis
Authors: Xiang Fu Yuan , Zhou Yi Chun
Published: March 2014

BH Virginis is a short-period eclipsing binary with two solar-type components. The photoelectric light curves in $UBVRI$, observed by Scaltriti et al. (1985), and in the $B$ and 5125 Å bands, observed by Hoffmann (1982), were analyzed by using the 1992 version Wilson–Devinney program to investigate the activity of spots. The results show that there was a small cool spotted active region on the secondary star in 1984. The position and area of the active region in 1984 are remarkably similar to those in 1991. The distortion waves in the light curves observed by Hoffmann (1982) can be fitted satisfactorily with two hot-spot active regions: one is on the primary star, and the other is on the secondary component. The mass ratio $q = m_{2} / m_{1}$, obtained from photoelectric light curves, is inside the range of 0.965–0.971. It is close to the spectroscopic value of 0.968 obtained by Zhai et al. (1990). To study the physical cause of the variations and the distortions in the light curve of BH Vir, the photoelectric observations in $BV$ observed by Koch (1967) were re-analyzed based on a new spot model with an assumption of one cool spot active region on the primary star and two cool spot active regions on the secondary star. The fit of the new spot model to the observations is better than that of our former result (Xiang et al. 2000). The present results suggest that BH Vir may have an active cycle with a period of 7–10 years.
Formation of Opposite-Sign Magnetic Helicity by an Erupting Filament in a Coronal Mass Ejection
Authors: Liu Yu , Kurokawa Hiroki
Published: March 2014

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.
CIAO: Coronagraphic Imager with Adaptive Optics on the Subaru Telescope
Authors: Murakawa Koji , Suto Hiroshi , Tamura Motohide , Kaifu Norio , Takami Hideki , Takato Naruhisa , Oya Shin , Hayano Yutaka , Gaessler Wolfgang , Kamata Yukiko
Published: March 2014

We present the performances of direct imaging with adaptive optics, coronagraph, and imaging-polarimetry of the coronagraphic imager with adaptive optics (CIAO) for the Subaru telescope. Combining with the 36-element adaptive optics system, CIAO produces high-resolution images with a full width at half maximum of ${0\rlap {.}{}^{\mathrm {\prime \prime }}072}$ and a Strehl ratio of 0.28 in the $K$ band. CIAO has a Lyot’s-type stellar coronagraph facility with ${0\rlap {.}{}^{\mathrm {\prime \prime }}1}$ to ${4\rlap {.}{}^{\mathrm {\prime \prime }}0}$ diameter masks. The limiting magnitude difference of a companion star at the $K$ band is 11.0 mag at $5\,\sigma$, 10 minutes integration time, and ${2\rlap {.}{}^{\mathrm {\prime \prime }}0}$ separation from the central star. CIAO also has a polarimetry facility with a rotatable half-wave plate and a wire grid polarizer. Currently, the measurement of $JHK$ band linear polarization is available.
Twin Peaks kHz QPOs: Mathematics of the 3:2 Orbital Resonance
Authors: Rebusco Paola
Published: March 2014

Using the method of multiple scales, one can derive an analytic solution that describes the behaviour of weakly coupled, non-linear oscillations in nearly Keplerian discs around neutron stars or black holes close to the $3:2$ orbital epicyclic resonance. The obtained solution agrees with a previous numerical simulation. Such a result may be relevant to the kilohertz quasi-periodic variability in X-ray fluxes observed in many Galactic black hole and neutron star sources. With a particular choice of tunable parameters, the solution fits accurately the observational data for Sco X-1.
Computation of the Adiabatic Eigenmodes of Stars Using the Riccati Method
Authors: Takata Masao , Löffler Wolfgang
Published: March 2014

In stellar oscillation problems, it is often necessary to compute a large number of stellar eigenmodes with wildly varying radial orders and angular degrees. Conventionally the relaxation method is used for this purpose. This method is, however, fraught with several numerical issues, which make it cumbersome and tedious to write the corresponding computer programs. For this reason we adopt the Riccati method as an alternative, in which the original system of linear equations is transformed into a nonlinear matrix Riccati equation. The dependent variable of the converted equation does not retain the dependent variables of the original linear equations themselves, but keeps the relations among them. This method is particularly useful when we compute eigenmodes, where the amplitudes of the eigenfunctions vary by many orders of magnitude, since the ratios of the amplitudes generally show much less variation than the amplitudes themselves. The Riccati method was successfully applied to the problems of nonadiabatic stellar oscillations in previous studies. Our aim is to do the same for the adiabatic case.
Astronomical Observation with a Nb-Al-AlOX-Al-Nb STJ Single Photon Detecor for Optical Wavelengths
Authors: Shiki Shigetomo , Sato Hiromi , Takizawa Yoshiyuki , Kurakado Masahiko , Shimizu Hirohiko M.
Published: March 2014

A test observation using a Nb-Al-$\mathrm{AlO}_{X}$-Al-Nb superconducting tunnel junction detector was carried out using a small commercial optical telescope. Single photons of visible wavelengths were detected from $\alpha$ Lyr, $\alpha$ Boo, and Jupiter, and pulse-height distributions were obtained. The observed spectra roughly agree with predictions.
Low-Ionization Emission-Line Regions around the Nucleus of the Seyfert Galaxy NGC 1068
Authors: Ishigaki Tsuyoshi , Hayashi Tadashi , Ohtani Hiroshi , Sasaki Minoru , Maemura Hiroyuki , Ozaki Shinobu , Hattori Takashi , Sugai Hajime , Ishii Motomi
Published: March 2014

We present the results of tridimensional spectrophotometric observations of the central region of the Seyfert galaxy NGC 1068 obtained by using Kyoto tridimensional spectrograph I. A brief description of the instrument is presented. We have found the existence of low-ionized gas extending out of the ionization cone. It is characterized by higher ([S II]$\lambda6716+\lambda6731) / \mathrm{H}\alpha$ than within the cone. The ratio peaks at $5{}^{\prime\prime} \hbox{--} 6{}^{\prime\prime}$ east and west of the nucleus and reaches to 0.5–0.6. The ionization of the gas outside the cone by the scattered nuclear continuum is examined. We argue that a substantial fraction of the gases outside the cone could be ionized by the scattered nuclear continuum, including the diffuse arc structure seen in an HST image. In addition, we also attempt discussions according to the kinematic and spectroscopic properties of two possible gaseous components derived by the line decomposition: a narrow component that seems to follow the galactic rotation, and a broad one that may be deviated from it.
Resonant Excitation of Disk Oscillations by Warps: A Model of kHz QPOs
Authors: Kato Shoji
Published: March 2014

The amplification of disk oscillations resulting from non-linear resonant couplings between the oscillations and a warp is examined. The disks are geometrically thin and general relativistic with non-rotating central objects. By using a Lagrangian formulation, a general stability criterion is derived. The criterion is applied to horizontal and vertical resonances of g-mode oscillations and to horizontal resonances of p-mode oscillations. The results of analyses show that g-mode oscillations (including p-mode oscillations of $n=0$) are amplified by horizontal resonances with the warp. Other modes of oscillations with other resonances are all damped by resonances. The amplified g-mode oscillations are located around the radius $4 \,r_{\mathrm{g}}$, the radius of the epicyclic frequency being maximum, i.e., $\kappa_\mathrm{max}$. The frequencies of amplified oscillations are harmonics of $\kappa_\mathrm{max}$, and well explain the $2:3$ pairs of observed QPOs for reasonable masses (and spins) of the central objects.