bluuebunny/crossref_metadata_2025 huggingface dataset:
The Hubble Diagrams for Quasars
Authors: Bahcall John N. , Turner Edwin L.
Published: July 2016

We discuss in this talk the optical and radio Hubble-diagrams for the brightest quasars. We shall infer from our results: (1) a strong correlation between redshift and received flux that is consistent with the cosmological interpretation of the emission-line redshifts; and (2) a quantitative upper limit on the permissible amount of pure luminosity evolution. We establish these conclusions twice, by examining the Hubble diagrams both with and without corrections for the selection effects introduced by the flux limits of the quasar catalogs considered.
Clusters of Galaxies and Radio Sources
Authors: Jaffe Walter
Published: July 2016

For some time there have been suggestions that there is a special association of radio galaxies with rich clusters of galaxies, and more recently that the radio galaxies in clusters may show different characteristics from those outside. I will discuss the evidence for three types of such differences, in luminosity function, morphology, and occurance of steep spectrum sources. In each case I will try to connect any difference I find to the cluster environment.
Rotation Measures and Cosmology
Authors: Kronberg Philipp P.
Published: July 2016

The very low upper limits on distributed intergalactic (i.g.) HI (Gunn and Peterson 1965, Wampler 1967), and H2 (Field et al. 1966) have made it clear for some time now that if a smooth distributed i.g. gas exists in significant amounts (Ωig ≳ 10^−3), it must be ionized. X-Ray emission from rich clusters of galaxies such as Coma, indeed show that an intracluster gas can be seen (cf. Field 1974). Also persuasive in this connection are the head-tail radio galaxies in clusters, whose prototype is NGC 1265 (Miley et al. 1972, Jaffe and Perola 1973).
Presupernovae
Authors: Imshennik V. S. , Nadyozhin D. K.
Published: July 2016

A survey is given of the present state of theories concerned with the mechanism of supernova outbursts. Special attention is paid to the state of the star immediately before the supernova explosion (presupernova).

The following topics are discussed.

(1) The thermonuclear model of supernova explosions.

(2) The gravitational collapse model of supernova explosions.

(3) The characteristics of presupernova models resulting from the comparison of theoretical light curves with observational ones.
White Dwarfs
Authors: Vila S. C.
Published: July 2016

The effects of core crystallization and of convection in the envelope on the cooling of white dwarfs are reviewed. The case of a 0.6 M⊙ white dwarf composed of an oxygen core and a helium envelope is taken as example. Also the amount of hydrogen that a white dwarf can accrete before nuclear burning occurs is estimated and possible evolutionary relations between white dwarfs of types DA, DB and DC, as advanced by Baglin and Vauclair, are presented.
What SNU? The Case of the Missing Solar Neutrinos
Authors: Fowler William A.
Published: July 2016

The current attempts to observe solar neutrinos are reviewed. It is concluded that serious consideration must be given to the possibility that the neutrino flux from the Sun is essentially zero even though we are not yet absolutely forced to this conclusion. Transient effects in the Sun are briefly discussed as a possible explanation for the lack of solar neutrinos.
On RW Aurigae Type Stars and Related Types
Authors: Hoffmeister C.
Published: July 2016

First of all it will be necessary to say a few words on terminology. Different names are now in use either for the same group of variables or for different variants of a rather heterogeneous class. Let me list the following:

RW Aurigae stars,

RR Tauri stars,

T Tauri stars,

Nebular type variables,

Orion type variables,

Nova-like variables,

Main sequence variables.
Phenomena of Non-Stability in Close Binary Systems
Authors: Martynov D. J.
Published: July 2016

(I) The non-stability of the components in close binary systems has been established in a number of systems, mainly among the eclipsing variables. It cannot be regarded as an unusual phenomenon.
Non-Stability in Close Binary Stars
Authors: Krat V. A.
Published: July 2016

Those eclipsing binaries whose components are non-stable stars deserve particular attention not only owing to the fact that in such cases the physical properties of the stars may be studied in greater detail, but also since the mechanism of the ejection of gases from the atmospheres of the components may then be established with some certainty.
B. The Solar Atmospheric Convection Zone
Authors: Spiegel Edward A. , Böhm Karl-Heinz
Published: July 2016

Observational progress has, in the last decade, greatly surpassed theoretical progress in our study of the non-thermal velocity fields in the solar photosphere and chromosphere. This differential progress has not been simply a matter of filling in details. Attempted formulation of the theoretical problem of the velocity fields arising from convective instability in stellar atmospheres has resulted in no really new conceptual developments, nor large clarifications in approach, to match the observational ones just summarized by Noyes. Discussion of the problem at Varenna consisted mainly in the expression by aerodynamicists of severe reservations on the likelihood of gaining deep physical insight, or reliable numerical results, from the mixing-length approach generally used in astrophysics, with essentially no suggestions of a better approach. What progress that has been made in the general area of convective problems similar to those of interest in stellar atmospheres lies in the exploration of the physical structure of simplified convective configurations, often by exploration of various intuitive approaches.
Secular Variation of Longitude and Related Problems
Authors: Torao M. , Okazaki S. , Fujii S.
Published: July 2016

The secular variations in longitude differences among several observatories were determined, but it is hard to consider that these results are literally due to continental drift. The large standard deviations of the data of longitude differences show the existence of external systematic errors in time observations.
Information Obtainable from Laser Range Measurements to a Lunar Corner Reflector
Authors: Alley C. O. , Bender P. L.
Published: July 2016

It has been proposed to the U.S. National Aeronautics and Space Administration that optical retro-reflector packages be placed on the lunar surface under either the Surveyor or Apollo Programs. Methods for measuring the range to the reflectors with an expected accuracy of 15 cm have been presented. The new technique is briefly discussed, and an analysis of the determination of geocentric longitude is given, indicating a potential uncertainty of 0·25 × 10−3s of time.
1. The radar meteor echo (survey paper)
Authors: Millman P. M.
Published: July 2016

From about 1930 on various scattered notes appeared from time to time, pointing out certain radio effects that probably resulted from meteors. However, the real birth of the serious observation of meteors by radio took place on the night of October 9–10, 1946, when the Giacobinid meteor shower returned in considerable strength. This was observed with re-built World-War II radar equipment in both England and the U.S.A., and the results achieved left no doubt concerning the value of the new technique in meteoric astronomy. Figure 1 illustrates two historic examples of meteor echoes recorded in England on this occasion (Appleton and Naismith, 1947; Hey et al., 1947). Since this date the field has expanded rapidly. Useful general summaries may be found in a number of monographs, e.g., Lovell (1954), McKinley (1961).
6. Simultaneous radar and optical observation of meteors at Ondřejov in 1962
Authors: Grygar J. , Kohoutek L. , Plavcová Z.
Published: July 2016

A program of simultaneous observation of meteors was organized in the period between August 25 and September 3, 1962 at the Ondřejov Observatory. Experienced amateur astronomers, 37 in number, took part in the visual and telescopic observation of meteors according to the following scheme: four visual observers surveyed an area, the centre of which coincided with the axis of the antenna diagram of the Ondřejov meteor radar: elevation 45°, south azimuth. 24 observers used 10 × 80 binoculars with a field of view of 7·3° diameter and kept under control three zones in the altitudes of 30°, 45°, and 60° above the horizon. In each zone, there were four azimuths of the centres of the fields of view, namely 349·5°, 356·5°, 3·5° and 10·5°; each of these areas being observed by two observers. All standard data of meteor statistics were recorded. Time recording was doubled: recorders read the time indicated by light signals on a chronometer, and independently the time was indicated on a film moving in synchronization with the radar recording film. Thus an accuracy in time recording of ±0·5 sec was guaranteed. Unfortunately, the motor of the time camera sometimes caused interference of variable intensity unfavourably affecting the radar data, particularly the radar hourly rates.
7. Meteor spectra (survey paper)
Authors: Ceplecha Z.
Published: July 2016

Meteor luminosity is frequently used for the computation of meteor mass. This procedure is a rough approximation only if the spectral distribution of the light energy and its changes during the meteor flight are not known. A good-quality photograph of a meteor spectrum includes much more information on the meteor phenomenon than any other method can provide. There is of course a stronger limitation by meteor brightness than for direct meteor photography. Detailed spectral analysis is available for meteors 4 or 5 magnitudes brighter than for those photographed directly. This could be the reason that meteor spectroscopy is not applied to a desirable extent for the study of meteor phenomenon.
11. Some unusual spectra of meteors from the Palomar 18-inch Schmidt file
Authors: Barbon R. , Russell J. A.
Published: July 2016

Five meteoric spectra have been studied that were obtained during the period mid-June to mid-December, 1966. They include spectra of a Perseid, a Geminid, and three sporadic meteors. Four were photographed on Royal Pan emulsion without a filter; the Geminid on Tri X Aerecon with a GG11 filter.

Lines in the spectrum of one of the sporadic meteors indicate that two meteoroidal fragments were involved which diverged with increasing atmospheric penetration and which flared at different altitudes, indicating that the flares were not the result of atmospheric stratification.

The second sporadic and the Perseid were photographed about 2½ hours apart. The sodium D line is strong in the Perseid but does not appear in the sporadic spectrum. If present, it is blended with the diagonal sequence Δv = + 4 of the first positive group of the neutral nitrogen molecule, which appears in both spectra. A line questionably identified as the forbidden line of oxygen at 5577 Å appears faintly in the sporadic. The strength of the N2 sequence in these two spectra, and the absence of the D line in the sporadic, are very unusual. The proximity in time of appearance of these two spectra, and the absence of the N2 bands from the other two sporadic spectra, suggest that a temporary atmospheric condition may be responsible for the strength of the nitrogen radiation.

The Geminid has as its principal feature the Δv = + 3 sequence of the first positive group of N2. We have not previously observed this band in meteors as low in velocity as the Geminids.
13. Atmospheric heights of telescopic meteors
Authors: Kohoutek L.
Published: July 2016

The heights of sporadic telescopic meteors were observed from three stations, distant from each other 9·1, 6·0 and 3·2 km respectively, during the meteor expedition in the summer of 1960 (Kohoutek, 1967). Three teams of four observers gathered individually data on 1187 meteors, together with 1864 drawings, during the period of 7 nights, August 15–27. Altogether, 189 pairs observed by at least two stations were identified from the complete material. The heights of the respective beginning (b), centre (c) or end (e) points of 159 pairs were determined by means of graphic-numerical analysis.
14. The physical theory of meteors
Authors: Cook A. F.
Published: July 2016

I wish to stress during the 20 minutes available to me that a very open-minded approach is required in making assumptions for a physical theory of meteors.
18. A note on the head echo problem
Authors: Rajchl J.
Published: July 2016

A model of the head echo is examined, in which, as a source of ionization and recombination, an interaction layer of impinging atmospheric molecules (O2) mixing with reflected ones is assumed. Dissociative recombination is considered as the most probable process. If we suppose that the interaction layer is that arising in nearly free molecular flow with no shock wave present, we obtain, using the observed heights of head echoes, dimensions of meteoroids in the range 10–1 cm for absolute magnitudes between −10 and −2. It is shown that such a layer may be used to explain the high initial recombination coefficient of the order of 10−5 cm3/sec. Using the ionization collision cross-sections measured by Utterback (1963) we obtain for the mean extent of the interaction layer a value 1–100 m for heights 80–130 km, in accordance with radar observations.
25. Orbits of photographic meteors
Authors: McCrosky R. E.
Published: July 2016

New photographic observations of meteors in the brightness range −5 > Mp > −18 (?) and with a median value of M = −8·5 have yielded orbits with a precision of better than 1° in the angular elements and of about 0·05 in e and 1/a. A comparison of 100 of these fireball orbits with Super-Schmidt orbits shows:

(1)

A class of orbits, comprising about 25% of the faint meteors, of long period, is almost completely absent among the fireballs.

(2)

Small perihelion distances (q < 0·2 AU) are not found. A maximum at q ~ 0·7 AU, which also appears in the Super-Schmidt orbits of short period, corresponds to the perihelion distances of all but two of the Apollo objects.

(3)

The distribution of aphelia shows a marked decrease at Jupiter when compared to a similar distribution of small, faint meteor orbits. With the existing material, we cannot determine whether this represents an important evolutionary distinction between meteoroids of different mass or is simply the result of an inappropriate choice of the division between ‘large’ and ‘small’ orbits in the faint meteor data.

Provisional values of the bulk density of 28 of the fireballs as determined from the photometric mass and the observed mass-area ratio indicate that these meteoroids do not differ significantly from those observed with the Super-Schmidt cameras. Evidence of gross fragmentation of these large objects at high elevation and evidence of small or negligible terminal masses suggest that the material is friable. There is no certain evidence that any appreciable fraction of fireballs is produced by high-density, cohesive material.

If the above analysis is correct, we should expect an occasional (1 year−1 106 km−2?) meteorite fall of discoverable size originating from a low-density meteoroid.
31. The interplanetary dust cloud (survey paper)
Authors: Kaiser T. R.
Published: July 2016

The first part of the paper reviews the present state of knowledge of the characteristics of cosmic dust in interplanetary space. Since this is derived from a variety of observational techniques, some attempt is made critically to assess the difficulties in interpretation, particularly those due to differences in observational selection. Attention is drawn to the doubts that recently have arisen concerning the existence of a terrestrial dust cloud. The second part describes some radio investigations of the structure of meteor streams and of the sporadic background. Systematic variations in magnitude distribution with solar longitude which are observed in both the Geminids and Perseids cannot be simply interpreted as due to selective perturbation of the smaller meteoroids. Experimental data are described which point to the existence of considerable radiant structure in the sporadic background.
36. Observations of meteoric dust from rockets and satellites
Authors: Nazarova T. N.
Published: July 2016

18 years have elapsed since the first data on meteoritic dust were obtained by means of the instruments installed on a rocket under the guidance of Professor Bohn. Since then these investigations, by means of different instrumentation, have been carried on in the vicinity of the Earth and in interplanetary space. By now rocket and satellite data have been obtained on the spatial density of meteoritic particles with masses of 10−7–10−16 grams and on their energy; a concept of the mass spectrum of these particles has been obtained as well as the first data on their velocities. Over recent years very difficult experiments have been initiated for obtaining samples of meteoritic particles directly from high altitudes with a view to determining their physical properties, chemical composition, and the destroying effect.
37. Structure and evolution of meteor streams
Authors: Kresák Ľ.
Published: July 2016

Our present knowledge of meteor streams is based on three types of meteor showers:

(1)

About one or two dozen major showers that recur annually in optical and radar records of meteor activity.

(2)

An indefinite number of minor showers, hardly distinguishable from the sporadic background, which can be traced only by comparing individual meteor orbits.

(3)

Rare appearances of temporary showers, sometimes producing extraordinary meteor displays. These include prominent concentrations of meteors within some of the annual streams, meeting the Earth under specific conditions.
39. On the grouping of meteors in meteor streams
Authors: Porubčan V.
Published: July 2016

It has been repeatedly suggested, on the basis of visual and radar observations, that meteors often appear in pairs or larger groups, within short time intervals. They usually have some similar characteristics (brightness, path, etc.) so they easily attract the observer's attention. This phenomenon could be a result of chance and only an analysis of its frequency can give an answer whether there is any a priori reason for it. The possible reality of this grouping has been studied by some authors. However, their observing data contained only meteors brighter than +8m, and did not yield unambiguously acceptable evidence for existence of real pairs in this range and said nothing about the region of very small meteors.
Observation des Nébuleuses Planétaires dans L'infrarouge
Authors: Andrillat Yvette
Published: July 2016

La région de l'infrarouge a été fort peu étudiée jusqu'à maintenant en astrophysique. En ce qui concerne les nébuleuses planétaires les seuls travaux publiés concernent la région de l'infrarouge photographique jusqu'à 1.2 µ.
Radio Observations of Planetary Nebulae
Authors: Davies J.G.
Published: July 2016

I am to report on a rather extensive series of observations of planetary nebulae, using the Mark-II radio telescope at Jodrell Bank. The method of observation adopted involves comparing the signal received from a beam centered on the nebula with two beam areas horizontally displaced to either side of it. If the source is not too far South, the confusion effects can be reduced by making observations at different hour angles. A second source of error, particularly in the earlier results, arises from the fact that the positions adopted for some nebulae were not as accurate as had been assumed. The anomalously low 6 cm flux for IC418 in particular is now believed to be due to this cause, and can be disregarded.
High-Resolution Radio Observations of Five Planetary Nebulae
Authors: Elsmore B.
Published: July 2016

Observations have been made of 5 planetary nebulae at 1407 and 408 MHz with beam widths of 23′′ of arc and 80′′ of arc respectively. Measurements of positions, fluxes and angular structure have been obtained; some results are presented in the form of contour maps.
The Determination of Electron Densities, Electron Temperatures and Central-Star Temperatures for a Series of Planetary Nebulae
Authors: Arhipova V. P. , Kostjakova E. B.
Published: July 2016

From theoretical treatments of the physical processes in planetary nebulae, the average physical conditions in these objects are known with some certainty. However, the physical parameters of the individual nebulae have not been determined exactly. This may be due to the different methods used for determining these quantities, and to the inhomogeneous data available. Therefore, it seems to be of great importance to obtain individual physical parameters for a large number of planetaries in a homogeneous system.
Radiative Transfer Processes in Planetary Nebulae
Authors: Hummer D.G.
Published: July 2016

The physical aspects of radiative transfer processes that may be of importance in planetary nebulae are discussed, and recent work on these problems is summarized.
The Chemical Composition of Planetary Nebulae
Authors: Aller Lawrence H. , Czyzak Stanley J.
Published: July 2016

The problem of the determination of the chemical compositions of planetary and other gaseous nebulae constitutes one of the most exasperating problems in astrophysics. On the one hand, the problem appears to be conceptually simple – the mechanisms of excitation of the various lines appear to be well understood and the necessary physical parameters can be obtained by quantum mechanical theory. Yet the task is a difficult one and we want to explore some of the significant features.
Filaments of the Helix Nebula
Authors: Vorontsov-Velyaminov B.A.
Published: July 2016

Thirty years ago Baade discovered in the Helix Nebula extremely thin radial filaments, but since then their existence has been neglected. Data presented below were obtained by studying a copy of a plate obtained in 1954 in the light of Hα with the 200-inch telescope. Our goal is to draw attention to these filaments, which are of great importance for the understanding of planetary nebulae in general.
Internal Motions in the Planetary Nebula NGC 6853
Authors: Sheglov P.V.
Published: July 2016

Je voudrai bien parler la langue classique de l'interférometrie, mais le temps nous est cher et je passerai à l'Anglais.
The Observation of Monochromatic Intensity Distributions in Planetary Nebulae by Means of Electronography
Authors: Walker Merle F. , Kron Gerald E.
Published: July 2016

The linear response and high information gain of the electronographic process make it an important new technique for the observation of monochromatic intensity distributions in planetary nebulae. Preliminary results for NGC 6720, obtained with the U.S. Navy electronic camera and the 61-inch astrometric reflector, are presented.
On the Variability of the Central Star of the Planetary Nebula HZ 1–5
Authors: Herbig G. H. , Boyarchuk A. A.
Published: July 2016

During 1960–67 we have studied the variable star FG Sge=377·1943 Sge, which is located exactly in the centre of an image of the planetary nebula Hz 1–5, as shown on Figure 1. The most significant feature of the central star is the continuous increase of its brightness during the past 70 years, as one can see from Figure 2. During the same time, the temperature of the central star has apparently decreased, although direct information to this effect is available only since 1955. In 1955 the star had spectral type B4, while by 1967 it had become A5. The observational data can be explained by the continuous ejection of gas from the central star, which began at the end of the preceding century. The central star at that time must have had T∗≈63 300°K and Mpg≈ + 1·3, on this model.
The Evolution of Helium Shell-Burning Stars
Authors: Faulkner D.J.
Published: July 2016

Evolutionary sequences of stellar models have been obtained, using the Henyey method, for stars of mass 0·8 M⊙, 0·9 M⊙ and 1·0 M⊙. The starting-point of each sequence is a star with a core of carbon and oxygen, comprising 25% of the star's mass, surrounded by helium-rich material. It is assumed that any remaining hydrogen-rich material has been ejected in the form of the planetary shell. The star contracts gravitationally until helium ignites in a shell at the composition discontinuity, and the subsequent evolution of the shell burning has been followed. No neutrino-loss processes have been considered in this investigation.
Magnetic classification of active regions
Authors: Smith Sara F. , Howard Robert
Published: July 2016

All the active regions observed on the Sun with the Mount-Wilson magnetograph between August 1959 and December 1962 have been given magnetic classifications in a system similar to the Mount-Wilson sunspot-classification scheme. The flare productivity of regions classified as unipolar, bipolar, and complex bipolar, as well as regions composed of multiple bipolar components has been studied. It has not been necessary to provide a classification corresponding to the γ class of sunspots. Although the relatively poor angular resolution employed in the magnetograms limits somewhat the accuracy of the data, it is clear that both complex bipolar regions and regions with multiple bipolar components produce more than three times the number of flares than the simple bipolar regions produce. The most flare-productive class of regions is the reversed polarity complex classification.

The statistical relation of the spot magnetic-field classification to the classification of the corresponding plage fields has been studied and found to be poor for these data.

The distribution of the magnetic regions in latitude shows that many of the regions with polarities reversed from the usual orientation are confined to the equatorial zone.
Development of magnetic fields in active regions
Authors: Tandberg-Hanssen E. , Porter C.
Published: July 2016

The magnetograph of the High Altitude Observatory station at Climax has been used to study changes in the longitudinal component of the magnetic field in a number of active regions. For a description of the instrument see Lee, Rust, and Zirin (1965). By securing simultaneous Hα pictures of the regions we compare the magnetic data with the optical appearance of the plages. From such studies we have selected the results of two active regions to present here.
Some patterns in the development of centers of solar activity, 1962–66
Authors: Dodson Helen W. , Hedeman E. Ruth
Published: July 2016

A graphical representation of the 66 solar rotations (Carrington) between January 1, 1962 and December 31, 1966 has been prepared. It includes all centers of activity for which the calcium plage attained an area of at least 1000 millionths of the solar hemisphere and/or intensity 3 (McMath scale). In this study the antecedents, descendents, and neighbors of each region can easily be discerned. The work shows clearly that zones of activity, apparently closely related and much larger than single plages existed for long intervals of time. For example, the significant increases in solar activity in February, May, and October of 1965 occurred in a ‘family’ of calcium plages apparently related through similarities of position and strong radio emission.

The members of ‘families’ of centers of activity are found at systematically changing longitudes. For some ‘families’ the change of longitude appears to be primarily a consequence of differential rotation; for others, the pattern of formation of active centers dominates.

According to the data for 1962–66 a meaningful study of the development of a center of activity may require consideration not only of the past history of the zone of the Sun in which it occurs but also of the zone approximately 180° away on the opposite hemisphere.
On some properties of the velocity field in a developed active region
Authors: Gopasyuk S. I.
Published: July 2016

Thirty-eight series of photoelectric recordings of radial velocities in a developed active region have been studied. The recordings were made in the Fei line γ 5250 Å from September 2–7, 1961, when the active region passed across the solar disk from E 30° to W 42°.
Oscillatory convection in strong magnetic fields and origin of active regions
Authors: Syrovatsky S. I. , Zhugzhda Y. D.
Published: July 2016

The convection in a compressible inhomogeneous conducting fluid in the presence of a vertical uniform magnetic field has been studied. It is shown that a new mode of oscillatory convection occurs, which exists in arbitrarily strong magnetic fields. The convective cells are stretched along the magnetic field, their horizontal dimensions are determined by radiative cooling. Criteria for convective instability in a polytropic atmosphere are obtained for various boundary conditions in the case when the Alfvén velocity is higher compared with the velocity of sound.

The role of oscillatory convection in the origin of sunspots and active regions is discussed.
Concerning the development of the Evershed motion in sunspots
Authors: Altschuler Martin D. , Nakagawa Yoshinari , Lilliequist Carl G.
Published: July 2016

The non-linear, partial differential equations of magnetohydrodynamics are iterated simultaneously by computer to determine the time development of a single sunspot. Axisymmetry and incompressibility are assumed. The initial conditions are (1) zero velocity everywhere, and (2) the magnetic-field distribution of a ring current embedded in the photosphere. The initial magnetic field is then allowed to relax by magnetic diffusion and by the creation of a velocity field. It is shown that (1) Evershed motion outward from the sunspot will develop from reasonable initial parameters, and (2) the growth rate of the magnetic configuration depends on the strength of the initial magnetic field.
Fluctuations of the magnetic-field strength of sunspots within one day
Authors: Künzel H.
Published: July 2016

In the period of May-June 1965, the magnetic-field strengths of twenty sunspots were measured in order to investigate fluctuations within one day. The results of spectrograms, which were taken in the interval of one hour, are given in graphs. The mean error of one value has the size of ± 169 gauss. The graphs show the general tendency in the behaviour of field strength. Fluctuations of magnetic-field strength up to 800 gauss within a few hours were found. The short-time fluctuations shown in the graphs are mostly smaller than the mean error and therefore probably not real.

For more details see Astron. Nachr., 289 (1967), 233.
On the structure of the magnetic field of sunspots
Authors: Mogilevsky E. I. , Demkina L. B. , Ioshpa B. A. , Obridko V. N.
Published: July 2016

The model of the magnetic field of sunspots, taking account of fine structure of magnetic field in solar plasma, is considered. Small-scale subgranules with their own field form magnetic filaments in the external current-free field. The filaments are vertical in the umbra, while in the penumbra they run along the surface with sharp bends. In a number of spot umbra the relation between Doppler velocity and the field is established on polarized spectrograms. The π-component splitting in umbra is interpreted as a result of a weak background magnetic-field existence together with a large field of magnetic filaments. Spectrographic definition of the magnetic field in spot umbra is accomplished on the effect of magnetic-lines intensification and directly on spectrograms of low-excitation (Fe I, Ti I) and high-excitation (Fe II) lines. Magnetic field measured in low-excitation lines exceeds twice the field value obtained in high-excitation lines. This result has been considered in the light of the proposed model of sunspot field.
The formation, structure and changes in filaments in active regions
Authors: Smith Sara F.
Published: July 2016

During periods of good image quality the large-scale films of the Lockheed Solar Observatory obtained during 1966 and 1967 have proven to be especially useful for studying filaments and their relationship to the Hα fine structure observed in active regions. Structures with dimensions on the order of 1 sec of arc can frequently be resolved, as illustrated in Figure 1. The ‘solar vortices’ are clearly resolved into numerous individual fibrils. Bright Hα plage is resolved into a fine granular structure resembling the solar granulation. Filaments are usually seen as irregular dense collections of material which are occasionally resolved into finer striations which run parallel to the path of the filaments.
Bright points (moustaches) and arch filaments in young active regions
Authors: Bruzek A.
Published: July 2016

A brief survey is given on the main characteristics of ‘bright points’ and of arch filaments in young bipolar spotgroups. Observations show that both features are closely associated, thus indicating that they have a common cause. It is suggested that the propagation of expanding and increasing active-region magnetic fields through the chromosphere might be that cause.
Correlation between Ca plages and longitudinal magnetic fields of the CSSAR active regions
Authors: Bumba V. , Godoli G.
Published: July 2016

The shapes of K2,3,2 Ca plages and longitudinal magnetic fields are compared for CSSAR active regions during their first transit on the solar disk.

The bipolar magnetic regions follow the Hale polarity law.

Often the region of inversion of the magnetic field corresponds to a gap in the Ca plage structure.

Bright patches of plages may coincide with magnetic inclusions, magnetic hills, and occasionally also with regions of inversion of the magnetic field. The outline of Ca plages follow well the isogauss of 20–40 oersted.

Histograms of the distances of individual magnetic field intensity peaks do not only correspond to the geometry of the supergranular network but also seem to indicate a difference in the organization of these peaks between the leading and following polarities.
Extreme ultraviolet observations of active regions in the solar corona
Authors: Burton W. M.
Published: July 2016

The coronal features associated with solar active regions can be observed by recording images of the Sun at extreme ultraviolet (XUV) wavelengths. Pinhole cameras have been flown on stabilized sun-pointing ‘Skylark’ rockets to obtain broad-waveband XUV solar images. These images show localised emission from high-temperature regions located in the corona above calcium-plage areas. An improved design of pinhole camera, which uses a plane-diffraction grating to give increased spectral resolution, has recorded spectroheliograms in several intense solar lines including He II (304 Å), Fe IX–XI (180 Å), and Si X–XII (50 Å). Estimates are made of the size and brightness of the coronal emission region associated with a developing calcium-plage area.
The high-energy flare plasma
Authors: De Jager C.
Published: July 2016

A solar flare has various aspects: the optical flare is often associated with emissions in the microwave or X-ray regions: this indicates the occurrence of a highly excited plasma, which we call the high-energy flare plasma. The existence of the high-energy flare plasma was first shown by radio observations in the microwave regions (Hachenberg) and later confirmed by X-ray observations in the energy range 102–106 eV.
Flare-produced coronal waves
Authors: Meyer Friedrich
Published: July 2016

We present a coronal propagation model for fast chromospheric disturbances following flares that were first observed by Moreton and Ramsey, and deduce estimates of average coronal magnetic fields (6 gauss) and disturbance energies (≤ 1029 erg).
The observation of 10–50 KeV solar flare X-rays by the OGO satellites and their correlation with solar radio and energetic particle emission
Authors: Arnoldy R. L. , Kane S. R. , Winckler J. R.
Published: July 2016

More than 70 cases have been observed of energetic solar flare X-ray bursts by large ionization chambers on the OGO satellites in space. The ionization chambers have an energy range between 10 and 50 KeV for X-rays and are also sensitive to solar protons and electrons. A study has been made of the X-ray microwave relationship, and it is found that the total energy released in the form of X-rays between 10 and 50 KeV is approximately proportional to the peak or total energy simultaneously released in the form of microwave emission. For a given burst the rise time, decay time and total duration are similar for the 10–50 KeV X-rays and the 3 to 10 cm radio emission. Roughly exponential decay phases are observed for both emissions with time constants between 1 and 10 min. All 3 or 10 cm radio bursts with peak intensity greater than 80 solar flux units are accompanied by an X-ray burst greater than 3 × 10−7 ergs cm−2 sec−1 peak intensity. The probability of detecting such X-ray events is low unless the radio spectrum extends into the centimetric range of wavelengths. The best correlation between cm-λ and energetic X-rays is observed for the first event in a flare. Subsequent structure and second bursts may not correspond even when the radio emission is rich in the microwave component. The mechanism for the energetic X-rays is shown to be bremsstrahlung probably of fast electrons on a cooler plasma. If the radio emission is assumed to be synchrotron radiation then a relationship is developed between density and magnetic field which meets the observed quantitative results. One finds, on the average, that 5 × 10−54 joules m−2 (CPS)−1 of microwave energy at the Earth are required per electron at the Sun to provide the radio emission for the various events.

A strong correlation between interplanetary solar flare electrons observed by satellite and X-ray bursts is shown to exist. This correlation is weak for solar proton events. One may infer a strong propagation asymmetry for solar flare electrons along the spiral interplanetary magnetic field.
Tendencies to repeating of type-IVm bursts and their relations to the stage of development of the sunspot group
Authors: Böhme A.
Published: July 2016

It has been shown that moving type-IV bursts at decameter waves are infrequent events compared with the moving type-IV bursts at meter waves. They belong preferably to sunspot groups of relatively homogeneous magnetic structure. Moving type-IV bursts at decameter waves have a very low tendency to repeat. This statement indicates that the magnetic structures producing them have only a short lifetime. The short duration of these bursts cannot be interpreted by radiation damping of high energetic electrons. Furthermore it can be shown that the storm continuum at decameter waves is related preferably to sunspot groups of complex magnetic structure. Probably stationary type-IV bursts at decameter waves are more representative for the acceleration of high-energetic particles than the moving type-IV bursts at decameter waves.
Some properties of the sources of slowly varying component and of bursts at 612 Mc/s
Authors: Swarup G. , Kundu M. R. , Kapahi V. K. , Isloor J. D.
Published: July 2016

A high-resolution 24-element, E–W interferometer situated at Kalyan near Bombay has been used to study the sources of slowly varying component and of bursts at a frequency of 612 Mc/s. This interferometer has a half-power beamwidth of 2·8 min of arc, and the fan beams are located about a degree apart in the sky. Thus, a strip scan is obtained roughly every 4 min as the Sun drifts through the beams. About 20 slowly varying sources and 11 bursts were observed during the period June 1965 to February 1967 at 612 Mc/s.
The effect of compression and expansion of plasma on the generation of synchrotron radiation
Authors: Gopasyuk S. J. , Erushev N. N. , Neshpor Y. I.
Published: July 2016

We consider the variation of the synchrotron-flux density of relativistic electrons with the power law spectrum when the region of generation of this emission initially experiences a homogeneous compression and then an expansion. Ionization losses have been taken into account. The velocities of compression and expansion have been taken as constant. It is shown that in the cases of compression or expansion the flux density at a given frequency changes as

S(t) ~ S0Kγ(t)

where S0 = flux density before the compression, γ = index of the power law spectrum, K(t) = (H(t))/(H0 (t = 0)), and H is the magnetic-field strength. In the case of compression K(t) > 1·0 and in the case of expansion K(t)< 1·0.

The results obtained are applied to an explanation of the increasing and decreasing parts of impulsive bursts of the centimeter range. Such a description of the impulsive bursts has allowed us to estimate both the parameters of the radiating region and the parameters of the differential energetic spectrum of relativistic electrons.
The great burst of May 23, 1967
Authors: Castelli John P. , Aarons Jules , Michael Glen A.
Published: July 2016

One of the largest radio bursts on record took place on May 23, 1967. Peak flux densities ranged between 23000 flux units (10−22 wm−2 Hz−1) at 8800 MHz to about 370000 units at 606 MHz. In addition to the high-accuracy measurements of the peak flux densities at 606, 1415, 2695, 4995, and 8800 MHz, sweep frequency observations from 19–39 MHz show Type-IV emission with Type-II bursts occurring during the Type-IV continuum. The associated flare was clearly visible in white light. In reviewing and compiling microwave-radio data recorded during earlier white-light flares, it was found that all but one of eight events listed by Svestka (1966) had high microwave flux densities associated with them. In comparing radio-burst intensity with optical flare importance for the series of three flares between 1809 and 2150 UT on May 23, there is only moderate agreement. The first radio burst was small; the third was by far the largest, while the second flare had the highest optical classification. The flux densities of the third burst may have been the highest ever recorded in the decimeter portion of the radio spectrum and amongst the largest four in the 8800 MHz region. It is suggested that the details of the development of the flare might be followed on radio flux-density plots to determine detailed correlation with particle events in space and with terrestrial effects.
Measurements of Magnetic Fields
Authors: Semel M.
Published: July 2016

It is demonstrated that certain interrelations between the Stokes parameters are much less dependent on line formation than generally expected. Thus the dependence of these parameters on the magnetic field may be made more explicit and may lead to reliable calibration of polarimetric measurements in terms of magnetic field.
A Pressure Scanning Fabry-Perot Magnetometer
Authors: Fay T. D. , Wyller A. A.
Published: July 2016

An oscillating magnetic analyzer (KDP crystal plus Glan-Thompson prism) is coupled to an echelle-interferometer spectrograph. The single slit magnetometer by pressure variations can be made to scan the entire profiles of the circularly and linearly polarized Zeeman components. Freon gas is used as the scanner gas with wavelength displacements of 0.02 Å per 0.1 in. Hg pressure change at the NaD lines. The available scan range is 15 Å in the visual spectral region.
Reduction of the Parasitical Signal of Circular Polarization on an Antenna of Variable Profile With the Help of a Grating
Authors: Esepkina N. A. , Petrunkin V. Y. , Soboleva N. S. , Timofeeva G. M. , Reiner A. V.
Published: July 2016

A method of reducing circular parasitical polarization in the antennas of variable profile with the help of a grating of curved wires is reported. The experimental verification of the method shows that the parasitical signal practically vanishes. It was established that using this method, simultaneous observations at three or even five wavelengths can be made.
Photoelectric Measurements of Sunspot Magnetic Fields
Authors: Deubner F.-L. , Göhring R.
Published: July 2016

Photoelectric polarization measurements in a stable sunspot (type H) with a particularly dark umbra, where ‘umbral dots’ were virtually lacking, have been carried out with the Capri magnetograph. The measurements were evaluated in terms of Unno's theory to give the value and direction of the magnetic field vector. The parameters η0 = 5, β0 = 2.5 and ΔλD = 40mÅ have been adopted for the Fe I 5250 line. Taking the configuration of the sunspot into account as well as simple conditions of steadiness of the distributions to be obtained, it is possible to derive the magnetic vector field from two-dimensional records of circular and linear polarization without ambiguities.
On the Structure of Magnetic Field and Electric Currents of a Unipolar Sunspot
Authors: Kotov V. A.
Published: July 2016

This talk deals with the spatial distribution of the total magnetic vector H and of electric currents in the big unipolar sunspot of October 17, 1966.
The Magnetic Fields at Different Levels in the Active Regions of the Solar Atmosphere
Authors: Tsap T. T.
Published: July 2016

The strengths of the longitudinal magnetic fields recorded at different depths of active regions with a double magnetograph of the Crimean Astrophysical Observatory are compared.

The recordings of the magnetic fields were made in the lines Fe Iλ5250Å, Ca Iλ6103Å, Na I D1, BIIλ4554Å, Mg Iλ5184Å, Hα, Hγ, Hδ.

It is shown, that there is a close correlation between the longitudinal magnetic field at different levels.
On the Circular Polarization in Active Regions
Authors: Wiehr E.
Published: July 2016

Advantages of ‘circular polarimetry’ (determination of the Stokes parameter V) in active regions as compared to ‘elliptical polarimetry’ (determination of all Stokes parameters) are discussed:

(1)

Complicated and doubtful reduction procedures by means of line formation theory generally are needed for ‘elliptical polarimetry’. This is not the case for ‘circular polarimetry’.

(2)

Even if the difficulties (1) could be removed, ‘elliptical polarimetry’ would not help to determine the total magnetic vector outside the disc center. This is due to the fact that the azimuth φ of the linear polarization is only defined for 0° ⩽ φ < 180°. When converting the measured inclination Ψ to the line-of-sight into the true inclination γ to the solar surface normal for active regions outside the disc center, the ambiguity of φ always yields an ambiguity of γ. The normal field component and thus the flux can therefore not be determined without making an important assumption on the unknown field structure (see Wiehr, 1970a).

(3)

For active regions near the disc center, however, where the difficulty (2) disappears, ‘circular polarimetry’ is sufficient for the determination of the normal field component and flux. It furthermore avoids the difficulty (1).
Evolution of the Magnetic Field Configuration in an Active Region
Authors: Schatz Dennis L.
Published: July 2016

Described and discussed is the evolution of the magnetic field configuration in an Active Region from observations made with high time resolution.
Electric Currents Connected With the Proton Flares of 7 July and 2 September, 1966
Authors: Severny A. B.
Published: July 2016

It is observed that the change of the net magnetic flux associated with flares can exceed 1017 Mx/s, which corresponds according to Maxwell's equation to the e.m.f. ∼ 109 V which is specific for the high energy protons generated in flares. It is shown that this value of e.m.f. can hardly be compensated by e.m.f. of inductance which should appear due to the actually measured motions in a flare generating active region. The values of electric field strength thus found, together with measured values of electric current density (from rotH), leads to an electric conductivity which is 103 times smaller than usually adopted.
Observations of Magnetic Field Changes in Active Regions
Authors: Harvey K. L. , Livingston W. C. , Harvey J. W. , Slaughter C. D.
Published: July 2016

A time sequence of longitudinal magnetograms of two active regions, McMath Regions 9281 and 9760, have indicated magnetic field changes occurring in localized areas with time scales of the order of hours. We believe the observed field changes are evolutionary in nature, rather than related to the occurrence of small flares. Three examples of evolutionary magnetic changes are discussed.