bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Extended CO(3 - 2) Emission in the Protogalaxy IRAS F10214+4724
Authors: Brown Robert L. 
Published: July 2016

AbstractPreliminary observations of the z = 2.286 protogalaxy in the redshifted J = 3 − 2 transition of CO made with the Owens Valley Radio Observatory array suggest that the CO emission is spatially extended. This is particularly evident in the narrow band spectral channels. There are indications of CO emission regions in the field of IRAS F10214+4724 that are not related to the IRAS galaxy.
Observations of Magnetically Split Lines in Ap Stars)
Authors: Mathys Gautier , Landstreet John D. , Lanz Thierry 
Published: July 2016

AbstractAp stars whose spectral lines are resolved in several magnetically split components are of particular interest, because their magnetic field can be diagnosed with unrivalled precision, in an essentially approximation-free manner. We are pursuing a systematic programme of search and study of such stars. At present 25 of them are known, of which 13 have been discovered in the course of the present project (Mathys 1990, hereafter Paper I; Mathys & Lanz 1992, hereafter Paper II; this paper).Up to now, we have obtained observations of 22 of these Ap stars with resolved magnetically split lines. We have recorded high-resolution spectra of a region containing, among others, the three lines Cr ɪɪ λ6147.154, Fe ɪ λ6147.741, and Fe II λ 6149.258. The Zeeman patterns of these three lines are, respectively, close to a triplet, close to a quadruplet, and a doublet. The doublet Fe ɪɪ λ 6149.258 is particularly interesting, because of its large Landé factor (2.7): it can be resolved even in stars with fairly modest fields.
The λ Boo and Related Stars
Authors: Gerbaldi M. , Faraggiana R. 
Published: July 2016

AbstractThe main properties of this class of rare objects are described, and the criteria selected for discovering new members are indicated. The abundance anomalies, resulting from the scanty analyses made up to now, are discussed together with the theoretical interpretation proposed in the framework of the modified diffusion theory and of the recent selective accretion proposal.Finally, we discuss the evolutionary stage of the λ Boo stars which, in the HR diagram, lie near, but not on the main sequence.
He-Abnormal Stars
Authors: Hunger Kurt , Groote Detlev 
Published: July 2016

AbstractThe He-rich variable HD 37479 has 2 axes of symmetry, one characterized by the depletion of metals, and one by the enrichment of He. The former is oriented along the axis of the magnetic dipole, while the latter is off set by some 45°. The 2 axes represent 2 different modes of diffusion, the first one being controlled solely by the magnetic field, irrespective of wind, the second one being due to stellar wind that is controlled by the magnetic field and intertial forces. It has been attempted to formulate simple physical conditions that allow to determine the diffusion regions on the surface. It is shown that the resulting surface map can well reproduce the observed phase variations of the equivalent widths of HeI 4471, of UV resonance lines of C IV and Si IV, and the effective magnetic field.
Abundances in Rapidly Rotating a Stars
Authors: Lemke Michael 
Published: July 2016

AbstractA study is undertaken to determine abundances in rapidly rotating main sequence A stars (v sin i = 100 − 180 km/s) in order to investigate if non-solar abundance patterns found in slow rotators (Lemke 1989, 1990) persist toward higher rotational velocities. This will provide some insight into how the Am phenomenon and other chemical peculiarities are connected with slow rotation and diffusion processes.Most stars were found to have a rather solar composition. At least one star, HR5023, is enriched in Ba by approximately one order of magnitude relative to the sun at a v sin i of 110km/s. Both C and Ba will be discussed.
Photometry of Chemically Peculiar Stars with Automatic Photoelectric Telescopes
Authors: Adelman Saul J. , Pyper Diane M. 
Published: July 2016

AbstractThe College of Charleston The Citadel, the University of Nevada, Las Vegas and Villanova University constitute the Four College Automatic Photoelectric Telescope Consortium which has a 0.75-m telescope on Mt. Hopkins, Arizona. It has been in regular operation for two years. Prior to this time we obtained some differential UBV observations with the Phoenix 10” APT of the Fairborn Observatory. We are coordinating observations of CP stars of the upper main sequence. Some initial results include evidence for significant changes in the light curve of 56 Ari, the constancy of the HgMn stars 53 Tau and HR 4072, an improved period for HD 244801, and new observations in the broad minimum of HD 9996.
The RASSCF, RASSI, and CASPT2 Methods Used on Small Molecules of Astrophysical Interest
Authors: Malmqvist Per-Åke 
Published: July 2016

To a quantum chemist with no particular background in astrophysics or astronomy, a brief glance at journals and textbooks in these fields shows at least three areas where computational quantum chemistry has had a valuable impact: Interstellar cloud chemistry; stellar atmosphere modelling; and chemistry in extreme conditions, such as at the surface of a neutron star. The first two uses are particularly suitable, since standard methods are directly applicable.For such problems, good calculations of potential energy as well as expectation values and matrix elements of dipole and other operators appears to be in demand. Many electronic states may be involved, at least a broad range of problems involve fairly small molecules, often radicals, and conformation regions far from equilibrium. Such problems are addressed by three methods originated in our laboratory, and known by the acronyms RASSCF (Restricted Active Space Self-Consistent Field, Malmqvist et al. 1990), RASSI (RAS State Interaction) and CASPT2 (Complete Active Space Perturbation Theory to Second Order-Complete Active Space Perturbation Theory to Second Order, Andersson et al. 1990; Andersson et al. 1992).
From Milliarcsecond Proper Motions to the Discovery of Dark Matter: Some Winning Cards still in the hands of Photographic Astronomy
Authors: Guibert J. , Souchay J. 
Published: July 2016

AbstractThe large field of Schmidt plates allows monitoring of hundreds of thousands or even millions of stars, either for magnitude variations or for proper motions. CCD cameras benefit from the sensitivity, linearity, and easy interface to computers of detectors of increasing dimensions. However, especially for proper motion studies, there is no substitute to plates of first or intermediate epochs. In addition, the photographic plates, with their large sky coverage free of gaps, are irreplaceable for the accurate astrometry of optical counterparts of sources detected at other wavelengths.We first introduce the subject by mentioning a few problems concerning the replacement of Schmidt plates by CCD detectors. After a brief survey of astronomical applications requiring accurate astrometry or massive processing in large fields, we develop in more detail the results obtained in proper motion studies by several groups using the MAMA system (Berger et al. 1991). The last part of this paper is devoted to the studies of stellar variability and to the EROS and DUO microlensing programmes. Our conclusion (not a surprise, we think), is that Schmidt telescopes with photographic facilities should remain available to the general astronomical community for at least a decade and probably more.
Compact Galaxies in the Virgo Field
Authors: Drinkwater M. J. , Hardy E. , Yearlsey J. M. 
Published: July 2016

AbstractWe present the preliminary results of a search for new blue compact dwarf (BCD) galaxies in the Virgo cluster. Our search is based on the automated selection of compact galaxies from digitised scans of UK Schmidt plates and is designed to put quantitative limits on the luminosity function of compact galaxies in Virgo.We have selected a sample of 310 candidate BCD galaxies and have obtained radial velocities for 177 of them using the UK Schmidt FLAIR-II multi-object fibre spectrograph. We have confirmed two new members of the cluster. One is classified as a member (but without velocity) in the Binggeli, Sandage and Tammann (1985) catalogue (VCC) and the other does not appear in the VCC and is therefore probably a new BCD. The other 175 galaxies are background objects at higher redshift, including one classified as ”BCD or background“ in the VCC which we now confirm to be a background object.
Astrometry with Schmidt Telescopes for Probing the Galaxy
Authors: Murray C. Andrew 
Published: July 2016

AbstractThe use of proper motions and parallaxes for large numbers of stars, obtainable from a combination of Schmidt telescopes and automatic plate scanners, is discussed. The importance of deriving the zero points of both absolute proper motion, and of parallactic motion, is emphasised. Calibrations of proper motion and of parallaxes should be based on dispersions of proper motion. These methods are illustrated by results from a study in the South Galactic Cap.
The Importance of Schmidt Astrometry for the Optical Identification of Sources detected in other Wavebands
Authors: Savage Ann , Cannon Russell D. 
Published: July 2016

AbstractThe early optical identifications of radio sources were restricted to bright galaxies and to quasars with ultraviolet excesses, since such objects were rare and unlikely to land by chance within the large radio position error boxes. Other types of objects, such as very high redshift quasars and distant galaxies, were discriminated against because they did not look unusual and so were not readily recognised. Eventually much more accurate interferometric radio positions became available, enabling unambiguous identification of many optically faint objects. Now the internal accuracy of the radio positions can exceed that of the optical positions, requiring optical astrometry to be done to higher precision than ever before. A related problem is the correct registration of the two reference frames, which should be solved soon using a combination of data from the Hipparcos satellite and the Hubble Space Telescope.The digitised data now available from the Schmidt sky surveys make it possible to automate the optical identification of sources, such as those in the IRAS infrared and Rosat X-ray surveys. Very accurate digitised optical surveys are also needed to prepare lists of targets for multi-object spectroscopy using fibre optic systems.
A Search for Late M Supergiant Stars in the Direction of Galactic Latitude −2° < b < 2° and Galactic Longitude 351° < l < 1°
Authors: Raharto Moedji , Ishida Keiichi , Hidayat Bambang , Ichikawa Takashi , Hamajima Kiyotoshi 
Published: July 2016

AbstractOptical late M stars (spectral type later than M4) with IRAS colours of 0.7 < m12 − m25 < 1.6 belong to two possible luminosity classes; giants or supergiants (Raharto 1994). We have searched for supergiant candidates among the late M stars at low galactic latitude, between galactic longitude 351° < l < 1° and galactic latitude −2° < b < +2°, using data from the M star Catalogue (Raharto et al. 1984) and the IRAS Point Source Catalogue (Beichman et al. 1987). The search area is located in the direction of the galactic centre. M supergiants found in this survey will be necessarily a mixture of M supergiants in star forming regions in the interarm and galactic centre regions and M supergiants in the inner galactic arms.We found 154 of 1146 late M stars with unique IRAS point source counterparts within 15 arcsec. 122 of the 154 stars have good flux qualities in the 12 and 25 μm bands. 112 of these, or 73 per cent of the late M stars (later than M4), have IRAS infrared colours in the range 0.7 < m12 − m25 < 1.6. Only two stars out of 122 have infrared colours redder than 1.7.
IRAS Identification of Complete Samples of Cool Carbon Stars: Results for a Region in Carina
Authors: Fuenmayor Francisco J. , Stock Jurgen 
Published: July 2016

AbstractResults for a near-infrared objective-prism survey for faint cool carbon stars in a Carina region centred at l = 290°, b = 0° are presented. A total of 37 identified carbon stars in area of about 16 square degrees were found, of which 4 are new discoveries. Accurate positions, IRAS identifications, infrared fluxes and colours, and associations of the stars in the sample axe given.
The Goddard Fabry-Perot Imager
Authors: Gelderman Richard , Woodgate Bruce E. , Brown Larry W. 
Published: July 2016

AbstractThe Goddard Fabry-Perot Imager (GFPI) is an optical scanning interferometer and CCD imaging system developed at the Goddard Space Flight Center’s Laboratory for Astronomy and Solar Physics for use at various astronomical observatories. Besides being transportable, its most notable characteristic is the relatively low spectral resolution (3 – 30Å bandpass). The instrument may be used in scanning mode for objects with a large range of velocities but is most often employed to match the observed wavelength of a Doppler shifted emission feature for objects with any velocity.
TAUMOK - a Multi-Object Spectrograph for the Tautenburg Schmidt Telescope
Authors: Lehmann H. , Ziener R. , Ball M. , Pitz E. 
Published: July 2016

TAUMOK is a joint project of the Max Planck Institut für Astronomie Heidelberg and the Thüringer Landessternwarte Tautenburg. It is based on the concept of the “Spaltspinne” (Pitz 1993) now in operation at the Calar Alto Observatory. A first describtion of the technical concept was given by Pitz et al. (1993). TAUMOK was built at the MPIA Heidelberg in collaboration with astronomers and technicians from Tautenburg. It is now in the test phase and will have its first operation at the Tautenburg telescope in the middle of this year.The use of a Schmidt telescope gives a very wide field for multi-object spectroscopy (TAUMOK will cover a field of 2.3°) but it also requires a series of special considerations. So, some of the details of the original “Spaltspinne” were modified to meet the site specific peculiarities. The size of the ground plate was minimized and yields a central obscuration of only 60 cm in diameter. The curved field of the Schmidt focus (deviation of up to ±400 µm from the mean focal plane) is flattened by a field lens - a solution alternative to the guiding of the fiber supporting rods on a sphere.
Zeeman Doppler Imaging
Authors: Semel M. 
Published: July 2016

AbstractStellar rotation maps the surface of a star into its line spectrum and gives a dimension to a point on the star - the Doppler dimension. This is of great importance for the detection of Zeeman polarization especially in certain cases. Typically a magnetic configuration will exhibit both polarities, thus the polarization signals of oposite signs may superpose and cancel. The Doppler coordinate will be in general different for parts of the stars having different polarities and therefore the polarization signals will also appear at different wavelengths and will not cancel. Moreover, the time variations plus the Doppler coordinate constitutes two variables that may allow the reconstruction of two dimensional map of the magnetic field over the star surface.Attention will be given to the set-up that allows spectropolarimetry with high spectral resolution and high S/N ratio. The use of cross dispersion spectrographs allows one to observe several tens of spectral lines. The method of adding signals to increase S/N ratio will be indicated.
Co Distributions towards the Southern Dark Cloud of DC 303.6+0.9
Authors: Wang Jing-sheng , Otrupcek Robina E. 
Published: July 2016

AbstractDark clouds in the southern skies have been observed with CO J = 1-0 line. The mm-wave telescope of 4-m diameter was used. The beam width was 2’.7 at 2.6 mm wavelength and beam efficiency 0.52. The authors have developed a high-resolution acousto-optical spectrograph with a velocity resolution of 0.07 kms-1 for this purpose. The 115.27 GHz line was detected over an area of 27’ x 21’ including the dark cloud of DC 303.6+0.9 in Crux. Most of the positions, out of a total number of 63, show a double peak line structure. Some positions also show red and blue shifted wings. An average profile shows a higher peak at the radial velocity of -2.8 kms-1 with a calibrated radiation temperature of 5.5 K, a half line width of 1.5 kms-1, and another peak in relative red at a velocity of -0.8 kms-1 with a temperature of 4.3 K, a half line widh of 1.0 kms-1. Profiles distributed over this area show a bipolar diagram. It hints that a certain systematic motions may exist in this region.
Cosmic Ray Induced Photodestruction of Interstellar Molecules
Authors: Gredel R. , Lepp S. , Dalgarno A. , Herbst E. 
Published: July 2016

AbstractUltraviolet photons are created in the interior of dense interstellar clouds by the impact excitation of molecular hydrogen by secondary electrons generated by cosmic ray ionization. The resulting photodissociation and photoionization rates of a wide range of interstellar molecules are calculated. The effects on the equilibrium chemical composition of dense clouds are briefly discussed.
Aperture Synthesis Observations of NH3 and CS in Orion-KL
Authors: Murata Y. , Kawabe R. , Ishiguro M. , Hasegawa T. , Takano T. , Kasuga T. , Morita K.-I. , Hayashi M. 
Published: July 2016

ABSTRACT.We have made aperture synthesis maps of Orion-KL in NH3(1,1),(2,2) and CS(J=l-0) emissions using the Nobeyama Millimeter Array. Both NH3 and CS maps show new detailed structures that have not been recognized before. Two NH3 filaments in the size of ~0.45 pc x0.04 pc are found extending to the northwest direction of Orion-KL. These filaments are associated with the HH objects and the finger-like H2 emissions; they are probably formed through the interaction with high velocity, highly channeled winds from the KL region. The CS maps show, on the other hand, shell structures around IRc2 as well as the well-known rotating disk. These shells coincide with the two lobes of the shock-excited H2 emission, being interpreted as the shock-compressed shells of ambient molecular gas interacting with the outflow from IRc2.
Ionized Gas and Stellar Content in a Sample of HII Galaxies
Authors: Vilchez J.M. , Cepa J. , Esteban C. 
Published: July 2016

AbstractWe present the first results of an extensive study of the stellar content and the ionized gas structure for a sample of BCGs. Deep broad (BVRI Johnson) and narrow (Hα) CCD images have been obtained for about 25 galaxies. For a subset of objects, selected on the basis of their apparent structure, long-slit spectroscopy has also been obtained in order to investigate the interaction between the underlying stellar population and the ionized gas.
Cycling of dust grains through the galactic halo
Authors: Ferrara A. , Franco J. , Barsella B. , Ferrini F. 
Published: July 2016

AbstractThe analysis of the vertical motion of dust grains inside the disk of spiral galaxies shows that grains at high latitudes (z/H > 0.3 — 0.5, where H is the scale height of the gaseous disk) can be removed from the gaseous disk by radiation pressure from field stars. Once the dust particles are located at the base of the galactic corona, and neglecting the presence of magnetic fields, their motion is determined by the global light and mass distributions. We follow the dynamical evolution of grains embedded in a hot galactic corona (T ≥ 105 K and n ≤ 10−2 cm−3), including drag and sputtering. We find that typical sputtering time scales are larger than 108 yrs, and, in these times scales, the grains can travel large radial and vertical distances from their original positions. This process can remove grains from the inner part of a galaxy and send them to large galactocentric distances. The evolution resembles a dusty galactic fountain which may pollute the outer galaxy with grains and heavy elements. Similarly, for some cases the dust particles can be detached from the galactic gravitational field and they are expelled to the intergalactic medium. In these cases, the chemical pollution is not restricted to the host galaxy and may reach material which is otherwise primordial.
Magnetic Structures of the Intermediate Corona
Authors: Koutchmy S. , Molodensky M. M. , Koutvitsky V. , Solov’ev L. S. 
Published: July 2016

AbstractThe fine structures of the corona are analized using SXR and WL eclipse pictures. The measurement of the finest features observed at the CFHT on July 11, 1991 is discussed. We call the attention to the 3D aspect of the magnetic structure which can be apprehended and analysed assuming the plasma is concentrated in thin curved sheets observed on eclipse WL pictures. More geometrical parameters can be deduced from the stereo-view based on the hypotheses of a rigid rotation. A preliminary 2.5D model calculation is put forward to explain the active region coronal rays. It is based on the assumption of ad hoc chromospheric current distribution and analytic calculations.
The Model of Coronal Streamers
Authors: Badalyan O. G. , Livshits M. A. 
Published: July 2016

AbstractResults of polarization observations of coronal streamers have been reviewed. We have adopted some typical distributions of polarizationPK+F(ρ) and brightnessB(ρ) at the distances up to 5R⊙. Then a sequence of theoretical functions ofP(ρ) andB(ρ) was computed using the size along the line of sight as a parameter. The theoretical model of streamer which satisfies the observational curve ofPK+F(ρ) and does not contradictBK(ρ) proves to be an axisymmetrical one. At the distances from 5R⊙to 10R⊙the size of structure along the line of sight tends to be greater than its dimension in the plane of the sky. The largest streamers appear to be composed of a few thin rays.
Rotation-Averaged Rates of Coronal Mass Ejections and Dynamics of Polar Crown Filaments
Authors: Cliver E. W. , St. Cyr O. C. , Howard R. A. , McIntosh P. S. 
Published: July 2016

AbstractWe obtained Carrington-rotation-averaged daily rates of coronal mass ejections (CMEs), corrected for duty cycle, for the period 1979-1989. The 27-day averages of CME rate and sunspot number are correlated over this 11-yr period, although significant discrepancies can occur for any given rotation. The baseline CME rate exhibited quasi-discontinuities in 1982 (decrease) and 1988 (increase) when the “tilt angle” of the heliospheric current sheet passed through values of ∼ 50°. We suggest that these quasi-discontinuities are related to the dynamics of the belts of polar crown filaments that reside at ∼ 50° north and south of the equator during solar minimum and move poleward during the rise phase of the solar cycle.
Photometrical Evidences in Favour of the “Flat Solar Corona”
Authors: Gulyaev R. A. , Vanyarkha N. Ya. , Vanyarkha E. S. 
Published: July 2016

AbstractThe conventional way of quantitative description of coronal forms is shown to be inadequate as compared with actual coronal configurations. The standard technique of determining the Ludendorff’s parameter in the heiiographic reference has no physical meaning. However the similar parameter as determined in the heliomagnetic frame of reference is of quite clear physical meaning since it depicts the actual concentration of the coronal material towards the heliospheric current sheet. Conclusion of a need to revise the conventional view on relation of coronal forms with the sunspot cycle is pointed out.
Structure and Development of Quiet Loops in the Solar Corona
Authors: Hiei E. 
Published: July 2016

AbstractSolar coronal features seen in X-ray emission change on two different timescales: a) flare loops and transient brightenings in active regions show a rapid variability, b) quiet region loops are quasi-steady and change only slowly with time. This different time behavior has been analyzed on the basis of Yohkoh SXT observations and we report here on the results from our analysis, mainly focussing on quiet loop variability.