bluuebunny/crossref_metadata_2025 huggingface dataset:
Fine Structure of Shocked Photodissociation Regions in the Orion Bright Bar
Authors: Omodaka Toshihiro , Murata Yasuhiro , Hayashi Masahiko , Kitamura Yoshimi , Ohishi Masatoshi
Published: July 2016

The Orion bright bar is a prominent ionization front located approximately 2’ southeast of the Trapezium stars. Because this ionization front is seen almost edge-on, it provides an opportunity to study the interaction between the HII region and the adjacent molecular cloud. The molecular bar has been thought to be a narrow layer of ~ 50” (0.1 pc) in width parallel to the ionization front with enhanced temperature, density and column density. The molecular gas outside the ionization front was redshifted with respect to the ambient molecular cloud by 1-2 kms−1 (Omodaka et al. 1984, 1986, 1992), suggesting that the expanding HII region generated by the Trapezium stars had driven a shock wave into the molecular cloud at the southeast of the bar. This layer is exposed to intense UV radiation from the Trapezium stars, resulting in the formation of photodissociated regions.

We have made aperture synthesis observations of CS(J=1-0) line and 49 GHz continuum in the Orion bright bar with the Nobeyama Millimeter Array. Figure 1, a map of integrated intensities of CS, clearly revealed fine structures of the molecular bar and more than six prominent features are confirmed. It is noted that these features are lined up at 30” from the ionization front inside the molecular cloud.
Aperture Synthesis Observations of M17 SW
Authors: Wang Y. , Zhou S. , Evans N. , Jaffe D. , Hayashi M. , Murata Y.
Published: July 2016

We present maps of M17 SW cloud core in the CS J=1→0 line and the 49 GHz continuum obtained with the Nobeyama Millimeter Array.
The Extended CO(3 - 2) Emission in the Protogalaxy IRAS F10214+4724
Authors: Brown Robert L.
Published: July 2016

Preliminary 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.
A High-Resolution CO Mapping of the Nucleus of the Barred-Spiral Galaxy, M83
Authors: Handa Toshihiro , Ishizuki Sumio , Kawabe Ryohei
Published: July 2016

M83 is the best sample to investigate gas response to bar potential because it is one of the nearest galaxy with a pronounced bar structure (distance=3.7 Mpc). Handa et al. (1990) observed it with the Nobeyama 45-m telescope in CO(J=1-0) and found concentration of the CO emission to the dust lanes along the bar and non-circular rotation. However we need better spatial resolution in order to investigate kinematics and distribution of molecular gas in the nuclear region. So we observe the central region of M83 using the Nobeyama Millimeter Array. The synthesized beamsize was 12″ × 6″ and frequency coverage was 325 km s-1.
Search for the Companion in the β CrB Spectrum
Authors: Faraggiana R. , Gerbaldi M.
Published: July 2016

Spectroscopic analyses of the β CrB spectrum have been performed in the past without taking into consideration the double nature of this well-known cool Ap star (e.g. Hiltner, 1945; Hack, 1958; Adelman, 1973). Recently, Kamper et al. (1990) have re-examined the astrometric (interferometric and visual) and spectroscopic (radial velocity) data and have given an improved orbit for the β CrB system (P=10.55 yr) and the passage at periastron at 1991.02.
Observations of Magnetically Split Lines in Ap Stars)
Authors: Mathys Gautier , Landstreet John D. , Lanz Thierry
Published: July 2016

Ap 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

The 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

The 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

A 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

The 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.
Computational Approaches to Determining Accurate Band Strengths
Authors: Langhoff Stephen R. , Bauschlicher Charles W.
Published: July 2016

With the advent of high-speed computing and improved algorithms, computational chemistry techniques have become competitive with the best experimental techniques for determining line strengths for rovibrational and electronic transitions in molecular systems (BauschlicherkLanghoff 1991). This is particularly the case at high temperatures where the molecules are highly rotationally excited. While it is difficult to measure line strengths at stellar temperatures, the theoretical values can be very reliable if a globally accurate transition moment function (TMF) is used in conjunction with high-quality experimental or theoretical potentials.
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).
Production, Detection and Study in the Infrared of Unstable Molecules and Radicals
Authors: Morillon-Chapey Mireille
Published: July 2016

This subject is very wide. I shall present, here, a summary of our works related to radicals created in electric discharges. I shall review the methods and technical means used for studying these species in the infrared. This review will be accompanied with a detailed bibliography in which one will find the description of these methods and the most typical results obtained in our group in Orsay since 1986.
Schmidt CCD Astronomy at BAO
Authors: Chen Jian-Sheng
Published: July 2016

Current users only use CCDs to cover a small fraction of the Schmidt fields. We discuss what kind of Schmidt astronomy is more efficient and the advantages of Schmidt telescopes over reflecting telescopes. The BAO CCD multi-object light curve survey system and the BATC 15 colour survey are introduced.
The Nova and Supernova Star Patrol at Abastumani
Authors: Kimeridze Givi N. , Kvernadze Teimuraz M.
Published: July 2016

The Schmidt telescope (360/333/625 mm) of the Abastumani Observatory is used for photographic observations. It provides a field of 7.3° (80 mm) and a non-vignetted field of 4° (44 mm). For an astronomic film of medium sensitivity (DIN 20, ASA 70) the limiting exposure time is 7–8 m and the limiting magnitude is 16.5. For fine grain emulsions, a 15 m exposure time provides the limiting magnitude of 18.0. Since 1961 systematic photographic (mainly photovisual) observations have been carried out, within the International Cooperation Program of the Supernova Patrol in the direction of 24 selected fields. During a night an average of 10 exposures are taken. About 10,000 exposures have been obtained up to now and 30 Supernovae discovered, of which 10 were first identified in Abastumani (Chuadze 1967; Kimeridze 1971, 1979; Kimeridze et al. 1984, 1988, 1989a, b) In parallel with the patrol observations, photovisual and photographic (sometimes UBV) photometry was performed for 9 discovered Supernovae. The observations are still continuing.
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

The 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

We 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

The 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

The 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

Optical 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

Results 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.
Imaging FP Scans: Comments on Interpolation, Sampling, Decomposition, Deconvolution, Binning, and Photometric Calibration
Authors: Caplan James
Published: July 2016

Several suggestions are made concerning Fabry-Perot data acquisition and reduction, in order to improve the quality of imaging Spectroscopy.
The Goddard Fabry-Perot Imager
Authors: Gelderman Richard , Woodgate Bruce E. , Brown Larry W.
Published: July 2016

The 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.
Spectroscopic Imaging of Solid Planetary Surfaces
Authors: Pinet P.C.
Published: July 2016

Seen from Sirius through the eye of the telescope, our inner solar system would easily fit within one CCD-pixel. The purpose of the present paper is: i) to provide with a general overview of the use of imaging or 3D-spectroscopy for the study of the solid planetary surfaces, ii) to demonstrate that the analysis of 3D spectroscopic data on the basis of spectral mixture modelling permits to describe the subpixel spectral variability related to mineralogy of the planetary solid surfaces. In the following, a few cases are discussed concerning the remote sensing investigation in the UV-VIS-nIR domain of the lunar, terrestrial and martian surfaces, documented by means of multispectral or hyperspectral data, produced by telescopic, airborne or orbital imaging spectroscopic techniques.
Zeeman Doppler Imaging
Authors: Semel M.
Published: July 2016

Stellar 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

Dark 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

Ultraviolet 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.
Fragmentation and the Initial Mass Function
Authors: Larson Richard B.
Published: July 2016

A central problem in the theory of star formation is to understand the spectrum of masses, or Initial Mass Function, with which stars are formed. The fundamental role of the IMF in galactic evolution has been described by Tinsley (1980), and an extensive review of evidence concerning the IMF and its possible variability has been presented by Scalo (1986). Although the IMF derived from the observations is subject to many uncertainties, two basic features seem reasonably well established. One is that the typical stellar mass, defined such that equal amounts of matter condense into stars above and below this mass, is within a factor of 3 of one solar mass. A theory of star formation should therefore be able to explain why most stars are formed with masses of order one solar mass. The second apparently universal feature is that the IMF for relatively massive stars can be approximated by a power law with a slope not greatly different from that originally proposed by Salpeter (1955). Thus we also need to understand why the IMF always has a similar power-law tail toward higher masses.
Silicon Bearing Molecules in Molecular Clouds
Authors: Martín-Pintado J. , Gómez-González J. , Bachiller R. , Planesas P. , Bujarrabal V.
Published: July 2016

We have used the IRAM 30-m telescope to make high angular resolution observations of the silicon-bearing molecule, SiO and SiS in region of massive star formation. We have mapped the J=2-l and the J=5-4 lines of SiO with angular resolutions of 26 and 12” respectively. For all the sources mapped, the SiO emission is more extended that the beam. The extreme cases are found toward NGC7538 and W49N where the SiO emission has sizes of 1x0.5 pc and 2.8x1 pc respectively. This result is in contrast with the size of the SiO region in Orion-IRc2 which is of the order 0.03 pc. The maxima of the SiO emission are found at the position of the H2O masers. This indicates, as previously thought, that SiO emission probes the high temperature regions and/or the shocked gas and dust surrounding young stars. In the DR21(OH) region we have found the unique SiO source which is not associated to H20 maser emission. This SiO condensation is 40” south of DR21(OH) and it was first detected as a source of 350µm emission. The SiO emission is elongated in the east-west direction. From an analysis of the FIR continuum emission this object appears to be cool (Tk < 30) and it has been proposed that this source represents a pre-stellar condensation which may be evolving toward the star formation stage. The detection of SiO, howevwer, casts some doubts about the evolutionary stage of this source. Futher high angular resolution observations are necessary to establish the nature of this source.
Sodium Ionization in T-Tauri Stars
Authors: Natta A. , Giovanardi C.
Published: July 2016

We present the results of a study of the sodium ionization and excitation in the winds of low-luminosity, pre-main-sequence stars. Line profiles for the Nal doublet at 5990,5986 Åare discussed and compared with the observations for those T Tauri stars with P-Cygni profiles. We find that the observed shape of the lines put significative constraints on the rate of mass-loss (M ≥ 3 x 10-8M⊙/yr).
Highly Excited Molecular Hydrogen in Orion
Authors: Hippelein Hans H. , Münch Guido
Published: July 2016

Observations of H2 lines in the IR have been mostly restricted to those with upper levels of low energy, which can be excited either collisionally in shocks or radiatively by UV starlight. In order to discriminate between the two excitation mechanisms we have measured in 11 μm range lines of the v=2-0 band arising from high rotational levels J≤;13. Their intensities, together with those of the IR lines, allow an estimate of the line of sight effective extinction and a determination of the rotational temperature measuring their joint degree of excitation. The latter parameter provides information about the energy state of the molecules at their formation and ejection from grain surfaces and thus constrains the hypothetical models for H2 molecule formation.
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

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

We 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

The 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.
Irradiance Observations of SMM, Spacelab 1, UARS, and ATLAS Experiments
Authors: Willson Richard C.
Published: July 2016

Detection of intrinsic solar variability on the total flux level was made using results from the first Active Radiometer Irradiance Monitor (ACRIM) experiment, launched on the Solar Maximum Mission (SMM) in early 1980. ACRIM I, specifically designed to start the high precision total solar irradiance database as part of the U.S. Climate Research Program, produced high precision results throughout the 9.75 years of the Solar Maximum Mission. The second ACRIM experiment was flown aboard the Space Shuttle as part of the NASA/ESA Spacelab 1 Mission in late 1983. Its primary function has been to provide a comparison with ACRIM I that could be used to relate its observations with future satellite solar monitors, should they and ACRIM I fail to overlap in time. The second ACRIM satellite solar monitoring experiment (ACRIM II) has provided high precision total solar irradiance observations since its launch as part of the Upper Atmosphere Research Satellite (UARS) mission in late 1991 and continues at present. The shuttle ACRIM instrumentation has been flown on the ATLAS 1 and 2 missions in 1992 and 1993, providing comparisons with the UARS/ACRIM II.
Irradiance Observations from the UARS/SUSIM and ATLAS/SUSIM Experiments
Authors: Brueckner Guenter , Floyd Linton E. , Lund Paul A. , Prinz Dianne K. , Vanhoosier Michael E.
Published: July 2016

The SUSIM (Solar Ultraviolet Spectral Irradiance Monitor) on board the UARS (Upper Atmosphere Research Satellite) has measured the solar UV output from 120 nm to 400 nm on a daily basis since October 1991. A reference channel records a solar spectrum semi-annually only to reduce the instrument degradation of this channel and to provide long-term stability marks. Four deuterium lamps are used at monthly, semi-annual and annual intervals to provide long term calibration of the instrument. A preliminary analysis of the long term stability of SUSIM-UARS indicates that the precision of the instrument should be better than a few percent. The repeatability of two scans is better than 0.2%. A simplified SUSIM instrument is flying on NASA’s ATLAS Spacelab missions anually to provide calibration points for the SUSIM-UARS.
Brightness Observations of the Sun
Authors: Kuhn Jeffrey R.
Published: July 2016

There are few solar surface brightness observations with sufficient accuracy to have direct bearing on the question of the origin of the Sun’s bolometric luminosity and irradiance changes (the correlative observations have been reviewed elsewhere in these proceedings). This paper contrasts these observations with a model for the solar variability and illustrates our clear need for high precision surface photometry, in combination with helioseismic data and numerical experiments.
Solar Variability Traced by Cosmogenic Isotopes
Authors: Beer Jürg , Baumgartner Stephan T. , Dittrich-Hannen Beate , Hauenstein Jürg , Kubik Peter , Lukasczyk Christian , Mende Werner , Stellmacher Rita , Suter Martin
Published: July 2016

10Be has been measured in a 300 m long ice core from Greenland. After a general analysis of the 10Be data the potential and the limitations of 10Be records in ice to reconstruct solar variability are discussed. Special emphasis is given to periods of low solar activity (Maunder Minimum etc.). The ‘clock problem’ is addressed, also the question whether the Schwabe cycle maintains its phase. Finally the question of what 10Be can tell us about changes of the solar irradiance in the past is explored.
Magnetic Structures of the Intermediate Corona
Authors: Koutchmy S. , Molodensky M. M. , Koutvitsky V. , Solov’ev L. S.
Published: July 2016

The 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

Results 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

We 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

The 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

Solar 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.
Diamagnetic Temperature Control in the Solar Wind
Authors: Steinitz R. , Sekeles B.
Published: July 2016

We have developed a model to account for changes in velocity distributions of protons in the solar wind. The essential operative mechanism is the diamagnetic effect on charged particles. Through numerical simulation, we explore the (distance 0.3 AU to 1 AU) evolution of thermal anisotropy. We find that as the initial ratio T+/T∥is increased, there is a larger growth in bulk speed, as is observed. Since any form of wave-particle interactions is exluded from our simulations but they fit well the observations, we conclude that the diamagnetic effect is most relevant in controlling both thermal anisotropy and bulk speed evolution.
Linear Visco-Resistive Computations of Magnetohydrodynamic Waves: II. Viscous Effects
Authors: Erdélyi R. , Goossens M.
Published: July 2016

Resonant absorption of MHD waves in coronal loops is studied in linear, viscous MHD. Viscosity is described by Braginskii’s viscosity stress tensor. The dependence of the process of resonant absorption on the viscosity coefficients is studied. The compressive viscosity and viscosity due to the finite Larmor radius do not produce absorption. Shear viscosity produces absorption and is a viable candidate for heating coronal loops. The width of the dissipation layer is found to be proportional to, whereη1is the shear viscous coefficient of the full viscous stress tensor.
The spatial Golf project
Authors: Turck-Chieze S. ,   the GOLF scientific and technical team, Bocchia R. , Boumier P. , Cantin M. , Charra J. , Cougrand B. , Cretolle J. , Denis N. , Duc R. , Dzitko H. , Decaudin M. , Gabriel A. , Herreros J. , Grec G. , Petrou N. , Cortes T. Roca , Robillot J.M.
Published: July 2016

This spatial experiment is under construction and has been defined as a 2 years mission on board SOHO, a satellite dedicated to the Sun which will be launched in mid 95. The main objectives are the detection of solar low degree acoustic modes and solar gravity modes for improving our knowledge of the solar nuclear region.
Denis
Authors: Forveille T.
Published: July 2016

The DENIS survey will survey the southern sky in the near-IR J (1.2 micron) and K (2.2 microns) bands at 3” resolution and to limiting magnitudes in J and K of respectively 16 and 14.5 (lmJy in both cases), and at 1” resolution in the red I band (0.9 microns). Astrophysical motivation is provided by basic problems concerning structure and evolution of galaxies, of types ranging from our own to active galaxies, and concerning specific stellar populations including stars with low temperature photospheres, those still embedded in their protostellar envelopes, and those currently losing mass on the AGB.
Computations of Static White Dwarf Models: A Must for Asteroseismological Studies
Authors: Brassard P. , Fontaine G.
Published: July 2016

We present briefly a new generation of white dwarf models incorporating the latest developments of the constitutive physics. These are static models especially designed for accurate seismological studies.
Coronal Heating by the Resonant Absorption of Alfvén Waves
Authors: Ofman L. , Davila J. M. , Steinolfson R. S.
Published: July 2016

Nonlinear evolution and stability of the resonant absorption layer is considered by solving the time-dependent 3D, low-β, resistive MHD equations with the Lax-Wendroff explicit method. The calculations are initiated with the solutions of the linearized version of the MHD equations (Steinolfson and Davila, 1993, Ofmanet al., 1994), with inhomogeneous background density, and a constant magnetic field. The narrow resonant heating layers are deformed by the self-consistent shear flow. When the driver amplitude is small compared to the average Alfvén speed the dissipation layer appears to be stable and the driver-period-averaged ohmic heating rate saturates at a slightly higher than the linear rate. When the driver amplitude is large (Fd≈ 1) the resonant heating may become unstable.
The Brazilian Program of Latitude and Time
Authors: Barreto Luiz Muniz
Published: July 2016

This brief communication covers the joint plans of the Brazilian National Observatory and the Astronomical and Geophysical Institute of the University of São Paulo, for the development in Brazil of the programs of latit ude and time.
Some Spectroscopic Observations of Visual Binaries
Authors: Scarfe C.D.
Published: July 2016

The use of a coudé spectrograph for securing the high-resolution spectrograms necessary to follow the slow variations of radial velocity exhibited by visual binaries is discussed. Recent observations, using the spectrograph at the coudé focus of the Dominion Astrophysical Observatory’s 48-in. reflector, are then presented for the systems ofαUMa,εHya,βLMi andγLeo.
The Absolute Proper Motion of the Pleiades Cluster
Authors: Altena W. F. van , Jones B. F.
Published: July 2016

The establishment of a truly inertial reference system is a problem that has defied solution for many years. However, with the completion of the Lick proper motion survey (Wright 1950) and the USSR program (Deutsch 1954) the situation for the northern hemisphere should be satisfactory.
The Yale – Columbia Southern Proper Motion Program
Authors: Wesselink A.J.
Published: July 2016

This program is the southern counterpart of the well-known Lick proper motion program. These programs are almost identical in design and execution, their chief feature being the use of faint extragalactic nebulae and QSO’s as stationary reference objects.

The Lick program has been described by S. Vasilevskis on various occasions; it serves as an example to the Yale-Columbia work.
Proceedings of Observatories: Nuffield Radio Astronomy Laboratories Jodrell Bank
Authors: Lovell Bernard
Published: July 2016

The structure of the Galaxy can be studied by the following techniques: (i) measurements of the continuum emission, both on the large scale and from discrete objects such as supernova remnants; (ii) measurements of line radiation, again both from large and small scale features; and (iii) measurements of the transmission properties of the interstellar medium. All these techniques have been pursued in recent work at Jodrell Bank. This section describes work in the categories (i) and (iii); work under (ii) is described in Sections 6 and 7.
Cambridge Observatories
Authors: Redman R.O.
Published: July 2016

At the Solar Research Station, Malta, Dr von Klüber has continued photoelectric measurement of central intensities of certain Fraunhofer lines on areas of the solar disk selected according to the local magnetic field, a large number of records being sent to Cambridge for further reduction. He also made a number of carefully calibrated photographs of the D lines for line profile investigations.
Determinations of Precession (Invited Review Paper)
Authors: Fricke Walter
Published: July 2016

Recent determinations of lunisolar precession and of the motion of the equinox are reviewed. Methods of determination are discussed which are based on proper motions referred to fundamental systems, on planetary motions, and on proper motions referred to galaxies. It is concluded that a new fundamental catalogue, which will replace the FK4 at some future date, should be based on revised values of precession and freed from errors in the motion of the equinox.
Notes on Equinox Motion and Corrections to Precession
Authors: Van Flandern T. C.
Published: July 2016

The coordinate system defined by the locations of distant galaxies should be an inertial coordinate system. Until that system becomes better observed, we must use the stars of our own Galaxy, and make certain assumptions in order to achieve an inertial system. Basically, we assume that the stellar proper motions consist of a component due to galactic rotation (a function of distance from the galactic center), a component due to solar motion, and a random component, peculiar to each star. The random component should not cause the star system as a whole to rotate in any particular direction – in other words, the sum of the random components of proper motion will be zero (to within their standard deviation) in every direction.
Sur l’effet d’une correction de la constante de la précession
Authors: Bec A.
Published: July 2016

La valeur conventionnellement admise pour la précession est trop faible. Il est bien connu que la correction à apporter à cette valeur est de l’ordre de 1” par siècle. On peut situer cette correction dans l’intervalle suivant (Fricke, 1967):
On Intensity, Magnetic Field, and Velocities of Small Bright Points in the Ca+ Network
Authors: Soltau Dirk
Published: July 2016

More than 1000 small isolated bright Ca+ structures (facular points) have been observed with the German VTT at the Observatorio del Teide, Tenerife. An analysis of Stokes V and Stokes I profiles of magnetically sensitive lines exhibit some typical properties of these features. The investigation is concentrated on those 40% of the observed structures for which the magnetic filling factor is larger than 10%
Spectral Characteristics of a Coronal Oscillation with a Period of the Order of 10 MS
Authors: Zhiguo Xia , Jingying Chen , Xiangmin Zheng , Yuan Ma
Published: July 2016

A coronal oscillation with a changing period was observed with the acousto-optic radio spectrometer of Yunnan Observatory. The bandwidth of the oscillation was about 10 MHz. It accompanied radiation which lasted for about 500 ms. A corresponding burst was found on a radio spectrogram obtained at Weissenau, Germany. A 245 MHz burst was reported at the same time and we found a bright spot on the Hα film records of Yunnan Observatory. In this paper, we present a series of spectra of the oscillation at 10 ms intervals. In the spectra the oscillation appears in the form of a 3.5 MHz drift of radio flux with frequency.