bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mars: Dissipating Behavior of the Cloud Belt
Authors: Nakakushi Takashi , Akabane Tokuhide , Iwasaki Kyosuke , Larson Stephen M. 
Published: March 2014

Abstract
This is a brief report on the Martian climate, based on our observations in 2001 as well as those in 1997 and 1999. The focus is the dissipating behavior of the low-latitude cloud belt appearing around the aphelion, the behavior of which has never been explicitly examined. We derive the optical thickness of water ice clouds (WICs) as $ \tau_{\mathrm{WIC}} \approx 0.1$ ($ \lambda \simeq 4400\,{Å}$) at the solar longitude $ L_{\mathrm{s}} = 174^\circ$ in 2001. The latitudinal coverage of the cloud belt is approximately $ L_{\mathrm{s}}$-independent just until its end. The cloud belt divides into a “semi-encircling” cloud band and discrete WICs before its dissipation (over $ L_{\mathrm{s}} \sim 100^\circ \hbox{--} 110^\circ$) in many cases. We suggest that this cloud division should embody localization of the cross-equatorial Hadley circulation.
Superhump Evolution in the Ultrashort Period Dwarf Nova 1RXS J232953.9+062814
Authors: Uemura Makoto , Kato Taichi , Ishioka Ryoko , Yamaoka Hitoshi , Schmeer Patrick , Krajci Tom , Starkey Donn R. , Torii Ken’ichi , Kawai Nobuyuki , Urata Yuji , Kohama Mitsuhiro , Yoshida Atsumasa , Ayani Kazuya , Kawabata Tetsuya , Tanabe Kenji , Matsumoto Katsura , Kiyota Seiichiro , Pietz Jochen , Vanmunster Tonny , Oksanen Arto , Giambersio Antonio 
Published: March 2014

Abstract
We report on the evolution of superhumps and late superhumps in an ultrashort period dwarf nova, 1RXS J232953.9$+$062814, during the superoutburst in 2001 November. Ordinary superhumps were observed throughout a plateau phase, a rapid fading phase, and a rebrightening phase. During the plateau phase, the superhump period increased with time at a large rate of $P_\mathrm{dot} = 1.19 \pm 0.24 \times 10^{-4}$. In conjunction with the rebrightening phenomenon, these characteristics indicate that an accretion disk expanded further outward from the $3:1$ resonance radius, which caused a large amount of left over matter at the outer disk, even after the superoutburst. In the post-outburst phase, we detected late superhumps superimposed on dominant double-peak modulations. Late superhumps were observed at least for 10 d without a significant period change. We detected the first normal outburst of this object on 2001 December 26. The interval between the superoutburst and this normal one is 53 d. This short recurrence time supports a high mass-transfer rate in this system. Concerning the evolutionary status of 1RXS J232953.9$+$062814, we propose that it is a progenitor of AM CVn stars on the evolutionary course of the cataclysmic variable channel in which systems have a secondary star with a hydrogen-exhausted core.
A Deep Optical Observation for an Enigmatic Unidentified Gamma-Ray Source 3EG J1835+5918
Authors: Totani Tomonori , Kawasaki Wataru , Kawai Nobuyuki 
Published: March 2014

Abstract
We report on a deep optical imaging observation using the Subaru Telescope for a very soft X-ray source, RX J1836.2$+$5925, which has been suspected to be an isolated neutron star associated with the brightest as-yet unidentified EGRET source outside the Galactic plane, 3EG J1835$+$5918. An extended source having a complex, bipolar shape is found at $B\sim 26$, which might be an extended pulsar nebular whose flux is about 5–6 orders of magnitude lower than gamma-ray flux, although finding a galaxy of this magnitude by chance in the error circle is of order unity. We have found two even fainter, possible point sources at $B \sim 28$, although their detections are not firm because of a low signal-to-noise ratio. If the extended object of $B\sim 26$ is a galaxy and not related to 3EG J1835$+$5918, a lower limit on the X-ray/optical flux ratio can be set as $f_\mathrm{X}/f_B \gtrsim 2700$, giving further strong support for the neutron-star identification of 3EG J1835$+$5918. Interestingly, if either of the two sources at $B \sim 28$ is the real counterpart of RX J1836.2$+$5925 and thermal emission from the surface of an isolated neutron star, the temperature and distance to the source become $\sim 4 \times 10^5 \,\mathrm{K}$ and $\sim 300 \,\mathrm{pc}$, respectively, showing a striking similarity of its spectral energy distribution to the proto-type radio-quiet gamma-ray pulsar Geminga. No detection of nonthermal hard X-ray emission is consistent with the ASCA upper limit, if the nonthermal flux of $\mbox{3EG J1835$+$5918} / \mbox{RX J1836.2$+$5925}$ 3EG J1835$+$5918$/$RX J1836.2$+$5925 is at a similar level to that of Geminga.
Reliability of Merger Tree Realizations of Dark Halos in the Monte Carlo Modeling of Galaxy Formation
Authors: Shimizu Mamoru , Kitayama Tetsu , Sasaki Shin , Suto Yasushi 
Published: March 2014

Abstract
We examine the reliability of the merger trees generated for the Monte Carlo modeling of galaxy formation. In particular we focus on the cold gas fraction predicted from merger trees with different assumptions on the progenitor distribution function, the timestep, and the mass resolution. We show that the cold gas fraction is sensitive to the accuracy of the merger trees at small-mass scales of progenitors at high redshifts. One can reproduce the Press–Schechter prediction to a reasonable degree by adopting a fairly large number of redshift bins, $ N_\mathrm{step}\sim 1000$, in generating merger trees, which is a factor of ten larger than the canonical value used in previous literature.
Chandra Observations and Optical Identification of Hard X-Ray Sources Discovered with ASCA
Authors: Watanabe Shin , Akiyama Masayuki , Ueda Yoshihiro , Ohta Kouji , Mushotzky Richard , Takahashi Tadayuki , Yamada Toru 
Published: March 2014

Abstract
We present the first results of Chandra and optical follow-up observations of hard X-ray sources detected in the ASCA Medium Sensitivity Survey (AMSS). Optical identifications were made for five objects. Three of them show either weak or absent optical narrow emission lines, and are at low redshift $ \langle z \rangle \sim 0.06$. One of them is a broad line object at $ z = 0.910$ and one is a $ z = 0.460$ object with only narrow lines. All of the narrow-line objects show strong evidence of absorption in their X-ray spectra. Their line ratios are consistent with a Seyfert II/LINER identification, as are the line widths. The three low-redshift objects have the colors of normal galaxies, and apparently the light is dominated by stars. This could be due to extinction of the underlying nuclear continuum by the same matter that absorbs X-rays and/or due to dilution of the central source by starlight. These results suggest that X-ray sources that appear as “normal” galaxies in optical and near-IR bands significantly contribute to the hard X-ray background. This population of objects has a high space density, and probably dominates the entire population of active galaxies.
Flat Spectrum X-Ray Emission from the Direction of a Molecular Cloud Associated with SNR RX J1713.7–3946
Authors: Uchiyama Yasunobu , Takahashi Tadayuki , Aharonian Felix A. 
Published: March 2014

Abstract
We report on the discovery of a diffuse X-ray source with ASCA, presumably associated with a molecular cloud in the vicinity of the supernova remnant RX J1713.7$-$3946. The energy spectrum (1–10 keV) of the hard X-ray source shows a flat continuum, which is described by a power-law with a photon index of $ \Gamma = 1.0^{+0.4}_{-0.3}$. We argue that this unusually flat spectrum can be best interpreted in terms of characteristic bremsstrahlung emission from the loss-flattened distribution of either sub-relativistic protons or mildly relativistic electrons. The strong shock of RX J1713.7$-$3946, which is likely to interact with the molecular cloud, as evidenced by CO-line observations, seems to be a natural site of acceleration of such nonthermal particles. The observed luminosity of $ L_\mathrm{X} = 1.7 \times 10^{35} \,\mathrm{erg} \,\mathrm{s}^{-1}$ (for a distance of 6 kpc) seems to require a huge kinetic energy of about $ 10^{50} \,\mathrm{erg}$ in the form of nonthermal particles to illuminate the cloud. The shock-acceleration at RX J1713.7$-$3946 can barely satisfy this energetic requirement, unless (i) the source is located much closer than the preferred distance of 6 kpc and/or (ii) the mechanical energy of the supernova explosion essentially exceeds $ 10^{51} \,\mathrm{erg}$. Another possibility would be that an essential part of the lost energy due to the ionization and heating of gas, is somehow converted to plasma waves, which return this energy to nonthermal particles through their turbulent reacceleration on the plasma waves.
V463 Scuti (Nova Sct 2000): Rapidly Evolving Nova with a Prominent Premaximum Halt
Authors: Kato Taichi , Uemura Makoto , Haseda Katsumi , Yamaoka Hitoshi , Takamizawa Kesao , Fujii Mitsugu , Kiyota Seiichiro 
Published: March 2014

Abstract
We summarize photometric and spectroscopic observations of V463 Sct (Nova Sct 2000), which was originally thought to be a red variable. The spectrum taken on 2000 March 16.81 UT showed prominent emission lines with a FHWM of $990 \,\mathrm{km} \,\mathrm{s}^{-1}$ ($\mathrm{H}\alpha$). The light curve shows a conspicuous premaximum halt lasting for at least 24d, and a late-phase flare-like maximum. The nova then started rapidly fading at a rate corresponding to $t_2 = 15 \pm 3 \,\mathrm{d}$. Long premaximum halts have been considered as a unique character of the “slowest” novae. The present observation, however, suggests that the long premaximum halts are not a unique character of the slowest novae, but a more general phenomenon spreading over a wider range of nova speed classes than has been previously believed. A recent interpretation of premaximum halts requires that the conditions of thermonuclear runaway were only marginally satisfied. Since such conditions are more difficult to meet in rapidly evolving novae, V463 Sct would provide an unique opportunity for testing this interpretation. The early post-outburst spectrum showed a co-existence of Fe II lines and some forbidden lines, which suggests that a substantial amount of material may have been ejected before the observed optical maximum. The impact of the modern global network (VSNET) on confirmatory processes of transient objects is briefly discussed.
Outburst Photometry of the Eclipsing Dwarf Nova GY Cancri
Authors: Kato Taichi , Ishioka Ryoko , Uemura Makoto 
Published: March 2014

Abstract
We observed the ROSAT-selected eclipsing dwarf nova GY Cnc ($= \mathrm{RX}\,\mathrm{J}0909.8{+}1849$) during the 2001 November outburst. We refined the orbital period to be 0.17544251(5)d. The fading portion of the outburst was indistinguishable from those of typical dwarf novae with similar orbital periods. However, the signature of the orbital humps (or a hot spot) was far less prominently observed in the orbital light curves and eclipse profiles than in usual dwarf novae with similar orbital periods. The combination of a low frequency of outbursts and an apparent lack of slowly rising, long outbursts in GY Cnc is difficult to reconcile within the standard framework of dwarf novae. We suspect that GY Cnc may be the first above-the-gap counterpart of the unusual eclipsing dwarf novae HT Cas and IR Com.
Dramatic Changes in the Outburst Properties in V503 Cygni
Authors: Kato Taichi , Ishioka Ryoko , Uemura Makoto 
Published: March 2014

Abstract
We examined the VSNET light curve of the unusual SU UMa-type dwarf nova V503 Cyg, which is known to show a short (89 d) supercycle length and exceptionally small (a few) normal outbursts within a supercycle. In 1999–2000, V503 Cyg displayed frequent normal outbursts with typical recurrence times of 7–9 d. The behavior during this period is characteristic to an usual SU UMa-type dwarf nova with a short supercycle length. On the other hand, V503 Cyg showed very infrequent normal outbursts in 2001–2002. Some of the superoutbursts during this period were observed to be shorter than usual. The remarkable alternations of the outbursting states in V503 Cyg support the presence of mechanisms of suppressing normal outbursts and prematurely quenching superoutbursts, which have been proposed to explain some unusual SU UMa-type outbursts. The observed temporal variability of the suppressing/quenching mechanisms in the same object suggests that these mechanisms are not primarily governed by a fixed system parameter, but more reflect the state changes in the accretion disk.
Spectroscopic Determination of Stellar Atmospheric Parameters: Application to Mid-F through Early-K Dwarfs and Subgiants
Authors: Takeda Yoichi , Sato Bun’ei , Kambe Eiji , Sadakane Kozo , Ohkubo Michiko 
Published: March 2014

Abstract
Takeda et al.–s (2002, PASJ, 54, 451) method for the spectroscopic determination of stellar atmospheric parameters ($T_\mathrm{eff}, \log g, v_\mathrm{t}$, and $[\mathrm{Fe/H}]$) from the equivalent widths of Fe I and Fe II lines was applied to 32 dwarfs/subgiants of mid-F through early-K types based on high-quality echelle spectra obtained at Okayama Astrophysical Observatory, for the purpose of examining the numerical performance of this technique as well as the precision of the results. The solutions of the parameters were confirmed to successfully converge, except for a few cases (e.g., for lower temperature and lower metallicity stars) where the microturbulent velocity could not be well determined. A comparison of the present results with the literature values, especially those of Fuhrmann (1998, AAA070.155.024), revealed that the agreement is mostly satisfactory, though a systematic tendency appears to exist that our method yields slightly lower (i.e., by $\sim 100 \,\mathrm{K}$) $T_\mathrm{eff}$ values. The results are further discussed in relation to the stellar fundamental parameters (mass, luminosity, etc.), while referring to the Hipparcos parallaxes or theoretical stellar evolutionary tracks.
Na I D Lines in the SN 2002ap Spectrum
Authors: Takada-Hidai Masahide , Aoki Wako , Zhao Gang 
Published: March 2014

Abstract
High-dispersion, high-$\mathrm{S/N}$ spectroscopic observations of SN 2002ap in M74 were carried out in the wavelength range of 4120–6860$\,{Å}$ using the High Dispersion Spectrograph of the Subaru Telescope. Neither emission nor absorption features relating to SN 2002ap itself were identified in the high-dispersion echelle spectrum, but a pair of Na I D1 and D2 absorption lines were detected at a redshift corresponding to the disk of M74, and each was found to show three components. The column densities of these components are log $N(\mathrm{Na{I}}) = 11.47$, 10.47, and 10.72 for the first, second, and third components, respectively. The interstellar reddening in M74 was estimated from these components, and was combined with that in the Galaxy to yield a total value of $E(B-V) = 0.09 \pm 0.01$ along the line of sight to SN 2002ap.
Carbon Monoxide in the Type Ic Supernova 2000ew
Authors: Gerardy Christopher L. , Fesen Robert A. , Nomoto Ken’ichi , Maeda Keiichi , Höflich Peter , Wheeler J. Craig 
Published: March 2014

Abstract
We present $K$-band (1.9–2.5$\,{\mu \mathrm {m}}$) spectra of the Type Ic SN 2000ew observed with IRCS on the Subaru Telescope. These data show the first detection of carbon monoxide (CO) emission in a Type Ic supernova. The detection of CO in SN 2000ew provides further evidence that molecule formation may be a common occurrence in core-collapse supernova ejecta. The spectrum also contains narrow emission lines of [Fe II] and He I probably from dense clumps of hydrogen-poor circumstellar gas surrounding SN 2000ew. Our spectrum of SN 2000ew shows no trace of an unidentified feature seen near 2.26$\,{\mu \mathrm {m}}$, just blueward of the CO emission, in the spectrum of SN 1987 A; we discuss proposed detections of this feature in other Type II supernovae.
Abundance Analyses of 12 Parent Stars of Extrasolar Planets Observed with the SUBARU/HDS
Authors: Sadakane Kozo , Ohkubo Michiko , Takeda Yoichi , Sato Bun’ei , Kambe Eiji , Aoki Wako 
Published: March 2014

Abstract
High $\mathrm{S/N}$ ratio (350–600) and high resolution ($R \sim 90000$) spectral data covering the wavelength region between 4200–8800$\,{Å}$ were obtained for 12 planet-harboring stars with the SUBARU/HDS. Detailed abundance analyses were carried out for these stars using the solar spectrum as a reference. Atmospheric parameters ($T_\mathrm{eff}, \log g$, microturbulent velocity $\xi_\mathrm{t}$, and $[\mathrm{Fe/H}]$) were determined spectroscopically using selected Fe I and Fe II lines. The abundances of 25 other elements have been determined relative to the Sun in a strictly differential manner. Three out of 12 stars (HD 82943, HD 92788, and HD 134987) are definitely metal rich, and two stars (HD 114762 and HD 190228) are metal deficient. The abundances in the remaining seven stars (HD 106252, HD 130322, HD 141937, HD 168746, HD 187123, HD 192263, HD 209458) coincide with the Sun. We find that the abundances of both volatile and refractory elements behave similarly in these stars, and do not confirm any significant dependence on the condensation temperature, $T_\mathrm{c}$. Comparisons of the $[\mathrm{X/Fe}]$ vs $[\mathrm{Fe/H}]$ relations for 19 elements between planet-harboring stars and nearby field stars reveal no distinct anomaly, except for possible enhancements of V and Co in the former group. These results suggest that the observed over-abundances of metallic elements in planet-harboring stars relative to normal disk stars in the solar neighborhood are primordial, and can be interpreted as being a consequence of the galactic chemical evolution.
Subaru Near-IR Coronagraphic Image of LkHα 198
Authors: Fukagawa Misato , Tamura Motohide , Suto Hiroshi , Itoh Yoichi , Murakawa Koji , Oasa Yumiko , Hayashi Saeko S. , Naoi Takahiro , Kaifu Norio , Doi Yoshiyuki 
Published: March 2014

Abstract
High-resolution near-infrared imaging of a Herbig Ae/Be star $\mathrm{LkH}\alpha$ 198 has been carried out using the coronagraphic camera CIAO (Coronagraphic Imager with Adaptive Optics) on the Subaru 8.2 m Telescope. Obtained images resolve the infrared companion (IRC) and an associated reflection nebula. The IRC exhibits near-infrared colors suggestive of a class I-like source. Faint nebulae associated with outflow activity and a bright flattened envelope are also found around the primary. Our observations provide morphological evidence of the IRC being an outflow source as well as the primary star.
SDSSp J104433.04−012502.2 at z=5.74 is Gravitationally Magnified by an Intervening Galaxy
Authors: Shioya Yasuhiro , Taniguchi Yoshiaki , Murayama Takashi , Ajiki Masaru , Nagao Tohru , Fujita Shinobu S. , Kakazu Yuko , Komiyama Yutaka , Okamura Sadanori , Oyabu Shinki , Kawara Kimiaki , Ohyama Youichi , Kawabata Koji S. , Ando Hiroyasu , Nishimura Tetsuo , Hayashi Masahiko , Ogasawara Ryusuke , Ichikawa Shin-ichi 
Published: March 2014

Abstract
During the course of our optical deep survey program on $\mathrm{L}\alpha$ emitters at $z \approx 5.7$ in the sky area surrounding the quasar SDSSp J104433.04$-$012502.2 at $z=5.74$, we found that a faint galaxy with $m_{B}(\mathrm{AB}) \approx 25$ is located at ${1\rlap {.}{}^{\mathrm {\prime \prime }}9}$ southwest of the quasar. Its broad-band color properties from $B$ to $z^\prime$ suggest that the galaxy is located at a redshift of $z \sim 1.5 \hbox{--} 2.5$. This is consistent with no strong emission line in our optical spectroscopy. Since the counter-image of the quasar cannot be seen in our deep optical images, the magnification factor seems not to be very high. Our modest estimate is that this quasar is gravitationally magnified by a factor of 2.
On the Origin of the Dispersion in the 7Li/6Li Ratio in the ISM
Authors: Casuso Emilio , Beckman John E. 
Published: March 2014

Abstract
Measurements of the ${{7\atop} \mathrm{Li}}/{{6\atop} \mathrm{Li}}$ ratio in the local interstellar medium (ISM) towards o Per and $\zeta$ Per by Knauth et al. (2000, AAA 073.131.129) show clouds with a range from near 2 (a value which points to GCR production by spallation or $\mbox{alpha} {+} \mbox{alpha}$ alpha${+}$ alpha fusion) to near 11 (the solar system value). These values can be very well accounted for within our model of general chemical enrichment of the Galaxy in which a key role is played by the continuing infall of metal-poor extragalactic gas to the Galactic plane, in the form of high-velocity clouds. Within this model, light nuclides are produced in the ISM, but destroyed in dense hot interstellar regions around massive stars, the process of which yields a differential depletion of ${{6\atop} \mathrm{Li}}$ relative to ${{7\atop} \mathrm{Li}}$, which can vary on quite short-distance scales.
Close Correlation among Hα Surges, Magnetic Flux Cancellations, and UV Brightenings Found at the Edge of an Emerging Flux Region
Authors: Yoshimura Keiji , Kurokawa Hiroki , Shimojo Masumi , Shine Richard 
Published: March 2014

Abstract
Surge activities were observed at the edge of an emerging flux region. We studied the relations between the features around the surges in various data sets: magnetogram, $\mathrm{H}\alpha$, G-band, UV, EUV, and soft X-rays. We showed that the surge activities in $\mathrm{H}\alpha$ and the brightenings in TRACE 1600 Å images correlate well in both time and space with the cancellation of magnetic fluxes around an emerging flux region. In particular, at the onset of surge activity, a close correlation among them was clearly found. These facts are consistent with the magnetic reconnection model. The released energy through magnetic reconnection, which is estimated to be $10^{28} \,\mathrm{erg}$, is sufficiently large to produce surge activities. No prominent brightenings were observed in soft X-ray and EUV images during the surge activities. This may suggest that the energy releases occurred at a layer of high densities.
On the Association among Periodic Comet 96P/Machholz, Arietids, the Marsden Comet Group, and the Kracht Comet Group
Authors: Ohtsuka Katsuhito , Nakano Syuichi , Yoshikawa Makoto 
Published: March 2014

Abstract
The orbital energies ($a^{-1}$) of released meteoroids (or fragments) from the periodic Comet 96P/Machholz must be slightly different from that of 96P. This results in the differences in their evolutional rates; therefore, the time-lags of the orbital evolutions should apparently occur in the course of time, stably holding the same amplitude in their orbital variations. In the present study, integrating the motion of 96P, we found that the orbital elements of 96P at epoch 2319 correspond to those of both the Arietids and the Marsden comet group, currently observed, and those of 96P at epoch 2408 agree with those of the Kracht comet group, similarly observable now. We also estimated a difference of the perihelion times, $\Delta T$, as: $\sim 320 \,\mathrm{yr}$ for 96P$-$Marsden comet group; $\sim 360 \,\mathrm{yr}$ for 96P$-$Arietids; and $\sim 410 \,\mathrm{yr}$ for 96P$-$ Kracht comet group, respectively. These may indicate such time-lags of orbital evolutions between 96P and released meteoroids (or fragments) from 96P. As a consequence, we conclude that 96P, Arietids, the Marsden group, and the Kracht group are further possibly associated with each other now.