bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dissipation of Magnetic Flux in Primordial Star Formation: From Run-away Phase to Mass-Accretion Phase
Authors: Maki Hideki , Susa Hajime 
Published: March 2014

Abstract
We investigate the dissipation of magnetic flux in primordial star-forming clouds throughout their collapse, including the run-away collapse phase as well as the accretion phase. We solve the energy equation and the non-equilibrium chemical reactions in the collapsing gas, in order to obtain the radial distribution of the ionized fraction during the collapse. As a result, we find that the ionized fraction is high enough for the magnetic field to couple with the gas throughout evolution of the cloud. This result suggests that the jet formation from protostars as well as the activation of magneto–rotational instability in the accretion disk are enabled in the presence of the cosmological seed magnetic flux proposed by Langer, Puget, and Aghanim (2003, Phys. Rev. D67, 43505).
Searching for a Companion Star of Tycho’s Type Ia Supernova with Optical Spectroscopic Observations
Authors: Ihara Yutaka , Ozaki Jin , Doi Mamoru , Shigeyama Toshikazu , Kashikawa Nobunari , Komiyama Yutaka , Hattori Takashi 
Published: March 2014

Abstract
We report on our first results of photometric and spectroscopic observations for Tycho’s supernova remnant (SNR Tycho) to search for the companion star of a type Ia supernova. From photometric observations using Suprime-Cam on the Subaru Telescope, we have picked up stars brighter than 22 mag (in $V$-band) for spectroscopy, which are located within a circular region with a radius of 30${}^{\prime\prime}$ around the center of SNR Tycho. If the ejecta of young supernova remnants, such as SNR Tycho, have a sufficient amount of Fe I, we should be able to detect absorption lines at 3720 Å and associated with transitions from the ground state of Fe I in the spectrum of the companion star. To identify the companion star of a SN Ia using these characteristic absorption lines of Fe I, we performed optical low-resolution spectroscopy of their targets using FOCAS on the Subaru Telescope. In our spectroscopic observations, we obtained spectra of 17 stars in the SNR Tycho region and compared them with template stellar spectra. We detect significant absorption lines from two stars at 3720 Å. In addition, spectra of four stars also have possible absorption lines. Since the widths of their absorption lines are broad, it is likely that the detected absorptions are due to Fe I in the expanding ejecta of SNR Tycho. However, none of stars exhibit a clear red wing in the observed profiles of the absorption, though a star in the background of the SNR should show it. Hence, we suggest another interpretation, that the detected absorption lines might be caused by the peculiarity of stars. Though Tycho(G) was raised as a candidate of the companion star of Tycho’s supernova in a previous study, we did not obtain evidence supporting the previous research. On the contrary, a star named Tycho(E) has an absorption line at 3720 Å, and its projected position is close to the center of SNR Tycho. Based on our observations, Tycho(E) is a new candidate as the companion star of Tycho’s supernova.
A New Model for the Structure of the DACs and SACs Regions in the Oe and Be Stellar Atmospheres
Authors: Danezis Emmanouel , Nikolaidis Dimitris , Lyratzi Evaggelia , Popovic Luka C. , Dimitrijevic Milan S. , Antoniou Antonis , Theodosiou Efstratios 
Published: March 2014

Abstract
We present a new mathematical model for the density regions where a specific spectral line and its SACs/DACs are created in the Oe and Be stellar atmospheres. In calculations of final spectral line function we consider that the main processes for the line broadening are the rotation of the density regions creating the spectral line and its DACs/SACs, as well as the random motions of the ions. This line function is able to reproduce the spectral feature, which enables us to calculate some important physical parameters, such as the rotational, radial, and random velocities, the full width at half maximum, the Gaussian deviation, the optical depth, the column density, and the absorbed or emitted energy. Additionally, we can calculate the percentage of the contribution of the rotational velocity and the ions’ random motions of the DACs/SACs regions to the line broadening. Finally, we present two tests and three short applications of the proposed model.
Near-Infrared Spectra of 29 Carbon Stars: Simple Estimates of Effective Temperature
Authors: Tanaka Masuo , Letip Ahmatjan , Nishimaki Yuichirou , Yamamuro Tomoyasu , Motohara Kentaro , Miyata Takashi , Aoki Wako 
Published: March 2014

Abstract
Near-infrared spectra of 29 carbon stars in the 0.9–2.4$\mu$m range were obtained by using a cross-dispersed echelle spectrograph. The target stars, which were classified into C-H, C-R, C-J, and C-N types, were selected from an atlas of Barnbaum, Stone, and Keenan (1996, ApJS, 105, 419). Because the stars are non long-period variables, the phase differences of the light curves do not strongly affect the spectra. The effective temperatures ($T_{\mathrm{eff}}$) of the carbon stars were estimated with errors of $\pm\;$200 K by fitting our spectra at wavelengths of 1.35, 1.74, and 2.29$\mu$m, with simple model spectra, while considering the H$^{-}$ opacity minimum to be around 1.6$\mu$m. At these wavelengths, molecular absorption due to CO, CN, and C$_{2}$ is not strong. The derived effective temperatures are distributed between 5100 K and 2600 K, and highly correlate with the temperature sequence in Barnbaum, Stone, and Keenan (ibid.), although the stars with temperature sequences beyond 4 have similar temperatures near $\sim$ 3000 K. We also compared our results with values derived by other methods in the literature: the aperture diameter method, the infrared flux method, and some model calculations.
Neutrino Emission from Type Ia Supernovae
Authors: Kunugise Takashi , Iwamoto Koichi 
Published: March 2014

Abstract
Type Ia supernovae (SNe Ia) produce a burst of neutrino emission due to electron captures on free protons and nuclei in the hot, dense matter synthesized by explosive nucleosynthesis. We calculated the luminosity and energy spectrum of the burst for a standard SN Ia model W7. We found a peak luminosity of the total three-flavor neutrinos of $\sim$10$^{50}$ergs$^{-1}$ and a neutrino emission duration of $\sim$1s. The average energy of the neutrinos was found to be $\sim$3 MeV. Electron neutrinos generated in the central region of SN Ia undergo flavor oscillations between $v_e, v_\mu$, and $v_\tau$. As a result, the fraction of electron neutrinos is reduced to $\sim$0.55. The detectability of these neutrinos and the implications for progenitor scenarios of SNe Ia are discussed.
Suzaku Observations of the Local and Distant Hot ISM
Authors: Smith Randall K. , Bautz Mark W. , Edgar Richard J. , Fujimoto Ryuichi , Hamaguchi Kenji , Hughes John P. , Ishida Manabu , Kelley Richard , Kilbourne Caroline A. , Kuntz K. D. , McCammon Dan , Miller Eric , Mitsuda Kazuhisa , Mukai Koji , Plucinsky Paul P. , Porter F. Scott , Snowden Steve L. , Takei Yoh , Terada Yukikatsu , Tsuboi Yohko , Yamasaki Noriko Y. 
Published: March 2014

Abstract
Suzaku observed the molecular cloud MBM 12 and a blank field less than $3^{\circ}$ away to separate the local and distant components of the diffuse soft X-ray background. Towards MBM 12, a local ($D \lesssim 275 \,\mathrm{pc}$) O VII emission line was clearly detected with an intensity of $3.5 \;\mathrm{photons} \;\mathrm{cm}^{-2} \,\mathrm{s}^{-1} \,\mathrm{sr}^{-1}$ (or line units, LU), and the O VIII flux was ${&lt;0.34 \;\mathrm{LU}}$. The origin of this O VII emission could be hot gas in the Local Hot Bubble (LHB), charge exchange within the heliosphere with oxygen ions from the solar wind (SWCX), or both. If entirely from the LHB, the emission could be explained by a region with emission measure of $0.0075 \,\mathrm{cm}^{-6} \,\mathrm{pc}$ and a temperature of $1.2 \times 10^6 \,\mathrm{K}$. However, this temperature and emission measure implies $1/4 \;\mathrm{keV}$ emission in excess of observations. There is no evidence in the X-ray light curve or solar wind data for a significant contribution from geocoronal SWCX, although interplanetary SWCX is still possible. In any case, the observed O VII flux represents an upper limit to both the LHB emission and interplanetary SWCX in this direction. The blank field was observed immediately afterwards. The net off-cloud O VII and O VIII intensities were (respectively) $2.34 \pm 0.33$ and $0.77 \pm 0.16 \;\mathrm{LU}$, after subtracting the on-cloud foreground emission. If this more distant O VII and O VIII emission is from a thermal plasma in collisional equilibrium beyond the Galactic disk, we infer it has a temperature of $(2.1 \pm 0.1) \times 10^6 \,\mathrm{K}$ with an emission measure of $(4 \pm 0.6) \times 10^{-3} \,\mathrm{cm}^{-6} \,\mathrm{pc}$.
Suzaku Observations of HESS J1616—508: Evidence for a Dark Particle Accelerator
Authors: Matsumoto Hironori , Ueno Masaru , Bamba Aya , Hyodo Yoshiaki , Mori Hideyuki , Uchiyama Hideki , Tsuru Takeshi Go , Koyama Katsuji , Kataoka Jun , Katagiri Hideaki , Takahashi Tadayuki , Hiraga Junko , Yamauchi Shigeo , Hughes John P. , Senda Atsushi , Kokubun Motohide , Kohmura Takayoshi , Porter Frederick S. 
Published: March 2014

Abstract
We observed the bright unidentified TeV $\gamma$-ray source HESS J1616$-$508 with the X-ray Imaging Spectrometers onboard the Suzaku satellite. No X-ray counterpart was found to a limiting flux of $3.1 \times 10^{-13} \,\mathrm{erg} \,\mathrm{s}^{-1} \,\mathrm{cm}^{-2}$ in the 2–10 keV band, which is some 60-times below the $\gamma$-ray flux in the 1–10TeV band. This object is bright in TeV $\gamma$-rays, but very dim in the X-ray band, and thus is one of the best examples in the Galaxy of a “dark particle accelerator.” We also detected soft thermal emission with $kT \sim 0.3 \hbox{--} 0.6 \,\mathrm{keV}$ near the location of HESS J1616$-$508. This may be due to a dust-grain scattering halo from the nearby bright supernova remnant RCW 103.
Suzaku Observation of the Metallicity Distribution in the Intracluster Medium of the Fornax Cluster
Authors: Matsushita Kyoko , Fukazawa Yasushi , Hughes John P. , Kitaguchi Takao , Makishima Kazuo , Nakazawa Kazuhiro , Ohashi Takaya , Ota Naomi , Tamura Takayuki , Tozuka Miyako , Tsuru Takeshi Go , Urata Yuji , Yamasaki Noriko Y. 
Published: March 2014

Abstract
The metallicity distribution in the Fornax cluster was studied with the XIS instrument on board the Suzaku satellite. The K-shell lines of O and Mg were resolved clearly, and the abundances of O, Mg, Si, S, and Fe were measured with great accuracy. The region within a $4'$ radius of NGC 1399 shows approximately solar abundances of Fe, Si, and S, while the $\mathrm{O/Fe}$ and $\mathrm{Mg/Fe}$ abundance ratios are about 0.4–0.5 and 0.7 in solar units, respectively. In the outer region of the radius range $6' &lt; r &lt; 23'$, the Fe and Si abundances drop to 0.4–0.5 solar and show no significant gradient within this region. The abundance ratios, $\mathrm{O/Fe}$ and $\mathrm{Mg/Fe}$, are consistent with those in the central region. We also measured the Fe abundance around NGC 1404 to be approximately solar, and the O, Ne, and Mg abundances to be 0.5–0.7 times the Fe level. A significant relative enhancement of Fe within 130 kpc of NGC 1399 and in NGC 1404 indicates an origin in SN Ia, in contrast to the species O, Ne, and Mg, which reflect the stellar metallicity. The mass-to-light ratios for O and Fe within 130 kpc of NGC 1399 are over an order of magnitude lower than those in rich clusters, reflecting the metal enrichment history of this poor cluster.
In-Orbit Performance of the Hard X-Ray Detector on Board Suzaku
Authors: Kokubun Motohide , Makishima Kazuo , Takahashi Tadayuki , Murakami Toshio , Tashiro Makoto , Fukazawa Yasushi , Kamae Tuneyoshi , Madejski Greg M. , Nakazawa Kazuhiro , Yamaoka Kazutaka , Terada Yukikatsu , Yonetoku Daisuke , Watanabe Shin , Tamagawa Toru , Mizuno Tsunefumi , Kubota Aya , Isobe Naoki , Takahashi Isao , Sato Goro , Takahashi Hiromitsu , Hong Soojing , Kawaharada Madoka , Kawano Naomi , Mitani Takefumi , Murashima Mio , Suzuki Masaya , Abe Keiichi , Miyawaki Ryouhei , Ohno Masanori , Tanaka Takaaki , Yanagida Takayuki , Itoh Takeshi , Ohnuki Kousuke , Tamura Ken-ichi , Endo Yasuhiko , Hirakuri Shinya , Hiruta Tatsuro , Kitaguchi Takao , Kishishita Tetsuichi , Sugita Satoshi , Takahashi Takuya , Takeda Shin’ichiro , Enoto Teruaki , Hirasawa Ayumi , Katsuta Jun’ichiro , Matsumura Satoshi , Onda Kaori , Sato Mitsuhiro , Ushio Masayoshi , Ishikawa Shin-nosuke , Murase Koichi , Odaka Hirokazu , Suzuki Masanobu , Yaji Yuichi , Yamada Shinya , Yamasaki Tomonori , Yuasa Takayuki ,   the HXD team
Published: March 2014

Abstract
The in-orbit performance and calibration of the Hard X-ray Detector (HXD) on board the X-ray astronomy satellite Suzaku are described. Its basic performances, including a wide energy bandpass of 10–600 keV, energy resolutions of $\sim 4 \,\mathrm{keV}$ (FWHM) at 40 keV and $\sim 11\%$ at 511 keV, and a high background rejection efficiency, have been confirmed by extensive in-orbit calibrations. The long-term gains of PIN-Si diodes have been stable within 1% for half a year, and those of scintillators have decreased by 5–20%. The residual non-X-ray background of the HXD is the lowest among past non-imaging hard X-ray instruments in energy ranges of 15–70 and 150–500 keV. We provide accurate calibrations of energy responses, angular responses, timing accuracy of the HXD, and relative normalizations to the X-ray CCD cameras using multiple observations of the Crab Nebula.
Formation of Moving Magnetic Features and Penumbral Magnetic Fields with Hinode/SOT
Authors: Kubo Masahito , Ichimoto Kiyoshi , Shimizu Toshifumi , Tsuneta Saku , Suematsu Yoshinori , Katsukawa Yukio , Nagata Shin’ichi , Tarbell Theodore D. , Shine Richard A. , Title Alan M. , Frank Zoe A. , Lites Bruce , Elmore David 
Published: March 2014

Abstract
Vector magnetic fields of moving magnetic features (MMFs) were well observed with the Solar Optical Telescope (SOT) aboard the Hinode satellite. We focused on the evolution of three MMFs with the SOT in this study. We found that an MMF having relatively vertical fields with the same polarity as the sunspot was detached from the penumbra around the granules appearing in the outer penumbra. This suggests that granular motions in the outer penumbra are responsible for disintegration of the sunspot. Two MMFs with polarity opposite to the sunspot are located around the outer edge of horizontal fields extending from the penumbra. This is evidence that the MMFs with polarity opposite to the sunspot are the prolongation of penumbral horizontal fields. Redshifts larger than the sonic velocity in the photosphere are detected for some of the MMFs with polarity opposite to the sunspot.
EUV Emission Lines and Diagnostics Observed with Hinode/EIS
Authors: Young Peter R. , Zanna Del Giulio , Mason Helen E. , Dere Ken P. , Landi Enrico , Landini Massimo , Doschek George A. , Brown Charles M. , Culhane Len , Harra Louise K. , Watanabe Tetsuya , Hara Hirohisa 
Published: March 2014

Abstract
Quiet Sun and active region spectra from the Hinode/EIS instrument are presented, and the strongest lines from different temperature regions discussed. A list of emission lines recommended to be included in EIS observation studies is presented based on analysis of blending and diagnostic potential using the CHIANTI atomic database. In addition we identify the most useful density diagnostics from the ions covered by EIS.
Probing the Physical Properties of the NGC 5548 Broad Line Region Using Balmer Lines
Authors: Popović Luka Č. , Shapovalova Alla I. , Chavushyan Vahram H. , Ilić Dragana , Burenkov Alexandr N. , Mercado Abelardo , Bochkarev Nikolay G. 
Published: March 2014

Abstract
We investigated the physical characteristics of the broad line region (BLR) of NGC 5548 using the Boltzmann plot (BP) method, which we applied to the Balmer lines observed from 1996 to 2004. We found that variability earlier detected in the lines is also present in the temperature parameter $A$, obtained from the BP method. Using the BP temperature parameter $A$ to calculate temperature, we found that the average temperature for the considered period was $T \approx$10000 K, and that it varies from 5000K (in 2002) to 15000K (in 1998). This variation correlates with the AGN-component of the optical continuum flux ($r=$ 0.85), and may indicate the existence of an accretion disk in the BLR of NGC 5548.
RT Leonis Minoris: Does It Belong to an A- or W-Type Overcontact Binary System?
Authors: Qian Sheng-Bang , He Jia-Jia , Xiang Fu-Yuan 
Published: March 2014

Abstract
New photometric observations and analyses of the W UMa-type binary system RT Leonis Minoris are presented. A period study with our four times of light minimum, including other eclipse times from the literature, suggests that the orbital period of the binary star is variable. The O – C curve can be explained as a cyclic variation with an amplitude of 0:d0049 and a period of 46.7 yr. Photometric solutions were derived by using the 2003 version of the Wilson–Devinney method (1971, ApJ, 166, 605), and absolute parameters of the system were determined. The results indicate that RT LMi is an ambiguous W UMa-type overcontact system for the following reasons: (i) the depths of both minima are nearly equal, which makes it very difficult to distinguish whether it belongs to an A- or W-type system; (ii) the primary minima in Hoffmann’s light curves are an occultation, indicating a W-type system, while the primary minimum in our light curve is a transit, suggesting an A-type light variation; and (iii) though our light curve shows an A-type variation, the photometric solutions indicate a higher secondary temperature of T2 = 6513 K (T1 = 6400 K), making the binary system, surprisingly, of W-type. These may indicate that Binnendijk’s classification based on the shape of the light curve cannot reveal the physical properties of W UMa-type binary stars of this kind.
Near-Infrared Coronagraphic Observations of a Classical T Tauri Star, DO Taurus
Authors: Itoh Yoichi , Hayashi Masahiko , Tamura Motohide , Oasa Yumiko , Hioki Tomonori , Fukagawa Misato , Kudo Tomoyuki 
Published: March 2014

Abstract
A high angular resolution near-infrared image of a classical T Tauri star, DO Tau, was obtained with Coronagraphic Imager with Adaptive Optics (CIAO) mounted on the Subaru Telescope. Circumstellar emission was detected at $\sim 1{\rlap{\hskip.75pt{^{\prime\prime}}}\hskip.75pt.\hskip1.75pt}7$ from the central star in the direction of the redshifted jet. No emission was found toward the opposite direction. We also found one faint point source 3${\rlap{\hskip.75pt{^{\prime\prime}}}\hskip.75pt.\hskip1.75pt}$46 away from the central star. The following observation will reveal whether it is an associated planetary mass object or a background object.
Subaru Weak Lensing Study of Seven Merging Clusters: Distributions of Mass and Baryons
Authors: Okabe Nobuhiro , Umetsu Keiichi 
Published: March 2014

Abstract
We present and compare projected distributions of mass, galaxies, and the intracluster medium (ICM) for a sample of merging clusters of galaxies based on a joint weak-lensing, optical photometric, and X-ray analysis. Our sample comprised seven nearby Abell clusters, for which we had conducted systematic, deep imaging observations with Suprime-Cam on the Subaru Telescope. Our seven target clusters, representing various merging stages and conditions, allowed us to investigate in detail the physical interplay between dark matter, ICM, and galaxies associated with cluster formation and evolution. A 1750 and A 1758 are binary systems consisting of two cluster-sized components; A 520, A 754, A 1758N, A 1758S, and A 1914 are on-going cluster mergers; and A 2034 and A 2142 are cold-front clusters. In the binary clusters, the projected mass, optical light, and X-ray distributions are overall similar and regular without significant substructures. On-going and cold-front merging clusters, on the other hand, reveal highly irregular mass distributions. Overall, the mass distribution appears to be similar to the galaxy luminosity distribution, whereas their distributions are quite different from the ICM distribution in a various ways. We also measured for individual targets global cluster parameters, such as the cluster mass, the mass-to-light ratio, and the ICM temperature. A comparison of the ICM and the virial temperatures of merging clusters from X-ray and weak-lensing analyses, respectively, shows that the ICM temperature of on-going and cold-front clusters is significantly higher than the cluster virial temperature by a factor of $\sim 2$. This temperature excess in the ICM could be explained by the effects of merger boosts.
Suzaku Results on Cygnus X-1 in the Low/Hard State
Authors: Makishima Kazuo , Takahashi Hiromitsu , Yamada Shin’ya , Done Chris , Kubota Aya , Dotani Tadayasu , Ebisawa Ken , Itoh Takeshi , Kitamoto Shunji , Negoro Hitoshi , Ueda Yoshihiro , Yamaoka Kazutaka 
Published: March 2014

Abstract
The black-hole binary Cygnus X-1 was observed for 17ks with the Suzaku X-ray observatory in 2005 October, while it was in a low/hard state with a 0.7-300keV luminosity of $4.6\times 10^{37}$ ergs $^{-1}$ . The XIS and HXD spectra, spanning 0.7-400keV, were reproduced successfully, incorporating a cool accretion disk and a hot Comptonizing corona. The corona is characterized by an electron temperature of $ \sim$ 100keV, and two optical depths of $ \sim$ 0.4 and $ \sim$ 1.5, which account for the softer and harder continua, respectively. The disk has an innermost temperature of $ \sim$ 0.2keV, and is thought to protrude half way into the corona. The disk not only provides seed photons to the Compton cloud, but also produces a soft spectral excess, a mild reflection hump, and a weakly broadened iron line. A comparison with the Suzaku data on GRO J1655 $-$ 40 reveals several interesting spectral differences, which can mostly be attributed to inclination effects, assuming that the disk has a flat geometry while the corona is grossly spherical. An intensity-sorted spectroscopy indicates that the continuum becomes less Comptonized when the source flares up on time scales of 1-200s, while the underlying disk remains unchanged.
Luminosity Dependence of the Electron Temperature in the Bright Hard
State of the Black Hole Candidate GX 339–4
Authors: Miyakawa Takehiro , Yamaoka Kazutaka , Homan Jeroen , Saito Koji , Dotani Tadayasu , Yoshida Atsumasa , Inoue Hajime 
Published: March 2014

Abstract
We have analyzed 200 Rossi X-ray Timing Explorer observations of the black hole candidate GX339 $-$ 4, all from bright hard state periods between 1996 and 2005. The purpose of our study is to investigate the radiation mechanisms in the hard state of GX 339 $-$ 4. The broadband 3-200keV spectra were successfully modeled by a simple analytic model, power-law with an exponential cut-off modified with a smeared edge. The obtained energy cut-off ( $E_{\rm {cut}}$ ) was distributed over 50-200keV, and the photon index over 1.4-1.7. We found a clear anti-correlation ( $E_{\rm {cut}} \propto L^{-0.70\pm0.06}$ ) between the X-ray luminosity ( $L$ ) in 2-200keV and $E_{\rm {cut}}$ , when $L$ is larger than $7 \times 10^{37}$ ergs $^{-1}$ (assuming a distance of 8kpc), while $E_{\rm {cut}}$ is roughly constant at around 200keV when $L$ is smaller than $7 \times 10^{37}$ ergs $^{-1}$ . This anti-correlation remained unchanged by adopting a more physical thermal Comptonization model, which resulted in an anti-correlation that can be expressed as $kT_{\rm {e}} \propto L^{-0.24\pm0.06}$ . These anti-correlations can be quantitatively explained by a picture in which the energy-flow rate from protons to electrons balances with inverse Compton cooling.