bluuebunny/crossref_metadata_2025_split huggingface dataset:
Rotating Protoplanetary Gas Disk in GG-Tau
Authors: Kitamura Yoshimi , Kawabe Ryohei , Omodaka Toshihiro , Ishiguro Masato , Miyama Syoken 
Published: July 2016

AbstractA rotating gas disk was discovered around a T-Tauri star, GG-Tau, in Taurus by using the Nobeyama Millimeter Array (NMA) (Kawabe et al. 1993). To analyze the observed data, we have numerically calculated velocity profiles of CO emitted from protoplanetary gas disks by taking account of the line radiative transfer.
Molecular Gas in the Centers of Barred and Starburst Galaxies
Authors: Kenney Jeffrey D. P. 
Published: July 2016

AbstractHigh resolution interferometric CO maps of the circumnuclear regions of several barred galaxies show intense CO emission arising from twin peaks, which are oriented perpendicular to the large-scale stellar bars and located where dust lanes intersect nuclear rings of HII regions. These twin gas concentrations can be explained by the crowding of gas streamlines near stellar inner Lindblad resonances. In the barred nuclear starburst galaxy NGC 3504, a large concentration of molecular gas is centered on the nucleus, apparently inside an inner Lindblad resonance. Star formation is consuming the gas most rapidly where the rotation curve is nearly solid body, suggesting that tidal shear helps control the rate of star formation. A comparison with M82 and NGC 1068 suggests that the starburst in NGC 3504 is in an early phase of its evolution, and that starburst evolution is strongly influenced by shear.
Molecular Gas Distribution and Dynamics in the Central Region of Galaxies
Authors: Ishizuki Sumio 
Published: July 2016

AbstractTo investigate the relation between a large-scale stellar bar and circumnuclear starburst, the CO (J=1→0) emission of circumnuclear regions of three starburst galaxies NGC2782, NGC3504, and M83 (NGC5236) have been mapped with the Nobeyama Millimeter Array. The high resolution CO (J=1→0) images indicate that the molecular gas in the three starburst galaxies is located interior to the innermost ends of the paired straight dust lanes. The molecular gas at the small radii is associated with their circumnuclear starburst sites which are indicated by radio continuum emission.
Interferometric Observations of HCO+ and HCN in the Nuclear Region of IC 342 and Maffei 2
Authors: Nguyen-Rieu  , Viallefond F. , Combes F. , Jackson J.M. , Lequeux J. , Radford S. , Truong-Bach  
Published: July 2016

AbstractThe IRAM interferometer has been used to image the distribution and kinematics of the HCO+ line in the nuclear region of IC 342 and of the HCN line in the nuclear region of Maffei2. Both regions were also imaged in the continuum at 3mm. These observations are compared with observations of HCN in IC 342 and CO in both galaxies.
Jet-Cloud Interactions in NGC 4258: CO Observations Using the Nobeyama Millimeter Array
Authors: Plante R. L. , Handa T. , Lo K. Y. 
Published: July 2016

Recent CO studies of spiral galaxy NGC 4258 have revealed a close relationship between the molecular gas and the anomalous arms, recently interpreted as jets (Cecil et al. 1992, Martin et al. 1990). An IRAM single dish study by Krause et al. (1991) showed the CO to be concentrated around the Hα arms. Interferometrie imaging of the inner 1’ by Martin et al. (1990) showed the molecular gas confining the arms; they suggested that the jet had initially plowed a tunnel through the disk gas, producing a free path for subsequent ejections. This data also shows strong evidence for a jet-cloud collision along the N W arm (Piante et al. 1991).To learn more about the jets, we are motivated to exploit the jet-gas relationship with multi-field imaging of the CO along the anomalous arms using the Nobeyama Millimeter Array. We present preliminary results from our first 60” field, centered on the SE Hα arm, 43.5” from the nucleus. Observations in the two most compact configurations (C and D) produced a 4” x 6” beam.
RATAN-600 as a MM-Array
Authors: Parijskij Yu.N. , Pinchuk G.A. , Verkhodanov O.V. , Khaikin V.B. , Zverev Yu.K. , Zhekanis G.V. 
Published: July 2016

AbstractIt is shown that multi-elements surface of the Russian biggest reflector may be considered as a 1000-element array with limited freedom of motions of each element. This limitation may be compensated by selection of the proper “virtual sub-array” of elements at any given direction of observations. This approach is especially effective for mm-waves where field of view of 600-meter reflector in usual mode is less than 1 arcsec. The present stage of realization of that project is shortly discussed, including requirements for multi-feed system near the focal plane of the radio telescope, wavelength limitations and error budget, and near field zone 3-dimensional synthesis mode of observation.
The Millimeter Array
Authors: Brown Robert L. 
Published: July 2016

AbstractThe Millimeter Array, under development in the United States, is a fast and flexible telescope capable of imaging the thermal sky at a resolution equal to that specified in the design goals of the Hubble Space Telescope. The MMA is a project of the U.S. National Science Foundation, and it has been highlighted as one of the four major U.S. initiatives in astronomy for the decade of the 1990s. Construction will begin toward the end of the decade at a site soon to be chosen.
A Southern Hemisphere Millimetre Array
Authors: Booth R.S. 
Published: July 2016

The southern night sky is a sight of overwhelming beauty. It is hard to forget one’s first view of the night sky from La Silla with the Galactic centre overhead and the brilliant constellations of Sagittarius and Scorpius with their bright stars and copious amounts of dust. In fact for a millimetre astronomer, it is the dust that is so striking and one feels for the first time that one is seeing tangible visual evidence of the intriguing molecular clouds that dominate our discipline.Ironically it is the observation of these southern molecular clouds that have shaped much of millimetre radio astronomy, yet we persist in observing them from the northern hemisphere through many air masses of atmospheric attenuation.Having built the Swedish ESO Submillimtre Telscope, SEST in the south, on La Silla, in Chile, Swedish and other European astronomers would like to follow up this initiative with a southern hemisphere millimetre array, taking advantage of the excellent dry mountain sites. There is much to be done with such an instrument.
Submillimeter Interferometry in Space
Authors: Brown Robert L. 
Published: July 2016

AbstractRadiation from the gaseous disk of a galaxy like the Milky Way principally occurs via fine structure transitions of carbon, oxygen, and nitrogen, all of which occur at submillimeter wavelengths at which the earth’s atmosphere is opaque. Indeed, more than ten percent of all the energy radiated by the stars and gas in the Milky Way comes out in the 1900 GHz line of once ionized carbon! This line can only be observed from space, and it can only be observed with arcsecond angular resolution with a space-based interferometer. The international space station Freedom provides a stable platform, with the right dimension, for the necessary submillimeter interferometer.
Using HST/GHRS Echelle Spectra as Templates for IUE Data Analysis
Authors: Wahlgren Glenn M. , Leckrone David S. , Johansson Sveneric , Rosberg Maria 
Published: July 2016

AbstractEchelle spectra obtained with the HST/GHRS are used to understand the blending in lower resolution IUE sprectra in the region of the raie ultime line of Au II. Laboratory analysis of the Au II transition has provided an accurate wavelength and transition probability from which the first Au abundances are determined for stars other than the Sun.
Comparison of Different Methods for Determining Atmospheric Parameters of A and F Stars
Authors: Smalley B. , Dworetsky M.M. 
Published: July 2016

AbstractThe atmospheric parameters of metallic-lined (Am) stars have been the subject of much debate. Using spectrophotometric flux fitting, Lane & Lester (1984) obtained values of Teff and log g for several classical Am stars that were systematically lower than those obtained by Dworetsky & Moon (1986), who used empirically calibrated uvbyß photometry. We have used the standard procedures of photometry, spectrophotometry and hydrogen-line profile fitting to determine the atmospheric parameters of many A and F stars, including several Am stars. Modifications to the standard techniques have been used to allow for the effects of cooler companion stars in the determination of such parameters. It is found that spectrophotometric methods give results for Teff and log g that are highly sensitive to the adopted metal abundance. This explains the anomalous results of Lane & Lester.
Line Variability in 33 Gem?
Authors: Hubrig Swetlana , Launhardt Rainer 
Published: July 2016

AbstractThe spectrum of 33 Gem exhibits a great similarity with that of a CP3 star, but in contrast to other members of this group, light variations and variability in helium lines were reported. Even an effective magnetic field strength up to 1.4 kG was measured in the lines of elements He I, Si n, P H, Mg II, Ti H, Mn II, Fe H (Glagolevskij et al., 1985). For these far-reaching differences high resolution (R≃ 40000), high signal-to-noise (> 100) CCD spectra of 33 Gem were observed with the Coudé spectrograph of 2.2 m telescope at Calar Alto. As well for the profiles of the He I lines as for those of the metallic lines no changes could be found. Our rough inspection of Zeeman spectograms taken with the 6 m telescope at Zelenschuk in which Glagolevskij et al. noticed a magnetic field revealed unexpected splitting of several lines into two components probably caused by a companion. The line components are separated approximately by 0.1 Å. For this splitting a confirmation of the presence of a magnetic field was difficult.
Hydrogen-Line Profiles of Some λ Bootis Stars
Authors: Iliev Ilian Kh. , Barzova Ina S. 
Published: July 2016

AbstractThe observed hydrogen-line profiles of four λ Boo type stars— HD 111786, HD 125162, HD 179791 and HD 192640 are presented. Existence of two separate groups based on the shape of these lines is confirmed. Radial velocity (Vr = −5 ± 3 kms−1) and projected rotational velocity (vsini = 130 ± 10 kms−1) for HD 111786 are measured.
Diffusion: Theoretical Computations for Non-Magnetic Stars
Authors: Alecian G. 
Published: July 2016

AbstractWe present the main aspects of diffusion calculations in the simplest realistic diffusion model for main-sequence CP stars. The results obtained with this kind of computations are generally used in modelling AmFm and HgMn stars. Important improvements in this field, essentially due to the new atomic data banks, may be expected in the near future.
Non-LTE Analysis of CNO Lines in Vega
Authors: Takeda Yoichi 
Published: July 2016

AbstractNon–LTE calculations for neutral C, N, and O are performed to determine the accurate abundances of these elements in the atmosphere of Vega by taking the non–LTE effects realistically into consideration. It is shown that C and O are mildly deficient by ∼0.2–0.3dex while N shows an appreciably large underabundance by ∼0.8dex.
CP Stars at High Galactic Latitude: Photometry Near the Galactic Poles ,
Authors: Schneider H. 
Published: July 2016

AbstractThe results of photometric observations of early type stars in regions around the Galactic poles are presented. The aim of these investigations was to search for CP2 and CP1 and to establish new and more precise frequencies for such objects including fainter stars.A mean frequency of 24.7% was found for the CP1 stars, 23.7% for the hot CP2, and 11.7% for the cooler ones, but with large differences between the two regions investigated.Furthermore, a substantial number of stars (20) were found to be good candidates for λ Boo stars.
Complications of Studies of Galactic Structure, Caused by Cp Stars
Authors: Lodén L.O. , Sundman A. 
Published: July 2016

AbstractWhen studying the distribution of stars and interstellar matter in the galactic environment, one relies upon objects which are numerous enough and also bright enough to constitute workable samples. A-type stars seem to be a natural choice, but a successful study then depends on the reliability of the spectroscopic distance determinations. Since chemical peculiarity affects a considerable fraction of the A-type main sequence stars we have found reason to investigate the reliability of luminosity estimates for stars of various types of peculiarity. The result indicates that peculiarity is a less serious problem than undetected multiplicity.
Stellar Photospheres and Molecules — A View From The Bridge
Authors: Lambert David L. 
Published: July 2016

The allegory alluded to in the subtitle of my review came to mind in the early morning hours when I was battling insomnia after a successful observing run at our McDonald Observatory. Similar bouts with insomnia are more widely classified as “jetlag,” a condition probably too familiar to many of the readers!Imagine two villages connected by a bridge spanning a deep, fast-flowing river. In my village on the south bank live the astronomers. Across the bridge live the chemical physicists and the physical chemists who are engaged in determining by all possible theoretical and experimental means the structure and spectra of molecules (and atoms). The astronomical community can be sorted into various clans of whom I consider here only the stellar spectroscopists and, in particular, the small subclan fascinated by quantitative spectroscopy who to pursue their trade must establish and maintain excellent communications with the village on the other side of the bridge. The necessity for contacts between the two villages has grown with the development of the tools of the stellar spectroscopists’ trade: e.g., the advances of telescopes and spectrographs with respect to coverage of the electromagnetic spectrum and sensitivity, and the theoretical developments in the construction of model stellar atmospheres and the computation of synthetic stellar spectra. The recent decades of astronomical advances have been matched by exciting years in the village across the bridge: e.g., tunable lasers have spawned a renaissance in molecular (and atomic) spectroscopy, and theoretical work on molecular structure and spectra has advanced with the awesome growth of computers. Yet, a curious paradox may be sketched. These welcome and remarkable developments in the two villages have made it more difficult to maintain effective communications across the bridge. How can I possibly exploit fully the successes of MRD-CI calculations and appreciate their limitations? My counterparts across the bridge will echo my question: What experiments or quantum calculations might be usefully made in support of the astronomers’ programs ATLAS, MARCS, SOSMARCS, and their relatives?
From Molecules to Grains
Authors: Sedlmayr Erwin 
Published: July 2016

Cosmic dust is an ubiquiteous component of the interstellar medium, the presence of which has severe bearings both upon the observations and upon the physical description and realistic modelling of astronomical objects. In most dusty objects, the grain component is intimately interwoven with the gas component and the radiation field, and, hence strongly affects the thermodynamical, the hydrodynamical and the chemical structure of the object. Therefore any consistent description of the astrophysical dust complex has to rely upon a treatment where these aspects are properly taken into account. In general this complex comprises the following problems:–Formation of small stable molecular clusters out of the gaseous phase–Growth of these clusters to macroscopic specimens (primary condensates: grains, plates, etc.)–Destruction of grains (e.g. thermal evaporation, sputtering, shattering), and–Physical and chemical processing of already existing grains (e.g. coagulation, chemical and thermal transformation, etc....).
CCD Cameras for the Kiso 105 cm Schmidt Telescope
Authors: Yoshida S. , Aoki T. , Soyano T. , Tarusawa K. , Sekiguchi M. , Doi M. , Kashikawa N. , Okamura S. , Shimasaku K. , Yagi M. , Yasuda N. 
Published: July 2016

AbstractWe report on the status of the CCD cameras for the Kiso 105-cm Schmidt telescope. We have two types of cameras – single-chip and mosaic. The single-chip camera is available for common use. At present about 90 % of the telescope time is allocated to observations with CCD cameras.
Near-Infrared Imaging with the 105 cm Kiso Schmidt
Authors: Ichikawa T. , Tarusawa K. , Yanagisawa K. , Itoh N. 
Published: July 2016

AbstractWe have carried out imaging observations in the near-infrared (J, H and K’ band) with a large format array camera attached to the prime focus of the 105 cm Schmidt telescope at Kiso Observatory. The image resolution, limiting magnitudes and effect of thermal radiation are presented, based on observations of nearby galaxies. Considering the results, we are constructing a new larger near-infrared camera optimized for use with the Kiso Schmidt.
T A U M O K—Multi-Object Spectroscopy with the Tautenburg Schmidt Telescope
Authors: Marx S. , Lehmann H. , Pluto M. , Ziener R. 
Published: July 2016

A multi-object camera for the Tautenburg Schmidt Telescope (134/200/400) was developed and constructed in cooperation with the Max-Planck-Institut für Astronomie in Heidelberg and the Thüringer Landesstemwarte Tautenburg. The experience with the “Spaltspinne” for the 3.5 m Telescope of the Calar Alto Observatory (Pitz 1993) was the foundation of TAUMOK. The technical concept was given by Pitz et al. (1993).Thirty six rods controlled by a processor can be moved in an area with a diameter of 16 cm. This area covers a field of 2.3° in the focal plane which is flattened by a plano-convex lens. Each of 34 rods carry two fibres with diameters of 100/µm with one fibre for the object and another for the background light. The fibres have a length of 7 m and their opposite faces form the entrance slit of a spectrograph. At present, reciprocal dispersions of 3.4, 10, 20 and 40 nm/mm can be realized. A CCD camera with a chip-size of 1152 × 770 pixels (pixel size 22.5/µm) is used as detector. Two of the 36 rods are equipped with image bundles for telescope guiding.
The Latest Results from the Durham/UKST Galaxy Redshift Survey
Authors: Broadbent A. , Shanks T. , Fong R. , Parker Q. A. , Watson F. G. 
Published: July 2016

AbstractWe report on a redshift survey of ∼ 4000 galaxies of B ≲ covering a 1500 square degree area of sky around the SGP region. This 1-in-3 sampled survey probes a contiguous volume of 4 × 106 Mpc3 to a depth of 300 h−1 Mpc. The survey has been compiled using the fibrelinked spectroscopy system, FLAIR, on the UK Schmidt Telescope and has produced high quality redshift maps giving a clear visual picture of structure in the universe as well as providing an excellent data base for a statistical analysis of galaxy clustering. Filamentary and sheet-like features are clearly discernible to the eye in the completed sections of the survey although the redshift two-point correlation function is consistent with zero on scales of r ≳ 10h−1 Mpc. The survey, which is now substantially complete, demonstrates the potential of the FLAIR spectroscopy system for extending this project to a medium-deep galaxy redshift survey of the whole of the southern sky on timescales which would remain competitive with other surveys under construction.
Digitisation, Archiving, and Distribution of Photographic Data from Schmidt Surveys
Authors: Lasker Barry M. 
Published: July 2016

AbstractThe limititations to the use of data from the major Schmidt surveys, i.e. grain noise as well as practical considerations of image processing and astrometry, are discussed, together with the question of mounting films on microdensitometer platens. Next, the major scanning systems dedicated to Schmidt surveys, their accomplishments, and their future programs are considered. Finally, the archiving and distribution of the scan data is discussed, and some suggestions regarding future directions are made.
A Deep Wide Field Survey from Digitally Stacked Schmidt Plates
Authors: Hawkins M. R. S. 
Published: July 2016

AbstractA large set of exposures of a single UK Schmidt Telescope field has been obtained, covering five colour bands over 18 years. Techniques have been developed for combining digitised data from many plates. The results of adding 64 exposures in Bj and R are demonstrated showing that the expected gain of ~ 2.5 magnitudes in limiting magnitude are achieved. By combining various subsets of the data, proper motions and variability can be determined. Two examples of the many possible uses of the dataset are given: the discovery of low mass brown dwarf candidates using colours and proper motions, and of quasars using variability and colours.
Objective-Prism Spectroscopy: Retrospective and Prospective
Authors: MacConnell D. Jack 
Published: July 2016

AbstractThe combination of the excellent large-field imaging capabilities of Schmidt telescopes and of prisms covering the full aperture has made an impact on stellar, galactic, and extragalactic astronomy far out of proportion to the numbers of such telescopes. I discuss some of the milestones in the continuing development of this combination with a view to signposts of the future.
The CIDA Schmidt Objective-prism Survey: Fields in Taurus-Auriga and Ophiucus
Authors: Briceño Cesar , Calvet Nuria 
Published: July 2016

AbstractWe have begun a deep objective prism Hα survey of starforming regions using the CIDA 1 m Schmidt Camera. We report here on the performance of the telescope for this kind of work, based on the study of selected areas in the Taurus-Auriga molecular clouds and the Ophiucus molecular clouds. Up to now seven plates taken in Taurus-Auriga have been visually scanned in a search for pre-main sequence candidates, with a coverage of about 120 square degrees over the whole complex, plus one plate taken in Ophiucus covering the entire cloud (≈ 18 square degrees).
Photometry of Galaxies on Kiso Schmidt Plates
Authors: Ichikawa Takashi 
Published: July 2016

AbstractIn spite of the lower S/N and smaller dynamic range of photographic plates compared to those of CCD data, Schmidt plates still have the advantage of a large field of view, which allows us to study the structure of nearby large galaxies and clusters of galaxies. Investigating the internal and external errors of our surface photometry, we show that a careful analysis of photographic plates results in reliable surface photometry data comparable to CCD data for galaxies brighter than ∼ 17 mag. Recent studies based on photographic surface photometry catalogues obtained from Kiso Schmidt plates are reviewed and it can be shown that surface photometry of galaxies on Schmidt plates is still useful for understanding the local universe.
Cosmology with Stacked Schmidt Plates
Authors: McNally S. J. , Peacock J. A. , Hawkins M. R. S. 
Published: July 2016

AbstractDigital stacking of Schmidt Plates greatly increases the depth of the data allowing detection of galaxies at ∼ 1. We can probe the angular correlations of galaxy and cluster positions over scales of ∼ 500h−1 Mpc. Radial distance information can be obtained by identifying radio galaxies in the field and using their “standard candle” properties. A search for cosmic string effects, beginning with the stacked dataset, has now been extended to ∼ 100 equatorial J-plates.