bluuebunny/crossref_metadata_2025 huggingface dataset:
Small Scale Fluctuations in the Microwave Background Radiation Associated with the Formation of Galaxies
Authors: Sunyaev R. A.
Published: July 2016

According to current ideas, massive extragalactic systems such as galaxies and clusters of galaxies formed as a result of the growth of small fluctuations in density and velocity which were present in the early stages of expansion of the Universe under the influence of gravitational instability. According to the hot model of the Universe at the epoch corresponding to a redshift z ≈ 1500, recombination of primaeval hydrogen took place and as a result the optical depth of the Universe to Thomson scattering decreased abruptly from about 1000 to 1 - the Universe became transparent. Therefore the observed angular distribution of the microwave background radiation (MWBR) contains information about inhomogeneities in its spatial distribution at a redshift z ∼ 1000. Silk (1968) was the first to note that this “photograph” of the Universe at the epoch of recombination must be enscribed with fluctuations associated with perturbations in the space density and velocity of motion of matter which will later lead to the formation of galaxies and clusters of galaxies.
Circulation and Mixing
Authors: Kippenhahn R.
Published: July 2016

In the preceding lecture Dr Arnett has shown us how exciting the inner life of a star can be when during late stages of evolution higher nuclear reactions take place. But in order to enjoy the variety of different nuclear species formed there stellar material from the deep interior has to be brought up to the surface, where the observers can see it.
Review of IAU Symposium No. 59 on Stellar Instability and Evolution, Canberra, August 1973
Authors: Iben Icko
Published: July 2016

Since the results of the Canberra Symposium are to be published, a complete review here would be redundant. I will therefore confine my written remarks to an enumeration of several topics which were discussed.
Nuclei of Planetary Nebulae
Authors: O'Dell C. R.
Published: July 2016

The nuclei of planetary nebulae are examined both observationally and theoretically. It is seen that the region occupied by these stars in the logT – logL diagram is quite wide but consistent with a general progression of stars from high to low luminosity, with a noticeable but not large increase in luminosity during the early phase. The ‘evolutionary path’ is intrinsically quite wide and may indicate the evolution of stars under different conditions or non-monotonic passage along the mean path. Among the several theoretical approaches to this subject, only the double shell burning models seem to offer enough luminosity and short enough timescales to match the observations.
The Possible Connexion Between T Tauri Stars and UV Ceti Stars
Authors: Haro Guillermo
Published: July 2016

As is well known, very rapid and non-periodic changes in brightness have been discovered in several late-type dwarf stars in recent years. In the vicinity of the sun, within a radius not exceeding 10 parsecs, nine or ten such objects have been found and named ‘flare’ stars because of their extraordinarily rapid variations. The prototype of these flare stars is UV Ceti. For the purpose of the present discussion, we shall call these objects ‘classical’ flare stars.
Flare Spectra in Dwarf Stars
Authors: Joy Alfred H.
Published: July 2016

Observational evidence of transient flares which produce conspicuous changes in the total brightness and in the spectra of dwarf stars is limited, at present, to a small number of faint late-type stars. The outbursts take place with extraordinary rapidity and the duration is usually only a few minutes or hours. Accompanying spectral changes such as veiled and fuzzy absorption lines, greatly increased intensity of the bright lines of hydrogen and helium, and the appearance of an emission continuum shortward of λ 3750, have been reported.
C. The Continuous Spectrum of Pulsating Variable Stars
Authors: Oke J. B. , Whitney C. A.
Published: July 2016

Pecker:The topic to be considered today is the continuous spectrum of certain stars, whose variability we attribute to a pulsation of some part of their structure. Obviously, this continuous spectrum provides a test of the pulsation theory to the extent that the continuum is completely and accurately observed and that we can analyse it to infer the structure of the star producing it. The continuum is one of the two possible spectral observations; the other is the line spectrum. It is obvious that from studies of the continuum alone, we obtain no direct information on the velocity fields in the star. We obtain information only on the thermodynamic structure of the photospheric layers of these stars–the photospheric layers being defined as those from which the observed continuum directly arises. So the problems arising in a study of the continuum are of two general kinds: completeness of observation, and adequacy of diagnostic interpretation. I will make a few comments on these, then turn the meeting over to Oke and Whitney.
Concurrent Astronomical Observations for Studying Continental Drift, Polar Motion, and the Rotation of the Earth
Authors: Markowitz Wm.
Published: July 2016

The analysis of 66 years of concurrent latitude observations of the ILS shows that the mean pole has a secular motion which consists of a progressive component of about 0′′.0035/yr (10 cm/yr) along the meridian 65°W and a librational component (oscillation) of 24-year period along the meridian 122°W (or 58°E). Crustal displacements in latitude are not found within the errors of observation, about 1 cm/yr.

Comparable, concurrent observations for time (longitude) have not been made but programs are being organized. From 30 to 50 years will be needed for detection of continental drift with PZT's and astrolabes if relative drifts in longitude of 3 cm/yr are occurring.
The Direction of the Minor Axis of Geodetic Reference Spheroids
Authors: Bomford Brigadier G. , Robbins A. R.
Published: July 2016

It is necessary to standardise the definition of the direction of the minor axes of spheroids used for geodetic computations. In view of polar motion, the definition “parallel to the axis of rotation” is ambiguous. Few countries have explicitly stated the direction adopted, and it has generally been implicitly defined by the corrections for polar motion applied to astronomical azimuths, latitudes, and longitudes. But these corrections have often been neglected or applied inconsistently, and errors of perhaps 0′′.5 of azimuth result. The choice for a recommended Geodetic Mean Pole, to which spheroidal minor axes can in future be defined to be parallel, seems to lie either with the Cecchini “new system, 1900–05” or with the Mean Pole of Epoch 1962·0.
Variation Séculaire des Longitudes
Authors: Stoyko Nicolas
Published: July 2016

The reduction of time service results on a uniform system permits the secular determination of longitudes with high precision. A long interval of time is needed to eliminate quasi-periodic effects. One notes that the variations are similar when stations are in the same terrestrial region and opposed when in different regions.
Polar Wandering and Continental Drift
Authors: Runcorn S. K.
Published: July 2016

The relations between paleomagnetic observations, polar wandering curves, and changes in the speed of rotation of the Earth are discussed.
8. A brief survey of upper-air spectra
Authors: Millman P. M.
Published: July 2016

The atomic multiplets and molecular band systems identified in six categories of upper-air sources are studied. These total 510 multiplets of 38 atoms and ions, and 54 band systems of 27 molecules. The average excitation decreases as one progresses from the sources resulting from the influx of the faster and smaller particles to those produced by the slower and larger objects.
16. Some aspects of the creation of meteor trains and radio-wave scattering from them
Authors: Kostylev K. V.
Published: July 2016

Small meteor particles are considered, which produce meteors with magnitudes between +3m and +10m to +12m, and for which the thermal conductivity may be assumed infinite. Fragmentation and air cap effects are neglected. The derivation is made taking into account radiation losses and temperature variation during the evaporation time. The temperature variation of the meteoroid is defined in this case by the equation:
17. Estimation of attachment rate from the different echo duration of night- and day-time meteors
Authors: Glöde P.
Published: July 2016

The probability distributions of echo durations as measured on a 33 Mc/sec horizontally beamed radar at Kühlungsborn, G.D.R. (54°07′N, 11°46′E) indicate significant differences between echo durations during night- and day-time. These differences are attributed to attachment during night, whereas the strong radiation detachment of electrons during day-time leaves effectively no negative ions. The nocturnal attachment rate found from the difference in the probability distributions is higher than the rates deduced from the aeronomical processes hitherto known in the meteor height range. The probable attachment processes, the rate coefficients and particle densities are listed as far as known.
24. Radar meteor orbits
Authors: Lebedinec V. N.
Published: July 2016

Regular and numerous measurements of individual radiants and velocities of meteors were carried out in Jodrell Bank (Davies and Gill, 1960), Kharkov (Kaščeev et al., 1960; Kaščeev and Lebedinec, 1961), Adelaide (Nilsson, 1964) and as part of the Harvard Radio Meteor Project in U.S.A. (Hawkins, 1962). Observed distributions of radar meteor orbits obtained from a great number of systematic observations have been published up to now only at Jodrell Bank (Davies and Gill, 1960) and Kharkov (Kaščeev et al., 1960; Lebedinec and Kaščeev, 1966). 2474 orbits for meteors about + 5m to + 7m have been obtained in Jodrell Bank, 12500 orbits for meteors brighter than about + 7m have been obtained in Kharkov.
27. On the radiant distribution of sporadic meteors
Authors: Carrara N. , Consortini A. , Ronchi L.
Published: July 2016

A research is described which had the purpose of deriving information about the physics and astronomy of sporadic meteors from the range distribution of radar echoes from meteor trails experimentally observed under given conditions.

The method is based on the comparison of the experimental distribution with a number of different theoretical distributions, corresponding to different sets of assumptions about the characteristics of sporadic meteors and the law of trail formation.

The quantities which can be derived by this method are: (1) the distribution of heliocentric radiants, (2) the type of meteors (stone, iron, dustballs), (3) the distribution of heliocentric velocities.

In the present paper are described the results of the first part of the theoretical computations. Evidence is obtained that, in order to fit the experimental curve, both the uniform distribution of heliocentric radiants over the celestial sphere and in the plane of the ecliptic must be taken into account.
28. Seasonal variation in the radiant distribution of meteors
Authors: Štohl J.
Published: July 2016

The seasonal changes in the sporadic radiant distribution are investigated on the basis of the complete data for different classes of echo duration from the Ottawa 32·7 MHz radar taken over the years 1958–62, using a more accurate response function for the Ottawa radar equipment recently determined by McIntosh (1966). A model of the radiant distribution with four point sources (i.e. apex, helion, antihelion, and toroidal) and a uniform background is assumed. The strengths of the sources have been calculated by a least-squares fit to the observed mean hourly rates in 5-day intervals. The seasonal variations have different trends for meteors with different echo duration, showing stronger shower properties for long-duration echoes (4–8 sec). Meteors with short duration echoes (≤ 1 sec) show the same properties in radiant distribution, as was found in a previous paper based on preliminary Ottawa radar records. The toroidal source is without significant activity from August till November and shows a maximum in January. The diurnal variation calculated from this model is compared with the observed hourly rates. Some recent calculations have been made by Veverka and McIntosh (unpublished) using a continuous source model, elliptical in ecliptic longitude and exponential in latitude. The agreement of their results with observed diurnal rates is not as good. This suggests that the seasonal changes in the sporadic radiant distribution have a significant influence on the diurnal and annual variations of the hourly meteor rates.
32. Meteor mass distribution from radar observations
Authors: McIntosh B.A.
Published: July 2016

There are many problems in deducing the meteor mass distribution from radar echo observations. Some of these are reviewed in this paper, particular emphasis being placed on the effects of electron attachment and of equipment parameters on the statistics of long-duration echoes.
33. Meteor shower mass distribution from radar echo counts
Authors: Elford W. G.
Published: July 2016

Theoretical hourly rates of radar echoes from meteor showers observed with narrow- and wide-aperture systems are calculated in terms of equipment parameters and the distribution of the number of meteors as a function of mass. From a comparison of the echo rates in selected range intervals, it is shown that it is possible to determine the value of the exponent in a simple inverse power flux law.

The effect on the echo rate of a change in the value of the exponent in the flux law with magnitude is described and the probability of detecting showers at different stations is discussed.

It is suggested that simple radar echo counts in several range intervals can be used to determine the mass distribution of meteor showers over a range of two or three magnitudes above the limiting magnitude of the system. The analysis is applied to some observations made at Christchurch and Ottawa.
44. Investigation of perturbed motion of the leonid meteor stream
Authors: Kazimirčak-Polonskaja E. I. , Beljaev N. A. , Astapovič I. S. , Terenteva A. K.
Published: July 2016

The investigation is based on a system of elements, obtained from the best observations made in England during the maximum of the meteor shower 1866. This system represents the most probable orbit of that part of the stream, which passed perihelion during the years 1864–67 and was later given the name of Ortho-Leonids. Seventeen points (meteor groups) have been chosen on this orbit, and differential equations of their motion have been integrated on the electronic computer BESM-2 by Cowell's method of quadratures, taking account of perturbations from eight planets (Venus–Pluto), with a variable step from 0·001 to 40 days and taking account of differences through to the 4th order. The motions of two groups (XI and XII) have been investigated in an interval of 300 years (1700–2000), and the motions of the rest of the groups for a space of 135 years (1866–2000). All the close approaches of these groups to the Earth, Jupiter, Saturn and Uranus have been determined. The results of integration are given in the tables, which clearly represent the evolution of the orbit of every group. It has been found that the basic factors determining the evolution of separate groups, and of the stream as a whole, are the close approaches to the outer planets. The perturbations by these planets, especially by Jupiter and Saturn, determine the conditions for an encounter of the meteor groups with the Earth, and cause a change in the activity of the Leonid shower at different apparitions. Apparitions of the Leonids have been investigated for the last millennium, and in more detail for the last 180 years. It has been stated that the orbit of the Ortho-Leonid stream remained stable over the interval of 1000 years; its stability has been confirmed by calculations during the last 300 years, and the limits of changes of its elements have been computed. The perturbing influence of the Earth on the motion of meteor bodies in its sphere of action has been investigated. It turns out that at exceptionally deep penetrations of meteor bodies into this sphere of action, at a distance of some 1000 km from the Earth, its perturbations can essentially transform the orbit of a meteor body, e.g. reduce its period of revolution by some years, and materially change the eccentricity of the orbit, its inclination, etc. Conditions for an encounter of the stream with the Earth in the period 1898–2000 have been clarified, and forecasts have been made for the times of maximum activity of the shower in the years 1966–68. In 1967 the maximum activity of the Leonids is predicted to occur from November 17, 18h to November 18, 1h UT.
48. Existence of meteor showers associated by short-period comets anomalous in motion
Authors: Sekanina Z.
Published: July 2016

The observed properties of non-gravitational effects in the motion of the short-period comets are described in connection with the possible mass-loss processes in their nuclei. The impulses on the nuclei have been found to be about 1 cm/sec to 3 m/sec per revolution. The contributions to the observed dynamic anomalies of gas- and dust-matter ejections from the nucleus into the comet's atmosphere are estimated. The existence of meteor showers is related to the characteristics of cometary activity. Methods of further investigations are suggested.
The Space Distribution of Planetary Nebulae
Authors: Cahn J.H.
Published: July 2016

A punched-card catalogue of planetary nebulae has been prepared, using data extracted from all existing catalogues. A computer program calculates distances and radii using the method of Shklovsky, in which all nebulae are assumed to have the same ionized mass, and allowance for interstellar extinction is made assuming a continuous galactic-dust distribution. The assumption made in Shklovsky's method, that the nebulae are optically thin, is considered to be satisfied if the calculated radii lie within a certain well-defined interval. The reddening constants obtained are in satisfactory statistical agreement with constants determined by other methods. The local density of planetary nebulae is in agreement with estimates of local white-dwarf densities.
Observations of Planetary Nebulae at Radio Wavelengths
Authors: Terzian Yervant
Published: July 2016

Planetary nebulae are weak radio sources. The radio emission of planetary nebulae is primarily due to free-free transitions in the ionized hydrogen cloud. Very large radio telescopes and sensitive receivers are needed to detect the weak radio emission of planetary nebulae. During the last 3 years about 80 planetary nebulae have been detected at some one radio frequency, and more than 60% of these have been detected at more than one frequency. Most of the measurements have been made to measure the flux densities of the nebulae and determine their radio spectra. A few interferometric observations have also been made to determine the radio widths of planetary nebulae. In some cases the radio observations have been used to determine the electron temperatures and emission measures of planetary nebulae, and also to derive the interstellar extinction at Hβ.
Emission-Line Profiles in Planetary Nebulae
Authors: Osterbrock Donald E.
Published: July 2016

This research was undertaken with the idea of measuring as accurately as possible the internal-velocity distribution in planetary nebulae, in order to compare the observational measurements with hydrodynamical models of expanding nebulae. Much of the work was done in collaboration with J. S. Miller and D.W. Weedman. All the observational data were obtained photographically with the Coudé spectrograph of the 100-inch telescope at Mt. Wilson, using an image rotator, a 900 line/mm grating, and an F/5-2 camera, giving a dispersion of about 4 Å/mm in the blue and about 6 Å/mm in the red. The measured velocity resolution is approximately 5–6 km/sec. The data for five nebulae have been published (Osterbrock et al., 1966) while data for three more, NGC 2392, NGC 3242, and IC 418 are discussed here for the first time.
Photometric Observations of the Central Stars of Planetary Nebulae
Authors: Liller William , Shao Cheng-Yuan
Published: July 2016

Currently at Harvard, we are engaged in a program for measuring multi-color magnitudes of the central stars of planetary nebulae. We plan to determine magnitudes of all favourable planetaries having central stars brighter than 16th photographic magnitude. The results, when completed, will give us improved information on (1) the amount of interstellar extinction for the individual objects, (2) the luminosities and colors of the central stars, (3) interstellar reddening corrections for spectrophotometric studies, and (4) the existence of variability among the central stars.
Chemical Composition and Distribution of White Dwarfs
Authors: Weidemann Volker
Published: July 2016

This contribution makes a few points which are relevant to the question of the fraction of white dwarfs formed via the planetary-nebula phenomenon.
Galactic Dynamics and Galactic Distribution
Authors: Feast M.W.
Published: July 2016

The main papers at this symposium dealing with the galactic dynamics and distribution of the planetary nebulae were those of Perek and Cahn, and I shall not attempt to summarize their work again. Rather, I want to draw attention to what I believe are some of the main problems we have to solve in order to make further progress in this field.
Origine des régions actives solaires ‘anormales’
Authors: Martres M. J.
Published: July 2016

Solar active regions are considered ‘anomalous’ when they belong to magnetic classes γ,βγ and βf-αf. The study of the solar activity of the region where, later on, these groups are born shows an evident correlation between the presence of an old active center and the complexity of the new active region.

It is found that the complexity is greater if the old active center is younger, and the superposition better. We also observe that the birth of anomalous sunspots groups occurs much more frequently on the western side of the magnetic inversion line of the old center.

When the birth of an active center occurs outside and on the West of the faculae, we observe the weakly anomalous groups βf-αf. The ‘perturbation’ decreases with distance and is extended at least to 10 heliographic degrees of the boundaries of the old faculae.
Chromospheric explosions and satellite sunspots
Authors: Rust David M.
Published: July 2016

Observations of the longitudinal component of the photospheric magnetic fields near sunspots imply that surges and Ellerman bombs occur at neutral points in the magnetic fields (i.e. |B|=0) in the chromosphere. The neutral points appear above satellite sunspots, which are defined as polarity reversals (in B||) near the edges of large-spot penumbrae. A series of magnetograph observations shows a point of satellite polarity vanishing during a period of almost continuous surge activity. The lost magnetic energy is comparable to the energy release evidenced by the surge.
Concentration of magnetic fields in the deep convection zone
Authors: Simon G. W. , Weiss N. O.
Published: July 2016

The strong magnetic fields observed between supergranules indicate that there must be subphotospheric convection in cells with a preferred diameter of about 30000 km. Orthodox mixing length theory assumes that the dimensions of cells are limited by the density scale-height. This is adequate for explaining granules but cannot account for supergranulation. A model is therefore proposed in which cellular motions extend over several scale-heights. In addition to granules and supergranules this model predicts a third characteristic scale of motion, with giant cells around 300000 km in diameter. These cells may produce a pattern of magnetic fields like that suggested by Bumba and Howard for complexes of activity.
On the magnetic structure of an active region
Authors: Ermakov F. A. , Mogilevsky E. I. , Shelting B. D.
Published: July 2016

(1)

A scheme of magnetic-field generation in an active region within the subphotospheric convective zone is discussed. Magnetic-field amplification is considered to result from the interaction of the local cyclonic motion and the turbulent motion of the subphotospheric plasma.

(2)

A model of the magnetoplasma of an active region is considered consisting of a current-free magnetic field, whose lines of force stretch deeply under the photosphere in the form of subgranules (force-free fine-scale plasma elements). The explanation of some peculiarities in the development of an active region with the considered structure is discussed.

(3)

Some peculiarities of the general structure of the magnetic field and the motion within photosphere and chromosphere obtained by the analysis of observations with the IZMIRAN two-channel magnetograph is discussed.
Preliminary communication on the short-period oscillations of solar magnetic fields
Authors: Severny A. B.
Published: July 2016

With the image of the Sun held fixed, time variations of solar magnetic field were recorded simultaneously in two lines (λ5250 and λ6103) with the aid of double magnetograph (for the description see Severny, 1966, examples of such records are on Figures 1 and 2). The resolution was 2″.5 × 4″.5. The records in both lines λ5250 and λ6103 covering a time interval of about 1 hour show oscillations with the period ∼7·4min and amplitudes 10–20 gauss for moderately active region (full lines on the top of Figure 2). The oscillations of the magnetic field at both levels (the heights of λ 5250 and λ6103 differ by 260 km) are sometimes synchronous but now and then phase shift appears. For quiet regions near the centre of the disk the oscillations with the period ∼ 9·0 min and amplitudes less than 5 gauss are recorded and presented in Figure 1 (full line). These 7–9 min oscillations are probably sometimes damped or interrupted by more short-period fluctuations (with the mean period 80s) of smaller amplitude, but these last oscillations could be due to the fluctuations of seeing.
On some spectrographic observations related to the structure with height of active regions and particularly solar flares
Authors: Öhman Yngve
Published: July 2016

A peculiar kind of double-peaked Hα lines in solar flare spectra is described. The most likely explanation to this phenomenon is an absorption in the centre of the line due to mottles and fibrils situated above the flare. Another explanation might be a rapid rotatory mass motion in the filamentary structure of the flare itself. In some other flare spectra a slight inclination of the Hα-emission streak has been found indicating as well that rotatory mass motions may be present in flares.
On the magnetic-field structure around filaments
Authors: Ioshpa B. A.
Published: July 2016

The results of an investigation of the magnetic-field structure in the chromosphere around filaments are briefly given in this paper. The hypothesis of the existence of a two-field system is suggested: an outer field which has the form of arches and supports the filament against gravity, and an inner one, directed along the filament.
Loop-prominence systems and proton-flare active regions
Authors: Švestka Z.
Published: July 2016

It is shown that proton flares and loop-prominence systems form in the same type of active regions. Quite often both these phenomena appear simultaneously, but there are also many cases, when only the proton flare or only the loop-prominence system fully develops. The proton-flare active regions are not randomly distributed on the solar disk, but they tend to occur in complexes of activity which stay on the solar surface for many months and even years. Attention is called to the peculiar clustering of proton-flare regions on the Southern hemisphere, where two sources of activity, at a longitudinal distance of about 180°, seemed to move on the solar disk between 1956 and 1962 opposite to the solar rotation, shifting in the longitude at about 70 heliographic degrees per 10 solar rotations.
Protons associated with centres of solar activity and their propagation in interplanetary magnetic-field regions co-rotating with the Sun
Authors: Fan C. Y. , Pick M. , Ryle R. , Simpson J. A. , Smith D. R.
Published: July 2016

The Pioneer-6 and Pioneer-7 space probes carried charged-particle telescopes which measure, for the first time, both the direction of arrival and differential energy spectra of protons and alpha particles. The intensity changes, directional distributions and energy spectra of proton fluxes associated with solar activity are investigated. The data were obtained in the beginning of the new solar cycle (no. 20), when it is possible to unambiguously associate proton-flux increases with specific solar active regions. The origin, possibly long-term storage, and propagation of these proton fluxes are investigated. It was observed that enhanced 0·6–13 MeV proton fluxes associated with specific active regions were present over heliographic longitude ranges as great as ~ 180°. These enhanced fluxes exhibit definite onsets and cut-offs which appear to be associated with the magnetic-sector boundaries observed by Ness on Pioneer-6. Discrete flare-produced intensity increases extending in energy to more than 50 MeV are observed, superposed on the enhanced flux. These increases displayed short transit times and short rise times. Both the enhanced and flare-produced fluxes propagate along the spiral interplanetary magnetic field from the Western hemisphere of the Sun. From these observations we are led to a model in which the magnetic fields from the active region are spread out over a longitude range of 100–180° in the solar corona. The existence of strong unidirectional anisotropies in the initial phases of flare-proton events implies that little scattering occurs between the Sun and spacecraft. However, the gradual approach to an isotropic flux at late times indicates that the decay phase is controlled by the interplanetary magnetic field.
Analysis of some solar flares from optical, X-ray, and radio observations
Authors: Falciani R. , Landini M. , Righini A. , Rigutti M.
Published: July 2016

Using an improved isodensitometric technique it has been possible to study in great detail the photometric structure and the evolution of eight flares. A comparison has been made between the evolutive curves and the ones obtained from measurements of solar X-rays and radio fluxes at λλ 3·2 and 21 cm.

A reduction of the flare areas (and of the emitted energies) before the flash phase and a continuous pulsation of the flare have been observed. Further it seems that the flares associated with radio bursts or X-ray events are those which show regions of a sufficiently high intensity, the emitting areas not being a very important parameter.

The correlation in time between the various examined aspects of the AR seems to indicate that the sequence for the beginning of the different phenomena is, in general: optical flare, X-ray events, radio events.
Properties of sources of the slowly varying component of 2 cm solar radio emission
Authors: Nagnibeda V. G.
Published: July 2016

To study the nature of the local sources of solar radio emission connected with active regions, it is important to investigate the structure of such sources and their emission spectra. These problems are being investigated in detail by a group of workers of the Radio Astronomy Department of the Pulkovo Observatory led by G.B. Gelfreikh. The Pulkovo large radio telescope used for the observations allows them to investigate the solar radio sources at the whole cm-wavelength range with a high resolution reaching 40 sec of arc at the 2-cm wave. Observations are taken at 2·0, 3·2, 4·4, 6·6, and 9-cm waves. The author observes at the 2-cm wave.
The Culgoora Magnetograph
Authors: Ramsay J. V. , Giovanelli R. G. , Gillett H. R.
Published: July 2016

The magnetograph is based on a high-resolution filter which serves in place of a spectrograph, except that a reasonably large field of view (one-quarter of the Sun's diameter) can be observed at the one instant. Observations are made by obtaining filtergrams of opposite circular polarizations simultaneously in the wing of a magnetically sensitive line. Exposure times are about 0.3 s, the angular resolution of the magnetic field is about 2 arc s, closest frame repetition rates about 8 s. The filtergrams are processed subsequently by photographic or television subtraction. Semiautomatic photographic and/or TV subtractions yield magnetograms suitable for cinematographic projection though the subtractions are not yet as perfect as those obtained by individual subtraction.
Paschen-Back Effect of the Lithium Resonance Doublet in Sunspots
Authors: Maltby P.
Published: July 2016

The formation of the resonance doublet lines of Li6 and Li7 in sunspots is discussed. It is shown that the magnetic splitting of the lines must be determined according to the (partial) Paschen-Back pattern. As a first approximation to the problem a detailed calculation of the line profile is given for the case of pure absorption and local thermodynamic equilibrium.
The Crossover and Magneto-Optical Effects in Sunspot Spectra
Authors: Grigoryev V. M. , Katz J. M.
Published: July 2016

Two peculiarities of the magnetic splitting of a line in sunspot spectra have been investigated. The one is that in a rather small region of the penumbra near the umbra-penumbra boundary the π-component is absent in one circular polarization spectrum while both σ-components are present. In the spectrum of opposite circular polarization the σ-components are absent but the π-component is present. The second peculiarity consists of the anomalous splitting of the π-component of Zeeman triplets which are of the same and opposite signs in comparison with splitting of the σ-components. The nature of these effects is discussed.
Solar Magnetic Fields in Association With Flares
Authors: Michard R.
Published: July 2016

The association of Hα flares with photospheric magnetic field patterns is reviewed on the basis of empirical evidence. The insertion of flares in the H∥ and H⊥ patterns is described. Present data on the evolution of magnetic structures in connection with flares suggest that flares result from special trends in this evolution leading to stressed and/or ‘misconnected’ fields. However no sudden changes with a flare-like time scale have been definitely observed in photospheric fields.
80 MHz Radioheliograph Evidence on Moving Type IV Bursts and Coronal Magnetic Fields
Authors: Smerd S. F. , Dulk G. A.
Published: July 2016

The characteristics of 12 moving type IV bursts observed with the 80 MHz radioheliograph at the Culgoora Observatory between February 1968 and April 1970 are summarized.

Three classes of moving sources can be recognized; they are described as: (1) Expanding arch; (2) Advancing front; (3) Isolated source.

The first class has been identified (Wild, 1969) with the expansion of a magnetic arch or loop; the second class is here identified with an advancing MHD disturbance which may accelerate the radiating electrons in situ when moving at greater than Alfvén speed; the third with solar ejecta in the form of magnetized plasma clouds, or plasmoids. In all cases the radiation mechanism is probably synchrotron radiation from mildly relativistic electrons; energies in the range ∼0.1 to ∼1 MeV could account for the observed strong circular polarizations.

With an expanding magnetic arch, source and magnetic-field movement are inseparable; the field remains a closed loop throughout the event. The MHD front probably moves largely along and the plasmoids between the open magnetic-field lines of unipolar regions or helmet structures. In the latter case it is the internal magnetic field – possibly toroidal – of the moving plasmoid that determines the polarization of the synchrotron radiation. A preliminary comparison of moving type IV sources with Newkirk-Altschuler maps of coronal magnetic fields shows suitably located closed loops for 2 events identified as expanding magnetic arches and unipolar open field lines along the path of a moving source identified as a plasmoid.
Radio-Astronomical Evidence for Magneto-Hydrodynamical Pulsations in the Corona
Authors: Rosenberg Hans
Published: July 2016

At Utrecht Observatory a 60-channel solar radiospectrograph has been in regular operation since the fall of 1968, in the bandwidth 160–320 MHz, with a time resolution of 0s.03 (DeGroot and Van Nieuwkoop, 1968). In addition to all generally known and classified emissions as noise storms, type IV bursts, type III bursts, type IV continua, a number of unclassified emissions have been observed. The spectrograph is particularly well suited to study short time scale fluctuations, even of small amplitude. One striking feature is an often recurring broad band (> 80 MHz) weak, quasiperiodic fluctuation superimposed on a type IV-like continuum (Figure 1). Since no interferometric measurements were available, it is not known whether it is a stationary or a moving type IV burst. However, due to the sometimes very long duration, we expect it to be a stationary type IV.
Observations of the Coronal Network
Authors: Simon George W. , Noyes Robert W.
Published: July 2016

Spectroheliograms of quiet regions obtained by the OSO-G satellite in chromospheric, transition zone, and coronal lines indicate that the chromospheric network as seen in Ca K can be resolved despite the low resolution (30 arc s) of OSO-G. The network pattern becomes more diffuse with increasing height, indicating that the magnetic field pattern spreads with height.
Dynamics of Large-Scale Magnetic Fields
Authors: Kuklin G. V.
Published: July 2016

A discussion is given of the dynamics of large-scale solar magnetic fields as a joint action of a transport by a regular velocity field, by a generalized diffusion, by coming to the surface and sinking and by sources of origin and destruction of magnetic fields. Also these processes are discussed using the observed picture of magnetic field dynamics.
Properties and Distribution of Galaxies in Relation to Their Formation and Evolution: Theoretical Situation
Authors: Peebles P. J. E.
Published: July 2016

This report is a review of several proposed pictures for how matter came to be concentrated in lumps like galaxies and clusters of galaxies. The proposals cover a broad range of unrelated possibilities. I attempt here to subject these proposals to critical discussion, to discover the major problems for each case and the more promising lines for further study.
Intergalactic Matter and Radiation and its Bearing on Galaxy Formation and Evolution
Authors: Burbidge G. R.
Published: July 2016

An up-dated review is given of the evidence for the presence of intergalactic matter and radiation in the Universe. It is concluded that the only important constituents which may make a sizable contribution to the total mass-energy are intergalactic gas and condensed objects with a very high mass-to-light ratio. If the QSOs are not at cosmological distances, cold atomic hydrogen may still be the most important constituent and may contribute much more mass than do the galaxies. The X-ray observations still do not unambiguously show that very hot gas is present, though it is very likely on general grounds that some hot gas is present in clusters of galaxies.

The question of whether or not large amounts of matter, enough to close the Universe, are present, remains unsettled. From the theoretical standpoint the answer depends almost completely on the approach taken to the problem of galaxy formation and to the cosmological model which is favoured.
Differences Between Galaxies
Authors: Van Den Bergh Sidney
Published: July 2016

It is pointed out that the metallicity of galactic and extragalactic globular clusters correlates with the density of the regions in which they were formed. Within individual galaxies the regions of highest density have the highest metallicity.

Some of the differences in family traits between the globulars in the Andromeda Nebula, the Galaxy and the Magellanic Clouds might be understood if the M31 cluster system is ~ 1 × 109 yr older and the SMC cluster system ~ 1 × 109 yr younger than galactic globular clusters.
Interpretation of the Illumination Measurements by the Automatic Interplanetary Station ‘Venera 8’
Authors: Feigelson E. M. , Lukashevich N. L. , Marov M. Ya.
Published: July 2016

Measurements of the downward light flux during the descent from an altitude of 50 km to the ground have been made. Atmospheric layers with different optical thicknesses have been discovered. The optical properties of Venus atmosphere for different cloud models have been studied.
Observations of O2, H2O and HD in Planetary Atmospheres
Authors: Traub W. A. , Carleton N. P.
Published: July 2016

We have searched for molecular lines in planetary atmospheres using the PEPSIOS spectrometer with an instrumental width about equal to that of the expected absorption line, and in the case of Jupiter, with the additional feature of Doppler compensation over the planetary disc.
TD1A Satellite Spectroscopic Observations of Jupiter in the Ultraviolet
Authors: Duysinx R. , Henrist M.
Published: July 2016

Three spectra of Jupiter were recorded by TD1A satellite between 1350 and 2600 Å. From these data, the geometrical albedo of the planet was computed.

From 2600 to 2100 Å, the value of the albedo matches the simple diffusing models of Jupiter's atmosphere (Greenspan and Owen, 1967).

From 2100 to 1800 Å, a broad absorption can be assigned to NH3 molecule (2168 Å transition).

Another absorption commences below 1800 Å. The absorbing molecule involved will be determined at a later date.
The Atmosphere of Saturn
Authors: Teifel V. G.
Published: July 2016

The results of recent studies of the optical properties, temperature, chemical composition and a probable structure of Saturn's atmosphere are reviewed.
Observational Constraints on Model Atmospheres for Uranus and Neptune
Authors: Encrenaz Thérèse , Hardorp Johannes , Owen Tobias , Woodman Jerry H.
Published: July 2016

We have re-examined the visible and near-IR regions of the spectra of Uranus and Neptune to provide additional data for constructing atmospheric models. We find that a true continuum exists only at wavelengths below 4700 Å, that the 6420 Å absorption previously attributed to hydrogen is probably caused by methane, that there is no evidence for ammonia, ethylene or ethane absorptions in our spectra, and that the abundance of methane is probably much higher than previous estimates suggest. This last finding implies that the value of H/C in the atmospheres of both planets is much less than 1/10 the solar (or Jovian) value. Clear, Rayleigh-scattering model atmospheres are not compatible with the observations, but more work is needed to establish viable alternatives.
A study of bright members of the large magellanic cloud
Authors: Feast M. W. , Thackeray A. D. , Wesselink A. J.
Published: July 2016

A progress report on work on (a) spectral types and (b) radial velocities of twenty-eight members of the Large Cloud (mostly mpg = 11 or brighter) will appear shortly in The Observatory. The commonest spectral types found lie between B 5 and A 2. A star with Mpg= − 10·1 has slightly narrower H-lines than the galactic A 2 super-giant HD 92207. [Fe 11] emission appears in four of the stars, including recent spectra of S Dor.
Galactic and extra-galactic radio frequency radiation due to sources other than the thermal and 21-cm emission of the interstellar gas
Authors: Brown R. Hanbury
Published: July 2016

At wave-lengths greater than about one metre the majority of the radio emission which is observed from the Galaxy cannot be explained in terms of thermal emission from ionized interstellar gas. This conclusion is widely accepted and is based on observations of the equivalent temperature of the sky and the spectrum of the radiation. The spectrum at metre wave-lengths is of the general form:
where TA is the equivalent black-body temperature of a region of sky and A is the wave-length. The exponent n varies with direction but lies between about 2·5 and 2·8, and is thus significantly greater than the value of 2·0 which is the maximum to be expected for thermal emission from an ionized gas. Furthermore the value of TA is about 1050 K at 15 m and thus greatly exceeds the electron temperature expected in H 11 regions.

At centimetre wave-lengths it is likely that the majority of the radiation observed originates in thermal emission from ionized gas; however, the present discussion is limited to a range of wave-lengths from about 1 m to 10 m where the ionized gas in the Galaxy is believed to be substantially transparent and where the origin of most of the radiation is believed to be non-thermal.
The observation of blue giant stars at great distances from the sun
Authors: Morgan W. W.
Published: July 2016

A method is described for the discovery and observation of early-type giants which are too faint for ordinary spectroscopic observation in the blue region.
The spatial distribution of novae and super-novae
Authors: Kopylov I. M.
Published: July 2016

In 1945 McLaughlin found that novae form a comparatively flat sub-system in the Galaxy with an appreciable concentration towards the centre. B. V. Kukarkin came to the same conclusion in 1949. However, it was found later that this result, which contradicts our ideas of galactic structure, was a result of poor absolute magnitudes and the consequent underestimate of the distances of the novae.
Comparison of the galactic system with other stellar systems
Authors: Oort J. H.
Published: July 2016

A comparison of the Galactic System with other stellar systems might be based on:

(a)

the regular aspect (the population 11);

(b)

what we might call the semi-chaotic aspect, presented by the gas and the other population 1 objects;

(c)

the spherical corona of continuous radio-emission.

As far as (a) is concerned we are not yet in a position to say very much. The only type of objects of extreme population 11 that we have recognized with certainty in the Galactic System as well as in other comparable systems are the globular clusters. They are very incompletely known in the Galaxy, perhaps somewhat more completely in the Andromeda nebula, but few systematic studies have been made in other systems. So far as we can tell, the Andromeda nebula and the Galactic System are comparable in the number and general distribution of globular clusters.
Heating and Ionization of the Interstellar Medium
Authors: Grewing Michael
Published: July 2016

Ionization and heating mechanisms are reviewed; some of them apply to the interstellar medium as a whole, others only to localized regions. Cooling processes are briefly summarized. Results are given from a recent model calculation for an intercloud medium heated by X-rays.
The Observed Characteristics of the Local Magnetic Field
Authors: Whiteoak J. B.
Published: July 2016

The main investigations of the local magnetic field are reviewed and are found to contain some conflict in interpretation. At radio wavelengths, studies have been made using both the Faraday rotation of the polarized radiation from extragalactic sources and pulsars, and the polarization of the galactic background radiation. With the former type of observation, although more data are available for extragalactic sources, any interpretation may be complicated by the influence of distant field structure. The results are consistent with a large-scale field parallel to the galactic plane, with a field strength of about 2 µG, and which is directed towards l=90°. This field contains irregularities in direction and strength on a scale of about 100–200 pc. The polarization of galactic background radiation may yield the most detailed information about the local field structure – the results to date show loops of magnetic fields extending along the radio spurs.

The interpretation in terms of small-scale irregularities embedded in a large-scale field parallel to the galactic plane differs from that proposed to explain the optical polarization of starlight, in which a helical field configuration near the Sun was preferred to a more disordered pattern.