bluuebunny/crossref_metadata_2025_split huggingface dataset:
Possibility of the Presence of S, SO2, and CO2 at the Poles of the Moon
Authors: Berezhnoy Alexey A. , Hasebe Nobuyuki , Hiramoto Takuji , Klumov Boris A. 
Published: March 2014

Abstract
The presence of volatiles near the lunar poles is considered. The chemical composition of a lunar atmosphere temporarily produced by comet impact is analyzed during the day and night. C-rich and long-period comets are insufficient sources of water ice on the Moon. O-rich short-period comets deliver significant amounts of $\mathrm{H}_{2} \mathrm{O}$, $\mathrm{CO}_{2}$, $\mathrm{SO}_{2}$, and S to the Moon. An observable amount of polar hydrogen can be delivered to the Moon by a single impact of an O-rich short-period comet with diameter of 5 km in the form of water ice. The areas where $\mathrm{CO}_{2}$ and $\mathrm{SO}_{2}$ ices are stable against a thermal sublimation are estimated to be 300 and $1500 \,\mathrm{km}^{2}$, respectively. If water ice exists in the 2 cm top regolith layer, $\mathrm{CO}_{2}$ and $\mathrm{SO}_{2}$ ices can be stable in the coldest parts of permanently shaded craters. The delivery rate of elemental sulfur near the poles is estimated to be $10^{6} \,\mathrm{g} \,\mathrm{yr}^{-1}$. The sulfur content is estimated to be as high as 1 wt% in the polar regions. The SELENE gamma-ray spectrometer can detect sulfur polar caps on the Moon if the sulfur content is higher than 1 wt%. This instrument can check the presence of hydrogen and minerals with the unusual chemical composition at the lunar poles.
The First Radioastronomical Observation with Photonic Local Oscillator
Authors: Shuro Takano , Ueda Akitoshi , Yamamoto Takashi , Asayama Shinichiro , Sekimoto Yutaro , Noguchi Takashi , Ishiguro Masato , Takara Hidehiko , Kawanishi Satoki , Ito Hiroshi , Hirata Akihiko , Nagatsuma Tadao 
Published: March 2014

Abstract
We present the results of experimental radioastronomical observations of an interstellar molecular spectral line with an SIS (superconductor–insulator–superconductor) receiver pumped by a photonic local oscillator (LO). A millimeter-wave LO signal was generated by feeding an optical comb signal into a W-band (75–110 GHz) photomixer using a uni-traveling-carrier photodiode (UTC-PD). A CS $J = 2 \hbox{--} 1$ line at 98 GHz was observed toward a high-mass star-forming region W 51 ($\mathrm{H}_2 \mathrm{O}$). We compared the obtained spectra with those obtained with a conventional Gunn oscillator as an LO. As a result, the line parameters, such as the width, intensity, and frequency, were consistent with each other. The results presented here show that the photonic LO is a very promising source for heterodyne receivers in millimeter–and submillimeter-wave astronomy.
Detectability of the Warm/Hot Intergalactic Medium through Emission Lines of O VII and O VIII
Authors: Yoshikawa Kohji , Yamasaki Noriko Y. , Suto Yasushi , Ohashi Takaya , Mitsuda Kazuhisa , Tawara Yuzuru , Furuzawa Akihiro 
Published: March 2014

Abstract
Most of the cosmic baryons predicted by the big-bang nucleosynthesis have evaded direct detection. Recent numerical simulations indicate that approximately 30 to 50 percent of the total baryons in the present universe are supposed to take the form of warm/hot intergalactic medium (WHIM) whose X-ray continuum emission is very weak. To identify those missing baryons, we consider in detail the detectability of WHIM directly through the emission lines of O VII (561, 568, 574, 665 eV) and O VIII (653 eV). For this purpose, we create mock spectra of the emission lines of WHIM using a light-cone output of cosmological hydrodynamic simulations. While the predicted fluxes are generally below the current detection limit, an unambiguous detection will be feasible with a dedicated X-ray satellite mission, which we also discuss in detail. Our proposed mission is especially sensitive to a WHIM with gas temperature of $T = 10^{6 \hbox{--} 7} \,\mathrm{K}$ and overdensity of $\delta = 10 \hbox{--} 100$ up to a redshift of 0.3 without being significantly contaminated by the cosmic X-ray background and the Galactic emissions. Thus, such a mission provides a unique and important tool to identify a large fraction of otherwise elusive baryons in the universe.
Hydrodynamic Modeling of a Flare Loop Connecting the Accretion Disk and Central Core of Young Stellar Objects
Authors: Isobe Hiroaki , Shibata Kazunari , Yokoyama Takaaki , Imanishi Kensuke 
Published: March 2014

Abstract
Many young stellar objects, such as protostars and T-Tauri stars, show strong flare activity. In this paper we present a hydrodynamic simulation of a flare loop that connects the central star and the accretion disk, and discuss the evaporation of the chromosphere of the central star and the disk. We assumed a long ($ \gt 10 \,{{{R}_{\odot}}}$$ \gt 10 \,{{{R}_{\odot}}}$) loop length, and that the flare energy is deposited near the half-way point between the disk and the stellar surface. We found that in some cases all of the plasma in the accretion disk is heated to the flare temperature and spreads over the flare loop. The condition for this “disk disappearance” was examined. The X-ray spectrum expected when we observe the simulation result was synthesized by taking into account the instrumental response of ASCA/GIS. However, we could not find any clear observational signature of the existence of the disk, because the bulk properties of a flare loop are determined by the flare heating flux and loop length, and not by the involvement of the disk. We found that the synthesized spectrum is reasonably fitted with a two-temperature model, and that the temperature of the hotter component is several factors lower than the maximum temperature of the simulation result.
Discovery of Interacting Molecular Gas toward the TeV Gamma-Ray Peak of the SNR G 347.3–0.5
Authors: Fukui Yasuo , Moriguchi Yoshiaki , Tamura Keisuke , Yamamoto Hiroaki , Tawara Yuzuru , Mizuno Norikazu , Onishi Toshikazu , Mizuno Akira , Uchiyama Yasunobu , Hiraga Junko , Takahashi Tadayuki , Yamashita Koujin , Ikeuchi Satoru 
Published: March 2014

Abstract
Supernova remnants ($=$ SNR) are suggested to be sites of cosmic-ray acceleration. In particular, it has been an issue of keen interest whether cosmic ray protons are being accelerated in a SNR which emits TeV $\gamma$-rays. A crucial observational test for this is to find dense molecular gas towards the SNR, because such molecular gas can best verify the existence of cosmic-ray protons via pion decay to $\gamma$-rays. Here, we show that new high-resolution mm-wave observations of interstellar CO molecule have revealed molecular gas at 1 kpc distance interacting with the TeV $\gamma$-ray SNR G 347.3$-$0.5, and that a molecular cloud of $\sim 200$ solar masses is clearly associated with the TeV $\gamma$-ray peak, providing strong evidence for proton acceleration. We have estimated the total energy of accelerated protons to be $\sim 1048 \,\mathrm{erg}$, which corresponds to an acceleration efficiency of $\sim 0.001$, posing an observational constraint on the proton acceleration.
One Approach to the Star-Formation History Inferred from the GRB Lag–Luminosity Relation
Authors: Toshio Murakami , Yonetoku Daisuke , Izawa Hisayo , Ioka Kunihito 
Published: March 2014

Abstract
The distances of about thirty gamma-ray bursts (GRBs) are known. The most remote one is at $z \sim 4.5$, and the remaining more dimmer GRBs are supposed to be more remote. If we can estimate the distances for the dimmer GRBs, their distances should be much beyond $z \sim 4.5$. Two independent studies to estimate their distances were previously conducted. One was based on the variability–luminosity relation, and the other was based on the lag–luminosity relation. However, these relations can apply only for a very limited range of luminosity. In this paper, we introduce the viewing angles and use a new lag-luminosity relation by Ioka and Nakamura (2001, ApJ, 554, L163), which is capable of explaining the luminosity of the nearest GRBs. By applying the new relation, we infer the star-formation history out to $z \sim 4$. Our result shows an increasing trend of star-formation out to $z \sim 4$. However, the lag–luminosity relation itself is still a matter of debate, and thus this work is a tentative approach. For example, we have used only eight known GRB distances. Our result should be checked and calibrated by future data with Swift, observing more distant GRBs.
Cloudy Accretion Disks
Authors: Kitabatake Etsuko , Fukue Jun 
Published: March 2014

Abstract
Gas and dust surrounding an accretion disk suffer from the influence of the strong radiation of the disk, to make cloud layers above and below the disk in some cases. We examined a stable configuration of such cloud layers formed around the standard accretion disk. The cloud configuration is drastically changed as the disk effective luminosity $\Gamma_\mathrm{eff}$ increases, where $\Gamma_\mathrm{eff}$ is defined as $\Gamma_\mathrm{eff} = (\sigma / \sigma_\mathrm{T}) (m_\mathrm{p}/m) (L_\mathrm{d} / L_\mathrm{E}), \sigma$ and $m$ being the particle cross-section and mass, respectively, $\sigma_\mathrm{T}$ and $m_\mathrm{p}$ the Thomson cross-section and proton mass, respectively, and $L_\mathrm{d}$ and $L_\mathrm{E}$ the disk and Eddington luminosities, respectively. When $\Gamma_\mathrm{eff}$ is smaller than 0.8, the cloud configuration is almost parallel to the disk plane, except for the innermost region, where the configuration is inclined to reach the inner edge of the disk. When $\Gamma_\mathrm{eff}$ exceeds about 0.8, on the other hand, the cloud layer is split at a middle region, where the stable cloud layer disappears. We also calculated the temperature distribution and continuous spectra of the cloud layer. For small $\Gamma_\mathrm{eff}$, the temperature distribution of the cloud resembles the standard disk. As $\Gamma_\mathrm{eff}$ increases, however, the temperature of the inner cloud decreases and that of the outer cloud somewhat increases, due to the irradiation and shadowing effects. As a result, the continuous spectra become softer with $\Gamma_\mathrm{eff}$.
Light-Curve Diagnosis of a Hot Spot for Accretion-Disk Models
Authors: Fukue Jun 
Published: March 2014

Abstract
Light curves of a hot spot rotating in a relativistic Keplerian disk were found to be periodic with typically two peaks, originating from a gravitational focusing effect and a Doppler boost. On the other hand, we found that light curves of a hot spot spirally infalling in a sub-Keplerian advective disk are aperiodic with typically a single peak, originating from a gravitational focusing effect or a Doppler boost. Such a difference in the light curves of a hot spot can discriminate background disk models.
Monte Carlo Modeling of Non-Gravitational Heating Processes in Galaxy Clusters
Authors: Shimizu Mamoru , Kitayama Tetsu , Sasaki Shin , Suto Yasushi 
Published: March 2014

Abstract
We consider non-gravitational heating effects on galaxy clusters based on the Monte Carlo modeling of merging trees of dark matter halos combined with the thermal evolution of gas inside each halo. Under the assumption of hydrostatic equilibrium and isothermal gas profiles, our model takes account of the metallicity evolution, metallicity-dependent cooling of gas, supernova energy feedback, and heating due to jets of radio galaxies in a consistent manner. The observed properties of galaxy clusters can be explained in models with higher non-gravitational heating efficiency than that in the conventional model. The possibilities include jet heating by the Fanaroff–Riley Type II radio galaxies, and the enhanced star formation efficiency and/or supernova energy feedback, especially at high redshifts.
Discovery of a Peculiar Pulsar in the Small Magellanic Cloud
Authors: Ueno Masaru , Yamaguchi Hiroya , Takagi Shin-ichiro , Yokogawa Jun , Koyama Katsuji 
Published: March 2014

Abstract
We report on a peculiar X-ray binary pulsar, IKT 1 $=$ RX J0047.3$-$7312, observed with XMM-Newton in 2000 October. The X-ray spectrum is described by a two-component spectrum. The hard component has a broken power-law with respective photon indices of 0.2 and 1.8, below and above the break energy at 5.8 keV. The soft component can be modeled by a blackbody of $kT = 0.6 \,\mathrm{keV}$. The X-ray flux shows a gradual decrease and periodic variations of about 4000 s. The averaged flux in 0.7–10.0 keV is $2.9 \times 10^{-12} \,\mathrm{erg} \,\mathrm{cm}^{-2} \,\mathrm{s}^{-1}$, which is $\sim 10$-times brighter than that in a ROSAT observation in 1999 November. In addition to the 4000-s variation, we found coherent pulsations of $263 \pm 1 \,\mathrm{s}$. These discoveries strengthen the Be/X-ray binary scenario proposed by the ROSAT and ASCA observations on this source, and confirm that most of the hard sources in the Small Magellanic Cloud are X-ray binary pulsars. A peculiar property of this XBP is that the coherent pulsations are found only in the soft component, and the folded light curve shows a flat top shape with a sharp dip. We discuss the nature of this XBP focusing on the peculiar soft component.
Study of the Bipolar Nebula IRAS 19312+1950. I. Mapping Observations
Authors: Nakashima Jun-ichi , Deguchi Shuji , Kuno Nario 
Published: March 2014

Abstract
IRAS 19312$+$1950 is an SiO maser source that exhibits a prominent bipolar nebulosity. Mapping observations of this object were made in the CO $J = 1 \hbox{--} 0$,${{13\atop} \mathrm{CO}} J = 1 \hbox{--} 0$, C${{18\atop} \mathrm{O}} J = 1 \hbox{--} 0$, CS $J= 2 \hbox{--} 1$, and HCN $J = 1 \hbox{--} 0$ lines and in the 150 GHz continuum band. Near-infrared imaging observations were also made in the $J, H$, and $K$-bands. The line profiles of the ${{12\atop} \mathrm{CO}}$ and HCN spectra consist of a weak component with the width of $50 \,\mathrm{km} \,\mathrm{s}^{-1}$ and a strong component of the width of $3 \,\mathrm{km} \,\mathrm{s}^{-1}$. The profiles of the ${{13\atop} \mathrm{CO}}$, C${{18\atop} \mathrm{O}}$, and CS lines have only the narrow component. Both of the components have an intensity peak at the IRAS position. The narrow component was clearly resolved with a $15^{\prime\prime}$ telescope beam. The spectral energy distribution of this object exhibits a doubly peaked profile between 1 and 25$\, {\mu \mathrm {m}}$. The 150 GHz continuum flux density was found to be 0.07 Jy, which is consistent with the flux density predicted by the expanding envelope model with a mass loss rate of $\sim 10^{-4} \,{{{M}_{\odot}}} \,\mathrm{yr}^{-1}$ at a distance of 2.5 kpc. We argue that the broad component originates from the expanding envelope of this object, and that the hot dust cloud, the source of the narrow component, is physically associated with this object. Though the present observations do not preclude the possibility of a young stellar object, we argue that it is less plausible. We conclude that IRAS 19312$+$1950 is an AGB/post-AGB star that evolved from a massive progenitor.
Three-Dimensional Magnetohydrodynamic Numerical Simulations of Coronal Loop Oscillations Associated with Flares
Authors: Miyagoshi Takehiro , Yokoyama Takaaki , Shimojo Masumi 
Published: March 2014

Abstract
We performed three-dimensional MHD numerical simulations for solar coronal magnetic loop oscillations and found: (1) The loop oscillation period is determined by its Alfvén time. (2) The amplitude of oscillation decreases exponentially in time. This is explained as energy transport by fast-mode MHD waves. The damping rate, $\omega _\mathrm{damp}$, is described as $\omega _\mathrm{damp} \propto V_\mathrm{a}/R$, where $V_\mathrm{a}$ is the Alfvén speed around loops and $R$ is the radius of the loop. Because of computer resources limitations, the plasma $\beta$ value is much larger than that of the real corona. We thus applied a scaling law derived from numerical simulation results to the real corona parameter ranges and analyzed the results.
A 8.8–50 GHz Complete Spectral Line Survey toward TMC-1 I. Survey Data
Authors: Kaifu Norio , Ohishi Masatoshi , Kawaguchi Kentarou , Saito Shuji , Yamamoto Satoshi , Miyaji Takeshi , Miyazawa Keisuke , Ishikawa Shin-ichi , Noumaru Chiaki , Harasawa Sumiko , Okuda Michiko , Suzuki Hiroko 
Published: March 2014

Abstract
We completed the first spectral line survey toward a cold, dark cloud TMC-1 (cyanopolyyne peak) in a frequency range between 8.8 and 50.0 GHz by the 45-m radio telescope of Nobeyama Radio Observatory. We detected 414 lines of 38 molecular species including 11 new molecules, such as $\mathrm{C_6H}$, CCO, $\mathrm{C_3O}$, CCS, $\mathrm{C_3S}$, HNCCC, HCCNC, $\mathrm{HC_3NH^{+}}$, HCCCHO, $\mathrm{CH_2CN}$, and cyclic $\mathrm{C_3H}$ ($c\hbox{-}\mathrm{C_3H}$), which were previously reported; only one significant line, U49536, remains unidentified. 177 out of 414 lines are reported for the first time. Some half of the detected molecules are linear carbon-chain species and their derivatives. We also discovered three new rarer isotopomers: CC${{34\atop} \mathrm{S}}, \mathrm{C_3}$${{34\atop} \mathrm{S}}$, and HDCS. Spectral charts are presented together with the observed line parameters of all detected lines. Improved molecular constants of several carbon-chain molecules obtained during the course of identification are also presented.
A High-Resolution Very Large Array Observation of a Protostar in OMC-3: Shock-Induced X-Ray Emission by a Protostellar Jet
Authors: Tsujimoto Masahiro , Koyama Katsuji , Kobayashi Naoto , Saito Masao , Tsuboi Yohko , Chandler Claire J. 
Published: March 2014

Abstract
Using the Very Large Array (VLA) in the A-configuration, we obtained a high-resolution 3.6 cm map of a hard X-ray source detected by the Chandra X-ray Observatory in a protostellar clump in Orion molecular cloud 3. Two radio continuum sources were detected in the vicinity of the X-ray source, both of which have NIR counterparts. We conclude that these VLA sources are free–free emission produced by shocks in protostellar jets from the NIR class I protostars. Using the centimeter data, we determined the power and orientation of the protostellar jets. The center position of the X-ray emission was found to be $\sim 1 {{}^{\prime \prime }} \hbox{--} 2 {{}^{\prime \prime }}$ offset from the exciting sources of the jets, and the displacement is in the direction of the jets and molecular outflows. We discuss the nature of the X-ray emission as the shock-excited plasma at the shock front where the jet propagates through the interstellar medium at a speed of $\sim 1000 \,\mathrm{km} \,\mathrm{s}^{-1}$.
X-Ray Expanding Features Associated with a Moreton Wave
Authors: Noriyuki Narukage , Morimoto Taro , Kadota Miwako , Kitai Reizaburo , Kurokawa Hiroki , Shibata Kazunari 
Published: March 2014

Abstract
We report on the simultaneous observation of a Moreton wave in $\mathrm{H}\alpha$ and two kinds of coronal expanding features in soft X-rays near the solar limb. We consider the faster X-ray feature and the slower one as being an “X-ray wave” and “ejecta”, respectively. The chromospheric Moreton wave propagated on the solar disk at a speed of $1040 \pm 100 \,\mathrm{km} \,\mathrm{s}^{-1}$, whereas the coronal X-ray wave propagated outside of the disk toward the outer corona at $1400 \pm 250 \,\mathrm{km} \,\mathrm{s}^{-1}$. We identified the X-ray wave as MHD fast-mode shock. The fast-mode Mach number ($M_{\mathrm{f}}$) of the X-ray wave was also estimated to be about 1.13–1.31, which decreases during propagation. The timing when the $M_{\mathrm{f}}$ became “1” is consistent with that of the disappearance of the Moreton wave. Moreover, we discuss the 3-dimensional structure of the shock wave and the relation between the shock wave and the ejecta (and $\mathrm{H}\alpha$ filament eruptions).
Observations of Cyclopropenylidene (Cyclic-C3H2) in the External Galaxies NGC 253 and M 82
Authors: Oike Tomoko , Kawaguchi Kentarou , Takano Shuro , Nakai Naomasa 
Published: March 2014

Abstract
Several transitions of the cyclopropenylidene (cyclic-$\mathrm{C}_3\mathrm{H}_2$) molecule have been observed in the 83–218 GHz region toward NGC 253 and M 82. Assuming local thermodynamic equilibrium, the rotational temperatures were determined to be $10.8 \pm 2.4 \,\mathrm{K}$ and $11.5 \pm 3.0 \,\mathrm{K}$ for NGC 253 and M 82, respectively, where the errors indicate three standard deviations ($3 \,\sigma$). The column densities of cyclic-$\mathrm{C}_3\mathrm{H}_2$ were determined to be ${N\mathrm{(NGC~253)} = (2.7 \pm 1.1) \times 10^{13} \,\mathrm{cm}^{-2}}$ and $N\mathrm{(M~82)} = (1.9 \pm 0.9) \times 10^{13} \,\mathrm{cm}^{-2}$. Large velocity gradient calculations were applied to estimate kinetic temperatures of around 60 K for NGC 253 and M 82. Considering the present result and recent observations of $\mathrm{NH}_3$ in both galaxies, molecular production mechanisms are discussed.
First mm-VLBI Observations between the TRAO 14-m and the NRO 45-m Telescopes: Observations of 86 GHz SiO Masers in VY Canis Majoris
Authors: Shibata Katsunori M. , Chung Hyung-Soo , Kameno Seiji , Roh Duk-Gyoo , Umemoto Tomofumi , Kim Kwang-Dong , Asada Keiichi , Han Seog-Tae , Mochizuki Nanako , Cho Se-Hyung , Sawada-Satoh Satoko , Kim Hyun-Goo , Bushimata Takeshi , Minh Young Chol , Miyaji Takeshi , Kuno Nario , Mikoshiba Hiroshi , Sunada Kazuyoshi , Inoue Makoto , Kobayashi Hideyuki 
Published: March 2014

Abstract
We have made VLBI observations at 86 GHz using a 1000-km baseline between Korea and Japan with successful detections of SiO $v = 1, J = 2$ -$1$ maser emissions from VY CMa and Orion KL in 2001 June. This was the first VLBI result for this baseline and the first astronomical VLBI observation for the Korean telescope. Since then, we observed SiO $v = 1, J = 2$ -$1$ maser emission in VY CMa in 2002 January and 2003 February and derived the distributions of the maser emissions. Our results show that the maser emissions extend over 2–4 stellar radii, and were within the inner radius of the dust shell. We observed other SiO maser sources and continuum sources, and 86-GHz continuum emissions were detected from three continuum sources. It was verified that this baseline has a performance comparable to the most sensitive baseline in the VLBA and the CMVA, and is capable of investigating the proper motions of maser features in circumstellar envelopes using monitoring observations.
Line-Profile Variations during an Eclipse of a Dwarf Nova, IP Pegasi
Authors: Ishioka Ryoko , Mineshige Shin , Kato Taichi , Nogami Daisaku , Uemura Makoto 
Published: March 2014

Abstract
Accretion disks are rotating disks formed by accreting matter onto compact objects, and are thought to be the source of various active phenomena. Dwarf novae, the best-studied disk systems, composed of a white dwarf with a surrounding disk and a red-dwarf companion star, exhibit double-peaked emission-line profiles because of disk rotation. When a disk is eclipsed by the companion star, the emission-line profiles vary with time, since a different portion of the disk having a different line-of-sight velocity is successively obscured. We report on spectacular variations of the line profiles during an eclipse that we obtained for the first time through Subaru spectroscopy of an eclipsing dwarf nova, IP Peg. Our fine data are useful for investigating detailed velocity profiles as well as the non-axisymmetric emissivity distribution. The observed variations are basically consistent with Keplerian rotation, but are more complex than those predicted by a simple axisymmetric model.