bluuebunny/crossref_metadata_2025_split huggingface dataset:
Subaru Weak-Lensing Survey II: Multi-Object Spectroscopy and Cluster Masses
Authors: Hamana Takashi , Miyazaki Satoshi , Kashikawa Nobunari , Ellis Richard S. , Massey Richard J. , Refregier Alexandre , Taylor James E. 
Published: March 2014

Abstract
We present the first results of a multi-object spectroscopic campaign to follow up cluster candidates located via weak lensing. Our main goals are to search for spatial concentrations of galaxies that are plausible optical counterparts of the weak-lensing signals, and to determine the cluster redshifts from those of member galaxies. Around each of 36 targeted cluster candidates, we obtained 15–32 galaxy redshifts. For 28 of these targets, we confirmed a secure cluster identification, with more than five spectroscopic galaxies within a velocity of $\pm$3000 kms$^{-1}$. This includes three cases where two clusters at different redshifts are projected along the same line-of-sight. In 6 of the 8 unconfirmed targets, we found multiple small galaxy concentrations at different redshifts, each containing at least three spectroscopic galaxies. The weak-lensing signal around those systems was thus probably created by the projection of groups or small clusters along the same line-of-sight. In both of the remaining two targets, a single small galaxy concentration was found. In some candidate super-cluster systems, we found additional evidence of filaments connecting the main density peak to an additional nearby structure. For a subsample of our most cleanly measured clusters, we investigated the statistical relation between their weak-lensing mass ($M_{\rm NFW}$, $\sigma_{\rm SIS}$) and the velocity dispersion of their member galaxies ($\sigma_{v}$), comparing our sample with optically and X-ray selected samples from the literature. Our lensing-selected clusters are consistent with $\sigma_v$$=$$\sigma_{\rm SIS}$, with a similar scatter to that of optically and X-ray selected clusters. We also derived an empirical relation between the cluster mass and the galaxy velocity dispersion, $M_{200}E$($z$) $=$ 11.0 $\times$ 10$^{14}$$\times$ ($\sigma_v/$1000 kms$^{-1}$)$^{3.0}h^{-1}M_\odot$, which is in reasonable agreement with predictions of $N$-body simulations in the $\Lambda$CDM cosmology.
Discovery of Molecular Loop 3 in the Galactic Center: Evidence for a Positive-Velocity Magnetically Floated Loop towards L
= 355$^\circ$–359$^\circ$
Authors: Fujishita Motosuji , Torii Kazufumi , Kudo Natsuko , Kawase Tokuichi , Yamamoto Hiroaki , Kawamura Akiko , Mizuno Norikazu , Onishi Toshikazu , Mizuno Akira , Machida Mami , Takahashi Kunio , Nozawa Satoshi , Matsumoto Ryoji , Fukui Yasuo 
Published: March 2014

Abstract
We have discovered a molecular dome-like feature towards 355$^{\circ}$$\leq$$l$$\leq$ 359$^{\circ}$ and 0$^{\circ}$$\leq$$b$$\leq$ 2$^{\circ}$. The large velocity dispersions of 50–100 km s$^{-1}$ of this feature are much larger than those in the Galactic disk, and indicate that the feature is located in the Galactic center, probably within $\sim $1 kpc of Sgr A$^{\ast}$. The distribution has a projected length of $\sim $600 pc and a height of $\sim $300 pc from the Galactic disk, and shows a large-scale monotonic velocity gradient of $\sim $130 km s$^{-1}$ per $\sim $600 pc. The feature is also associated with HI gas having a more continuous spatial and velocity distribution than that of ${}^{12}$CO. We interpret the feature as being a magnetically floated loop similar to loops 1 and 2, and name it “loop 3”. Loop 3 is similar to loops 1 and 2 in its height and length, but is different from loops 1 and 2 in that the inner part of loop 3 is filled with molecular emission. We have identified two foot points at both ends of loop 3. HI, ${}^{12}$CO, and ${}^{13}$CO datasets were used to estimate the total mass and the kinetic energy of loop 3 to be $\sim $3.0 $\times$ 10$^{6} M_\odot$ and $\sim $1.7 $\times$ 10$^{52} $erg. The huge size, velocity dispersions, and energy are consistent with the magnetic origin of the Parker instability, as in the case of loops 1 and 2, but is difficult to be explained by multiple stellar explosions. We argue that loop 3 is in an earlier evolutionary phase than loops 1 and 2 based on the inner-filled morphology and the relative weakness of the foot points. This discovery indicates that the western part of the nuclear gas disk of $\sim $1 kpc radius is dominated by the three well-developed magnetically floated loops, and suggests that the dynamics of the nuclear gas disk is strongly affected by magnetic instabilities.
Thermally Driven Winds from Radiatively Inefficient Accretion Flows
Authors: Kawabata Ryoji , Mineshige Shin 
Published: March 2014

Abstract
Radiatively inefficient accretion flows (RIAFs) are a common feature of low-luminosity accretion flows, including quiescent states of X-ray binaries and low-lunimosity active galactic nuclei. Thermally driven winds are expected from such hot accretion flows. By assuming that the flow has a self-similarity structure in the radial direction, we solved the vertical structure of the wind and accretion flows simultaneously and evaluated the mass loss rates by wind. We have found that the ratio of the outflow rate to the accretion rate is approximately unity for a viscosity parameter of $\alpha $$\lesssim$ 0.1, despite some uncertainties in the angular momentum and temperature distributions. That is, the accretion rate in the RIAFs is roughly proportional to the radius. Moreover, we elucidated the effect of cooling by wind on the underneath accretion flow, finding that this effect could be important for calculating the energy spectrum of the RIAF. Observational implications are briefly discussed in the context of Sgr A$^\ast$.
Implications of Bulk Velocity Structures in AGN Jets
Authors: Yang Jianping , Wang Jiancheng , Dai Benzhong , Gao Xiaoyan 
Published: March 2014

Abstract
Synchrotron self-Compton (SSC) models and External Compton (EC) models of AGN jets with continually longitudinal and transverse bulk velocity structures have been constructed. The observed spectra show complex and interesting patterns in different velocity structures and viewing angles. These models were used to calculate the synchrotron and inverse Compton spectra of two typical BL Lac objects (BLO) (Mrk 421 and 0716$+$714) and (one) Flat Spectrum Radio Quasars (FSRQs) (3C 279), and to discuss the implications of jet bulk velocity structures in a unification of the BLO and FR I radio galaxies (FRI). By calculating the synchrotron spectra and SSC spectra of BL Lac object jets with continually bulk velocity structures, we have found that the spectra are much different from those in jets with a uniform velocity structure under increasing viewing angles. The unification of BLO and FRI is less constrained by the viewing angles, and would be imprinted by velocity structures intrinsic to the jets, themselves. By considering jets with bulk velocity structures constrained by the apparent speed, we discuss the velocity structures imprinted on the observed spectra for different viewing angles. We find that the spectra are greatly impacted by longitudinal velocity structures, because the volume elements are compressed or expanded. Finally, we present the EC spectra of FSRQs and FR II radio galaxies (FRII), and find that they are weakly affected by the velocity structures compared to synchrotron and SSC spectra.
A Massive Disk Galaxy at z$&gt;$ 3 along the Line of Sight of QSO 1508$+$5714
Authors: Wang Yiping , Yamada Toru , Tanaka Ichi , Iye Masanori 
Published: March 2014

Abstract
We have obtained deep images in the BVRIJHKs bands of the field centered on QSO 1508$+$5714 ($z_{\rm em}$$=$ 4.28) with the Suprime-Cam, FOCAS, and MOIRCS cameras on Subaru telescope. We report here on the detection of a $B$-dropout galaxy, which is 3${\rlap{\hskip.75pt{^{\prime\prime}}}\hskip.75pt.\hskip1.75pt}$5 north-west of the QSO sightline. A photometric redshift analysis is presented to complement the color selection. Given the photometric properties of this object ($M$$=$$-$22.2, making $L$$\approx$ 3$ L^{\ast}$, if placed at its photometric redshift, $z$$\sim$ 3.5), as well as the Sérsic index ($n$$\sim$ 1) derived from a 2-D imaging decomposition of the HST WFPC2 image taken with the $I_{\mathit{F814}}$ filter, the identified system is consistent with a massive disk galaxy at $z &gt; $ 3. If confirmed, it would be one of the most distant massive disk galaxies known so far.
Suzaku X-Ray Imaging and Spectroscopy of Cassiopeia A
Authors: Maeda Yoshitomo , Uchiyama Yasunobu , Bamba Aya , Kosugi Hiroko , Tsunemi Hiroshi , Helder Eveline A. , Vink Jacco , Kodaka Natsuki , Terada Yukikatsu , Fukazawa Yasushi , Hiraga Junko , Hughes John P. , Kokubun Motohide , Kouzu Tomomi , Matsumoto Hironori , Miyata Emi , Nakamura Ryoko , Okada Shunsaku , Someya Kentaro , Tamagawa Toru , Tamura Keisuke , Totsuka Kohta , Tsuboi Yohko , Ezoe Yuichiro , Holt Stephen S. , Ishida Manabu , Kamae Tsuneyoshi , Petre Robert , Takahashi Tadayuki 
Published: March 2014

Abstract
Suzaku X-ray observations of a young supernova remnant, Cassiopeia A, were carried out. K-shell transition lines from highly ionized ions of various elements were detected, including Chromium (Cr-K$\alpha $ at 5.61 keV). The X-ray continuum spectra were modeled in the 3.4–40 keV band, summed over the entire remnant, and were fitted with a simplest combination of the thermal bremsstrahlung and the non-thermal cut-off power-law models. The spectral fits with this assumption indicate that the continuum emission is likely to be dominated by non-thermal emission with a cut-off energy at $&gt; $1 keV. The thermal-to-nonthermal fraction of the continuum flux in the 4–10 keV band is best estimated as $\sim $0.1. Non-thermal-dominated continuum images in the 4–14 keV band were made. The peak of the non-thermal X-rays appears at the western part. The peak position of the TeV $\gamma$-rays measured with HEGRA and MAGIC is also shifted at the western part with the 1-sigma confidence. Since the location of the X-ray continuum emission was known to be presumably identified with the reverse shock region, the possible keV–TeV correlations give a hint that the accelerated multi-TeV hadrons in Cassiopeia A are dominated by heavy elements in the reverse shock region.
Detection of Hard X-Rays from the Compton-Thick Seyfert 2 Galaxy NGC 2273 with Suzaku
Authors: Awaki Hisamitsu , Terashima Yuichi , Higaki Yuusuke , Fukazawa Yasushi 
Published: March 2014

Abstract
We have obtained a broad-band spectrum of the Compton-thick Seyfert 2 galaxy NGC 2273 with Suzaku. The spectrum reveals the first detection of hard X-rays above $\sim$10 keV from NGC 2273. The broad-band spectrum is well represented by a three component model, accompanied by both a strong iron K$\alpha$ line with an equivalent width of $\sim$1.8 keV and several weak lines. The three component model consists of a soft component, a reflection component from cold matter, and an absorbed power law component. The soft component can be represented by thin thermal emission with $kT$$\sim$ 0.56 keV or by a scattered component with a scattering fraction of 0.4%. Fixing the photon indices of the power law and reflection components at 1.9, we found that the power law component, heavily absorbed by gas with a column density of $\sim$1.5 $\times$ 10$^{24}$cm$^{-2}$, has an intrinsic 2–10 keV luminosity of $\sim$1.7 $\times$ 10$^{42}$ergs$^{-1}$. We also applied a reflection model based on a Monte Carlo simulation, assuming a simple torus geometry. We found that the model fits the broad band spectrum well, and we placed some tentative constraints on the geometry of the putative torus in NGC 2273.
Proper Motions with Subaru II. A Sample in the Subaru/XMM-Newton Deep Survey Field
Authors: Richmond Michael W. , Morokuma Tomoki , Doi Mamoru , Komiyama Yutaka , Yasuda Naoki , Okamura Sadanori 
Published: March 2014

Abstract
We search for stars with proper motions in a set of deep Subaru images, covering about 0.48 square degrees to a depth of $i^{\prime} \simeq$ 26, taken over a span of five and a half years. We follow the methods described in Richmond et al. (2009, PASJ, 61, 97) to reduce and analyze this dataset. We present a sample of 69 stars with motions of high significance, and discuss briefly the populations from which they are likely drawn. Based on photometry and motions alone, we expect that 14 of the candidates may be white dwarfs. Our candidate with the largest proper motion is surprisingly faint and likely to prove interesting: its colors and motions suggest that it might be an M dwarf moving at over 500 km s$^{-1}$ or an L dwarf in the halo.
AKARI Near- to Mid-Infrared Imaging and Spectroscopic Observations of the Small Magellanic Cloud. I Bright Point Source List
Authors: Ita Yoshifusa , Onaka Takashi , Tanabé Toshihiko , Matsunaga Noriyuki , Matsuura Mikako , Yamamura Issei , Nakada Yoshikazu , Izumiura Hideyuki , Ueta Toshiya , Mito Hiroyuki , Fukushi Hinako , Kato Daisuke 
Published: March 2014

Abstract
We carried out near- to mid-infrared imaging and spectroscopic observations of patchy areas in the Small Magellanic Cloud using the Infrared Camera aboard AKARI. Two 100 arcmin$^2$ areas were imaged in 3.2, 4.1, 7, 11, 15, and 24$ \mu$m, and also spectroscopically observed in the wavelength range continuously from 2.5 to 13.4$ \mu$m. The spectral resolving power, $\lambda/ \Delta \lambda$, values were about 20, 50, and 50 at 3.5, 6.6, and 10.6$ \mu$m, respectively. Other than the two 100 arcmin$^2$ areas, some patchy areas were imaged and/or spectroscopically observed as well. In this paper, we overview the observations and present a list of near- to mid-infrared photometric results, which lists $\sim $12000 near-infrared and $\sim $1800 mid-infrared bright point sources detected in the observed areas. The 10$ \sigma$ limits are 16.50, 16.12, 13.28, 11.26, 9.62, and 8.76 in Vega magnitudes at 3.2, 4.1, 7, 11, 15, and 24$ \mu$m bands, respectively.
Analytical Calculation of the Mergers of Black Hole–Neutron Star Binaries
Authors: Cho Hee-Suk , Lee Chang-Hwan 
Published: March 2014

Abstract
Black hole (BH)–neutron star (NS) mergers have been studied as one of the primary sources of gravitational wave radiation and a strong candidate for the sources of short-hard gamma-ray bursts (SHBs). In this work, we investigated the criterion for a tidal disruption to occur outside the innermost stable circular orbit with various initial conditions of BH and NS. We studied the merger processes due to Roche-lobe overflow by an analytical method with Newtonian orbital functions. By using the polytropic equation of state for the NS, we calculated the time scale of merger for both irrotating (IR) and corotationg (CR) configurations. The resulting time scale is $\sim $10$^{-3} $s for the IR case, which agrees well with that of hydrodynamic simulations. We present a simple comparison with the most recent simulation result. The connection to the SHBs is also discussed.
Subaru Near-Infrared Imaging of Herbig Ae Stars*
Authors: Fukagawa Misato , Tamura Motohide , Itoh Yoichi , Oasa Yumiko , Kudo Tomoyuki , Hayashi Saeko S. , Kato Eri , Ootsubo Takafumi , Itoh Yusuke , Shibai Hiroshi , Hayashi Masahiko 
Published: March 2014

Abstract
We report results of $H$-band ($\lambda =$ 1.65$ \mu$m) imaging observations of young intermediate-mass stars using the Subaru 8.2-m Telescope with the adaptive optics AO36 and the infrared coronagraph CIAO. The targets consist of 16 Herbig Ae/Be stars (15 Herbig Ae stars and one Herbig Be star) and four additional main-sequence stars with infrared excesses. Five protoplanetary disks have been spatially resolved around the Herbig Ae stars with ages of 2–8 Myr. The resolved disks have outer radii of several 100 AU, and their surface brightnesses range from 10 mag arcsec$^{-2}$ to 18 mag arcsec$^{-2}$. The images reveal various morphologies in optically thick disks: spiral arms around AB Aur, a banana-split structure with an outer arm for HD 142527, a compact circumprimary disk of HD 150193, a faint discontinuous ring around HD 163296, and an unstructured face-on disk of HD 169142. The detection of an optically thick disk in scattered light implies that it is vertically flared, and intercepts stellar light at least in the outer region where those images were obtained. However, the surface brightness distribution, the resolved structure, and other observational characteristics suggest that the disks are unlikely to be continuously flared young disks with small grains well mixed with gas. The detection rate and the disk brightness do not correlate with the stellar age and the disk mass, but there is a tendency that the brightest disks are still surrounded by long-lived envelopes (AB Aur, HD 100546, HD 142527). The significant diversity of the disk structure can be attributed to the multiplicity and the initial condition of the local star-forming environments. The detections of companion candidates around our targeted stars are also reported.
DM Delphini: A Progenitor of a Contact Binary with a Compact Tertiary Companion
Authors: Jia-Jia He , Sheng-Bang Qian 
Published: March 2014

Abstract
The orbital period of the short-period eclipsing binary DM Del was analyzed by using two newly determined eclipse times together with the others compiled from the literature. It has been discovered that the period shows a long-time continuous decrease at a rate of $dP/dt = -$2.27 $\times$ 10$^{-7}$ d yr$^{-1}$, while it undergoes a cyclic variation with a period of 31.73 years. Meanwhile, photometric light curves of a close binary in the $B$ and $V$ bands, published by Güdür et al., were analyzed with the 2003 version of the W–D code. It was found that the system is a semi-detached binary with a lobe-filling primary and a mass ratio of $q =$ 0.55. The long-time period decrease can be explained by mass transfer from the primary to the secondary. This is consistent with the semi-detached configuration. The geometrical structure of the binary and the long-term period decrease suggest that DM Del may be a progenitor of an overcontact binary or just in a broken-contact stage predicted by thermal relaxation oscillations. A cyclic period change reveals the presence of a tertiary unseen companion that may play an important role in the formation of the close binary by removing angular momentum from the central system.
Thermal and Magnetic Parameters in Solar Flares Derived from GOES X-Ray Light Curves
Authors: Yamamoto Tetsuya T. , Sakurai Takashi 
Published: March 2014

Abstract
The purpose of this study is to reproduce the GOES X-ray (1–8 ${Å}$) light curves of the impulsive phase of 20 solar flares and to estimate the thermal and magnetic parameters in flare loops. The expected X-ray light curves are calculated from the values of the coronal field strength and inflow velocity under some assumptions. We used the magnetic reconnection heating model of Shibata and Yokoyama (2002, ApJ, 577, 422), photospheric vector magnetic field data, and a simple 1-D flare loop model. It is found the maximum inflow velocities are $\sim $10$^{7} $cm s$^{-1}$, and that the maximum magnetic reconnection rates are 0.006–0.9, and further that the characteristic coronal field strengths are 6–100 G. Using the thermal and magnetic parameters derived, we found that geometrically our calculated flare loops are higher than the potential fields that model the postflare loops, and are also higher than the preflare loops containing magnetic free energy that is large enough to provide the thermal energy of a flare. Hence, we conclude that the plasma $\beta $ value would be near unity in the flare loops we studied, and the magnetic field lines shrunk during the decay phase. The downward velocities of the field-line shrinkage are estimated to be 10$^{6}$–10$^{7} $cm s$^{-1}$ except one event. The height of the reconnection point was roughly estimated to be from 10$^{10} $cm to 4 $\times$ 10$^{10} $cm. We propose a new interpretation of the Neupert effect, and also discuss a temporal relationship between the X-ray flux and the flare loop heating.
Stellar Parameters and Abundance Analysis of 58 Late G Giants
Authors: Liu Yujuan , Sato Bun’ei , Takeda Yoichi , Ando Hiroyasu , Zhao Gang 
Published: March 2014

Abstract
We present stellar atmospheric parameters, and kinematic parameters for a part of Xinglong Planet Search Program sample – 58 late G-type giants, obtained at Okayama Astrophysical Observatory. Additionally, we determined the chemical abundances, especially for the elements C, O, and Na. The metallicity distribution of our sample ranges covered from $-$0.6 to 0.2 in [Fe$/$H], which supports the previous results, suggesting a lack of super metal-rich giants with [Fe$/$H] $\gt +$0.2. The abundance of C is depleted by 0.13 dex, and [Na$/$Fe] shows an overabundance of 0.1 dex compared to a dwarf with the same spectral type, while the O abundance was not altered after the first dredge up. These results are consistent with theoretical predictions of stellar evolution. The behaviors of Si, Ca, Ti, Cr, Ni, Mn, ScII, YII, and CeII in our giants follow the same trends as in dwarfs.
Mass Estimation of Merging Galaxy Clusters
Authors: Takizawa Motokazu , Nagino Ryo , Matsushita Kyoko 
Published: March 2014

Abstract
We investigate the impact of mergers on the mass estimation of galaxy clusters using $N$-body $+$ hydrodynamical simulation data. We estimate the virial mass from these data and compare it with the real mass. When a smaller subcluster’s mass is larger than a quarter of that of the larger one, the virial mass can be larger than twice the real mass. The results strongly depend on the observational directions, because of an anisotropic velocity distribution of the member galaxies. We have also made X-ray surface brightness and spectroscopic-like temperature maps from the simulation data. The mass profile is estimated from these data on the assumption of hydrostatic equilibrium. In general, a mass estimation with X-ray data gives us better results than a virial mass estimation. The dependence upon observational directions is weaker than in the case of a virial mass estimation. When the system is observed along the collision axis, the projected mass tends to be underestimated. This fact should be noted, especially when the virial and/or X-ray mass is compared with gravitational lensing results.
Optical Spectroscopy of Candidates of Young Stellar Objects in NGC 1333
Authors: Itoh Yoichi , Gupta Ranjan , Oasa Yumiko , Sen A. K. , Tanaka Munechika , Terai Tsuyoshi , Nakaoka Seina 
Published: March 2014

Abstract
We carried out low-resolution optical spectroscopy of 14 low-luminosity young stellar object (YSO) candidates in the NGC 1333 cluster. These objects were previously identified by a near-infrared imaging survey. Eleven objects were confirmed to be YSOs by the H$\alpha$ line emission. The strengths of the H$\alpha$ emission are correlated with the near-infrared excesses of the objects. The spectral types of all YSOs are estimated to be M-type, indicative of low mass. Comparisons of the results of our spectroscopic observations and previous photometric observations with evolutionary tracks on the HR diagram suggest two objects to be young brown dwarfs.