bluuebunny/crossref_metadata_2025_split huggingface dataset:
Radial Velocity and Magnetic Variations of a Draconis
Authors: Lehmann Holger , Scholz Gerhard 
Published: July 2016

AbstractBased on photographic Zeeman spectra a magnetic field has been detected for the giant star α Dra. One of the two periods derived for the magnetic changes can be interpreted as the half rotational period corresponding to a slight variation of the radial velocity of 3.57 days. The application of an eguatorially symmetric rotator model with a magnetic field dominated by the quadrupole moment leads to a good agreement with the observed magnetic variation. The orbital elements of α Dra were newly derived.
First Results for CCD Observations with the 70 cm Meniscus Telescope
Authors: Kurtanidze Omar M. , Kvernadze Teimuraz M. 
Published: July 2016

AbstractFrom the middle of 1993, a ST-6 CCD Camera (375 × 242 array with 23 × 27 microns pixel size) was mounted at the Newtonian focus (f/3) of the 70 cm meniscus telescope of the Abastumani Observatory. The photometer is now equipped with various sets of narrow-band interference, intermediate and wide band standard niters. Some pilot observations were carried out in direct imaging mode and in combination with an 8° objective prism (166 Å mm−1 at Hγ). Spectrophotometric standard stars with absolute calibrations were observed in the 8° mode to determine the CCD spectral response. Some other observations were performed with a prism-interference filter combination to estimate the observational mode efficiency.
Fibre Optic Light Guide for the Telescope: Some Experiments
Authors: Handojo Andrianto , Fachrizal Noor 
Published: July 2016

AbstractOptical fibres are used to convey light from star images to the entrance slit of a spectrograph. Using an arrangement, the position of the fibre ends are monitored. The spectral transmission factor of the system and modification in the beam divergence have been measured.
Detecting Extra-solar Planetary Transits with a Schmidt
Authors: Parry Ian R. , Watson Fred G. , Carrasco B. Esperanza 
Published: July 2016

AbstractWe describe an instrumental configuration for detecting large gas-giant planets orbiting main sequence stars via the small drop in stellar brightness that occurs when the planet transits the stellar disk. Our proposed scheme involves the long-term monitoring of the light-curves of tens of thousands of stars using a Schmidt telescope coupled to a CCD via a bundle of 10,000 optical fibres. Using an existing theoretical model of planetary system formation we calculate a detection rate of 14 transits per year for our proposed system.
Schmidt-Plate Astrometry – Dinosaurs in Action
Authors: Reid Neill 
Published: July 2016

AbstractPhotographic plates are well established as stable detectors, well suited for positional astronomy. The completion of the current second epoch 48 inch Schmidt surveys in both hemispheres will provide material spanning baselines of 20–45 years, allowing proper motions to be determined to an accuracy of 4–7 mas yr−1. This paper discusses some of the Galactic structure problems that these data, combined with accurate photometry, can be used to address.
Large Scale Galactic Structure
Authors: Gilmore Gerard , Ibata Rodrigo 
Published: July 2016

AbstractModern models of Galaxy formation make fairly specific predictions which are amenable to detailed tests with galactic kinematic and chemical abundance data. For example, popular Cold Dark Matter models ‘predict’ growth of the Galaxy about a central core, which should contain the oldest stars. Later accretion of material forms the outer halo and the disks, while continuing accretion will continue to affect the kinematic structure of both the outer halo and the thin disk. This picture, which contains aspects of both the monolithic (‘ELS’) and the multifragment (‘Searle-Zinn’) pictures often discussed in chemical evolution models, makes some specific predictions which can be tested. The essential feature of these predictions is that they are believable only for the largest scale effects. Large scale properties of the Galaxy must be measured to test them. It is these studies which need large angular scale data. One specific example of current interest is the ‘prediction’ that mergers of small satellites are an essential feature of galactic evolution. This leads one to look for kinematic and spatial structures, and ‘moving groups’, as a primary test of such models.
Star Counts and Spectral Classification in Star Formation Regions of the Magellanic Clouds
Authors: Kontizas M. , Morgan D. H. , Bellas-Vellidis Y. , Kontizas E. 
Published: July 2016

AbstractLarge complexes of young objects are common features in galaxies and are called superassociations, complexes and supercomplexes according to their size. They contain HII regions, early-type stars, associations and young clusters. Such large structures are expected to trace the star formation regions within galaxies. Star counts and spectral classification over extended areas, using direct and objective prism Schmidt telescope plates are good methods of determining the boundaries of these complexes and supercomplexes where the spatial density of early-type stars is enhanced. A project of tracing the supercomplexes in the Magellanic Clouds has started using plates taken with the UK 1.2 m Schmidt Telescope.
A Survey for Low Surface Brightness Galaxies using Tech Pan Films
Authors: Schwartzenberg Jean Marc , Phillipps Steven , Parker Quentin A. 
Published: July 2016

AbstractWe report on a new survey for low surface brightness galaxies using Kodak Tech Pan 4415 film on the UKST, and demonstrate the advantages of this film over conventional IIIa plates when searching for faint, extended objects. Recent experiments with films of the Virgo cluster have shown that the noise per pixel in deep exposures is only 0.7 % of sky, enabling known objects to be traced out to an isophote around 27 Rµ. In addition, a preliminary survey has revealed several new galaxies with central surface brightnesses around 24 Rµ. With the digital coaddition of several films, we expect to be able to measure objects out to the 28 Rµ isophote and detect galaxies with central surface brightnesses as faint as ∼ 25 Rµ, i.e. below 3 % of sky.
Out of the Archive: Faint Features of Bright Galaxies
Authors: Malin David , Hadley Brian 
Published: July 2016

AbstractSimple photographic techniques are used to enhance and combine many images of (mostly) bright galaxies made from plates in the archive of the UK Schmidt Telescope in Edinburgh. The purpose of this project is to reveal extended faint features of these objects that are less than 0.5 % as bright as the night sky. Presented here are the preliminary results of what we intend to be a substantial atlas. The early results suggest that a remarkably large number of apparently normal galaxies reveal unexpected features when very deep images are produced.
Comments on Extragalactic Objective-Prism Work
Authors: Bidelman William P. 
Published: July 2016

I much regret not being able to attend this interesting meeting. However, I have two comments concerning useful Schmidt work on galaxies that I would like to pass on to you for further consideration.Both relate to objective-prism surveys for emission-line galaxies. The first is a suggestion that the work of Wasilewski (1983) should be continued. (Additional studies of his objects have been made by Bothun et al. (1989), Osterbrock & Shaw (1988) and Osterbrock et al. (1992)). This utilized the Burrell Schmidt with a 4° prism that gave a dispersion of some 400 Å/mm in the neighborhood of N1, N2 and Hβ. With this relatively high dispersion one can clearly separate these three lines, giving useful information on their relative strengths and widths that cannot be obtained from lower-dispersion material. It might be worthwhile to employ even somewhat higher dispersions than Wasilewski used, though this would no doubt affect the limiting magnitude somewhat. My second suggestion is that one should carry out objective-prism survey work in longer-wavelength spectral regions than are currently being used. The purpose is the detection of additional extragalactic objects in the z = 3–5 range; this search should utilize the lowest available dispersion.
An Optical Study of a Sample of Active Galaxies
Authors: Surace C. , Comte G. , Guibert J. , (Liege) O. Moreau 
Published: July 2016

AbstractA new sample of active galaxies was obtained with the ESO Schmidt telescope. We derived quantitative redshifts for 97 emission line galaxies and semi-quantitative photometric and spectro-photometric properties for 62 of them. The results are directly extracted from the Schmidt plates after digitization by the MAMA machine of Observatoire de Paris (C.A.I, INSU Paris).
BVRI CCD Photometry of Galaxies in Abell Clusters: Hubble Types From Undersampled Data
Authors: Moody J. W. , Hintz E. G. , Joner M. D. 
Published: July 2016

AbstractWe have obtained BVRI CCD frames of the inner Abell radius of 14 Abell clusters as part of a survey that will eventually include 45 clusters with 0.03 < z < 0.08. We report on how the colours and surface brightness profiles can be used to identify galaxy Hubble type despite having rather large (2.1 arcsec) pixels and small images.
A Deep Multicolour CCD Survey for Quasar Candidates with the OCA Schmidt Telescope
Authors: Moreau O. , Gosset E. , Royer P. 
Published: July 2016

AbstractWe intend to perform a deep multicolour survey for quasar candidates using the CCD equipment recently installed at the Schmidt telescope of Observatoire de la Côte d’Azur (OCA). As a first step, we will study small areas of 0.3 square degrees but we are especially interested in the forthcoming full coverage of the Schmidt field with a CCD mosaic. In order to prepare the selection of quasar candidates, we have computed their predicted colours on the basis of a composite quasar spectrum.
Imaging and Spectroscopy with Focal Reducers
Authors: Seifert W. , Fürtig W. , Böhnhardt H. , Nicklas H. 
Published: July 2016

AbstractFocal reducers are nowadays widely used on large telescopes as multi-mode instruments. Some general aspects of the design of focal reducers are discussed. FORS, the focal reducer/low-dispersion spectrograph for the ESO VLT is presented as an example for such a multi-mode instrument on a large telescope.
A Set of Grisms for FORS
Authors: Fürtig W. , Seifert W. 
Published: July 2016

The University Observatories of München and Göttingen and the Landessternwarte Heidelberg are building in cooperation with ESO two almost identical FOcal Reducer /low-dispersion Spectrographs (FORS) for the ESO Very Large Telescopes. FORS allows low-dispersion multiobject spectroscopy (19 slits) and longslit spectroscopy in the wavelength range of 330 to 1100 nm. A set of standard grisms with reciprocal dispersions of 45 ...230 Å/mm working in the first order are foreseen. With a slitwidth of 1 arcsec the resulting spectral resolutions range from 180 to 1800.For further FORS details see Appenzeller and Rupprecht (1992) and Seifert et al. (1994).The standard grisms are located in a grism wheel in the parallel beam between the collimator and the camera. Seven of eight positions are available for grisms. The free diameter of the grisms is 135 mm to cover the whole field of view of FORS. To avoid reflection ghosts the entrance surfaces are all tilted by .
HIFI Survey of Emission-Line Galaxies: recent Results on the Nuclear Superbubble of NGC 3079
Authors: Veilleux S. , Cecil G. 
Published: July 2016

AbstractThe Hawaii Imaging Fabry-Perot Interferometer (HIFI) was used to produce a large data cube of the edge-on SBc galaxy NGC 3079 covering Hα + [NII] λλ6548, 6583. The complete two-dimensional coverage of the Fabry-Perot data allowed us to derive the general flow pattern of the nuclear gas that constitutes the energetic superbubble.
Deep Hα Survey of the Milky Way
Authors: Marcelin M. , Georgelin Y.M. , Amram P. , Georgelin Y.P. , le Coarer E. 
Published: July 2016

AbstractAn Hα Survey of the Milky Way is being led at La Silla with a small telescope equipped with a scanning Fabry-Perot interferometer and IPCS. This Survey gives detailed Hα maps with a 9” spatial resolution and radial velocity maps with a 5km/s resolution. About 200 fields (38’×38’) have been already observed along the galactic plane. They furnish mosaics ranging from galactic longitude 234° to 350°. Combined with distances of exciting stars and radio data our kinematic data of the ionized gas enable to draw precisely the spiral arms of our Galaxy. Examples of the results obtained are given for galactic longitudes 234°, 283°, 290°, 298°, 328° and 338°.
Tridimensional Observations of Nearby Active Galaxies Using OAO Spectronebulagraph
Authors: Yoshida M. , Shimizu Y. , Koyano H. , Kosugi G. , Aoki K. , Ohtani H. , Sasaki T. , Sasaki M. 
Published: July 2016

We developed a slit-scanning type 3D-spectroscopic system named as Spectronebulagraph (hereafter SNG; Kosugi et al. 1994) at Okayama Astrophysical Observatory. A detailed description about SNG is presented by Ohtani et al. elsewhere in this colloquium. We present here the results of the 3D-spectroscopy of four nearby active galaxies by using SNG.This nearby (at distance of 5.4 Mpc) Magellanic irregular galaxy has many H II regions in its main body suggesting violent star-formation activity. We performed tridimensional observations of NGC 4449 using SNG in order to obtain detailed kinematic structure and then to investigate the star-formation mechanism of NGC 4449. Hα intensity map, Hα velocity field are shown in figure 1. As is obvious in lower panel of figure 1, no global rotational motion was detected. Most impressive feature of the velocity field is kpc-scale mosaic structure of low velocity and high velocity components. Also, many filamentary components were newly found in 3D-datacube of the SNG observation.
Integral Field Spectroscopy of Gravitational Mirages
Authors: Angonin-Willaime M.-C. , Vanderriest Christian 
Published: July 2016

AbstractThis paper deals with applications of bi(tri)dimensional spectroscopy methods to some gravitational mirages. Optical fibre devices are well adapted to the study of the structure and geometry of such phenomena. The improvement that brought bidimensional spectroscopy of few mirages is presented and the need to observe the other candidates is discussed.
The integral field spectrograph TIGER: results and prospects
Authors: Bacon R. 
Published: July 2016

AbstractThe integral field spectrograph TIGER, in operation at CFHT since a few years, has been successfully used on a large variety of astrophysical objects, ranging from the planet Mars to distant radio-galaxies and quasars. This review discussed the peculiarities of the TIGER design and gives the main characteristics of the instrument. Two examples of scientific applications are presented to highlight the new possibilities offered by integral field spectrography. Finally the OASIS project dedicated to the CFHT adaptive optics bonnette is briefly presented.
Reconstruction of Spectra obtained with PYTHEAS through Photometric Methods
Authors: Gray M. 
Published: July 2016

PYTHEAS is an imaging spectrophotometer giving high spectral and spatial resolutions in joining together several optical concepts (Le Coarer et al 1992, and Georgelin et al. in these Proceedings). It will be shown in this paper that, contrary to other spectrographs using somewhat complex methods of data reduction, the PYTHEAS imaging spectrometer requires simple photometric methods in order to reconstruct the spectra of astrophysical objects.The CCD image of a continuous spectral energy distribution for a permanent gap between the layers of the Fabry-Perot consists in a series of channelled spectra: each elementary beam, spectrally filtered by the FP interferometer and sampled by a microlens in the frame, gives light to the whole surface of the grism which separates the various F-P orders by displaying them in a line on the detector. Each line or channelled spectrum consists of a series of Fabry pupils (spectral elements), each of them containing the luminous flux emitted on a certain wavelength by the object under investigation. After scanning the FP interferometer across its free spectral range, we obtain a series of shifted channelled spectra whose set provides us with a chart showing the photometric values of flux according to the wavelength. Consequently, some forms of calibration (continuum lamp, spectral lamp) allow the reconstruction of the spectra of the astrophysical object through simple photometric measures.
Low Order Fabry-Perot Low Dispersion Multicolor Large Field Survey System
Authors: Shi-Yang Jiang 
Published: July 2016

AbstractCrossing a low interference order Fabry-Perot etalon with an objective prism on a Schmidt telescope leads to a simple large field multiband spectrophotometric survey system well-adapted to the study of the spectral energy distribution of faint galaxies and redshift estimates.
3-D Spectroscopy with a Fourier Transform Spectrometer
Authors: Maillard J.P. 
Published: July 2016

AbstractWith the advent of bidimensional array detectors the throughput advantage of a Fourier Transform Spectrometer (FTS) can be used to create a new type of 3-D spectrometer. The classical multiplex property in the spectral domain of a FTS is multiplied by the number of pixel of the array. The points of the entrance field are all observed in parallel. After discussing the properties of this instrument, the coupling of the FTS of the CFH Telescope to a camera equipped with a NICMOS 3 array is described. With this combination, spectro-imaging in any bandpass between 1 and 2.5 µm is possible within a circular 24” field of view, with a scale of 0.33”/pixel, at seeing-limited spatial resolution. Any spectral resolution is choosable up to 30,000. Illustrations are given by a study of the dark side of Venus at 1.27 µm and of planetary nebulae at 2 µm. Many other objects can benefit from this observing mode in the near infrared. Further developments of this 3-D technique are discussed.
The Field-Widened SHS: An Extremely High etendue, Unscanned, Michelson-Based Spectrometer
Authors: Harlander John , Roesler F. L. , Reynolds R. J. 
Published: July 2016

AbstractThis poster described a method under development that promises to be useful for 3-D spectroscopic studies of extremely faint, spatially extended astronomical sources. The method, which we call Spatial Heterodyne Spectroscopy (SHS), is a relative of the conventional scanning Fourier Transform Spectrometer (FTS), but is free of any scanning elements. We foresee ground-based and space applications for studies of the interstellar medium and the upper atmospheres of solar system objects. Basic configurations that have been tested in the laboratory were described. The SHS instrument we are currently emphasizing for development is intended for a rocket experiment to measure C IV λ1548,51 doublet emission at a resolving power of 20,000 from the hot ISM. Eventually we hope to provide velocity-resolved all-sky maps of selected FUV lines to complement maps obtained at other wavelengths.
Molecular Hydrogen Emission from Photodissociation Regions
Authors: Hasegawa Tetsuo 
Published: July 2016

AbstractWe review new observational and theoretical developments of the understanding of the H2 infrared emission in the last 5 years since the discovery of the fluorescent emission in NGC 2023. An excitation analysis of H2 in a variety of Galactic sources has revealed that in many sources the excitation is expressed as a mixture of thermal and fluorescent components. This finding is in good agreement with theories of photodissociation regions, in which the population of H2 changes its character from pure fluorescence to thermal as the density of the region increases. The ortho/para abundance ratio of the fluorescent H2 is observed to lie within a limited range of 1.1 — 1.8 which is well reproduced by depth-dependent model calculations of the ultraviolet excitation and dissociation of H2 molecules. This may be understood as due to the independent self shielding of each of the ortho- and para-H2, rather than the ortho/para abundance ratio of the predissociated H2, a low formation temperature of H2 on grains, or gas phase interchange reactions. A laser emission of molecular hydrogen discovered in the planetary nebula NGC7027 further demonstrates the nonthermal nature of the H2 emission in photodissociation regions.
On the Nature of the Beta Pictoris Circumstellar Nebula
Authors: Paresce Francesco , Artymowicz Pawel 
Published: July 2016

SummaryWe summarize the observed properties and deduced physical characteristics of the Beta Pictoris circumstellar nebula obtained from a detailed analysis of existing IR and optical data. On the basis of these results, we reject the hypothesis that the observed feature is a bipolar nebula surrounding an evolved star. We claim the nebula is a flattened disk of orbiting particles making up a planetary system in its clearing out phase as small grains collide, erode, and are swept out by radiation pressure.
Submillimetre Mapping and Photometry of Bipolar Flows - Evidence for Compact Disks
Authors: Sandell Göran 
Published: July 2016

ABSTRACT:The mm/sub-mm dust emission from bipolar outflow sources is discussed. In nearby outflows the stars driving the flows appear point like and unresolved, i.e. apparent angular sizes < 7” (i.e. 700AU at lOOpc). The spectra are surprisingly flat, suggesting that the dust emission is affected by temperature and density gradients or that the dust surrounding these stars differs from that of the general interstellar medium. If the spectra are characterized with a conventional dust emissivity index, our sample gives an average value of 1.1, rather than the figure of 2, which is usually claimed at these wavelengths for dust in molecular clouds. The total dust and gas masses associated with these stars are a few tenths of a solar mass for nearby low luminosity sources and the gas densities are >107 cm−3, if the gas is in a shell, and the densities could be much higher if the gas densities fall off as a function of radius, or if the mass is distributed in a disk. These masses correspond to extremely high extinctions, which are not observed, and we therefore argue that the mass distribution must be anisotropic, most likely as an inclined disk surrounding the star. Hence, stars driving outflows are surrounded by a dense disk, possibly an accretion disks and/or collimating disk. If these stars are compared to the more evolved T Tauri stars, we find that the difference in disk mass could account for the mass loss observed in these stars. Because of the high gas densities in the disk, most commonly used molecular lines will be optically thick, and molecular observations should be done in rare isotopes and high density tracers in order to yield reliable results of gas densities and gas dynamics.
On the Formation and Propagation of Interstellar Jets
Authors: Tenorio-Tagle Guillermo 
Published: July 2016

Summary.The flow that results from stationary supersonically converging conical streams is studied by means of two dimensional numerical calculations. Convcrgency leads to a “colimator” conical shock and this to the formation of an underexpanded hydrodynamical jet. The properties of the conical shock and of the collimated stream are summarized for a variety of initial conditions. The resultant jets are followed to large distances (≥ 7.5X1017 cm) away from the injection point, and are shown to develop a complicated structure that eventually approaches a stationary state. Stationary features such as crossing shocks are shown to evolve from working surface shocks, left behind the head of the jet to ensure self-collimation of the beam matter.