bluuebunny/crossref_metadata_2025 huggingface dataset:
Relation between a Moreton Wave and an EIT Wave Observed on 1997 November 4
Authors: Eto Shigeru , Isobe Hiroaki , Narukage Noriyuki , Asai Ayumi , Morimoto Taro , Thompson Barbara , Yashiro Seiji , Wang Tongjiang , Kitai Reizaburo , Kurokawa Hiroki , Shibata Kazunari
Published: March 2014

We consider the relationship between two flare-associated waves, a chromospheric Moreton wave and a coronal EIT wave, based on an analysis of an X-class flare event in AR 8100 on 1997 November 4. A Moreton wave was observed in $\mathrm{H}\alpha$, $\mathrm{H}\alpha {+} 0.8\,$$Å$, and $\mathrm{H}\alpha-0.8\,$$Å$ with the Flare-Monitoring Telescope (FMT) at the Hida Observatory. An EIT wave was observed in EUV with the Extreme ultraviolet Imaging Telescope (EIT) on board SOHO. The propagation speeds of the Moreton wave and the EIT wave were approximately $715 \,\mathrm{km} \,\mathrm{s}^{-1}$ and $202 \,\mathrm{km} \,\mathrm{s}^{-1}$, respectively. The times of visibility for the Moreton wave did not overlap those of the EIT wave, but the continuation of the former is indicated by a filament oscillation. Data on the speed and location clearly show that the Moreton wave differed physically from the EIT wave in this case. The Moreton wave preceded the EIT wave, which is inconsistent with an identification of the EIT wave with a fast-mode MHD shock.
A Helical Magnetic Field in the Jet of 3C 273
Authors: Asada Keiichi , Inoue Makoto , Uchida Yutaka , Kameno Seiji , Fujisawa Kenta , Iguchi Satoru , Mutoh Mutsumi
Published: March 2014

Both in the Faraday Rotation Measure and the intrinsic polarization angle, new features are revealed to indicate a helical magnetic field operating along the jet of the bright active galactic nucleus 3C 273. The helical field has been suggested to be related to the formation and collimation of jets by magnetohydrodynamic models. The distribution of the rotation measure shows a systematic gradient with respect to the jet axis, which is expected by a helical magnetic field. In addition, the helical field can consistently explain two types in the direction of the projected magnetic field: parallel and perpendicular to the jet axis. Further, if the helical magnetic field is generated by winding up of an initial field by rotation of the accretion disk, we can uniquely determine the direction of the disk rotation, since the jet is approaching us.
Multi-Wavelength Variation Properties of γ-Ray-Loud Blazars
Authors: Fan Jun-Hui , Cheng K. S. , Zhang Li
Published: March 2014

Based on multi-waveband (radio, optical, and X-ray) observation data of 61 $\gamma$-ray-loud blazars (Cheng et al. 2000, ApJ, 537, 80) and $\gamma$-ray data by Hartman et al. (1999, AAA72.002.011) we have studied the variability properties using the variability index, $v = (F_{\mathrm{max}}-F_{\mathrm{min}}) / (F_{\mathrm{max}} + F_{\mathrm{min}})$, and the relations between the flux density and both the redshift and the variability index. The mainly results are as follows: 1) the average variability indexes are almost the same within the error-bar range for the radio, optical, X-ray, and $\gamma$-ray bands. 2) The variabilities in the optical, X-ray, and $\gamma$-ray bands are found to be correlated with the flux densities of the source, implying that the more variable is the source, the brighter it is.
Diffuse and Gravitationally Stable Molecular Gas in the Post-Starburst Galaxy NGC 5195
Authors: Kohno Kotaro , Tosaki Tomoka , Matsushita Satoki , Vila-VilarÓ Baltasar , Shibatsuka Toshihito , Kawabe Ryohei
Published: March 2014

The Nobeyama Millimeter Array (NMA) has been used to make aperture synthesis CO($1-0$) observations of the post-starburst galaxy NGC 5195. CO($1-0$) and HCN($1-0$) observations of NGC 5195 using the Nobeyama 45 m telescope are also presented. High-resolution (${1\rlap {.}{}^{\mathrm {\prime \prime }}9} \times {1\rlap {.}{}^{\mathrm {\prime \prime }}8}$ or $86 \,\mathrm{pc} \times 81 \,\mathrm{pc}$ resolution at $D = 9.3 \,\mathrm{Mpc}$) NMA maps show a strong concentration of CO emission toward the central a few $\times 100 \,\mathrm{pc}$ region of NGC 5195, despite the fact that the current massive star formation is suppressed there. The face-on gas surface density, $\Sigma_\mathrm{gas}$, within the $r<2{}^{\prime\prime}$ or 90 pc region reaches $3.7 \times 10^3 M_\odot$ pc$^{-2}$ if a Galactic $N_\mathrm{H_2}/I_\mathrm{CO}$ conversion factor is applied. The extent of the central CO peak is about $5{}^{\prime\prime}$, or 230 pc, and is elongated along the E-W direction with two-armed spiral-like structures, which are typical for barred disk galaxies. The HCN-to-CO integrated intensity ratio on the brightness temperature scale, $R_\mathrm{HCN/CO}$, is about 0.02 within the central $r < 400$ pc region. This $R_\mathrm{HCN/CO}$ is smaller than those in starburst regions by a factor of $5 \hbox{--} 15$. These molecular-gas properties would explain why NGC 5195 is in a post-starburst phase; most of the dense molecular cores (i.e., the very sites of massive star formation) have been consumed away by a past starburst event, and therefore a burst of massive star formation can no longer last, although a large amount of low density gas still exists. We find a steep rise of the rotation velocity toward the center of NGC 5195. As a consequence, the critical gas surface density for a local gravitational instability of the gas disk becomes very high ($\Sigma_\mathrm{crit} \sim 6.9 \times 10^3 \,{{{M}_{\odot}}} \,\mathrm{pc}^{-2}$), suggesting that the molecular gas in the central region of NGC 5195 is gravitationally stable, in contrast to that of starburst galaxies. We propose that dense molecular gas can not be formed from remaining diffuse molecular gas because the molecular gas in the center of NGC 5195 is too stable to form dense cores via gravitational instabilities of diffuse molecular gas. The deduced very high threshold density seems to be due to a high mass concentration in NGC 5195. The known trends on the occurrence and luminosity of nuclear star formation in early-type galaxies can be understood naturally if the high threshold density is characteristic for early-type galaxies.
Near-Infrared Spectroscopy of Very Low-Luminosity Young Stellar Objects in the Taurus Molecular Cloud
Authors: Itoh Yoichi , Tamura Motohide , Tokunaga Alan T.
Published: March 2014

We carried out near-infrared spectroscopic observations of 23 very low-luminosity young stellar object (YSO) candidates and 5 of their companions in Heiles Cloud 2, one of the densest parts of the Taurus molecular cloud. Twelve objects were confirmed to be YSOs by the $\mathrm{B}\gamma$ feature. The effective temperatures of the YSOs and of the companions are estimated from the 2.26-${\mu \mathrm {m}}$ feature, the 2.21-${\mu \mathrm {m}}$ feature, and the $\mathrm{H}_{2}\mathrm{O}$ band strengths. Detailed comparisons of our photometric and spectroscopic observations with evolutionary tracks on the HR diagram suggest some objects to be very low-mass YSOs.
Asymmetrical Distribution of Sunspot Groups in the Solar Hemispheres
Authors: Li Ke-Jun , Liu Xiao-Hua , Yun Hong-Sik , Xiong Song-Ying , Liang Hong-Fei , Zhao Hai-Zhuan , Zhan La-Sheng , Gu Xiao-Ma
Published: March 2014

In the present work, the north–south asymmetry of solar activity was examined by analyzing statistically the hemispheric distribution of annual numbers of sunspot groups, using the Royal Greenwich Observatory data set from the year 1874 through 2000. An interesting phenomenon is found that the solar activity of a cycle usually has the same beginning and end times, but different maximum amplitudes at different maximum times in the hemispheres. Some characteristics of the asymmetry of solar activity were investigated and explained. For solar cycle 23, a dominance of solar activity is predicted to occur in the southern hemisphere in several forthcoming years.
Polarization in Blazars
Authors: Fan Jun-Hui
Published: March 2014

Based on the beaming model, a relation between the observed polarization and the Doppler factor was obtained by Fan et al. (1997, AAA068.159.190), who showed that the polarization is associated with the Doppler factor (boosting factor) in BL Lacertae objects (BLs). Polarization and Doppler factors have also been obtained for some optically violently variable quasars (OVVs). Do OVVs also fit a similar relation to that of BLs? In the present Letter, BLs and OVVs are plotted in a polarization–Doppler factor diagram. The results indicate that OVVs follow a similar polarization–Doppler factor relation as the BLs, and that the parameter $f$, the ratio of the beamed luminosity to the unbeamed luminosity in the source frame for BLs, is greater than that for OVVs. This result suggests that the polarization mechanism in the two subclasses of active galactic nuclei is the same. The difference in $f$ means the intrinsic polarization in OVVs is lower than that in BLs. The boosted emissions in BLs dominate the unbeamed emissions, and therefore the emission lines in BLs are weak or invisible, which is consistent with observations.
Effects of Relativistic Expansion on Late-Time Supernova Light Curves
Authors: Iwamoto Koichi
Published: March 2014

The effects of relativistic expansion on late-time supernova (SN) light curves (LCs) were investigated, and an analytic expression for a correction term to the (quasi-)exponential decay was obtained. It has been shown that the relativistic effects brighten the LC owing to (1) a delayed decay of radioactive nuclei (time-dilation) as well as to (2) Lorentz boosting of the photon energies. The leading correction term is quadratic in $\beta$, where $\beta$ is the maximum velocity of ejecta divided by the speed of light, and grows as a quadratic function of time. Thus, the relativistic effect is negligibly small at early times, but becomes of considerable size at late times. It was also shown that including the differential time-dilation effect is essential for an accurate LC prediction better than to first order in $\beta$. For ordinary SNe, the effect is too small to be detected. However, in SNe having a very large energy (hypernovae) or exploding in an aspherical geometry, radioactive ${{56\atop} \mathrm{Ni}}$ is likely to be boosted to higher velocities. We might then see an appreciable excess of the flux. The relative importance of the relativistic effects remain uncertain, depending on the abundances of various radioactive isotopes and other energy sources that may power the LC.
3-D Kinematics of Water Masers in the W 51A Region
Authors: Imai Hiroshi , Watanabe Teruhiko , Omodaka Toshihiro , Nishio Masanori , Kameya Osamu , Miyaji Takeshi , Nakajima Junichi
Published: March 2014

We report on proper-motion measurements of water masers in the massive-star forming region W 51A and analyses of the 3-D kinematics of the masers in three maser clusters of W 51A (W 51 North, Main, and South). In W 51 North, we found a clear expanding flow having an expansion velocity of $ \sim 70 \,\mathrm{km} \,\mathrm{s}^{-1}$, which indicates deceleration. The originating point of the flow coincides within $ {0\rlap {.}{}^{\mathrm {\prime \prime }}1}$ with a silicon-monoxide maser source near the H II region W 51d. In W 51 Main, no systematic motion was found over the whole velocity range ($- 58 \,\mathrm{km} \,\mathrm{s}^{-1} \leq V_{\mathrm{LSR}} < 158 \,\mathrm{km} \,\mathrm{s}^{-1}$), although a stream motion was previously reported in a limited range of the Doppler velocity ($ 54 \,\mathrm{km} \,\mathrm{s}^{-1} \leq V_{\mathrm{LSR}} < 68 \,\mathrm{km} \,\mathrm{s}^{-1}$). Multiple driving sources of outflows are thought to explain the kinematics of W 51 Main. In W 51 South, an expansion motion like a bipolar flow was marginally visible. Analyses based on diagonalization of the variance–covariance matrix of maser velocity vectors demonstrate that the maser kinematics in W 51 North and Main are significantly tri-axially asymmetric. We estimated the distance to W 51 North to be $ 6.1 \pm 1.3 \,\mathrm{kpc}$ based on a model-fitting method adopting a radially expanding flow.
VLBI Observations of Water Masers in the Circumstellar Envelope of IRC$ +$60169
Authors: Sudou Hiroshi , Omodaka Toshihiro , Imai Hiroshi , Sasao Tetsuo , Takaba Hiroshi , Nishio Masanori , Hasegawa Wataru , Nakajima Junichi
Published: March 2014

Water masers around an AGB star, IRC$ +$60169, were observed at four epochs using the Japanese VLBI networks. The distribution of the maser features is limited in a thick-shell region, which has inner and outer expansion velocities of $ 7 \,\mathrm{km} \,\mathrm{s}^{-1}$ and $ 14 \,\mathrm{km} \,\mathrm{s}^{-1}$ at radii of 25 mas and 120 mas, respectively. The distribution of the red-shifted features exhibits a ring-like structure, the diameter of which is 30 mas, and corresponds to the inner radius of the maser shell. This implies that dense gas around the star obscures red-shifted emission. Although a position–radial velocity diagram for the maser features is consistent with a spherical shell model, the relative proper motions do not indicate an expansion motion of the shell. A remarkable property has been found that is a possible periodic change of the alignment pattern of water maser spots.
Spectroscopic Studies of the Solar Corona II. Properties of Green and Red Emission Lines in Open and Closed Coronal Structures
Authors: Singh Jagdev , Sakurai Takashi , Ichimoto Kiyoshi , Suematsu Yoshinori , Takeda Aki
Published: March 2014

We obtained profiles of the green (Fe XIV 5303 Å) and red (Fe X 6374 Å) emission lines simultaneously on 1998 July 18–19 for about 4 hours with a cadence of 10 minutes, covering an area of about $ 200'' \times 500''$ in the solar corona. The line width (FWHM), intensity, and Doppler shift for both lines were computed using Gaussian fits to the observed line profiles. We then studied any systematic differences in these parameters between closed and open field structures, and their time variations. The derived line widths indicate that the FWHM of the red line increases with height above the limb at a rate of $ 0.5 \hbox{--} 2.6 \,\mathrm{m}$ Å$ \,\mathrm{arcsec}^{-1}$ and the green-line width decreases with height at a rate of $ 1.2 \hbox{--} 3.4 \,\mathrm{m}$ Å$ \,\mathrm{arcsec}^{-1}$. The difference in the time-averaged values of the widths of the green line in open and closed coronal structures at a given height above the limb is small, whereas the width of the red line in open structures is substantially larger than that in the closed loop-like coronal structures.
Spectroscopic Studies of the Solar Corona III. Density Diagnostics Using the Infrared Lines of Fe xiii
Authors: Singh Jagdev , Sakurai Takashi , Ichimoto Kiyoshi , Takeda Aki
Published: March 2014

We have obtained spectrographic observations of several coronal regions in three emission lines (6374 Å [Fe x ], 10747 Å [Fe xiii], and 10798 Å [Fe xiii]) simultaneously. The 25-cm coronagraph at Norikura Observatory and two large-format CCD cameras were used. The peak intensity, velocity, and line-width values were derived from Gaussian fits to the observed line profile at each location of the observed region. The ratio of the intensities of the 10747 Å and 10798 Å emission lines in the individual coronal structures range between 1.0 and 2.5 at $ 10''$ above the limb, which corresponds to a density range of $ 9.8 \times 10^9 \hbox{--} 2.4 \times 10^8 \,\mathrm{cm}^{-3}$. The scale-height temperature values, derived from the variations of the intensity ratio with height above the limb for all individual coronal structures, range between $ 0.6 \times 10^ 6 \,\mathrm{K}$ and $ 8.3 \times 10^6 \,\mathrm{K}$ with a most frequent value around $ 1.8 \times 10^6 \,\mathrm{K}$. The large values of the scale-height temperature for 70% of the structures indicate that these structures may not be in hydrostatic equilibrium nor be isothermal in nature.
FOCAS: The Faint Object Camera and Spectrograph for the Subaru Telescope
Authors: Kashikawa Nobunari , Aoki Kentaro , Asai Ryo , Ebizuka Noboru , Inata Motoko , Iye Masanori , Kawabata Koji S. , Kosugi George , Ohyama Youichi , Okita Kiichi , Ozawa Tomohiko , Saito Yoshihiko , Sasaki Toshiyuki , Sekiguchi Kazuhiro , Shimizu Yasuhiro , Taguchi Hiroko , Takata Tadafumi , Yadoumaru Yasushi , Yoshida Michitoshi
Published: March 2014

The Faint Object Camera and Spectrograph (FOCAS) is a Cassegrain optical instrument for the Subaru Telescope. Its capabilities include $6^\prime \phi$ FOV direct imaging, low-resolution spectroscopy ($R=250 \hbox{--} 2000$ with ${0\rlap {.}{}^{\mathrm {\prime \prime }}4}$ slitwidth), multi-slit spectroscopy and polarimetry. We describe the overall design of FOCAS, its observing functions, and the performance verification procedures that have been carried out.
High Dispersion Spectrograph (HDS) for the Subaru Telescope
Authors: Noguchi Kunio , Aoki Wako , Kawanomoto Satoshi , Ando Hiroyasu , Honda Satoshi , Izumiura Hideyuki , Kambe Eiji , Okita Kiichi , Sadakane Kozo , Sato Bun’ei , Tajitsu Akito , Takada-Hidai Masahide , Tanaka Wataru , Watanabe Etsuji , Yoshida Michitoshi
Published: March 2014

We present the design and performance of the High Dispersion Spectrograph (HDS) of the Subaru Telescope. HDS is an echelle spectrograph located at the Nasmyth focus of the telescope. The collimated beam size is 272 mm, and the echelle is 300 mm by 840 mm in total size ($31.6 \,\mathrm{gr} \,\mathrm{mm}^{-1}, R=2.8$). HDS has two cross-dispersing gratings with $400 \,\mathrm{gr} \,\mathrm{mm}^{-1}$ and $250 \,\mathrm{gr} \,\mathrm{mm}^{-1}$, which are optimized for the blue and red wavelength regions, respectively. The camera is of the catadioptric type system, consisting of three corrector lenses and a mirror. Two EEV-CCD’s with $4100 \times 2048$ pixels and a pixel size of 13.5 ${\mu \mathrm {m}}$ are used as the detector. A standard configuration with a ${0\rlap {.}{}^{\mathrm {\prime \prime }}4}$ slit gives a spectral resolution of $R=90000$, and a narrower slit width enables higher resolution of up to $R \sim 160000$. The spectrograph has sensitivities from 3000 ${Å}$ to 1 ${\mu \mathrm {m}}$, and one exposure covers a range of 1500–2500 ${Å}$, depending on the wavelength region. The throughput of the telescope and the spectrograph, including the efficiency of the detector, is about 13% in 5000–6000 ${Å}$ and about 8% at 4000 ${Å}$. The stability of the spectrograph and scattered light level are also reported.
Development of Iodine Cells for the Subaru HDS and the Okayama HIDES: II. New Software for Precise Radial Velocity Measurements
Authors: Sato Bun’ei , Kambe Eiji , Takeda Yoichi , Izumiura Hideyuki , Ando Hiroyasu
Published: March 2014

We have developed a computer code for precise measurements of stellar radial velocity variations with iodine ($\mathrm{I}_2$) cells attached to the High Dispersion Spectrograph (HDS) on Subaru Telescope and the HIgh Dispersion Echelle Spectrograph (HIDES) on Okayama 188 cm reflector. Our modeling technique for $\mathrm{I}_2$ data is similar to those described by Butler et al. (1996, AAA 65.036.447) and Valenti et al. (1995, AAA 64.036.209) concerning the point that the stellar spectrum taken through the $\mathrm{I}_2$ cell (star$+ \mathrm{I}_2$ spectrum) is modeled as the product of high-resolution stellar and $\mathrm{I}_2$ template spectra convolved with the modeled instrumental profile (IP) of the spectrograph. In order to generate a template stellar spectrum, we have devised a new method to extract an intrinsic stellar spectrum from observed star$+ \mathrm{I}_2$ spectra. This enables us to obtain a well-established template stellar spectrum even in cases when the IP and the wavelength scale are apt to vary with time and the observational conditions, and the existing method which reconstructs the IP from a B-star$+ \mathrm{I}_2$ spectrum (Butler et al. 1996; Endl et al. 2000, A&A, 362, 585) fails. We here report on the results of our Doppler measurements of three solar-type stars, 16 Cyg B, $\tau$ Cet, and $\upsilon$ And, based on data collected with HDS and HIDES for about one year. These results show that we have achieved a precision of about $5 \hbox{--} 6 \,\mathrm{m} \,\mathrm{s}^{-1}$ over a time span of one year with our current analysis package with both spectrographs.
Candidates for Intracluster Planetary Nebulae in the Virgo Cluster Based on the Suprime-Cam Narrow-Band Imaging in [O III] and $\mathrm{H}\alpha$
Authors: Okamura Sadanori , Yasuda Naoki , Arnaboldi Magda , Freeman Kenneth C. , Ando Hiroyasu , Doi Mamoru , Furusawa Hisanori , Gerhard Ortwin , Hamabe Masaru , Kimura Masahiko , Kajino Toshitaka , Komiyama Yutaka , Miyazaki Satoshi , Nakata Fumiaki , Napolitano Nicola R. , Ouchi Masami , Pannella Maurilio , Sekiguchi Maki , Shimasaku Kazuhiro , Yagi Masafumi
Published: March 2014

We have identified 38 candidates of intracluster planetary nebulae (ICPNe) in a $34^\prime\times27^\prime$ field in the core of the Virgo cluster based on Suprime-Cam imaging through two narrow-band filters centered at redshifted wavelengths of the [O III] $\lambda=5007 \,$$\,{Å}$ and the $\mathrm{H}\alpha \lambda = 6563 \,$$\,{Å}$ lines. Broad-band images in the $V$ and $R$ bands are used to check for any emissions in the adjacent continuum. We describe the method briefly and present a list of the intracluster planetary nebula candidates, together with their finding charts. The ICPN candidates show a highly inhomogeneous distribution, which may suggest an association with the M 86–M 84 subcluster. The fraction of diffuse intracluster light with respect to the total light in galaxies is estimated to be about 10%, leading to an estimate of about 20% for the baryon fraction. A spectroscopic follow up and a wider survey are critical to reveal the nature of the intracluster stellar population.
Aperture Synthesis CO(J=1—0) Observations and Near-Infrared Photometry of the Non-Barred Seyfert Galaxy NGC 5033
Authors: Kohno Kotaro , Vila-Vilaró Baltasar , Sakamoto Seiichi , Kawabe Ryohei , Ishizuki Sumio , Matsushita Satoki
Published: March 2014

Aperture synthesis observations of CO($J = 1 \hbox{-} 0$) emission and near-infrared broad-band photometry of the non-barred Seyfert galaxy NGC 5033 ($D = 18.7 \,\mathrm{Mpc}$) were performed. Our ${3\rlap {.}{}^{\mathrm {\prime \prime }}9} \times {3\rlap {.}{}^{\mathrm {\prime \prime }}6}$ resolution CO observations reveal a perturbed distribution and the kinematics of molecular gas in the center of NGC 5033; we find the characteristic gaseous features that are widely observed in barred spiral galaxies, such as two bright CO peaks near the center (separated by $\sim 3^{\prime\prime}$ or 270 pc from the nucleus), two offset ridges of CO emission emanating from the CO peaks, and a CO ring (with a radius of $\sim 14^{\prime\prime}$ or 1.3 kpc). Double-peaked velocity profiles are also evident near the two CO peaks, implying that these CO peaks are orbit crowding zones in a barred/oval potential. Although NIR data only give an upper limit of the possible bar lengths due to a large inclination of the NGC 5033 disk ($i = 68^{\circ}$), our CO data clearly suggests the presence of a small (the semi-major axis of about $12^{\prime\prime} \hbox{-} 15^{\prime\prime}$ or 1.1–1.4 kpc) nuclear bar (or oval structure) in the center of the “non-barred” galaxy NGC 5033. Our results demonstrate that high-resolution CO imaging-spectroscopy is useful to search for nuclear bars, even in highly inclined systems where isophoto fitting techniques are not applicable. We find that the gas mass-to-dynamical mass ratio, $M_\mathrm{gas}/M_\mathrm{dyn}$, is small ($\leq 1\%$) within a radius of $2^{\prime\prime}$ or 180 pc, in contrast to starburst nuclei. This implies that the starburst does not cohabitate in the type-1.5 Seyfert nucleus of NGC 5033.
Black Hole-Bulge Relation for Narrow-Line Objects
Authors: Bian Wei-Hao , Zhao Yong-Heng
Published: March 2014

It has been thought that narrow-line Seyfert 1 galaxies are likely to be in the early stages of the evolution of active galaxies. To test this suggestion, the ratios of the central massive black hole (MBH) mass to the bulge mass ($M_{\mathrm{bh}} / M_{\mathrm{bulge}}$) were estimated for 22 Narrow Line AGNs (NL AGNs). It is found that NL AGNs appear to have genuinely lower MBH/Bulge mass ratio ($M_{\mathrm{bh}} / M_{\mathrm{bulge}}$). The mean $\log (M_{\mathrm{bh}}/M_{\mathrm{bulge}})$ for 22 NL AGNs is $-3.9 \pm 0.07$, which is an order of magnitude lower than that for Broad Line AGNs and quiescent galaxies. We suggest a nonlinear MBH/Bulge relation and find there exists a relation between the $M_{\mathrm{bh}} / M_{\mathrm{bulge}}$ and the velocity dispersion, $\sigma$, derived from the [O iii] width. A scenario of MBH growth for NL AGNs is one of our interpretations of the nonlinear MBH/Bulge relation. The MBH growth timescales for 22 NL AGNs were calculated, with a mean value $(1.29 \pm 0.24) \times 10^8 \,\mathrm{yr}$. Another plausible interpretation is also possible: that NL AGNs occur in low-$M_{\mathrm{bulge}}$ galaxies and that in such galaxies $M_{\mathrm{bh}} / M_{\mathrm{bulge}}$ is lower than that in galaxies with a higher $M_{\mathrm{bulge}}$, if we consider that NL AGNs already have their “final” $M_{\mathrm{bh}} / M_{\mathrm{bulge}}$. More information of the bulge in NL AGNs is needed to clarify the black hole-bulge relation.
Greenhouse Effect of Cloudy Accretion Disks
Authors: Kitabatake Etsuko , Fukue Jun
Published: March 2014

When an accretion disk is not naked, but covered with an optically-thick cloud, mutual irradiation between the disk and the cloud layer becomes important. We calculated the temperature distribution and the continuous spectra of the clouds as well as the disk. The temperature distribution of the cloud becomes somewhat flat in the central region, and gradually decreases in the outer part, while that of the disk is greatly enhanced, compared with the initial standard disk. The continuous spectrum emitted from the clouds is also modified, and resembles a blackbody spectrum with a single temperature, compared with the disk blackbody spectrum.
Orbital Period Studies of Three Algols: TW And, RW Leo, and AY Vul
Authors: Shengbang Qian
Published: March 2014

The changes in the orbital periods of three EA-type eclipsing binaries, TW And, RW Leo, and AY Vul, are discussed based on an analysis of their $O-C$ curves. For RW Leo, its orbital period was revised and, assuming a cyclic oscillation in the orbital period, a period of 38.4 yr was determined. For the other two systems, TW And and AY Vul, their $O-C$ diagrams show complex variations. Under the assumption of periodic oscillation, cyclic changes with periods of 56.4 and 78.6 yr were discovered to superimpose on upward parabolic changes, indicating a secular period increase. The secular period increases for the two binary systems indicate that they are on an active phase of mass transfer. Assuming the oscillations in the periods to be caused by light-time effects due to the presence of “third bodies” rotating around these binary stars, the orbital parameters of the third bodies were determined. For RW Leo, it is possible to detect an additional third body photometrically and spectroscopically. However, for the other two systems, TW And and AY Vul, it is less likely to see additional bodies, unless the orbital inclination is very small (i.e., $i^{\prime}<30^{\circ}$). New photometric and spectroscopic observations and a careful analysis of those data are needed to check the presence of third bodies.
TRACE Observation of an Arcade Flare Showing Evidence Supporting Quadruple Magnetic Source Model for Arcade Flares
Authors: Uchida Yutaka , Title Alan , Kubo Masahito , Tanaka Tomohiro , Morita Satoshi , Hirose Shigenobu
Published: March 2014

The result of analyses of an arcade flare on 1999 July 19, observed by the Satellite TRACE, is reported, and the significance of the following findings is stressed. It is clearly seen that four magnetic regions of alternating polarities [named A($+$), B($-$), C($+$), and D($-$) from the East in the flaring region] are involved in this arcade flare event in an essential way. The high structure covering the triangular region between A and the northern part of D disappears when the dark filament lying between B and C erupts. The X-ray arcade is formed only between B and C. The overlying structure connecting regions A and the northern part of D disappears and the entire region is involved in the flare. Low-lying loops connect the inner sources to the outer sources. The field lines from regions B to A and C to D are not much affected by the eruption of the dark filament, itself, but the loops near the upper surfaces of the closed loop regions are clearly seen to move toward each other (from both sides to the central line) as the arcade flare progresses between the inner pair, B and C; some of them appear to be converted into a flare arcade. The observed behavior can best be understood in terms of the quadruple magnetic source model advocated by one of the authors (YU). The long-conceived “reclosing of once opened bipolar magnetic arcade” models by the rising dark filament (called CSHKP model) find it difficult to explain this.
The Virgo High-Resolution CO Survey: II. Rotation Curves and Dynamical Mass Distributions
Authors: Sofue Yoshiaki , Koda Jin , Nakanishi Hiroyuki , Onodera Sachiko
Published: March 2014

Based on a high-resolution CO survey of Virgo spirals with the Nobeyama Millimeter-wave Array, we determined the dynamical centers using velocity fields, and derived position–velocity diagrams (PVDs) along the major axes of the galaxies across their dynamical centers. We applied a new iteration method to derive rotation curves (RCs), which reproduce the observed PVDs. The obtained high-accuracy RCs generally show a steep rise in the central $\sim 100$ to 200 pc regions, followed by flat rotation in the disk. We applied a deconvolution method to calculate the surface-mass density (SMD) using the RCs based on two extreme assumptions that the mass distribution is either spherical or thin-disk shaped. Both assumptions give nearly identical results, agreeing with each other within a factor of two at any radii. The SMD distributions revealed central massive cores with peak SMD of $\sim 10^4 \hbox{--} 10^5 \,{{{M}_{\odot}}} \,\mathrm{pc}^{-2}$ and a total mass within 200 pc radius of the order of $\sim 10^9 \,{{{M}_{\odot}}}$. A correlation analysis among the derived parameters shows that the central CO-line intensity is positively correlated with the central SMD, which suggests that the deeper is the gravitational potential, the higher is the molecular gas concentration in the nuclei, regardless of the morphological types.
Biasing and Genus Statistics of Dark Matter Halos in the Hubble Volume Simulation
Authors: Hikage Chiaki , Taruya Atsushi , Suto Yasushi
Published: March 2014

We present a numerical analysis of genus statistics for dark matter halo catalogs from the Hubble volume simulation. The huge box-size of the Hubble volume simulation enables us to carry out a reliable statistical analysis of the biasing properties of halos at a Gaussian smoothing scale of $R_\mathrm{G} \ge 30 \,h^{-1} \,\mathrm{Mpc}$ with a cluster-mass scale of between $7\times 10^{13} \,h^{-1} \,{{{M}_{\odot}}}$ and $6\times 10^{15} \,h^{-1} \,{{{M}_{\odot}}}$. A detailed comparison of the genus for dark matter halos with that for the mass distribution shows that the non-Gaussianity induced by the halo biasing is comparable to that by nonlinear gravitational evolution, and both the shape and the amplitude of the genus are almost insensitive to the halo mass at $R_\mathrm{G} \ge 30 \,h^{-1} \,\mathrm{Mpc}$. In order to characterize the biasing effect on the genus, we apply a perturbative formula developed by Matsubara (1994, AAA 062.161.289). We find that the perturbative formula well describes the simulated halo genus at $R_\mathrm{G} \ge 50\,h^{-1} \,\mathrm{Mpc}$. The result indicates that the biasing effect on the halo genus is well approximated by nonlinear deterministic biasing up to the second-order term in the mass density fluctuation. The two parameters describing the linear and quadratic terms in the nonlinear biasing accurately specify the genus for galaxy clusters.
Characteristic Variability Time Scales of Long Gamma-Ray Bursts
Authors: Shen Rong-Feng , Song Li-Ming
Published: March 2014

We determined the characteristic variability time scales (${\Delta t}_\mathrm{p}$) of 410 bright and long GRBs, by locating the peaks of their Power Density Spectra, defined and calculated in the time domain. We found that the averaged variability time scale decreases with the peak flux. This is consistent with the time-dilation effect expected for the cosmological origin of GRBs. We also found that the occurrence distribution of the characteristic variability time scale shows bimodality, which might be interpreted as that the long GRB sample is composed of two sub-classes with different variability time scales. However, we found no difference for some other characteristics of these two sub-classes.
Lyman Break Galaxies at z ∼ 5: Luminosity Function
Authors: Iwata Ikuru , Ohta Kouji , Tamura Naoyuki , Ando Masataka , Wada Shinpei , Watanabe Chisato , Akiyama Masayuki , Aoki Kentaro
Published: March 2014

We present the results of a search for Lyman break galaxies (LBGs) at $z \sim 5$ in a 618 square-arcmin field including the Hubble Deep Field-North (HDF-N) taken by the Subaru Prime Focus Camera. Utilizing the published redshift data of the HDF-N and its flanking fields, the color selection criteria were chosen so that LBGs could be picked out most efficiently and least contaminated by foreground objects. The numbers of detected LBG candidates were 96 in $23.0 \leq I_c \; (\mathrm{mag}) \leq 24.5$ and 310 in $23.0 \leq I_c \leq 25.5$. There is a hint of a deficiency of bright blue galaxies, although it is not as clear as has been suggested for LBGs at $z \sim 3$ to 4. With 305 LBG candidates in a 575 square-arcmin field, the rest-frame UV luminosity function of LBGs at $4.4 \lesssim z \lesssim 5.3$ was derived statistically by considering both the contamination by objects at the intermediate redshift and the incompleteness of the survey. The fraction of the contamination was estimated to be $\sim 50 \%$ in the faintest magnitude range. The completeness of the survey was $\sim 80\%$ at the bright part of the sample, and $\sim 20\%$ in the faintest magnitude range ($25.0 < I_c \leq 25.5$). The luminosity function of LBG candidates at $z \sim 5$ did not show a significant difference from those of LBGs at $z \sim 3$ and 4, though there might be a slight decrease in the fainter part. The UV luminosity density within the observational limit was 0.56–0.69 times smaller than that obtained for LBGs at $z \sim 3$, depending on the adopted cosmology and the integration range of the luminosity function. This decrease in the UV luminosity at $z \sim 5$ compared to that at $z \sim 3$ is due to the smaller number density of faint galaxies at $z \sim 5$. The similarity of the luminosity functions at redshifts 5 to 3 implies that most of the LBGs at $z \sim 5$ should have faded out at $z \sim 3$, and that the LBGs at $z \sim 5$ are different galaxies from those seen at $z \sim 3$, if we take the face values for the ages of the LBGs at $z \sim 3$ obtained by a SED fitting in which a continuous star formation in an individual galaxy was assumed. However, if the star formation in LBGs is sporadic, the similarity of the luminosity function at $z \sim 3$ and 5 would be explained. Such sporadic star formation has been suggested by hydrodynamical simulations and semi-analytic models with collisional starbursts, and the trend of the cosmic star formation history predicted by these studies resembles that estimated from an integration of the UV luminosity density within the observational limit.
Photon Emission in a Cascade from Relativistic Protons Initiated by Residual Thermal Photons in Gamma-Ray Bursts
Authors: Asano Katsuaki , Takahara Fumio
Published: March 2014

Gamma-ray bursts are generally considered to be the result of internal shocks generated in an inhomogeneous relativistic outflow that arises from a fireball. In such shocks, the Fermi acceleration of protons is naturally expected to be at least as efficient as that of electrons. We investigate the consequences of proton acceleration in the residual thermal photon field of a fireball, especially those on the emission spectra of photons. In contrast to most other studies, we do not invoke a direct electron acceleration in shock waves. We show that the residual radiation field of the fireball can ignite the photopion production and subsequent cascade, and that the photons emitted in this process further enhance the photon-initiated cascade. We find that Fermi-accelerated protons with $\gtrsim 10^{13} \,\mathrm{eV}$ efficiently bring their energy into pion production and subsequent photon emission. The particles cascading from the pions emit photons over a wide energy range. The photons emitted from electron–positron pairs distribute continuously from the GeV range down to the X-ray range, while muons can emit gamma-rays by synchrotron radiation with a break at around 1–10 MeV. We also discuss several radiation processes which may possibly produce a break feature in the MeV range, as observed in addition to muon synchrotron radiation.
Parent Distributions of the Periods and Magnetic Inclination Angles of Radio Pulsars
Authors: Zhang Li , Jiang Ze-Jun , Mei Dong-Cheng
Published: March 2014

We studied the parent distributions of pulsar periods and inclination angles by means of the Monte Carlo method. In our simulations, assuming that the parent period distribution satisfies a gamma function with two parameters, we tested a number of various parent distributions of the inclination angles ($\alpha$), which are the inclination angles of the magnetic axis to the pulsar spin axis, and different relations between the beam angular radius ($\rho$) and the pulsar period ($P$) (i.e. $\rho \hbox{-} P$ relation). The simulated periods, pulse widths, and inclination angles were compared with the observed data using the Kolmogorov–Smirnov significance test. Our results indicate that: (i) the parent inclination angles could not be expressed by a flat function (a possible parent distribution is cosine-like or $\propto \{ 0.6/ \cosh[ 3.5 (\alpha-0.43) ] \} + \{ 0.15 / \cosh[ 4.0 (\alpha-1.6) ] \}$); (ii) the parent period distribution depends slightly on the $\rho \hbox{-} P$ relation, and is different from the observed period distribution (their differences can be expressed by different values of two parameters when the parent and observed period distributions can be described as gamma functions); and (iii) the average beaming fraction is about 0.12.
Meteor Storm Activity and Average Size of Meteoroids for the 2001 Leonids by FM Broadcasting Radio Observation
Authors: Yoshida Hideto
Published: March 2014

Radio-wave observations using FM broadcasting frequencies have been performed on the 2001 Leonids. The observations were designed so that only a long echo could be received. The following results were obtained. First, the peak activity of the 2001 Leonids was approximately 18h10m (UT) on November 18 and the solar longitude of this peak corresponded to ${236\rlap {.}{}^{\mathrm {\circ }}45}$ (J2000.0). Second, it is inferred that the peak activity of the 2001 Leonids (1699 and 1866 dust trails) contained meteoroids of a larger average size than those of the 1999 Leonids (1899 dust trail).
Another Interpretation of the Disk-Line Profile for the Seyfert 1 Galaxy MCG $-$ 6-30-15
Authors: Inoue Hajime , Matsumoto Chiho
Published: March 2014

The Seyfert 1 galaxy MCG$-$6-30-15 is a representative object possessing a “disk-line” (a broad and skewed feature around 5–7 keV in an X-ray spectrum). Using the longest MCG$-$6-30-15 observation with ASCA, Matsumoto et al. (2003, PASJ, 55, 615) found an interesting time-variability: the RMS variability as a function of a time-bin-width decreases more rapidly in the disk-line energy band (5.0–6.6 keV) than those in the other energy bands, as the time-bin-width increases from $\sim 10^{4} \,\mathrm{s}$ to $\sim 10^{5} \,\mathrm{s}$. In this paper, we argue that this energy-dependent change in the RMS variability as a function of the time-bin-width is difficult to be reproduced by simply considering the variability of a “disk-line”, but that the RMS variability of the continuum component should have an energy-dependent evolution associated with the time-bin-width change. Such an energy-dependent variability of the continuum component can be realized by introducing absorption components with the typical variation time scale longer than that of the continuum. In this interpretation, a significant part of the broad excess feature in 5–7 keV is considered to be the result of a transparent spectral window of the warm absorbers.
X-Ray Observation on the Monoceros R2 Star-Forming Region with the Chandra ACIS-I Array
Authors: Nakajima Hiroshi , Imanishi Kensuke , Takagi Shin-ichiro , Koyama Katsuji , Tsujimoto Masahiro
Published: March 2014

We report on the results of the Chandra ACIS-I observation on the central region of the Monoceros R2 cloud (Mon R2), a high-mass star-forming region (SFR) at a distance of 830 pc. With a deep exposure of $\sim 100 \,\mathrm{ks}$, we detected 368 X-ray sources, $\sim 80\%$ of which were identified with the near-infrared (NIR) counterparts. We systematically analyzed the spectra and time variability of most of the X-ray emitting sources and provided a comprehensive X-ray source catalog for the first time. Using the $J$-, $H$-, and $K$-band magnitudes of the NIR counterparts, we estimated the evolutionary phase (classical T Tauri stars and weak-lined T Tauri stars) and the mass of the X-ray emitting sources, and analyzed the X-ray properties as a function of the age and mass. We found a marginal hint that classical T Tauri stars have a slightly higher temperature (2.4 keV) than that of weak-lined T Tauri stars (2.0 keV). A significant fraction of the high- and intermediate-mass sources have a time variability and high plasma temperatures (2.7 keV) similar to those of low-mass sources (2.0 keV). We performed the same analysis for other SFRs, the Orion Nebula Cluster and Orion Molecular Cloud-2/3, and obtained similar results to Mon R2. This supports the earlier results of this observation obtained by Kohno et al. (2002, ApJ, 567, 423) and Preibisch et al. (2002, A&A, 392, 945) that high- and intermediate-mass young stellar objects emit X-rays via magnetic activity. We also found a significant difference in the spatial distribution between X-ray and NIR sources.
A Systematic Study of X-Ray Flares from Low-Mass Young Stellar Objects in the
$\rho$
Ophiuchi Star-Forming Region with Chandra
Authors: Imanishi Kensuke , Nakajima Hiroshi , Tsujimoto Masahiro , Koyama Katsuji , Tsuboi Yohko
Published: March 2014

We report on the results of a systematic study of X-ray flares from low-mass young stellar objects, using two deep exposure Chandra observations of the main region of the $\rho$ Ophiuchi star-forming cloud. From 195 X-ray sources, including class I–III sources and some young brown dwarfs, we detected a total of 71 X-ray flares. Most of the flares have the typical profile of solar and stellar flares, fast rise and slow decay, while some bright flares show unusually long rise timescales. We derived the time-averaged temperature ( $\langle kT\rangle$ ), luminosity ( $\langle L_{\mathrm{X}}\rangle$ ), rise and decay timescales ( $\tau_{\mathrm{r}}$ and $\tau_{\mathrm{d}}$ ) of the flares, finding that (1) class I–II sources tend to have a high $\langle kT\rangle$ , which sometimes exceeds 5 keV, (2) the distribution of $\langle L_{\mathrm{X}}\rangle$ during flares is nearly the same for all classes from $\sim 10^{29.5}$ to $\sim10^{31.5} \,\mathrm{erg} \,\mathrm{s}^{-1}$ , although there is a marginal hint of a higher $\langle L_{\mathrm{X}}\rangle$ distribution for class I than class II–III, and (3) positive and negative log-linear correlations are found between $\tau_{\mathrm{r}}$ and $\tau_{\mathrm{d}}$ , and $\langle kT\rangle$ and $\tau_{\mathrm{r}}$ . In order to explain these relations, we used the framework of magnetic reconnection model with heat conduction and chromospheric evaporation to formulate the observational parameters ( $\tau_{\mathrm{r}}$ , $\tau_{\mathrm{d}}$ , and $\langle kT\rangle$ ) as a function of the pre-flare (coronal) electronic density ( $n_{\mathrm{c}}$ ), the half-length of the reconnected magnetic loop ( $L$ ), and magnetic field strength ( $B$ ). The observed correlations are well reproduced if loop lengths are nearly the same for all classes, regardless of the existence of an accretion disk. The estimated loop length is almost comparable to the typical stellar radius of these objects ( $10^{10} \hbox{--} 10^{11} \,\mathrm{cm}$ ), which indicates that the observed flares are triggered by solar-type loops, rather than larger ones ( $\sim 10^{12} \,\mathrm{cm}$ ) connecting the star with its inner accretion disk. The higher $\langle kT\rangle$ observed for class I sources may be explained by a slightly higher magnetic field strength ( $\approx 500 \,\mathrm{G}$ ) than for class II–III sources (200–300 G).
The Radiant Structure of the Leonid Meteor Storm in 2001: Observations with a Telephoto Lens System
Authors: Ken’ichi Torii , Kohama Mitsuhiro , Yanagisawa Toshifumi , Ohnishi Kouji
Published: March 2014

We measured the radiant of the Leonid meteor storm in 2001 November by using new observational and analysis techniques. The radiant was measured as the intersections of lines which were detected and extrapolated from images obtained at a single observing site (Akeno Observatory, Japan). The images were obtained by two sets of telephoto lenses equipped with cooled CCD cameras. The measured radiant, $($R.A., Dec.$) = ( {154\rlap {.}{}^{\mathrm {\circ }}35} \pm {0\rlap {.}{}^{\mathrm {\circ }}15}, {21\rlap {.}{}^{\mathrm {\circ }}55} \pm {0\rlap {.}{}^{\mathrm {\circ} }15})$ (J2000), was found to be in reasonable agreement with theoretical prediction by McNaught and Asher (2001, WGN, 29, 156), which supports their dust trail theory.
Excitation of g-Mode Oscillations on Relativistic Disks by Parametric Resonances with a Warp
Authors: Kato Shoji
Published: March 2014

Excitations by parametric resonances of axisymmetric ($m=0$) and one-armed ($m=1$) $g$-mode oscillations on the innermost region of geometrically thin, relativistic disks are examined. As a deformation of the unperturbed disks from an axisymmetric steady state, which is necessary for the operation of parametric resonances, we assume a long-living warp. Analyses are made under the approximations that the oscillations are local in the radial direction in the sense that their radial wavelength is short compared with a radial characteristic length of the disk, but long compared with the disk thickness. The results show that $g$-mode oscillations are amplified by coupling with the warp through an intermediate state, which is higher harmonics in the vertical direction. The oscillations amplified have some particular frequencies. The frequency ratio of two typical oscillations is $\sim \sqrt{2}$, which is close to $3:2$ observed as twin kHz quasi-periodic oscillations in some X-ray binaries.