bluuebunny/crossref_metadata_2025 huggingface dataset:
La conception soviétique du droit international
Authors: Patry André
Published: June 2019

Dans un Discours prononcé le 25 janvier 1962 devant la Chambre de commerce américaine en France, l’ex-premier ministre Michel Debré mentionna qu’un délégué aux Nations Unies avait, quelques jours auparavant, tenu les propos suivants: “Le droit international est l’oeuvre des Européens. Les Européens sont colonialistes. Par conséquent, nous n’avons pas à connaître le droit international”.

Il n’y a pas de doute que le droit international classique, celui qui fut à une époque récente le droit de la planète tout entière, est, pour l’essentiel, celui des nations chrétiennes. D’abord exclusivement européen, il était destiné à régir les rapports entre Etats dits “civilisés”. Au XVIIIe siècle, ce droit fut étendu à la Russie. Au siècle suivant, il fut jugé applicable à la Turquie (1856), puis au Japon (1895). Aux yeux des Européens, il y eut donc, à une certaine époque, à côté du jus gentium, un jus inter gentes, sorte de droit aristocratique liant entre eux les sujets chrétiens de l’ordre juridique international. Mais, dès les débuts du XXe siècle, ce droit européen était devenu universel, comme en témoignent les deux conférences de LaHaye.
External Relations of the Swiss Cantons
Authors: Wildhaber Luzius
Published: June 2019

In the past years, the most important impetus for the renewed interest in the relationship between federal states and international law has come primarily from Canada. In Switzerland, the extent and significance of the external relations of the cantons is not a burning political problem. It seems, however, worthwhile to sketch the empirical state of these cantonal affairs, because there is, in this field, a constant feedback from comparative to international law, which makes a precise knowledge of the municipal law of the main federal states imperative. Questions concerning the treaty-making capacity and responsibility of member units in federal states should not be answered on the basis of dogmatic and a priori assertions, but rather on the basis of exact comparative studies.
Seabed Issues at the Law of the Sea Conference: The Caracas Session
Authors: Buzan Barry
Published: June 2019

The caracas meeting was only the first of three, or possibly four, sessions of the Third Law of the Sea Conference that will try to bridge the gap between the rambling six volume result of the Seabed Committee’s work and the concise articles of a new Law of the Sea Convention. The work at Caracas did not reach a stage at which it became possible to submit draft articles for the approval of the Conference. As a result, the final documents of the session made no commitment on any matters of substance. Such movement towards agreement as was achieved is therefore not binding, and is extremely vulnerable to changes of position by states in the six months preceding the next session in Geneva. Because of this, the emphasis of the present report will be more on the political process at Caracas than on the development of international law. My purpose is, first, to examine the new proposals on seabed issues and relate them to previously existing positions; second, to analyse the alignments behind the key positions; and third, to look at the other factors emerging as influences on the seabed negotiations.
Choice of Law Methods in the Private International Law of Contract
Authors: Blom Joost
Published: June 2019

This article examines the choice of law methods developed in four legal systems for problems relating to the substantial or essential validity of contracts. The complicated questions of formation and capacity have had to be left aside. The first two parts of this article discussed the choice of law methods used by courts in France, Germany, and the United States. This concluding part deals with the law in England and the common law jurisdictions in Canada, and also, by way of epilogue, with the recently completed European Communities Convention on the law applicable to contractual obligations. Finally, some general conclusions will be offered about the patterns of law that have emerged in the course of this survey.
Pulsar NP 0532: Recent Results on Strong Pulses Obtained at Arecibo
Authors: Heiles Carl , Rankin John M.
Published: June 2019

New observations have been made of strong pulses from NP 0532. Linear polarization is typically 25 per cent and circular polarization is less than 10 per cent but definitely not zero. A comparison of pulse shapes at 429.9 and 430.1 MHz showed significant differences in detailed structure and polarization. In another study strong pulses at 318 and 111 MHz did not occur together although a strong pulse at one frequency was accompanied by an above average intensity at the other frequency. Similar behaviour was found at 111 and 74 MHz. We conclude that strong pulses do not have a smooth continuous frequency spectrum.
Comments on Supernova Remnants and Ancient Novae
Authors: Minkowski R.
Published: June 2019

The low expansion velocity of the Crab Nebula proves conclusively that the supernova of + 1054 was not type I. Only five supernova remnants found in radio surveys are connected with ancient novae, +185, +1006, +1054, +1572, +1604. This corresponds to reasonable expectation. Most of the objects in historical records were comets, the remainder mostly ordinary novae. Most radio remnants are too old, some too heavily obscured to be found in historical records.
Nuclear Forces in High Density Matter
Authors: McNaughton M. R.
Published: June 2019

The conditions for superfluidity or ferromagnetism in neutron stars are presented and discussed (but not derived). It is suggested that present estimates relating to these are in error and that the predictions made contradict at least one of three sets of nuclear physics data cited in the text. This is due to neglecting the action of the exclusion principle.

A comparatively simple method for calculating the strength of nuclear forces in the presence of many-body effects is outlined. Some preliminary results are presented together with projected future developments.
The Radiation Mechanism in Pulsars
Authors: Smith F. G.
Published: June 2019

The properties of the radio pulses from pulsars are described. The formation of pulses seems to be a geometric phenomenon, for which the beaming due to relativistic motion of the source is the only candidate at present. Values of the volume emissivity and surface flux density indicate that all the particles near the source must have relativistic energies.
The Role of Magnetic Fields in the Heating of Stellar Atmospheres — Theory
Authors: Chiuderi C.
Published: June 2019

The last ten years of observations have shown beyond doubt the fundamental role played by the magnetic field in the heating of stellar atmospheres. After the recognition of the extreme inhomogeneity of the solar corona, two basic new trends have appeared in the theoretical literature on the coronal heating problem. One is the adoption of a global point of view that stresses the connection of the properties of the upper layers to those of the underlying ones. In this way a general framework is provided, capable of accomodating many possible heating mechanisms that need not to be specified at this stage. The second novelty is the explicit inclusion in the theory of the inhomogeneous nature of the stellar envelopes, as a result of the presence of magnetic fields. The present status of knowledge on the subject as determined by the above evolution of the theoretical approach will be reviewed.
Heating of Intense Magnetic Flux Tubes by Magnetohydrodynamic Waves
Authors: Musielak Z. , Bielicz E.
Published: June 2019

Theoretical models of intense magnetic flux tubes embedded in the photospheres of late-type stars have been calculated. Magnetohydrodynamic waves generated in the convective zone are radiatively damped in the lower part of the flux tube and then dissipated. We discuss how the presence of flux tubes in stellar photospheres influences the temperature minimum and the chromospheric activity. We suggest a possible interpretation of the Wilson-Bappu effect in stars with strong chromospheric activity.
Closed and Open Magnetic Fields in Stellar Atmospheres: Effects on Mass Loss from Cool Giant Stars
Authors: Mullan D. J.
Published: June 2019

We propose that the onset of rapid mass loss among cool giants, and the absence of hot coronal material from their atmospheres, is associated with a transition in the large-scale magnetic topology of the atmosphere from closed to open. According to this view, field loops in the atmospheres of giants of spectral class K and later cannot find equilibrium, but are in a state of dynamical evolution throughout their lifetime in the atmosphere.
Stellar Winds and Spindown in Red Giants
Authors: Endal A. S.
Published: June 2019

Recent observations of rotation rates in G and K giants show a sudden drop in the rotation rate at spectral type G5. The observed behavior requires a strong external brake, such as applied by a magnetized stellar wind. Since spectral type G5 coincides with the onset of deep envelope convection in giants, a dynamo mechanism is suggested as the controlling factor. Stellar evolution models have been used to estimate the time scale for the rotational braking, the angular momentum loss rate, and the required magnetic field strengths.
Binary evolution and observational constraints
Authors: de Loore C.
Published: June 2019

The evolution of close binaries is discussed in connection with problems concerning mass and angular momentum losses. Theoretical and observational evidence for outflow of matter, leaving the system during evolution is given: statistics on total masses and mass ratios, effects of the accretion of the mass gaining component, the presence of streams, disks, rings, circumstellar envelopes, period changes, abundance changes in the atmosphere.

The effects of outflowing matter on the evolution is outlined, and estimates of the fraction of matter expelled by the loser, and leaving the system, are given. The various time scales involved with evolution and observation are compared. Examples of non conservative evolution are discussed.

Problems related to contact phases, on mass and energy losses, in connection with entropy changes are briefly analysed. For advanced stages the disruption probabilities for supernova explosions are examined. A global picture is given for the evolution of massive close binaries, from ZAMS, through WR phases, X-ray phases, leading to runaway pulsars or to a binary pulsar and later to a millisecond pulsar.
A new test case for normal giant evolution: TZ Fornacis
Authors: Andersen J. , Clausen J.V. , Nordström B. , Mayor M.
Published: June 2019

For normal giants, the only binary system known until recently with completely determined masses was Capella (αAur, GO III+G5III). Being non-eclipsing, its masses are, however, so uncertain (20% and 8%, respectively) that the properties of the corresponding range of theoretical models are considerably more uncertain than the observationally determined temperatures and luminosities. The discovery of the eclipsing nature of TZ For = HD 20301 (Olsen, 1977) thus provides a unique opportunity to obtain absolute parameters of much higher precision.
The role of rotation in stellar evolution
Authors: Tassoul Jean-Louis
Published: June 2019

During the seventeenth century, in the wake of the discovery of the solar differential rotation, some scientists argued that stellar variability was a direct consequence of axial rotation, the spinning body showing alternately its bright (unspotted) and dark (spotted) hemispheres to the observer (Brunet 1931). Although this idea did not withstand the passage of time, it is nevertheless an interesting one because it is clearly indicative of the kind of fascination stellar rotation has aroused since its inception. And yet, at this writing there is no longer any doubt that spherically symmetric models do explain the major observed properties of stars. Moreover, if one excepts the very early and very late moments of a star's lifetime, the effects of rotation on stellar structure are apparently dynamically unimportant (e.g., Tassoul 1978, hereafter T.R.S.; Moss and Smith 1981, and references therein). What is the purpose, then, to discuss the role of rotation on the main-sequence and post-main-sequence phases of stellar evolution?
3He+ in galactic H II regions: Possible evidence for non-convective mixing in low mass stars
Authors: Rood Robert T. , Bania Thomas M. , Wilson Thomas L.
Published: June 2019

We have detected the 8.7 GHz hyperfine line of 3He+ in the HII regions W43, W51, and W3 and obtained significant upper limits for M17, W49, and Orion A. Even though the abundances derived from measured line parameters can have large uncertainty due to the detailed structure of the sources, it seems almost certain that the 3He+ abundance in W3, 12 kpc from the galactic center is significantly higher than in sources closer to the galactic center. If this is the result of general chemical evolution of the galaxy, it is exactly the opposite of what is expected.
For a Clear Terminology in the Polar Motion Investigations
Authors: Melchior P.
Published: June 2019

The useless introduction of the new words “wobble” and “sway” has produced a flourishing rise in confusing terminology in most of the recent papers. These two words even if picturesque are fundamentally unprecise. They perhaps help to describe – in the English language – the nature of the movement but in no way correspond to the classical terminology of fundamental mechanics. They have apparently no convenient translation into the other usual languages.
HI Observations of the Irregular Galaxy IC 10
Authors: Shostak G. S. , van Woerden H.
Published: June 2019

IC 10 is seen optically as a patchy nebulosity, approximately 3 × 4 arcmin in size, possibly heavily obscured due to its low (−3°) Galactic latitude. De Vaucouleurs and Freeman (1972) have classified it as a Magellanic barred irregular. With a heliocentric radial velocity of −350 km/sec, its distance is uncertain, and various investigators have placed it as far away as 3, and as near as 1 Mpc (Bottinelli et al., 1972; Roberts, 1962). For the latter value, IC 10 would be a Local Group member.
Cold Molecular Material in the Galaxy
Authors: Evans Neal J. , Federman S. R. , Combes F. , Falgarone E.
Published: June 2019

The kinetic temperatures in molecular clouds are usually considered to range upward from about 10 K (e.g., Dickman 1975). These temperatures are generally measured by observing the CO J = 1 → 0 transition and assuming that this line is optically thick and thermalized. This assumption also underlies estimates of the total mass and distribution of molecular material in our galaxy based on CO surveys. Because a significant amount of molecular material could in principle be missed by galactic CO surveys, a search was undertaken for “ultra-cold” molecular gas, by which is meant an excitation temperature, Tex < 5 K. No evidence was found for a large amount of such material (Evans, Rubin, and Zuckerman 1980), but many clouds with Tex between 5 and 10 K were found. To determine if this low Tex is due to low kinetic temperature, low density, or low CO abundance, we have undertaken observations of a large number of clouds in the J = 2 → 1 CO line and the J = 1 → 0 13CO and CO lines. These observations will be analyzed to determine the properties of these clouds.
HI in the Barred Spiral Galaxies NGC 1365 and NGC 1097.
Authors: van der Hulst J. M. , Ondrechen M. P. , van Gorkom J. H. , Hummel E.
Published: June 2019

In this paper we present preliminary results from 21-cm line observations with the Very Large Array (VLA) of the southern barred spiral galaxies NGC 1365 and NGC 1097. Despite a wealth of theoretical models describing the gas flow in a non-axisymmetric bar potential (see Prendergast this volume), few observations of the HI distribution and motions in barred spiral galaxies exist. A notable exception is NGC 5383 (Sancisi et al. 1979). The observations we performed with the VLA are described below. The velocity resolution is 25 km sec−1. The angular resolution is 28″x20″, p.a. 20° for NGC 1365 and 30″x25″, p.a. 20° for NGC 1097. Velocities are heliocentric.
Lenses and Low Surface Brightness Disks
Authors: Bosma A.
Published: June 2019

The 21.65-“law” for disk galaxies has been debated ever since Freeman's (1970) paper in which he found that for 28 out of 36 galaxies the extrapolated central surface brightness of the exponential disk component I0, follows this rule with little intrinsic scatter. Some people think it significant, while others invoke selection effects. Bosma and Freeman (1982) made a new attempt to clarify this problem by studying ratios of diameters of disk galaxies on the various Sky Surveys in a region of overlap. The limiting surface brightness levels were calibrated to be 24.6 and 25.6 magn/arcsec2 for the Palomar blue prints and the SRC J films, resp. The distribution of the ratio Γ = diameter (SRC) / diameter (PAL) gives a measure of the true distribution of Io if the galaxy has an exponential disk in the brightness interval 24.6 to 25.6; e.g. Io = 21.6 corresponds to Γ = 1.32, Io = 22.6 to Γ = 1.50 and Io = 23.6 to Γ = 1.90, etc.
The Stability of Axisymmetric Galaxy Models with Anisotropic Dispersions
Authors: de Zeeuw Tim , Franx Marijn , Meys Jacques , Brink Karel , Habing Harm
Published: June 2019

The possible equilibrium configurations for elliptical galaxies and the bulges of spiral galaxies are no longer thought to be confined to the small class of axisymmetric systems with isotropic velocity dispersions. Many of these systems are not supported by rotation but instead by anisotropic velocity dispersions which are maintained by nonclassical integrals of motion (e.g., Binney 1978), and may be triaxial. Few theoretical models for such systems exist (Schwarzschild 1981). Here we discuss some axisymmetric models that we have constructed by means of Schwarzschild's (1979) selfconsistent method, and in particular their stability.
What May Superclusters Tell us About Galaxy Formation?
Authors: Dekel Avishai
Published: June 2019

The structure and dynamical properties of superclusters (SC's) may help us distinguish between various scenarios for galaxy formation. N-body simulations and analytic estimates show that (contrary to a common belief) a nondissipative pancake scenario can explain the observed flattening of SC's. Then, the disk-halo structure of the Local SC (LSC) and its velocity field suggest that galaxies form before SC's and not necessarily as a result of a dissipative gas collapse to SC pancakes. A confrontation of the simulations with the data indicates that the LSC has collapsed along its short axis only after z~l.
Structural Changes in Cas A, Tycho and Other Young Supernova Remnants
Authors: Strom Richard G.
Published: June 2019

Structural changes have been found and investigated in a handful of young supernova remnants (SNR). The variations in the Crab Nebula (Trimble, 1968) have been known for some time. Here I am concerned with young shell remnants of which the best studied is Cas A. It is, like the Crab nebula, undergoing an overall radial expansion, although other forms of motion have also been observed. Simple expansion has been found in Tycho (3C10) and the remnant of SN 1006. Optical measurements of the remnant of Kepler's supernova (SN 1604), however, have failed to show motion of the magnitude expected from this relatively young SNR.
An X-ray Halo Around Cassiopeia A
Authors: Stewart G. C. , Fabian A. C. , Seward F. D.
Published: June 2019

We report on evidence for weak large scale (r ≥ 6 arcmin) X-ray emission from Cassiopeia A. We investigate several mechanisms for producing such an X-ray halo. Further observations will be required to determine which mechanism is operative.
The Effect of SNR Structure on Non-equilibrium X-ray Spectra
Authors: Hamilton A. J. S. , Sarazin C. L.
Published: June 2019

A technique is presented for characterizing the ionization structure and consequent thermal x-ray emission of a SNR when non-equilibrium ionization effects are important. The technique allows different theoretical SNR models to be compared and contrasted rapidly in advance of detailed numerical computations. In particular it is shown that the spectrum of a Sedov remnant can probably be applied satisfactorily in a variety of SNR structures, including the reverse shock model advocated by Chevalier (1982) for Type I SN, the isothermal similarity solution of Solinger, Rappaport and Buff (1975), and various inhomogenous or ‘messy’ structures.
Recent Radio Studies of SNR
Authors: Dickel John R.
Published: June 2019

SNR can generally be recognized as extended sources of continuum radio emission with non-thermal spectra located near the galactic plane. The emission is synchrotron radiation from relativistic electrons which have either been accelerated or trapped in the expanding shell and its associated shocks. Early lists of remnants (e.g. Milne 1970) were culled from general catalogs of radio sources and confirmed by several other kinds of evidence including the presence of shell structure, significant polarization, lack of recombination line emission, strong optical [S II] lines, and soft x-ray emission. While a few efforts to detect more data on faint remnants are continuing (e.g. Bonsignori and Tomasi 1979; Reich and Braunsfurth 1981), about 150 SNR are now known in the Milky Way and most studies have turned to detailed investigation of specific objects to determine their energy sources, emission mechanisms, and interactions with their surroundings. These studies have shown that while most remnants fall within two general categories, standard shell and filled center, there is no unique evolution within a class and irregularities in the local interstellar medium dominate any statistical properties of individual remnants. A few objects, in particular Cas A and CTB80, do not fit within either category.
SPectral Observation of the Soft X-Ray Background and of the North Polar Spur with Solid State Spectrometers
Authors: Rocchia R. , Arnaud M. , Blondel C. , Cheron C. , Christy J. C. , Koch L. , Rothenflug R. , Schnopper H. W. , Delvaille J. P.
Published: June 2019

In this paper, we present preliminary results of soft X-ray diffuse background observations. We observed two particular regions of the sky in the 0.3–1.5 keV range. The detection system consisted of three independent, 1 cm diameter, cooled solid state detectors. Nearly overlapping fields of view subtended a solid angle of approximately 1/4 sr. Except for the field of view, the whole set was similar to that described in Schnopper et al. (1982) (hereafter referred to as paper 1). This system was flown on board a three-axis stalibized rocket. The flight took place at White Sands Missile Range on 1981 May 4 at 0755 UT.
Structure of Extended Radio Emission in W50 and its Relation to SS 433
Authors: Velusamy T. , Rao A. Pramesh
Published: June 2019

The association of SS 433 with SNR W50 suggests several interesting scenerios for the complex emission features observed in W50. Since W50 lies close to galactic plane (b = −2°.5), it is possible some of these features are just chance superpositions. Several of these are seen in association with diffuse X-rays (Seward et al. 1982) and optical filaments (Zeally et al. 1980). At radio wavelengths W50 has been well studied, at 11 cm (Velusamy and Kundu, 1974; Geldzahler et al. 1980) and at 18 cm (Downes et al. 1981; 1982). In this paper we present new observations at 92 cm (327 MHz).
Energy Distribution and Variability of BL LAC Objects. The Cases of PKS 2155–304 and 3C 66A.
Authors: Maraschi L. , Maccagni D. , Tanzi E. G. , Tarenghi M. , Treves A.
Published: June 2019

PKS 2155–304 was repeatedly observed in 1979 and 1980 with the International Ultraviolet Explorer. Variations up to a factor of 2 in one year and by 20% in a day are found. The maximum amplitude of variation in X-rays is similar but the timescales are much shorter (a factor of 2 in one day; Urry and Mushotzky, 1982). In all cases the 1200–3100 A continuum is well fitted by a power law with frequency spectral index αUV between −0.7±0.03 and −0.9±0.03. Optical and ultraviolet observations taken within one day show different spectral slopes (Fig. 1). Separate power law fits in the two bands yield αopt = −0.46±0.01 and αUV = −0.80±0.02. The observations by Urry and Mushotzky indicate that the energy distribution steepens further in the soft X-ray region.
Spectroscopy of Distant Galaxies in Clusters
Authors: Dressler Alan
Published: June 2019

Butcher and Oemler have reported that many clusters of galaxies at high redshift have enhanced populations of blue galaxies when compared to nearby clusters of similar type. Since this claim is based on broad-band colors alone, it is essential to obtain spectra of these blue objects to determine if they are actually cluster members. These spectra can also be used to provide a rough morphological classification of these objects that are too distant for detailed imaging with ground-based telescopes.
Was the Big Bang Hot?
Authors: Wright Edward L.
Published: June 2019

I consider experiments to confirm the substantial deviations from a Planck curve in the Woody and Richards spectrum of the microwave background, and search for conducting needles in our galaxy. Spectral deviations and needle-shaped grains are expected for a cold Big Bang, but are not required by a hot Big Bang.
Catalogue of Clusters that are Members of Superclusters
Authors: Kalinkov M. , Stavrev K. , Kuneva I.
Published: June 2019

An attempt is made to establish the membership of Abell clusters in superclusters of galaxies. The relation

is used to calibrate the distances to the clusters of galaxies with two redshift estimates. One is m10, the magnitude of the ten-ranked galaxy, and the other is the “mean population,” P, defined by:

where p = 40, 65, 105 … galaxies for richness groups 0, 1, 2 …, and r is the apparent radius in degrees given by:

The first iteration for redshift, z1, is obtained from m10 alone:

The standard deviation for Eq. (1) is 0.105, the number of clusters with known velocities is 342 and the correlation coefficient between observed and fitted values is 0.921. With zi from Eq. (1), we define Cartesian galactic coordinates Xi = Rih−1 cosBi cosLi, Yi = Rih−1 cosBi sinLi, Zi = Rih−1 sinBi for each Abell cluster, i = 1, …, 2712, where Ri is the distance to the cluster (Mpc), and Ho = 100 h km s−1 Mpc−1.
A2197 + A2199 Supercluster Region
Authors: Thompson Laird A. , Gregory Stephen A.
Published: June 2019

A2197 and A2199 are among the nearest rich clusters of galaxies. They are worthy of special attention because (i) they form a close binary system, the analysis of which provides an independent estimate of the clusters' mass to light ratio, and (ii) these two clusters fall along a bridge of interconnected clusters that stretches at least 50 Mpc. We report 78 new redshifts in the A2197+A2199 region, thus tripling the number of known redshifts.
The Horologium Supercluster
Authors: Chincarini G. , Tarenghi M. , Sol H. , Crane P. , Manousoyannaki J. , Materne J.
Published: June 2019

We measured redshifts for a random subsample of 286 objects, m (Shapley) ≤ 16.5, drawn from the catalogue of the Horologium region published by Shapley. The distribution of the sample objects on the celestial sphere is shown in Fig. 1, the characteristics of the redshift distribution are represented in Figs. 2 and 3.
Massive Neutrinos and Ultraviolet Astronomy
Authors: Sciama D. W.
Published: June 2019

Massive neutrinos (or photinos) dominating galactic halos may decay into less massive particles by emitting ultraviolet photons. The lifetime for this process can be calculated from particle physics in a model-dependent way. The observed ultraviolet background constrains this lifetime to exceed about 1024 seconds. If the photon energy exceeds 13.6 ev, the existence of HI structures from the galactic plane imposes a similar constraint. The existence of Si IV and C IV in the halos of our own and other galaxies could be due to ∼ 50 ev photons emitted by neutrinos or photinos of rest-mass ∼ 100 ev if their lifetime ∼ 1027 seconds. This lifetime could be in agreement with the theoretical value for 100 ev particles.
Causal Structure of the Early Universe
Authors: Gott J. Richard
Published: June 2019

The standard big bang model has always had a couple of fundamental problems: the universe's matter excess and the isotropy of the cosmic microwave background radiation. Recent developments in particle physics now point to answers to these problems and lead to new models for the causal structure of the early universe. One interesting possibility is the formation of multiple bubble universes. In such models there exist event horizons and the thermal background radiation can be produced by the Hawking mechanism.
The Spatial Distribution of Young Objects in the Large Magellanic Cloud - A Problem of Pattern Recognition
Authors: Feitzinger J. V. , Braunsfurth E.
Published: June 2019

Methods used in pattern recognition and cluster analysis are applied to investigate the spatial distribution of OB associations and emission regions in the LMC. For our analysis we used the catalogue of associations of Lucke and Hodge (1970) and the catalogue of emission regions of Davies et al. (1976).
The Multiple-Phase Structure of the Interstellar Medium in the LMC
Authors: Shull P.
Published: June 2019

Physical properties of the ISM near SNRs in the LMC can be deduced from their very high-resolution, two-dimensional spectra. The ISM around the N49 and N63A SNRs apparently has as many as three different phases of varying density, dumpiness, and spatial distribution.
Analysis of the Solar Granulation in the Opacity Minimum Region
Authors: Koutchmy Serge
Published: June 2019

An observing program in the spectral region of the opacity minimum region near 1650 nm was started at NSO/SP–VTT many years ago and few results were presented. Thanks to an image processing unit connected to a rather conventional TV camera, IR images taken at 1650 nm can be displayed on the TV monitor and images stored on a VCR for subsequent comparison with corresponding images in the visible spectrum. This rather qualitative analysis is substantiated thanks to results coming from one–dimensional time series obtained with an IR pin–hole spectrophotometer. Power spectra of the o.m.r. granulation as well as its temporal behaviour are compared with results obtained using the same method in the optical region of the solar spectrum. Noticeable differences are emerging, including the reduced effect of 5-min oscillations.
Empirical Models of Photospheric Flux Tubes
Authors: Solanki S.K.
Published: June 2019

The empirically derived properties of magnetic flux tubes at both ends of the size spectrum, i.e. magnetic elements and sunspots, are reviewed. Emphasis is placed on quantitative results. The following parameters are discussed in greater detail: The strength and structure of the magnetic field, the temperature stratification and the structure of the velocity field.
Origin of the Sun's Differential Rotation
Authors: Kichatinov L.L.
Published: June 2019

The present status of the Sun's differential rotation theories is reviewed. Attention is mainly focused on mechanisms for differential rotation based on the anisotropic viscosity concept and their modern developments within the framework of the mean-field hydrodynamics. The models with latitude-dependent heat transport and non-axisymmetric numerical simulations are briefly discussed.
The Sun's Rotation Rate as Inferred from Magnetic Field Data
Authors: Stenflo J.O.
Published: June 2019

The pattern of solar magnetic fields has been used as a tracer to determine how the sun's rotation rate varies with latitude and time. Two distinctly different rotation laws emerge from such an analysis, one agreeing with the surface Doppler rotation rate, the other corresponding to much more rigid rotation with a small polar spin-up. Detailed analysis shows that this second law cannot be explained in terms of flux redistribution on the solar surface, but that it represents the rotation properties of the sources of magnetic flux, which are likely to be located at the bottom of the convection zone.

The rotational phase velocity of the source pattern is found to be constant with time, which suggests that the depth at which the magnetic flux is stored and amplified inside the sun does not vary with the solar cycle, and that the phase velocity also represents the plasma velocity.
Torsional Oscillations and the Solar Dynamo Regime
Authors: Tuominen I. , Rüdiger G. , Brandenburg A.
Published: June 2019

We discuss the observational results of cyclic variations of solar rotation and how these can be used as a means of probing the solar dynamo. We shortly describe two examples of dynamo models where the α-effect has been modified, and compare the resulting flows to the observations.
Wolf-Rayet Stars in the Old Days
Authors: Kuhi Leonard V.
Published: June 2019

This morning, as part of the welcoming ceremonies opening this conference, we were reminded that Indonesia consists of over 13,000 islands and that the coat of arms carries the phrase: “Unity in Diversity.” We might take the same theme for the study of Wolf-Rayet Stars. There has certainly been no shortage of diversity over the 120 years since their discovery and we all keep hoping for unity; perhaps IAU Symposium No. 143 will provide it! The conference was opened this morning with three strokes of the ceremonial gong to chase away all the bad spirits. So far that symbolic action has been most successful but perhaps more likely due to the kind hospitality of our hosts and the special warmth of Bali. We owe them all a vote of thanks!
Observations Versus Atmospheric Models of WR Stars
Authors: Schmutz Werner
Published: June 2019

Current knowledge of Wolf-Rayet continua is reviewed and observed continuum energy distributions are compared with model predictions. Good agreement is found. For WN stars a large range in intrinsic color is found for each subclass and the so far unexplained large range in the observed reddening-free continuum indices can be understood on the basis of atmospheric models. The strength of the continuum discontinuities determines the value of the index. Because of severe blending by the emission lines in WC spectra it can not be decided whether the intrinsic colors of WC stars of a given spectral type vary over a range of values or whether all stars of a given spectral type are similar. The reliability of model calculations for Wolf-Rayet stars is further tested by comparing observed and predicted correlations of helium line strengths. Satisfactory agreement is found for the Kiel/JILA models but not for the Bhatia-Underhill models. Methods used to determine the reddening due to interstellar extinction are reviewed and their accuracies estimated.
The Properties of Population I WO Stars
Authors: Kingsburgh R. L. , Barlow M. J.
Published: June 2019

High and low resolution UV and optical spectra of the four Population I WO stars originally classified by Barlow and Hummer (1982), Sanduleak 1, 2, 4 and 5, have been analyzed. Reddenings, terminal velocities and the relative abundances of He2+, C4+ and O6+ have been determined. The results are presented in Table 1.
Modelling the Wind Eclipses in WR+O Binaries: The Qualitative Picture
Authors: Koenigsberger Gloria , Auer Lawrence H.
Published: June 2019

The phase dependent profile variations due to wind eclipses in WR + O binary systems are shown to be a means of establishing the WR wind structure. The results of two model calculations are presented which indicate that there are important qualitative differences between the profile variatons which will be observed in slowly -and rapidly- accelerating winds.
EZ (Easy?) Canis Majoris
Authors: Robert C. , Moffat A. F. J. , Drissen L. , Niemela V. S. , Barrett P. , Seggewiss W. , Lamontagne R.
Published: June 2019

EZ CMa (HD 50896, WN5) is an enigmatic object. New photometry and polarimetry of EZ CMa are presented in the figure. Again the 3.77 day period is found but, as observed at previous epochs (e.g. Drissen et ai. 1989, Ap. J., 343, 426), the shapes of the curves change. The new photometry can also be interpreted in terms of a shorter period, of 1.254 days. A period of about one day is also claimed in other sets of photometric data (e.g. van der Hucht et ai., 1990, A. A., 228, 108) and in the IUE spectra of St.-Louis et ai. (1990, this symposium). However, despite the complex nature of the light curve, the 3.77 day period is strongly supported by the polarimetry, which shows no evidence for the shorter period.
IUE and Massive Binaries
Authors: Stickland D. J.
Published: June 2019

The role of IUE in the determination of orbital elements of massive stars is reviewed, emphasising the complementary value of ultraviolet observations when combined with archival optical data. Results on eight systems are described and the potential of the IUE archive for radial velocity work in general is advocated.
V444 Cygni and CQ Cephei, Key Wolf-Rayet Binary Stars
Authors: Underhill Anne B.
Published: June 2019

Radial-velocity and photometric observations of eclipsing binaries allow one to estimate the masses of the stars in such systems, their relative brightnesses and sizes. If polarization variations are detected throughout the binary period, one may confirm the inclination of the system. All three types of information are available for V444 Cygni and CQ Cephei, see Underhill, Yang, and Hill (1988a,b), Underhill, Gilroy, and Hill (1990), and the references quoted in those papers.
Polarization Variability of Wolf-Rayet Binaries: Constraints on WR Parameters
Authors: Moffat A. F. J. , Niemela V. S. , Seggewiss W. , Magalhaes A. M. , Cerruti M. A.
Published: June 2019

We have recently used the PISCO and VATPOL Polarimeters at the MPI (Chile) and CASLEO (Argentina) 2.2 m telescopes to monitor over several weeks the brightest WR+O systems fainter than 9th magnitude in the Galaxy (V filter) and LMC/SMC (GaAs tube without filter). Each data point is accurate to ~ 0.02% in polarization P.
Detection of Strong Winds in Giant Extragalactic HII Regions
Authors: Castañeda H.O. , Vilchez J.M.
Published: June 2019

The existence of supernova remnants and strong stellar winds in giant extragalactic HII regions should be associated with the existence of gas at very high velocities (≈ 102 − 103 km s–1). The detection of large velocity/low intensity gas within the regions could be possible with the use of CCD detectors with long slit intermediate spectroscopy and long integration times. To test this observational approach we have conducted a survey in the brightest giant HII regions of M 101 and M 51. We report on the preliminary results of our programme, and discuss the implications for the energetics of the regions.
Single-Lined Spectroscic Appearances During the Evolution of a Massive Binary System
Authors: de LOORE C. , DE GREVE J.P.
Published: June 2019

We calculated the evolution of both components of a massive binary system with masses 26 MO and 23.4 MO, initial period 27.4 days, through a case B of mass transfer, up to the end of the core helium burning phase of the primary (and further to the end of the main sequence of the secondary). For the WC phase we adopted Langer's (1989) mass dependent mass loss rate Ṁ ~ M2.5). The luminosities were transformed to visual magnitudes, applying bolometric corrections for O stars of Code et al. (1976) and Flower (1977) and BC = − 4.5 for the WR star (Smith and Maeder, 1989). If conservative mass transfer is adopted, the WR star is about 1.2 to 2.0 magnitude less brighter in the visual than the O star during the WN phase (lasting 1.5 105 yr). The brightness difference reaches almost 3 magnitudes during the WC + 08 phase (lasting 4.3 105 yr), showing the system as a single-lined O-type (!) spectroscopic binary. During the WR phase the mass function of this system varies from 0.67 sin3i to 0.05 sin3i! Nonconservative mass transfer and (or) a smaller initial mass ratio may result in the inverse situation, a single-lined WR binary with a large mass function (De Greve et al., 1988). Some of the results are shown in table 1 below.
Nucleosynthetic Activity of WR Stars: Implications for 26Al in the Galaxy and Isotopic Anomalies in Cosmic Rays and the Early Solar System
Authors: Prantzos N.
Published: June 2019

The implications of the nucleosynthetic activity of WR stars are reassessed, in view of recent experimental and observational data. It is confirmed that WR stars may 1) contribute significantly (up to ~20%) to the ~3 M⊙ of 26Al detected in the galactic plane through its 1.8 MeV line, 2) be responsible for the isotopic anomalies of 22Ne and 25,26Mg, detected in galactic cosmic rays (GCR), and 3) be responsible for the inferred presence of 26Al and 107Pd in the early solar system (and, perhaps, some other nuclei as well).
The WR/WRProgenitor Number Ratio: Theory and Observations
Authors: Vanbeveren D.
Published: June 2019

A direct comparison between the observed WR/WRprogenitor number ratio within 2.5 kpc from the sun and the predicted value (using evolutionary computations of single stars of Maeder and Meynet, 1987, A.&A.182, 243) reveals a discrepancy of at least a factor of two. In a previous study (Vanbeveren, 1990, A.&A. in press) I proposed a solution based on the incompleteness of the observed OB type star sample within 2.5 kpc from the sun. In this summary, I propose a theoretical explanation for the discrepancy. The theoretically predicted WR/WRprogenitor number ratio critically depends on the adopted M formalism in evolutionary computations during the red supergiant phase (RSG) of a massive star, especially in the mass range 20-40 M⊙. Since any M formalism predicts the mass loss rate with an uncertainty of at least a factor of two, I have tried to look for solutions for the WR/WRprogenitor problem by using different values of M during the RSG (in the mass range 20-40 M⊙); the M values and formalism that were adopted were always choosen within the observational uncertainty (i.e. within a factor of two when compared to the formalism used by Maeder and Meynet, 1987).
Photometric Evidence of Small “S Dor Type Eruptions” in S Dor Type Stars in or Near Minimum
Authors: van Genderen A.M.
Published: June 2019

It is shown that a number of S Dor type stars in or near minimum brightness show small S Dor eruptions: δ VJ < 0m5
Wolf-Rayet Populations in Dwarf Galaxies
Authors: Smith Lindsey F.
Published: June 2019

The Wolf-Rayet (WR) feature at 4650 A is observed in about 10% of the dwarf galaxies with high surface brightness knots. The intensity of the feature implies the presence of tens to thousands of WR stars. Hbeta fluxes imply correspondingly large numbers of O stars. The easily observed intensity ratio WRbump/Hbeta is a measure of the WR/O star numbers.

The metallicity of dwarf galaxies ranges from Z = Zo/30 to Zo/2, or O/H” = log(O/H)+12 = 7.4 to 8.6. WRbump/Hbeta correlates with O/H′ and O/H″ > 7.9 appears to be a necessary condition for the presence of the WR feature. Giant HII regions in ordinary galaxies extend to higher than solar metallicities and, in extreme cases, WR/O ≈ 1 are implied.

The subtypes present in giant HII regions in nearby galaxies appear to be exclusively late type WN and, occasionally, early type WC. Spectra of most BCD galaxies are compatible with a similar population. However, some high metallicity giant HII regions in large galaxies appear to have stronger NIII4640 relative to HeII4686 than occurs in WN subtypes in the Galaxy and the Magellanic Clouds.

The data needed for more detailed analysis of dwarf galaxy observations is collected.
Optical Spectroscopy of WR Stars in M33 and M31
Authors: Schild H. , Smith L.J. , Willis A.J.
Published: June 2019

We present new optical spectroscopy obtained with the Faint Object Spectrograph on the William Herschel Telescope of 6 WR stars in the local group galaxy M33 and 6 WR stars in M31. These spectra cover the wavelength range λλ3500-9750 å. We confirm the previous WR classifications of the M31 stars. In the M33 sample, 4 stars are classified as WC4-5, one is confirmed as WN-WCE and a further WN-WCE star has been identified. The widths of the CIV λ5800 emission differ by a factor of three amongst the M33 WC4-5 sample, spanning values exhibited by galactic WC8-WC4 stars and confirming the existence of narrow-lined WC4-5 stars in M33. We find that the M33 WCE line widths appear to be correlated with galactocentric distance and loosely connected to ambient metallicity. The narrowest lined WCE star MC 53 is in an unusually high (above solar) metallicity region. Further observations of a larger sample of M33 stars are required to confirm these preliminary results.
Computer Simulation of the Evolution of Active AGN: Single Supermassive Star Versus a Cluster of Massive WR Stars
Authors: Spurzem R. , Herzig K.
Published: June 2019

The evolution of gas and stars in galactic nuclei is reconsidered and numerical models of early evolutionary phases of galactic nuclei are discussed, in particular the evolution of a supermassive gaseous object as a hypothetical precursor of a supermassive black hole.
Luminosity Calibration of Giants and Supergiants, G0–M5
Authors: Keenan Ph. C.
Published: June 2019

Calibration curves giving Mv for stars of luminosity classes III, II, Ib, Iab and 0 are derived and shown graphically in the HR diagram. There are serious gaps in which the calibration needs to be improved.
Distribution de l'énergie dans le spectre ultraviolet de quelques étoiles
Authors: Chalonge D. , Divan L. , Hua C. T.
Published: June 2019

Preliminary results of recent direct comparisons between some early type O, B standards (and also α Lyr) and a terrestrial source previously compared to a black body are given for the ultraviolet range. It appears that the previously-used gradients ɸuv must be corrected on the average by +0.10.
An Infrared Camera Based on a Large PtSi Array
Authors: Glass I. S. , Sekiguchi K. , Nakada Y.
Published: June 2019

A large-format PtSi array (effectively 1k × 0.5k pixels) has been incorporated into an infrared camera intended for survey work using the 0.75-m telescope at Sutherland. The array is very uniform and almost free of cosmetic defects. The camera, its electronics and the operational procedures that we use are described, together with the methods of data reduction. The limiting magnitudes that can be observed in the JHK broad bands are given.
Choosing Filters to Make CCD Photometry Transformable to Other Detectors
Authors: Young Andrew T.
Published: June 2019

Transforming CCD data is difficult. Until recently, the general transformation problem was so poorly understood that there were no established design criteria. Now, the Hilbert-space approach to photometry tells us to match the standard passbands in the least-squares sense.

Unfortunately, the spectral responsivities of CCDs vary much more than do conventional detectors, and must be known to design filters. Each individual chip generally requires its own set of filters, if results are to be better than second-rate. Even so, spatial variations in spectral response limit the accuracy that can be reached, unless color terms are determined for individual pixels. Such CCD calibration problems involve the generally neglected optical properties of CCDs and the systems in which they are used.

Large observatories will have to establish calibration laboratories, and to abandon the common practice of moving “standard” filter sets from one instrument to another. Smaller institutions will need to purchase the services of such calibration laboratories if they are to produce accurate CCD photometry. These are major changes in the way astronomers are accustomed to working; but such changes are necessary to stem the backlash developing against CCD photometry.