bluuebunny/crossref_metadata_2025 huggingface dataset:
Extraterrestrial Molecules: Present and Future Observations from Space
Authors: Cosmovici Cristiano Batalli
Published: July 2016

In the last ten years Molecular Astrophysics has become an extremely interesting field of interdisciplinary research as a result of unexpected discoveries of complex organic molecules made by radioastronomy in many regions and objects of the Galaxy. Since not all molecules have detectable transitions through the atmospheric windows, the development of UV and IR space astronomy will allow us to study new important molecular transitions in the interstellar medium and in the atmospheres of cool stars and comets. In this paper the present status of molecular astrophysics will be described and special emphasis will be devoted to the importance of IR space astronomy for the future knowledge of molecular species in the interstellar medium and in the atmospheres of Carbon stars where the low temperatures are particularly, suitable for infrared studies
Classification Spectrale Dans Le Futur
Authors: Fehrenbach Ch.
Published: July 2016

Ce Colloque, organisé en l’honneur du Centenaire du Père Secchi, arrive a un bon moment pour faire le point sur le passe: les classifications de Secchi, de Harvard, le systeme Morgan et Keenan et examiner les problèmes d’avenir.

D’abord, quel est le but des classifications? Certains théoriciens ont l’impression que nous sommes dans la même position qu’un zoologiste classant des animaux. Mais cette impression est fausse: d’abord les animaux existent en espèces discontinues alors que les spectres stellaires forment un continuum.
The Pictorial Presentation of Digital Data for Classification Purposes
Authors: Kinman T. D. , Mahaffey C T.
Published: July 2016

More and more spectra are being generated in digital form from photo-electronic devices. The digital form has important advantages for sky subtraction, telemetry and general analysis but it is cumbersome for publication and quick inspection where the pictorial form is better.
Simultaneous Five Color (Ubvri) Polarimetry of EF Eri
Authors: Piirola V. , Reiz A. , Coyne G.V.
Published: July 2016

We present the first observations of the AM Her type object EF Eri where both the polarization and the photometric data are recorded simultaneously in five color bands (UBVRI). The position angle rotates strongly (~30° ) vs. wavelength from U to 1, probably due to Faraday rotation or due to fact that the polarized radiation seen in the different wavelength bands comes from different parts of the accretion region. The phase dependence of the position angle requires field and accretion geometry more complicated than a simple centered dipole and a second emitting region producing weaker intermediate pulses in the infrared seems to be present. We derive the value of the inclination of the system i = 55° ± 5° , the colatitude of the active pole βl = 38° ± 5° i and the second emitting region β2 = 115° ± 5° , both of which are nearly at the same longitude facing the main accretion stream.
EUV and FUV Observations of Cataclysmic Variables
Authors: Polidan R.S. , Carone T.E.
Published: July 2016

In this paper we present recent results from a continuing investigation of cataclysmic variables in the 500 to 1700 A region with the Voyager ultraviolet spectrometers. Observations of outbursts show a substantial delay (~0.5 day) in the rise to maximum in the FUV (912–1200 Å) with respect to optical wavelengths. Both FUV and optical light decline simultaneously. Flux distributions show a significant flattening in the FUV and with the possible exception of CPD-48 1577 no EUV flux has been observed in any catalclysmic variable. CPD-48 1577 shows a marginal, 2 σ EUV flux.
A Review of the Classical Nova Outburst
Authors: Starrfield S. , Sparks W.M.
Published: July 2016

We review the recent observational and theoretical studies of the nova outburst. The observational studies have not only identified a new class of novae but theoretical simulations of this class have been found to be in excellent agreement with the observations. This new class consists of outbursts occurring on ONeMg white dwarfs in close binary systems in contrast to the other outbursts which are occurring on CO white dwarfs. We also review the effects of the β -unstable nuclei and show how their presence has a major effect on the evolution.
A Survey of Nova Remnants
Authors: Duerbeck H.W. , Seitter W.C.
Published: July 2016

Exnovae and nova shells are generally faint and difficult to observe. Only a few have been studied, and even less of them in sufficient detail. We give a progress report on our survey of exnovae and nova shells, especially on the results of a spectral survey of novae in the southern Milky Way. The three-dimensional structure in the light of Hα derived for the nebula of GK Per is displayed.
Properties of the Emission Regions in AM Her Stars
Authors: Beuermann K.
Published: July 2016

The emission regions on the white-dwarf primaries of AM Her type systems are suggested to be extended and offset from the magnetic pole similar to the oval arc of emission formed by the Earth’s auroral zone. In ST LMi and EF Eri, the emitting areas of the bremsstrahlung, the soft X-ray, and the cyclotron sources are shown to display a hierarchy with a small bremsstrahlung core being surrounded by a larger cyclotron halo. Core and halo are characterized by large differences in specific accretion rate with that in the bremsstrahlung core corresponding to a sizable fraction (≳10%) of the Eddington rate.
Accretion-Induced Collapse of Old White Dwarfs
Authors: Isern J. , Canal R. , Hernanz M. , Labay J.
Published: July 2016

There is observational evidence of the presence of young neutron stars in old binary systems. A likely explanation is that those neutron stars were produced in the collapse of old CO white dwarfs. We show how mass accretion on initially solid white dwarfs can leave central solid cores when dynamical instability sets in and we study the different effects of the existence of such cores on the outcome of the competition between thermonuclear explosion and gravitational collapse.
EXOSAT Medium Energy Observations of CYG X-2 Spectra and QPOs
Authors: Chiappetti L. , Ciapi A.L. , Maraschi L. , Stella L. , Tanzi E.G. , Treves A.
Published: July 2016

He report on a series of observations of Cyg X-2 obtained with EXOSAT in September 1983 at five phases in a single orbital cycle (P = 9.8 days, see Cowley et al. 1979). Here we present spectral data obtained with the Argon counters of the Medium. Energy experiment (HE) (see Turner et al. 1981), together with the search of Quasi Periodic Oscillations (QPOs) in high tine resolution data.
Optical Spectroscopy of CH Cygni in 1985/86
Authors: Mikolajewski M. , Tomov T. , Mikolajewska J.
Published: July 2016

Some arguments for the explanation of the spectroscopic and photometric behavior of CH Cyg in terms of an eclipsing binary with P=5700 days, consisting of M6 III star and an accreting white dwarf, are presented. Physical and geometrical parameters of the system have been estimated and discussed.
Combined Satellite and Ground-Based Observations of the Quiescent, High Latitude Symbiotic Variable AG Draconis = BD+67°922
Authors: Slovak M.H. , Cassinelli J.P. , Anderson C.M. , Lambert D.L.
Published: July 2016

Satellite observations, from Einstein, IUE, and IRAS, have been combined with ground-based observations to derive the quiescent energy distribution of the symbiotic star AG Draconis. A detailed comparison is made between the combined observations and various steady-state composite models, including blackbody accretion disks.
The Asterisms
Authors: Chakravarty A.K.
Published: July 2016

A system of 27 asterisms, or nakṣatras, plays an important role in Indian astronomy and calendrical science. The present convention is that the ecliptic is divided into 27 equal parts each 13°20' long commencing from one initial point. These arcs are called nakṣatras. Again a bright or prominent star of each division is called yogatārā bearing the name of the are division e.g., Kṛttikā as nakṣatra means an are division and as a yogatārā it means the star η Tauri of the Pleiades group.

The origin of this asterism system is very old. The names of these stars appearin Vedic litrature. The Taittirīya, Kāṭhaka, Maitrāyaṇī Saṃhitas and the 19th book of Atharva Veda, each has given a list of 27 nakṣatras (the last two have included an additional star, Abhijit (αLyrae), making a total of 28 nakṣatras). All these lists always begin with the name kṛttikas (the star group Pleiades), and order of names of stars are more or less the same. Some of the stars changed their names in different hands; but they are always either star groups or single stars, and never arc divisions.
Ancient Chinese Auroral Records: Interpretation Problems and Methods
Authors: Teboul Michel
Published: July 2016

In recent years a number of auroral catalogues have been compiled from Oriental records, but the auroral identifications given vary greatly from one catalogue to another. This is due to the fact that, up to now, no reliable criteria have been found which could help us discriminate between auroral and non-auroral ancient records. In this paper two new criteria are propounded and their usefulness illustrated by the solution of a few currently much debated questions.
Two Treatises on Astronomical Instruments by cABD Al-Munc IM Al-cĀmilī & Qāsim cAlī Al-Qāyinī
Authors: Razaullah Ansari S.M. , Khan Ghori S.A.
Published: July 2016

A characteristic feature of Arab-islamic astronomy during the Middle Ages is the promotion and tremendous growth of practical astronomy which was in turn manifested primarily by the establishment of scores of observatories in West-Central Asia, from Abbasid Caliph al-Māmūn (813-833) to the Turkish king Murād III (1574-1595), and by the production of copious literature on astronomical Tables (the zījes) as well as on astronomical instruments (ālāt al-rasad). The enormity of the literature on the latter could be gauged by the list of extant works as given by Matvievskaya and Rosenfeld (1983) in their recent Biobibliography: 349 treatises on astrolabes, 138 on sine-instruments, 81 on quadrants, 4 on sextants and octants, 41 on armillary spheres and celestial globes, 77 on sundials and again 77 on “other instruments”—in all 767 treatises. As a matter of fact the instruments developed by Arab-islamic astronomers could be broadly classified into four groups: a) Time measuring instruments (e.g. sundials, shadow quadrants), b) Angle measuring instruments for astronomical parameters (e.g. armilla of various kinds, dioptre and parallactic rulers), c) instruments for transformation of system of coordinates and/or solving nomographical problems (e.g. astrolabes, quadrants, dāstūr instrument), d) Mathematical instruments for evaluating trigonometric functions, (e.g. sinequadrants). Apart from the fourth and the most important of all, the astrolabe, which in turn embodies all the four groups of instruments to a certain extent, works on “other instruments” were compiled in almost every century (down from 9th to 18th A.D.), also by well-known Arab-Islamic astronomer-mathematicians.
Schmidt Telescopes as Discovery Instruments
Authors: Woltjer L.
Published: July 2016

In 1930 B. Schmidt invented the telescope that bears his name. Eleven years later, there were already two dozen Schmidt telescopes with primaries of 25 cm or more in diameter (Dimitroff and Baker 1945). An invention spreading so rapidly must have fulfilled a basic need – the need for a large field with good image quality over a substantial wavelength range. Here I shall briefly review the role of the large Schmidt telescopes in contemporary astronomy.
Sky Surveys with the UK 1.2m Schmidt Telescope
Authors: Cannon Russell D.
Published: July 2016

On 1983 September 3 we will be celebrating the tenth anniversary of the formal hand-over of the UK 1.2m Schmidt Telescope (UKST) by the manufacturers, Messrs. Grubb Parsons of Newcastle-upon-Tyne, to the Science and Engineering Research Council (SERC). The completion of commissioning was marked in 1973 by the taking of the first completely successful sky-limited photograph on hypersensitised Eastman-Kodak Illa-J emulsion, plate J149 of field 416. That plate itself led very quickly to exciting new scientific results, including the discovery of extraordinary and still apparently unique jets in the barred spiral galaxy NGC 1097 by Wolstencroft & Zealey (1975), a discussion of the clustering of 3000 faint galaxies (Dodd et al., 1975; 1976) and a suggestion that faint blue stellar objects are not randomly
distributed (Hawkins & Reddish, 1975).
Astronomical Performances of the Mepsicron, A New Large Area Imaging Photon Counter
Authors: Firmani C. , Gutiérrez L. , Ruíz E. , Salas L. , Bisiacchi G.F. , Paresce F.
Published: July 2016

The new detector MEPSICRON (microchannel electron position sensor with time resolution) is an image photomultiplier sensor for high spatial and time resolution, working in a photon counting regime. It has been especially designed for deep sky photometric pictures, for high resolution spectrophotometry with single or crossed dispersion spectrographs for long slit spectroscopic techniques, for high time resolution pictures and spectrophotometry especially related with speckles techniques and very fast varying sources as pulsars, and for Fabry-Pérot interferometry.
Space Distribution of Red Giants and the Galactic Structure
Authors: Ishida K.
Published: July 2016

Stellar content contributing to near IR radiation do not show radial differentiation in the Galaxy. Late-type giants and supergiants supply about 70% of the total volume emissivity at the K band, in the solar vicinity within 1 kpc, and also at the distance of several kpc in the Scutum region.
Objective Prism Survey of the Outer Galactic Halo
Authors: Ratnatunga Kavan , Freeman K.C.
Published: July 2016

The aim of this survey is to locate samples of very distant field halo stars, to study the kinematics and metal abundance distribution in the outer regions of the galactic halo. Field halo K giants were chosen for the study, as they are intrinsically bright stars whose evolution is well understood. Halo K giants, near the tip of the giant branch and between 10 and 40 kpc from the sun, will have apparent magnitudes in the range 13 < V < 18, and colours (B-V) > 0.9.
Stellar Population Synthesis and Star Counts to Constrain the Galactic Structure
Authors: Robin Annie , Creze Michel
Published: July 2016

Our model of stellar population synthesis allows to derive synthetic star counts and distribution of colors, ages, and spectral types of stars in any given direction of observations. Here we compare results of the model with the distribution of stars in space and in absolute magnitude of stars of Gilmore and Reid. We find a small disagreement between observations of GR and predictions of our model in the space density of stars of 4 < Mv < 5. Ue show that this discrepancy can well be explained by a contamination of their sample of assumed main sequence stars by red giants and subgiants.
Photographic Photometry With Schmidt Plates of Star Clusters in the SMC
Authors: Kontizas M.
Published: July 2016

The star clusters have always been the most important tools of testing the stellar evolution theories and when these stellar systems belong to other galaxies, then our knowledge on stellar evolution can be extended for different initial conditions than those of our Galaxy. The Magellanic Clouds being our nearest neighbour galaxies offer ideal conditions for such studies.

Since the powerful southern telescope came into operation deep plates of these two galaxies revealed a large number of new star clusters. The Schmidt plates are most useful since they have the advantage of large field where many objects can be investigated homogeneously on the same plate.
Objective-Prism Redshifts of Faint Galaxies
Authors: Cooke J.A. , Kelly B.D. , Beard S.M. , Emerson D.
Published: July 2016

A large sample of spectra of faint galaxies has been obtained using COSMOS measurements of UKST objective-prism plates. Computer software has been developed to obtain the radial velocities of large numbers of these galaxies automatically over a magnitude range of about B = 16 to 19. Initial tests have been performed on a sample of about 1400 galaxies from an area of about 5 x 4 degrees square.
An Optical Survey for Very Faint Quasar Candidates
Authors: Hamilton Donald
Published: July 2016

In recent years the development of fast optical telescopes with large corrected fields, of fine-grained, high DQE emulsions such as IIIa-J/F, and the use of rapid scanning microdensitometers and computers, have all made deep photometric studies of large areas of the sky tractable. I am in the process of conducting such a survey using the prime focus cameras of the CTIO and KPNO 4-meter telescopes. Skylimited plates are taken in four colors defined by filter/emulsion characteristics. Pertinent information about the photometric system is given in Table 1. The large database from this survey of about fifteen areas of the sky is being used to address many problems both extragalactic and galactic in nature. A preliminary report on studies of faint blue stellar objects, quasar candidates, will be presented here for seven of the fifteen fields. Table II lists some information about the fields used for this study.
ON the Cross-Correlation of Galaxies with UVX Objects and QSOS
Authors: Boyle B.J. , Shanks T. , Fong R.
Published: July 2016

Recent measurement of UK Schmidt plates have yielded interesting results on the cross-correlation of galaxies with QSOs and ultra-violet excess (UVX) objects. We find that in all Schmidt fields so far analysed there appears to be a significant anti-correlation (at angular scales less than 5') between the positions of galaxies and QSOs and between the positions of galaxies and UVX objects. This anti-correlation appears to be restricted to those galaxies that are found in clusters. These observations can very naturally be explained using a model in which dust within clusters of galaxies obscures the QSOs lying at cosmological distances behind them. This hypothesis may be further corroborated by tentative evidence that the UVX objects and the QSOs appear to be reddened close to clusters of galaxies.
Faint Galaxy Number Counts
Authors: Shanks T. , Stevenson P.R.F. , Fong R. , Gillivray H.T. Mac
Published: July 2016

Using photographic data obtained from the U.K. Schmidt and Anglo-Australian telescopes we have determined galaxy number counts in the range 17m≤B≤23m and 15mm≤R≤22m. By comparing our observations with models we find that the blue counts show strong evidence for galaxy luminosity evolution. We find that the red counts are better fitted by non-evolving models and that, here, the effects of the cosmological deceleration parameter, qo, and luminosity evolution are comparable. We discuss the implications of these results, with particular reference to the prospects of using the red counts to obtain constraints on qo.
Observation of Intergalactic Dust by Schmidt-Telescopes
Authors: Marx S.
Published: July 2016

About 25 years ago Zwicky (1957), Holmberg (1958) and Hoffmeister (1962) found intergalactic dust by observations. Zwicky (1957) explained the deficiency of distant clusters of galaxies by intergalactic dust inside the near clusters. Holmberg (1958) made extensive observations of the Virgo cluster. He found systematic differences of the colour indexes between cluster and field galaxies. Intergalactic dust inside of the Virgo cluster should be the reason of these differences. Hoffmeister (1962) found a clear deficiency of galaxies in the region of Microscopicum. Again the reason should be a large cloud of intergalactic dust.
XUV Absorption Spectra of Carbon Ions
Authors: Jannitti E. , Nicolosi P. , Tondello G.
Published: July 2016

The photoabsorption spectra of the carbon ions have been obtained by using two laser-produced plasmas. The photoionization cross-section of the CV has been absolutely measured and the value at threshold, σ=(4.7±0.5) × 10−19cm2, as well as its behaviour at higher energies agrees quite well with the theoretical calculations.
Fine Structure of the 1s2s2p 4P0 and 1s2p2 4P Doubly Excited States of Lithiumlike Si XII
Authors: Buchet J.P. , Buchet-Poulizac M.C. , Denis A. , Désesquelles J. , Druetta M. , Martin S. , Ouerdane Y.
Published: July 2016

The ls2s2p4P0- ls2p24P transitions of Si XII have been investigated using fast ion beam spectroscopy in the far ultraviolet. The results for fine structure intervals and term separation represent the highest Z test of electron correlation effects and relativistic contributions in doubly excited states of lithiumlike ions.
Monochromatic X-ray and XUV Imaging with Multilayer Optics
Authors: Walker A.B.C. , Lindblom J. , Hoover R.B. , Barbee T.W.
Published: July 2016

The development of techniques for the fabrication of multilayer coated mirrors which can function as energy selective X-ray and XUV mirrors at normal incidence has greatly expanded the options available to the astronomical spectroscopist. We have developed a rocket spectroheliograph which utilizes multilayer optics in three configurations: i) As Cassegrain telescopes for imaging at 256 Å (He II) and 173 Å (Fe IX, X); ii) As tertiary mirrors used with a conventional Wolter I telescope for imaging at 44 Å (Si XI, XII), 173 Å, and 256 Å; iii) As off-axis spherical mirrors for imaging at 44 Å and 256 Å. We report on laboratory images and performance measurements obtained with these optical systems, and briefly on Solar Observations.
Euv Emission Line Ratios for Si IV in the Solar Transition Region
Authors: Keenan F.P. , Doyle J.G.
Published: July 2016

Theoretical electron temperature sensitive emission line ratios in Si IV involving the 3d2D − 3p2P and 4s2S - 3p2P multiplets at ~1125A and 816A respectively are derived using R-matrix electron excitation rate calculations. A comparison of these with observational data for a solar active region obtained with the Harvard S-055 spectrometer on board Skylab reveals that there is good agreement between theory and observation for the ratio that includes the2D3/2, 5/2 −2p3/2 transition at 1128.3A. This is in contrast to the findings of Keenan, Dufton and Kingston, and provides support for the atomic data adopted in the calculations. However the2D3/2 −2pl/2 line at 1122.5A appears to be severely blended, as it leads to electron temperature estimates that differ significantly from that expected in ionisation equilibrium. The fact that the I(1122.5A)/I(1128.3A) intensity ratios determined from several flare spectra are closer to theory than that for the active region indicates that the blending is probably due to species with relatively low ionisation potentials, such as an Fe III transition at 1122.53A, as suggested previously by Burton and Ridgeley, and Feldman and Doschek. Electron temperatures deduced for a sunspot are much lower than that predicted from ionisation balance calculations, in agreement with earlier results, and imply that a cooling flow may be present.
Observed and Theoretical Spectra in the 10–100Å Interval
Authors: Brown W.A. , Bruner M.E. , Acton L.W.
Published: July 2016

The soft x-ray spectra recorded in two sounding rocket flights in 1982 and 1985 are compared with with predicted spectra. The poster presents the processed densitometer trace of the full spectrum together with the new spectrum from the 1985 experiment. This note compares the intensities of the lines with predictions.
Plasma Shifts of Ion Lines
Authors: Griem H.R.
Published: July 2016

Shifts due to interactions of radiating or absorbing atoms or ions with charged particles in a plasma are generally assumed to be negligible, e.g., in ments of atomic energy levels or in calculations of radiative transfer. However, it has long been known that electron collisions can cause shifts which are a significant fraction of the corresponding widths, and that ion-radiator interactions give rise to shifts and profile asymmetries through quadratic Stark effects and quadrupole corrections to the usual dipole interactions. The interplay between these various effects is particularly interesting for highly charged radiators for which electron effects are enhanced by the strong electron-radiator Coulomb attraction (plasma polarization shift). As examples, calculations for hydrogen- and helium-like ions will be discussed and be compared with measurements.
He-Like Titanium Spectra from Tokamak Plasmas
Authors: Kato T. , Masai K.
Published: July 2016

X-ray spectra of titanium He- like ions from JIPPT-IIU, TFTR and DoubletIII tokamak plasmas have been analysed by the same computer code. The disagreements between measurements and theoretical calculations are discussed in terms of atomic processes.
Large Telescope Wind Loading
Authors: Forbes Fred F.
Published: July 2016

One important large telescope design study area is the dynamic image degradation caused by wind forces upon various telescope structures and optical elements. The need to establish rapid thermal equilibration with the observatory environment further complicates the wind exposure problem. On the other hand, a telescope deeply embedded in a large enclosure is subject to dome induced seeing difficulties unless great care is used to eliminate any thermal differences among telescope structure, optics, dome interior and inside and outside air. While dome seeing is outside the scope of this paper, it should not be neglected in the consideration of enclosure design because wind protection and seeing are inexorably coupled.
The Two-Mirror Telescope (2MT)
Authors: Bingham Richard G.
Published: July 2016

Two eight-metre mirrors on an alt-azimuth mount are considered as a Future Large Telescope. The combined collecting area is ten times that of a four-metre class telescope, and the main modes of use are for optical spectroscopy and infrared imaging. In one square arc second, at 10µm wavelength, the telescope with adaptive auxiliary optics will yield 30 to 100 fully resolved image elements (not speckles). The mechanical arrangement proposed to give path length stability is to link the two tube centre sections along a horizontal axis and to use a total of four altitude bearings. A combined focus is necessary for the highest angular resolution, but other work such as spectroscopy can be carried out either at a combined focus or using separate instrumentation for the two eight-metre apertures. Twin prime and Cassegrain foci and horizontal Nasmyth platforms are intended for such pairs of spectrographs and other instruments, depending on their weight and field requirements. A pair of prime focus spectrographs with f/0.8 cameras is one appropriate system. (The horizontal Nasmyth platforms to accommodate larger spectrographs are a feature of this telescope which is not feasible in other MMT-type configurations). Another significant capability is that for a coud6-type light path from either aperture to the vertical axis. This can be achieved with four reflections (including the primary) for some applications. In addition to the conventional uses of the coudg light path, there is the possibility of using it to produce interferometric links to other telescopes. These links may be important as a future extension of the instrument.
C.F.H.T. Focal Reducer: Image and Multiaperture Spectroscopy
Authors: Fort B. , Lelièvre G. , Picat J.P. , Rio Y. , Vigroux L.
Published: July 2016

In this poster paper we shortly present recent developpment and preliminary results obtained with the focal reducer of the Canada French Hawai 3.6 meter telescope with new trends for deep imagery and multiaperture spectroscopy.
Qualifying a Mosaic of Detectors for Infrared Astronomy - Observatoire de Meudon
Authors: Lacombe F. , Rouan D. , Stefanovitch D. , Talureau B. , Berezné J. , Epstein G. , Pau S. , Van D.Phan , Zéau Y.
Published: July 2016

A 8x8 InSb CID array, developed in France by SAT (1) (Société Anonyme de Télécommunications) for terrestrial applications, has been tested at Meudon Observatory in order to evaluate if its performances at LHe temperature, meet the requirements of infrared astronomy. Next sections give : 1) Description of the array and the experimental conditions; 2) The test results; 3) Work under development.
The Nature of Galaxies and Clusters of Galaxies at Very Large Distances
Authors: Oke J.B.
Published: July 2016

The previous speaker, Marie-Helene Ulrich, discussed several problems in extragalactic research which require the use of a very large ground-based telescope. She emphasized studies of relatively nearby objects. In my talk I will discuss problems which have to do with observations of objects at very large distances.

Most studies of very distant objects involve studies of distant clusters of galaxies since this is one of the very few ways to pick a galaxy which is almost certainly very distant rather than a low-luminosity nearby object. Two exceptions are studies of radio and X-ray selected galaxies which very often are distant objects. Another exeption is the study of quasars which are almost all at very large distances. Even in these exceptions there is an interest in knowing whether these objects are associated with clusters or not.
Abundance Analysis of Alpha Ursae Minoris
Authors: Giridhar Sunetra
Published: July 2016

We have derived atmospheric abundances of the bright Cepheid a UMi in order to study the abundance anomalies in different elements. The atmospheric abundance of C, 0, Fe-peak elements Ca, Sc, Ti, Cr, Fe and heavier s-process elements Y, Ba, Ce and Sm have been derived using the method of spectrum synthesis. The abundance of carbon is derived using the C I lines in 4700A region, whereas for oxygen, the forbidden line at 6300.311A is employed. Abundances of the Fe-peak elements and s-process elements are obtained by synthesizing selected portions in the wavelength range 4330A - 4650A. The estimates of C/0 derived from the present investigation are compared with other Cepheids of similar period. The evolutionary status of a UMi is discussed in the light of these derived abundances.
A Search for Long-Period Cepheids in Associations
Authors: van den Bergh Sidney
Published: July 2016

Skeleton photoelectric sequences and plates in U, B and V have been obtained for fields surrounding all known Cepheids with P ≳ 12 days in the Southern Milky Way. The study of 14 of these fields has been completed and is discussed in this paper.
Eight PopII Cepheids Recently Identified in Globular Clusters
Authors: Clement C. , Sawyer Hogg H. , Wells T.
Published: July 2016

The University of Toronto 24-inch telescope at the Las Campanas Observatory of the Carnegie Institution of Washington has beerused for the study of variables in four southern globular clusters: NGC 6273=1119, NGC 6284, NGC 6293 and NGC 6333-M9.

The first three of these clusters lie about 2° from one another in the sky at southern declinations ranging from about 24.5° to 26.5°. They were investigated by one of us (Sawyer 1943) using photographs obtained at the Steward Observatory in Arizona in 1939. A number of variables were discovered, but even with additional David Dunlap plates, it was not possible to determine any periods because of the large southern declinations. At Las Campanas (latitude 29°S), they pass close to the zenith and therefore the periods are more readily determined. From our Las Campanas data, we have found that there are four Cepheids in NGC 6273, two in NGC 6284 and one in NGC 6293.
Current Problems in Horizontal-Branch Theory: Some Implications for RR Lyrae Variables
Authors: Demarque Pierre
Published: July 2016

There are a number of good reasons for wanting to improve our understanding of the structure and evolutionary status of horizontal-branch (HB) stars. To mention a few:

1)

The HB morphology of globular clusters can be used as a tool for studying the evolution of the galactic halo (Searle and Zinn 1978) and the time scale for halo collapse (Demarque 1980; Zinn 1980).

2)

HB stars offer an opportunity to evaluate the helium abundance of globular clusters. This can be done either by using the R-method (Cole et al. 1983) or the width of the RR Lyrae instability strip [Deupree 1977; but see also the paper by Stellingwerf (1984) in these preceedings which casts doubt on the validity of previous calculations of the dependence of the blue edge on helium content].

3)

HB stars may play an important role in understanding the integrated light of old stellar systems. In particular, blue HB stars seem to make a significant contribution to the ultraviolet light of elliptical galaxies. (Ciardullo and Demarque 1978; Gunn, Tinsley and Stryker 1981). At the same time, HB stars are believed to be the direct progenitors of asymptotic giant branch stars which have proved to be powerful tracers of stellar populations in nearby external systems (Blanco et al. 1980)

4)

The RR Lyrae variables are part of the HB population. One would wish to relate the observable properties of RR Lyrae variables to their chemical compositions and ages so as to use them: a) as distance indicators for galactic globular clusters (Sandage 1982a,b) and in the Magellanic Clouds; b) as tracers of stellar populations. This has been attempted for the galactic halo and disk by Sandage (1982a,b) and for the Magellanic Clouds by Butler et al. (1982).
Fourier Decomposition Parameters for the Halo RR Lyrae Variables U and V Caeli
Authors: Hansen L. , Petersen J. O.
Published: July 2016

UBVRI light curves are obtained for the two halo RR Lyrae variables U Caeli with period 0.420 days (73 observations) and V Caeli with period 0.571 days (42 observations). It is shown that their light curve characteristics are very similar to those of field RR Lyrae stars.

Fourier decompositions are studied for all five magnitudes and the resulting amplitude ratios and phase differences are discussed. The differences in the Fourier decomposition parameters between the five magnitudes are shown to be relatively small. Comparisons of the Fourier decomposition parameters for the two halo RR Lyrae stars with recently published data for field RR Lyrae stars show no systematic differences.
Cometary Orbital Dynamics and Astrometry
Authors: Yeomans D.K.
Published: July 2016

Comets are the only large solar system bodies where nongravitational forces directly affect their dynamic motions. Their approach to within a few AU of the Sun initiates the vaporization of nucleus ices, and the resulting rocket-like effects either add to or subtract from the comet’s orbital energy; the sign of the energy change depends upon the comet’s rotation direction and its spin pole orientation. The cometary outgassing phenomena have generally been modeled by assuming a rapidly rotating nucleus of water ice that outgasses symmetrically with respect to perihelion. Although this nongravitational acceleration model has been quite successful in providing accurate orbits and ephemerides, several comets exhibit water production rates and visual light curves that are noticeably asymmetric with respect to perihelion. New asymmetric models are being developed that attempt to represent more closely the cometary outgassing phenomena. For the same comet, derived nongravitational parameters can differ widely, depending upon which model is used to fit the astrometric data. The uncertainties in the data and in the nongravitational acceleration model prevent realistic extrapolations of these objects’ motion beyond a few hundred years, particularly if close planetary encounters are involved. Accurate orbits, ephemerides and efforts to model the nongravitational effects ultimately depend upon the quality of the astrometric data. Using a combination of long-focus telescopes, charge coupled device (CCD) detectors, microdensitometer reductions and modern star catalogs, cometary astrometric data can be generated that are accurate to the sub arcsecond level. While occultation, spacecraft, and radar observations can provide powerful astrometric data when available, it is still the ground-based optical observations that must provide the vast majority of data for cometary astrometry in the foreseeable future.
Cometary Photometry
Authors: Jewitt D.
Published: July 2016

The study of comets using modern optical photometric techniques is reviewed. Particular emphasis is given to the physical constraints imposed on the nature of comets by photometric data. The photometric study of bare nuclei and of active comets is discussed.
Infrared Techniques for Comet Observations
Authors: Hanner Martha S. , Tokunaga Alan T.
Published: July 2016

The infrared spectral region (1–1000μm) is important for studies of both molecules and solid grains in comets. Infrared astronomy is in the midst of a technological revolution, with the development of sensitive 2–dimensional arrays leading to infrared cameras and spectrometers with vastly improved sensitivity and resolution. The Halley campaign gave us tantalizing first glimpses of the comet science possible with this new technology, evidenced, for example, by the many new spectral features detected in the infrared. The techniques of photometry, imaging, and spectroscopy are reviewed in this chapter and their status at the time of the Halley observations is described.
Debris from Comets: The Evolution of Meteor Streams
Authors: Mcintosh Bruce A.
Published: July 2016

The evolution of meteor streams is controlled basically by: (a) the initial velocities with which the particles were ejected from the parent body; (b) gravitational perturbations by the planets; (c) radiation forces; and (d) collisions. This review focuses mainly on recent numerical modelling dealing with (b) and (a).

Ejection velocities spread the particles around the orbit, closing the ring in a few tens of revolutions. The greater ejection velocities of smaller particles cause more rapid dispersion both around the orbit and in the cross section.

A determination of the effects of gravitational perturbations must take into account the distributed properties of the stream. The stream’s evolution is dependent on the short-term impulse nature of planetary perturbations, as well as on long-term secular effects. The combined effects produce complex stream cross-sections as in the ribbon-like form of the Halley stream (Orionid and η Aquarid showers) or as in the changes in the annual position of peak shower activity shown by the Quadrantids. Perturbations may cause the orbit of a parent body to sweep rapidly across the orbit of the Earth. But the associated particle stream may not be lost as a meteor shower because it tends to become dispersed in a manner that ensures a continuing supply of particles in Earth-crossing orbits. The nodes of the observed meteoroid orbits may show very little motion compared with the rapid motion of the nodes of the orbit of the parent object.

Radiation effects contribute to size separation of particles. Very small particles are blown out of the stream or spiral in toward the sun because of Poynting–Robertson drag. Older meteor streams usually show a predominance of large particles.
Physical Aging in Comets
Authors: Meech Karen J.
Published: July 2016

Recent evidence suggests that comets formed at low temperatures (≤ 25 K) and that, while the interiors have not been considerably altered since formation, the outer layers have undergone substantial modification. Comets exhibit a wide range of physical characteristics, some of which may be attributed to systematic physical differences between comets making their first close approach to the Sun from the Oort cloud (new comets) and those having made many approaches (old comets). These differences may reflect either primordial differences between two populations or the differences may be a manifestation of aging processes. There are many processes that might be responsible for causing aging in comets. These include: (i) radiation damage in the upper layers of the nucleus during the long residences in the Oort cloud, (ii) processing from heating and collisions within the Oort cloud, (iii) loss of highly volatile species from the nucleus on the first passage through the inner Solar System, (iv) buildup of a dusty mantle, which can eventually prohibit further sublimation, and (v) a change in the porosity, and hence the thermal properties of the nucleus. Although Oort’s (1950) original work on the comet cloudrequiredthat new comets fade after their first close passage, past searches for evidence of aging in comets have produced conflicting results, partly due to a lack of systematic data sets. An understanding of the evolutionary processes of comet nuclei that give rise to compositional or physical differences between ‘fresh’ Oort cloud comets and thermally processed periodic comets will improve our knowledge of the possibly primordial comet composition and therefore conditions in the early Solar System. Recent observations suggest that there are distinct differences between the two groups with respect to intrinsic brightness and rate of change of activity as a function of distance.
UNSTEADY TWO-LAYERED BLOOD FLOW THROUGH A -SHAPED STENOSED ARTERY USING THE GENERALIZED OLDROYD-B FLUID MODEL
Authors: ZAMAN AKBAR , ALI NASIR , ANWAR BEG O. , SAJID M.
Published: July 2016

A theoretical study of an unsteady two-layered blood flow through a stenosed artery is presented in this article. The geometry of a rigid stenosed artery is assumed to be$w$-shaped. The flow regime is assumed to be laminar, unsteady and uni-directional. The characteristics of blood are modelled by the generalized Oldroyd-B non-Newtonian fluid model in the core region and a Newtonian fluid model in the periphery region. The governing partial differential equations are derived for each region by using mass and momentum conservation equations. In order to facilitate numerical solutions, the derived differential equations are nondimensionalized. A well-tested explicit finite-difference method (FDM) which is forward in time and central in space is employed for the solution of a nonlinear initial boundary value problem corresponding to each region. Validation of the FDM computations is achieved with a variational finite element method algorithm. The influences of the emerging geometric and rheological parameters on axial velocity, resistance impedance and wall shear stress are displayed graphically. The instantaneous patterns of streamlines are also presented to illustrate the global behaviour of the blood flow. The simulations are relevant to haemodynamics of small blood vessels and capillary transport, wherein rheological effects are dominant.
Endurance at the Top: Gender and Political Ambition of Spanish and Swedish MPs
Authors: Galais Carol , Öhberg Patrik , Coller Xavier
Published: July 2016

The gender gap in political ambition is an important explanation for the absence of women in legislative assemblies. However, previous research on this matter is limited by two facts: it is conducted mostly in the United States and does not pay much attention to cultural and institutional factors. In this article, we test the extent to which established mechanisms behind female politicians' career ambitions—such as differentiated political socialization and family support for men and women—are related to gender inequality among parliamentarians. We also draw attention to other lesser-known aspects, such as political culture and gender policies. To do so, we compare Spain and Sweden, two countries with a relatively high number of female members of parliament (MPs) but different cultures and gender policies. We make use of two representative surveys on Swedish and Spanish MPs. The results show that female MPs in Spain have to sacrifice their family life more than Spanish males and Swedish MPs regardless of sex. In addition, Spanish female MPs' long-term political ambitions are more dependent on family support. Female MPs' ambition in Sweden, in turn, is highly influenced by a politicized upbringing.
Mapping the public/private-law divide: a hybrid approach to corporate accountability
Authors: Hackett Ciara , Moffett Luke
Published: July 2016

Images of oil-covered seabirds or radioactive fallout from nuclear disasters easily evoke concerns over the risks to personal integrity and environmental degradation. The energy-extraction industry, like others, is profit-driven – a competitive enterprise, with little regard for the social impact of its activities beyond corporate social responsibility (CSR) rhetoric. CSR is neither a precautionary measure nor a remedial framework. Outsider stakeholder influence from government is limited and CSR is written on companies’ terms. What emerges is a distortion between companies’ responsibility and accountability for breaches. We propose a hybrid form of accountability that incorporates public international law to ensure the state, as a guardian of society, plays a more definitive role. This will require more binding obligations on states and companies beyond the current soft-law principles, to curtail jurisdictional constraints and forum shopping of large corporations, through an international court of reparations to guarantee effective remedies for victims.
Judging in lower courts: Conventional, procedural, therapeutic and feminist approaches
Authors: Hunter Rosemary , Roach Anleu Sharyn , Mack Kathy
Published: July 2016

Recent theorising about feminist judging has concentrated on appellate courts and their judgments. This paper develops a conceptualisation of feminist judging in lower, first instance courts, which are dominated by high case volume and limited time for each matter, with decisions given orally and ex tempore rather than in elaborated written judgments. Through careful accounts of the philosophy, goals and practices of conventional as well as newer, more engaged approaches to judging, the paper compares and contrasts feminist judging with other approaches to judging in the lower courts. This entails considering dimensions such as the judicial officer's orientation to substantive law and practice in court, concepts of fairness, ethical commitments, the view of the defendant, and judicial qualities and capacities.
The Impact of Gender on Anthropometric Measures of Twins
Authors: Jahanfar Shayesteh , Lim Kenneth
Published: July 2016

Introduction: Literature suggests that male hormones influence fetal growth in singleton pregnancies. We hypothesized that the same phenomenon is seen in twin gestations. Objectives: (1) to identify the impact of gender associated with fetal birth weight, head circumference, and birth length for twins; (2) to examine the effect of gender on standardized fetal growth at birth, according to gestational age and birth order; (3) to examine the effect of gender on placenta weight and dimensions. Methodology: This was a population-based retrospective cohort study of twins (4,368 twins, 2,184 pairs) born in British Columbia, Canada from 2000–2010. We excluded twins with stillbirth, congenital anomalies, and those delivered with cesarean section. We also controlled for confounding factors, including birth order, gestational age, maternal anthropometric measures, maternal smoking habits, and obstetric history. A subsample of this population was analyzed from Children and Women Hospital to obtain chorionicity information. Results: Male–male twins were heavier than male–females and female–female twin pairs (p=.01). Within sex-discordant twin pairs, males were also heavier than females (p=.01). Regression analysis suggested that gender affects birth weight independent of birth order and gestational age. Other newborn anthropometric measures were not found to be dependent on gender. In analyzing a subsample with chorionicity data, birth weight was the only anthropometric measure that was both statistically and clinically affected by sex, even after adjustment for gestational age, chorionicity, birth order, and maternal age. Conclusion: Birth weight was affected by gender while head circumference and birth length were not.