bluuebunny/crossref_metadata_2025_split huggingface dataset:
Gamma-Ray-Bright Blazars: The Spectral Properties in X-Rays and Gamma-Rays
Authors: Dai Ben-Zhong , Zhang Li 
Published: March 2014

Abstract
We have studied the spectral properties in the soft X-ray (0.1–2.0 keV), hard X-ray (2.0–10.0 keV), and $\gamma$-ray energy bands for a sample of bright $\gamma$-ray ($E \gt 100 \,\mathrm{MeV}$$E \gt 100 \,\mathrm{MeV}$) blazars. In our analysis, we used the methods of weighted and un-weighted correlation analysis using a non-parametric Spearman rank test. Our results indicate: (i) there are significant anti-correlations both between the soft X-rays and $\gamma$-rays spectral shapes and between hard X-ray and $\gamma$-ray of flat spectrum radio quasars (FSRQs) and BL Lac objects; (ii) the weighted correlation analysis on spectral indices gives a positive correlation while the un-weighted analysis gives a negative correlation between the soft and hard X-ray bands, yielding contrary results. Because the weighted correlation analysis eliminates the effect of the observational errors, we may believe that the results of weighted analysis are more reliable than those of the un-weighted analysis.
A Possible Signature of Connection between Blazars and Seyfert Galaxies
Authors: Liang En-Wei 
Published: March 2014

Abstract
The accretion rates ($\dot{M}$) and their correlation with cosmological redshifts for a sample of blazars and Seyfert galaxies are presented. The sample includes 77 blazars (28 FSRQs, 26 LBLs, and 23 HBLs) and 60 Seyfert galaxies, of which the extended spectral energy distribution information and redshifts are available. Within the framework of accreting black holes, the accretion rates for these sources were estimated based on their bolometric luminosities. The result shows that the accretion rates are significantly different for each subclass of the blazars and Seyfert galaxies. Their averages are, respectively, 50.2, 17.0, 1.0, $0.1 \,{{{M}_{\odot}}} \,\mathrm{yr}^{-1}$ for the FSRQs, LBLs, HBLs, and the Seyfert galaxies, exhibiting a well descending sequence of FSRQs—LBLs—HBLs—Seyfert galaxies. They are strongly correlated with the redshifts for both blazars and Seyfert galaxies. The linear correlation coefficients are 0.81 and 0.68 with a chance probability of $p &lt; 0.0001$, respectively. A plot of $\dot{M} \hbox{--} z$ shows that the blazars and the Seyfert galaxies distribute in a distinguishable regions with a connection at $z\sim 0.7$, and almost all the sources lie in a narrow region of $z^{1.40} \leq \dot{M} \leq 250 \, z^{1.40}$, illustrating a strong correlation between the two quantities for the whole sample. The regression line is $\dot{M} = (14.5\pm 1.2) z^{1.40\pm 0.06} \,{{{M}_{\odot}}} \,\mathrm{yr}^{-1}$ with a linear coefficient of 0.93 and a chance probability of $p &lt; 0.0001$. These results confirm D’Elia and Cavaliere’s argument and expand this argument to Seyfert galaxies, suggesting a connection between blazars and Seyfert galaxies. This connection might imply that the two classes are on the same evolutionary sequence. Although the correlations of the data are formally solid, the conclusion may be affected by one source of considerable uncertainty at the data level, which is also discussed.
Effects of Dust in Distorted, Irradiated, and Expanding Atmospheres of Close Binary Components
Authors: Rao Mynampati Srinivasa 
Published: March 2014

Abstract
We studied the transfer of line radiation with dust in distorted and expanding atmospheres of close binary components. We assumed that the distortion of the atmosphere is caused by self rotation and a tidal force exerted by the presence of a secondary component. A seventh degree equation is defined to describe the distorted surface for uniform rotation. The equation of line transfer in the presence of gas and dust is solved in the comoving frame of the expanding atmosphere of the primary component in a binary system. We have considered a complete redistribution of photons in the line and that dust scatters radiation isotropically. We used a linear law of velocity of expansion so that the density varies as $r^{-3}$, where $r$ is the radius of the star, satisfying the law of conservation of mass. We noticed that considerable changes occur in line fluxes in dusty and dust-free atmospheres. The expansion of the atmosphere produces double-peak emission lines with P Cygni characteristics. These emission peaks are reduced in a dusty atmosphere.
Spectroscopic Observations of Split Comet C/2001 A2 (LINEAR)
Authors: Furusho Reiko , Kawakita Hideyo , Fujii Mitsugu , Kinugasa Kenzo , Yamamuro Tomoyasu , Takeyama Norihide 
Published: March 2014

Abstract
Low-dispersion spectroscopic observations of C/2001 A2 (LINEAR) were performed before and after its perihelion passage. C/2001 A2 (LINEAR) showed the first outburst late in 2001 March, and its visual magnitude increased by more than 5 mag. In addition to this outburst, three outbursts were recognized around the perihelion passage of the comet. These outbursts are thought to be associated with splitting events of the cometary nucleus. Our first observation was performed on 2001 April 4, during the first outburst. After its perihelion passage, its spectra were obtained on July 2, with its normal activity, and July 12, during an outburst. We determined the gas-to-dust ratios $[Q(\mathrm{H_2O}) / Af\rho]$, as well as gas production rate ratios of CN, $\mathrm{C}_2$, and $\mathrm{NH}_2$ relative to water $[Q(\mathrm{X}) / Q(\mathrm{H_2O})]$ for each observation. Obtained gas-to-dust ratios (26.4–26.7) showed that C/LINEAR was a gas-rich comet. Our results showed that there were no significant changes in the gas-to-dust ratio and gas production rate ratios during 3 months around perihelion passage. In comparison with other comets, there were no significant differences in the chemical composition for C/2001 A2 (LINEAR).
Bulge Formation in Late-Type Galaxies—Cuspy–vs Soft-Core Dark-Matter Density Profiles
Authors: Huang Jie-Hao , Deng Zu-Gan , Fu Yan-Ning 
Published: March 2014

Abstract
The dynamical evolution of super star clusters has been investigated in dark-matter halos depicted with a cuspy- or soft-core density profile. Simulations show that (1) exponential bulges with central cusps form in both cases; (2) distinctive bulge formation fractions are derived for cuspy- and soft-core profiles; (3) the masses of the formed bulges are causally connected with the masses of nuclear clusters, which are heavier in the case of a cuspy-core profile; (4) massive, nuclear star clusters possibly form with no discernible bulges at different ages in cuspy- or soft-core cases. Based on comparisons with observations, both the soft- and cuspy-core dark matter density profiles are suitable to relevant dwarf galaxies.
Galaxy Structures and External Perturbations in Gravitational Lenses
Authors: Kawano Yozo , Oguri Masamune , Matsubara Takahiko , Ikeuchi Satoru 
Published: March 2014

Abstract
In modeling strong gravitational lens systems, one often adopts simple models, such as singular isothermal elliptical density plus lowest-order external perturbation. However, such simple models may mislead us if the real mass distribution is more complicated than that in the assumed models. In particular, assumptions on mass models are crucial in studying flux ratio anomalies that have been suggested as evidence for a cold dark-matter substructure. We reinvestigated four quadruple lens systems using power-law Fourier models, which have advantages of clear physical meanings and the applicability of a linear method, as well as a simple singular isothermal elliptical density model. We also investigated the effect of external perturbations, including a singular isothermal sphere, lowest-order expansion, and next-order expansion. We have found that the $\cos 3\theta$ terms of the primary galaxy and/or of external perturbation significantly reduce the $\chi^2$ in PG 1115$+$080 and B1422$+$231. In particular, we could reproduce the flux ratios of B1422$+$231 with next-order external perturbation assuming 5% flux uncertainties, suggesting that external perturbation cannot be described by a simple singular isothermal sphere approximation. On the other hand, we could not fit B0712$+$472 and B2045$+$265 very well even with our models, although the $\chi^2$ were reduced compared with the case of using simple models. Our results clearly demonstrate that both the primary lens galaxy and the external perturbation are often more complicated than we usually assume.
Soft X-Ray Transients as Ultraluminous X-Ray Sources
Authors: Lee Chang-Hwan , Brown Gerald E. 
Published: March 2014

Abstract
We discuss the possibility that the soft X-ray transient GRS 1915$+$105 evolved from a binary similar to V4641 Sgr (XTE J1819$-$254) by conservative mass-transfer, and estimate the possible mass-transfer rates during the evolution. The results indicate that the high mass-transfer rates could explain the high luminosities in ultraluminous X-ray sources. Although the high mass-transfer rates during evolution are accompanied by high luminosities, we find that much of the transferred matter may sweeps accompanying radiation in an adiabatic inflow of super-Eddington accretion. We suggest that soft X-ray transients with evolved companions (initial companion mass $ \gt 3 \,{{{M}_{\odot}}}$), e.g. GRS 1915$+$105, can be ultraluminous X-ray sources if they are seen through their beaming axis.
Reflection Component in the Hard X-Ray Emission from the Seyfert 2 Galaxy Mrk 1210
Authors: Ohno Masanori , Fukazawa Yasushi , Iyomoto Naoko 
Published: March 2014

Abstract
The Seyfert 2 galaxy Mrk 1210 was found to exhibit a flat hard X-ray component by ASCA, although ASCA could not distinguish whether it is an absorbed direct component or a reflected one. We then observed Mrk 1210 with BeppoSAX, and found that the X-ray spectral properties are quite different from those of ASCA, as have been confirmed with XMM-Newton; the flux is significantly higher than that in the ASCA observation, and a clear absorption cut-off appears below 5 keV. A bright hard X-ray emission is detected up to 100 keV. The reflection component is necessary to describe the BeppoSAX PDS spectrum, and represents the ASCA hard component very well. Therefore, the hard component in the ASCA spectrum is a reflected one, whose intensity is almost constant over 6 yr. This indicates that a dramatic spectral variability is attributed to a large change of the absorption column density by a factor of $&gt;5$, rather than the variability of the nuclear emission. The change in the absorption column density means that the torus is not homogeneous, but has a blobby structure with a typical blob size of $&lt; 0.001 \,\mathrm{pc}$.
Virgo High-Resolution CO Survey: IV. Spiral-Driven Gas Dynamics in the Non-Barred Seyfert Galaxy NGC 4501
Authors: Onodera Sachiko , Koda Jin , Sofue Yoshiaki , Kohno Kotaro 
Published: March 2014

Abstract
We report on high-resolution interferometer observations of the ${{12\atop} \mathrm{CO}}$ ($J = 1 \hbox{--} 0$) emission in the central 5 kpc region of the Seyfert 2 galaxy NGC 4501. The observations were made using the Nobeyama Millimeter Array during a long-term CO line survey of Virgo spirals. The major features are: (1) a nuclear concentration with a radius of $r\sim 5^{\prime\prime}$ (390 pc), which is resolved into double peaks, and (2) spiral arms which extend out from the nuclear region. The nuclear component has a mass of $1.3 \times 10^8 \,{{{M}_{\odot}}}$, which corresponds to $\sim 3.5\%$ of the dynamical mass, and shows a slight non-circular motion. The double peaks are separated by $\sim {4\rlap {.}{}^{\mathrm {\prime \prime }}7}$ ($370 \:\mathrm{pc}$), and located on the root of optical spiral arms in a HST image. The gas arms are associated with the spiral dust lanes, and are linked to the central double peaks. The non-circular motions along the molecular arms indicate the fact that the gas is driven by the density wave, rather than the stochastic processes. We calculated the gas cloud orbits in a stellar spiral potential, and explained the observed CO spiral arms and non-circular motions. We suggest that the central gas condensation arises from spiral-driven gas transfer. We estimated and compared the effect of two possible mechanisms of angular-momentum transfer: galactic shock and gravitational torques. We discuss that the galactic shock is dominant.
Radiative Shocks in Rotating Accretion Flows around Black Holes
Authors: Okuda Toru , Teresi Vincenzo , Toscano Elena , Molteni Diego 
Published: March 2014

Abstract
It is well known that rotating inviscid accretion flows with adequate injection parameters around black holes could form shock waves close to the black holes, after the flow passes through the outer sonic point and can be virtually stopped by the centrifugal force. We numerically examined such shock waves in 1D and 2D accretion flows, while taking account of the cooling and heating of the gas and the radiation transport. The numerical results show that the shock location shifts outward compared with that in adiabatic solutions, and that a more rarefied ambient density leads to a more outward shock location. In 2D-flow, we find an intermediate frequency QPO behavior of the shock location, as is observed in the black hole candidate GRS 1915$+$105.
Sunyaev-Zel’dovich Effect toward Distant Galaxy Clusters at 43 GHz; Observation and Data
Authors: Tsuboi Masato , Miyazaki Atsushi , Kasuga Takashi , Kuno Nario , Sakamoto Akihiro , Matsuo Hiroshi 
Published: March 2014

Abstract
We have observed the Sunyaev–Zel’dovich (SZ) effect on eight X-ray bright galaxy clusters from $z = 0.18$ to 0.55 at 43 GHz using a newly developed 6-beam receiver installed on the Nobeyama 45-m telescope. The SZ effects were detected for all clusters as temperature decrements of 0.5–1 mK at the center. The Hubble constant is estimated to be $H_{0} = 64 \pm 17 \,\mathrm{km} \,\mathrm{s}^{-1} \,\mathrm{Mpc}^{-1}$ for a flat $\Lambda$CDM cosmology, which shows good agreement with other SZ effect observations. Although most of the observed profiles should be described by the isothermal spherical $\beta$-model density distribution, the deviation from the model seems to be larger for clusters with an irregular distribution in the X-ray image than those without such an irregularity.
A Shape-and-Density Model of the Putative Binary EKBO 2001QG298
Authors: Takahashi Shigeru , Ip Wing-Huen 
Published: March 2014

Abstract
Recent observations of the Edgeworth-Kuiper belt object (EKBO) 2001 $\mathrm{QG}_{298}$ (Sheppard, Jewitt 2004) have shown that the lightcurve of this object has a very large amplitude ($1.14 \pm 0.04 \,\mathrm{mag}$), indicating that it is either of an elongated shape or of a binary structure with two components of similar sizes nearly in contact with each other. On the basis of these interesting published data, we employed Roche binary lightcurve simulations to construct a shape model of EKBO 2001 $\mathrm{QG}_{298}$. The shape parameters of the best-fitted model were $260\ (164) \times 205 (130) \times 185\ (116) \,\mathrm{km}$ for the primary, and $265 (168)\times 160\ (102) \times 150\ (94) \,\mathrm{km}$ for the secondary in the case of an albedo of 0.04 (0.10). An additional result of this calculation is that the average bulk density of the contact binary system could be estimated to be $630 \,\mathrm{kg} \,\mathrm{m}^{-3}$. This value is similar to that of several icy moons of Saturn with a diameter of less than 200 km. We have also used the Jacobi ellipsoidal approximation to compute the shape of one of the largest EKBOs, Varuna. The corresponding shape parameters are $a : b : c = 1.00 : 0.76 : 0.50$. The lower limit of the bulk density is $\rho \ge 1000 \,\mathrm{kg} \,\mathrm{m}^{-3}$. These results are in good agreement with the published values of Jewitt and Sheppard (2002), and are consistent with their suggestion that larger icy bodies have higher densities (Sheppard, Jewitt 2002).
Offsets between Hα and CO Arms of a Spiral Galaxy, NGC 4254: A New Method for Determining the Pattern Speed of Spiral Galaxies
Authors: Egusa Fumi , Sofue Yoshiaki , Nakanishi Hiroyuki 
Published: March 2014

Abstract
We examined the offsets between H II regions and molecular clouds belonging to spiral arms of a late-type spiral galaxy, NGC 4254 (M99). We used a high-resolution ${{12\atop} \mathrm{CO}}$ ($J = 1 \hbox{--} 0$) image obtained by Nobeyama Millimeter Array (NMA) and an $\mathrm{H}\alpha$ image. We derived angular offsets ($\theta$) in the galactic disk, and found that they show a linear dependence on the angular rotation velocity of the gas ($\Omega_{\mathrm{G}}$). This linear relation can be expressed by the equation $\theta = (\Omega_{\mathrm{G}}-\Omega_{\mathrm{P}}) \cdot t_{\mathrm{H}\alpha}$, where $\Omega_{\mathrm{P}}$ and $t_{\rm H\alpha}$ are constant. Here, $\Omega_{\mathrm{P}}$ corresponds to the pattern speed of the spiral arms and $t_{\mathrm{H}\alpha}$ is interpreted as being the timescale between the peak compression of the molecular gas in the spiral arms and the peak of massive star formation. We could thus determine $\Omega_{\mathrm{P}}$ and $t_{\mathrm{H}\alpha}$ simultaneously by fitting a line to our $\theta \hbox{--} \Omega_{\mathrm{G}}$ plot, if we assume they are constant. From the plot for NGC4254, we obtained $t_{\mathrm{H}\alpha} = (4.8 \pm 1.2) \times 10^6 \,\mathrm{yr}$ and $\Omega_{\mathrm{P}} = 26^{+10}_{-6} \,\mathrm{km} \,\mathrm{s}^{-1} \,\mathrm{kpc}^{-1}$, which are consistent with previous studies. We suggest that this $\theta \hbox{--} \Omega_{\mathrm{G}}$ plot can be a new tool to determine the pattern speed and the typical timescale needed for star formations.
Periods of Activity Cycle of Polar Faculae
Authors: Li Kejun , Qiu Jiong , Su Tongwei , Irie Makoto , Gao Pengxin 
Published: March 2014

Abstract
The periodicity of the high-latitude solar activity has been studied using monthly-averaged polar facula counts obtained at the National Astronomical Observatory of Japan (NAOJ) and the annual number of polar faculae observed by Mount Wilson Observatory (MWO). The complex Morlet wavelet was utilized to analyze the periodicity in the two data sets. For the NAOJ and MWO data, the most eminent period is 10.89 and 10.48 years, respectively, which is the Schwabe period of the high-latitude solar activity. All possible periods detected at the low-latitude solar activity were also detected in the two data sets, and we found no distinct periods existing just in the two data sets of the high-latitude solar activity. The periodicity of the high-latitude solar activity is inferred to be the same as that of the low-latitude solar activity.
A Deeply Eclipsing SU UMa-Type Dwarf Nova with the Shortest Orbital Period, XZ Eridani
Authors: Uemura Makoto , Kato Taichi , Ishioka Ryoko , Bolt Greg , Cook Lewis M. , Monard Berto , Stubbings Rod , Torii Ken’ichi , Kiyota Seiichiro , Nogami Daisaku , Tanabe Kenji , Starkey Donn R. , Miyashita Atsushi 
Published: March 2014

Abstract
We discovered superhumps in an eclipsing dwarf nova, XZ Eridani, during an outburst in 2003 January–February. We determined the orbital and average superhump periods to be $0.061159602 \pm 0.000000044 \,\mathrm{d}$ and $0.062808\pm 0.000017 \,\mathrm{d}$, respectively. Our observations thus established that XZ Eri belongs to a rare class of deeply eclipsing SU UMa-type dwarf novae. The object has the shortest orbital period among seven known objects in this class. The superhump period decreased with time during a mid-plateau phase of the superoutburst, as observed in a number of ordinary, long-period SU UMa stars. During an early phase of the superoutburst, however, the superhump period increased, as observed in several short-period systems. XZ Eri is a unique object with which we can study the evolution of accretion-disk structures through eclipses during the phase of the superhump period increase.
V803 Centauri: Helium Dwarf Nova Mimicking a WZ Sge-Type Superoutburst
Authors: Kato Taichi , Stubbings Rod , Monard Berto , Butterworth Neil D. , Bolt Greg , Richards Tom 
Published: March 2014

Abstract
We observed the long-term behavior of the helium dwarf nova V803 Cen, and clarified the existence of at least two distinct states (a state with 77-d supercycles and a standstill-like state) that interchangeably appeared with a time-scale of 1–2 yr. We also conducted a time-resolved CCD photometry campaign during a bright outburst in 2003 June. The overall appearance of the outburst closely resembles that of the late stage of the 2001 outburst of WZ Sge, consisting of the initial peak stage (superoutburst plateau), the dip, and the oscillating (rebrightening) states. During the initial peak stage, we detected a large-amplitude superhump-type variation with a period of $0.018686(4) \,\mathrm{d} = 1614.5(4) \,\mathrm{s}$, and during the oscillation stage we detected variations with a period of $0.018728(2) \,\mathrm{d} = 1618.1(2) \,\mathrm{s}$. We consider that the former period better represents the superhump period of this system, and the latter periodicity may be better interpreted as arising from late superhumps. The overall picture of the V803 Cen outburst resembles that of a WZ Sge-type outburst, but apparently with a higher mass-transfer rate than that in hydrogen-rich WZ Sge-type stars. We suggest that this behavior may be either the result of difficulty in maintaining the hot state in a helium disk, or the effect of an extremely low tidal torque resulting from the extreme mass ratio.
AGN Black Hole Masses and Methods to Estimate the Mass
Authors: Xie Guang-Zhong , Chen Luo-En , Xie Zhao-Hua , Ma Li , Zhou Shu-Bai 
Published: March 2014

Abstract
The black hole mass, along with the ratio of the accretion rate to the Eddington accretion rate, is a fundamental parameter of active galactic nuclei. Using our new method to estimate the black hole mass, we developed our sample and estimated black hole masses, indicated by $M_\mathrm{H}$ for 12 blazars. We compared 12 cases, for each of which the relevant black hole mass was also estimated by the $L_\mathrm{5100} \hbox{--} R_\mathrm{BLR}$ relation or the $M_\mathrm{BH} \hbox{--} \sigma$ correlation method, which is indicated by $M_\mathrm{\sigma}$. We also found that (1) $M_\mathrm{H}$ values are systematically lower than $M_\mathrm{\sigma}$, but the differences between $M_\mathrm{\sigma}$ and $M_\mathrm{H}$ are very small for most sources; (2) there is a significant correlation between $M_\mathrm{\sigma}$ and $M_\mathrm{H}$, the correlation coefficient being $r = 0.66$ with a chance probability of $p \sim 1.9 \times 10^{-2}$. Based on these properties mentioned above, we have shown that the small systematical difference between $M_\mathrm{\sigma}$ and $M_\mathrm{H}$ is probably due to some systematic errors in our method.
Development of Real-Time Frame Selector 2 and the Characteristic Convective Structure in the Emerging Flux Region
Authors: Kozu Hiromichi , Kitai Reizaburo , Funakoshi Yasuhiro 
Published: March 2014

Abstract
A new image-grabbing system, Real-Time Frame Selector 2 (RTFS2), was developed and installed in the Domeless Solar Telescope at Hida Observatory. The purpose of this system is to acquire high-quality images in ground-based observations. We observed the emerging flux region NOAA 8582 in the G-band wavelengths from 20:59 UT to 23:32 UT on 1999 June 11 with RTFS2. Simultaneous $\mathrm{H}\alpha$ line center and wing wavelength observations with a Lyot filter system showed emerging flux loops and surge activities in this region. We applied a Local Correlation Tracking Method to the G-band data set in order to derive the horizontal convective structure in the upper convective zone. In addition to a meso-scale convective structure, we found divergent-flow structures under emerging flux loops, which were stable during the whole observation period, and located at the middle of the foot points of each flux loop. We suggest that the divergent-flow structure is a newly found characteristic of emerging flux regions.