bluuebunny/crossref_metadata_2025 huggingface dataset:
Stability of amorphous circumstellar silicate grains
Authors: Henning Th. , Svatoš J.
Published: July 2007

Berechnungen innerhalb der klassischen Nukleationstheorie zeigen, daß Mg2SiO4‐Staubteilchen mit Radien von etwa 0,1 μm, die sich mit hoher Wahrscheinlichkeit im zirkumstellaren Raum um Sterne späten Spektraltyps bilden, bei etwa 750 K auskondensieren müssen, um amorph zu bleiben. Beträgt die Kondensationstemperatur 1000 K, müssen die neugebildeten Teilchen kleiner als 0,01 μm sein, wenn sie während der Abkühlung amorph bleiben sollchen. MgSiO3‐Teilchen mit Radien kleiner als 1 μm sind bei Tcond ≤ 1000 K gegenüber der Kristallisation stabil.
Verwendbarkeit des Prismas auf der Korrektionsplatte des Tautenburger Schmidt‐Spiegels bei Positionsbestimmungen
Authors: Hirte S. , Schilbach E.
Published: July 2007

To overcome a possible magnitude equation a weakly refracting prism fitted on the correcting plate of the Tautenburg Schmidt telescope was used, forming a secondary image of every object 3.8 mag weaker than the primary one. Because the distances between these two images are not constant, a polynomial was searched which could reflect these variation in dependence on the magnitude of a star and its position on the plate. For each of the 11 plates tested we have got another polynomial, therefore this way to tide over large magnitude differences is unefficient for astrometric investigations.
Bestimmung der Helligkeitsgleichung auf Tautenburger Schmidt‐Platten
Authors: Schilbach E.
Published: July 2007

Aus Messungen von 3 Plattenpaaren, die mit dem Tautenburger Schmidt‐Teleskop im B‐System aufgenommen wurden, wurden die Koeffizienten dx und dy des Reduktionsmodells in Abhängigkeit von der Sternhelligkeit abgeleitet. Die Analyse der Ergebnisse zeigt, daß bei der Bestimmung von Eigenbewegungen von Sternen mit Helligkeitsunterschieden von mehr als 6‐‐7 mag in bezug auf die Refrenzpunkte systematische Fehler auftreten können, die größer als die Meßfehler sind. Diese Fehler entstehen auf Grund der Helligkeitsgleichung und variieren von Plattenpaar zu Plattenpaar.
Compilation of clusters of galaxies with published redshifts
Authors: Schmidt K.‐H.
Published: July 2007

The spectroscopic measured redshifts of 863 clusters of galaxies have been compiled from literature.
Investigations of spherical kinematic mean‐field dynamo models
Authors: Rädler K.‐H.
Published: July 2007

The paper supplements an earlier one on the mean‐field approach to spherical kinematic dynamo models (Rädler1980a) by results of numerical investigations.

A number of dynamo models working on the basis of the α2‐mechanism are considered. Cases of pure α2‐mechanism are studied, which includes only the simplest form of α‐effect and no other induction effect, as well as cases with several additional effects due to fluctuating or mean motions. By the pure α2‐mechanism axisymmetric and non‐axisymmetric fields, can be excited and maintained with nearly equal ease. Part of the additional induction effects, however, clearly favour axisymmetric fields, and others non‐axisymmetric fields. The non‐axisymmetric fields are waves which travel in azimuthal direction, eastward or westward, depending on the models.

For special dynamo models the transition from α2to αω‐mechanism and properties of the latter are investigated. The results support the presumption that the αω‐mechanism is able to maintain only axisymmetric but never non‐axisymmetric fields. Conditions for the occurrence of non‐oscillatory or oscillatory fields are discussed, and again the influence of additional induction effects is studied.

There are further presented a model with βω‐mechanism maintaining an axisymmetric non‐oscillatory field, and models with two kinds of δω‐mechanisms allowing axisymmetric non‐oscillatory and oscillatory fields.

Some ideas concerning dynamo models for the Earth, the Sun and magnetic stars are discussed.

It seems possible to construct dynamo models for the Earth, on the basis of the α2‐mechanism which explain not only the presence of a magnetic field with a strong dipole part but also the inclination of the dipole axis against the axis of rotation, the occurrence of higher multipoles and the westward drift of the non‐axisymmetric parts. Models with αω, βω or δω‐mechanism, which have to be considered in the case of a strong differential rotation inside the core, provide an explanation at first only of the axisymmetric parts of the field, and the non‐axisymmetric parts have then to be interpreted, for example, as MAC‐waves.

As far as dynamo models for the Sun are concerned, in addition to the possibility of an αω‐mechanism also that of a βω or δω‐mechanism is discussed, which, however, does not look not very promising. In the models developed so far, which work with the αω‐mechanism, only a few of the induction effects of fluctuating motions have been included; it seems necessary to investigate also influences of other effects. The sectorial structure of the solar magnetic field can hardly be understood in terms of the traditional mean‐field concept.

The magnetic stars possess fields which strongly deviate from symmetry with respect to the axis of rotation. The occurrence of such fields seems understandable only if there is no noticeable differential rotation. They can be maintained by an α2‐mechanism but hardly by αω, βω or δω‐mechanisms.
Mass loss from very young massive stars (Mitteilungen der Universitäts‐Sternwarte zu Jena Nr. 172)
Authors: Henning Th.
Published: July 2007

A very important property of very young and massive stars (BN objects) is their intensive mass loss. We describe the main methods to derive the mass loss rates. Available observations are used to characterize the ionized stellar winds and the CO flows. The results are confronted with theories describing the anisotropic mass loss.
Empirical properties of nearby groups of galaxies
Authors: Vennik J.
Published: July 2007

Virial parameters of individual groups and of synthesized groups of galaxies are determined on the basis of a new list of nearby groups of galaxies (V0 < 3200 km/s). Small values of the crossing time ({TcrosH0} ≈ 0.2) allow us to consider the groups of being gravitationally bound systems. The cumulative mass of the synthesized groups increases up to ∼1 Mpc from the center, giving the total mass‐to‐luminosity ratio f = 97 f⊙ (H0 = 75 km/s/Mpc). Statistically significant correlations between virial parameters (σv, RVT, f) are found: f ∝ σv1.5 and f ∝ RVT0.7; σv and RVT are uncorrelated.
Zur Abschätzung der Zyklenlänge bei langzyklischen U‐Geminorum‐Sternen
Authors: Wenzel W. , Richter G. A.
Published: July 2007

Verschiedene Methoden zur Ermittlung mittlerer Zyklenlängen werden beschrieben, und der Einflß von Beobachtungslücken wird diskutiert. Am Beispiel von SW UMa werden statistische Aussagen und direktere Bestimmungen verglichen; die übereinstimmung ist nicht schlecht.
The influence of velocity fields on the formation of spectral lines in stellar atmospheres ‐‐ correlations of the Voigt function
Authors: Stahlberg J.
Published: July 2007

A method is developed to take into account the influence of velocity fields with finite correlation length via a Voigt function on the line formation process.
Vacuum polarization and scalar field effects in the early Universe
Authors: Gottlöber S. , Müller V.
Published: July 2007

Homogeneous isotropic cosmological models driven at early times by a coherent scalar field and the vacuum polarization are considered. Both effects can lead to the existence of a finite minimal value of the scale factor and an inflationary stage of expansion. The early as well as the late time behaviour of the cosmological evolution depends critically on the ratio of the contribution from the vacuum polarization and the scalar field.
Extraterrestrial possibilities to measure cosmic antimatter
Authors: Halm I.
Published: July 2007

The question of the existence of primary cosmic antimatter (PCA) is of fundamental interest for cosmogony and cosmology. The relcvance of PCA to processes in the very early Universe (corresponding to an energy of 1015 GeV) is shown. A satellite experiment consisting of a magnet spectrometer is proposed, which identifies antiprotons (p̄), antihelium nuclei (α), and positrons (e+) in the kinetic energy range from 100 MeV to 10 GeV to get statistically significant p̄‐ and e+‐spectra and possibily some α events in a year of exposure.
Generalized harmonic gauge conditions in General Relativity as field equations for lapse and shift
Authors: Hirschmann T. , Schimming R.
Published: July 2007

The prescription of the harmonicity quantities to a spacetime metric may be read, in the ADM decomposition, as a system of evolution equations. Cauchy's initial value problem for this system is investigated here. Additionally, the differential‐geometric substance behind the ADM scheme is analysed.
Influence of time dependent gravitational fields on superconducting oscillatory circuits
Authors: Salié N.
Published: July 2007

For oscillatory circuits consisting of superconducting material in a time dependent weak gravitational field a differential equation of third order for the total current is derived on the basis of the general relativistic two component theory.
The Newtonian limit of fourth‐order gravity
Authors: Schmidt H.‐J.
Published: July 2007

The weak‐field slow‐motion limit of fourth‐order gravity will be discussed.
Cometary dust coma models. I. Analytic calculations
Authors: Gottlöber S. , Liebscher D.‐E. , Mücket J. P. , Müller V.
Published: July 2007

The dust coma of comets is calculated within the fountain model of isotropically ejected particles. A method to estimate the particle size distribution is proposed.
Oscillatory α2‐dynamo: numerical investigation
Authors: Baryshnikova Y. , Shukurov A.
Published: July 2007

Linear and nonlinear equations describing the generation of a large‐scale magnetic field (α2‐dynamo) in a thin disc of turbulent conducting fluid are derived and discussed. The numerical procedure is based on a finite‐difference implicit scheme for the corresponding nonlinear Cauchy problem with boundary conditions. In addition, the QR‐algorithm for the linear eigenvalue problem is realized.

It is demonstrated that the α2‐dynamo is able to generate oscillatory magnetic fields. The periods of oscillation are typically of the order of or less than the diffusion time. These oscillations are suggested to be due to boundary effects. Dependence of the solutions on the generation efficiency and on the distribution of the mean helicity across the disc are discussed in detail.

The period of oscillations only slightly depends on the specific form of distribution of the mean helicity across the disc and is determined mainly by the magnitude of the helicity and by the position of the helicity extremum: the nearer this point to the boundary, the greater the oscillation frequency. Nonlinear effects suppress oscillations when the mean helicity attains its maximum at a depth not more than a quarter of the disc thickness, and promote them otherweise.

The one‐dimensional system of nonlinear α2‐dynamo equations is reduced to a single nonlinear equation of the Schrödinger type.
On the oscillatory behaviour of kinematic mean‐field dynamos
Authors: Rädler K.‐H. , Bräuer H.‐J.
Published: July 2007

The paper considers the question after the circumstances in which kinematic mean‐field dynamos can have oscillatory magnetic field modes. The conducting fluid body is allowed to be of almost arbitrary shape; its surroundings are vacuum. A general relation for the frequency of oscillation is derived. This relation is discussed more closely for models with pure α2‐mechanism. Proof is given that no oscillations can occur for constant α. The investigations published so far on spherical models with pure α2‐mechanism call up the question whether there is a chance for axisymmetric modes to be oscillatory. For both spherical models and disk models the possibility of oscillatory axisymmetric modes is demonstrated by examples.
Combined UBV and uvby photometry of open clusters. I. NGC 1502
Authors: Reimann H.‐G. , Pfau W.
Published: July 2007

For at all 24 stars in the field of the heavity reddened open cluster NGC 1502 we obtained UBV and uvby photometry. 19 of these stars we classified definitely as members. From the photometric results we derived 1·1 × 107 years as the cluster age, 960 pc as its distance, and  = 0·78 mag as mean reddening of the cluster. From the reddening of the foreground stars we evaluated that the intracluster reddening has to be smaller than 0·2 mag. The value of the colour excess ratio E(b—y)/E(B—V) = 0·770 leads us to the conclusion that in the spectra of the cluster stars a very broadband structure (VBS) with a central depth of about 0·04 mag is present.
The influence of the electromagnetic core‐mantle coupling torques on earth's rotation
Authors: Greiner‐Mai H.
Published: July 2007

The electromagnetic core‐mantle coupling is one of the most likely hypotheses to explain the connections between both, the decade fluctuations of the Earth rotation and such of the magnetic field of the Earth. Within this paper, the axial and equatorial electromagnetic torques are computed at time intervals of two years from 1903.5 to 1975.5. They are compared with mechanical torques necessary for the excitation of the decade variations of the rotation of the Earth. The comparison is made with regard to the magnitude of the torques, to their time behaviour and to the periods within the time variations of both types of the torques. The computed electromagnetic torques are comparable with that necessary to excite the variations of the rotation of the Earth. But they are two or three orders less than that necessary to excite the decade variations of the polar motion. Some comparable periods were found within the spectra of the electromagnetic and the mechanical torques. This speaks in favour of the core‐mantle coupling. But there are differences between both spectra too hinting at other processes which we cannot describe by a simple model of the core‐mantle coupling.
A search for lunar sodium
Authors: Graham F. G.
Published: July 2007

A search of the Moon for traces of sodium vapor similar to that found on Mercury was made with a multiprism spectroscope. The results were negative.
Photoelectric photometry of comets in the system of standard IHW filters and the special case of comet P/Halley
Authors: Stecklum B. , Pfau W. , Hesse M.
Published: July 2007

Magnitudes of comets P/Giacobini‐Zinner (1984e), P/Halley (1982i), P/Hartley‐Good (1985 1), and Thiele (1985 m) in the bandpasses of the standard IHW comet filters are presented. For comet P/Halley production rates for CN, C3, C2, and solids were derived. For the gaseous components these show a strong dependence on heliocentric distance. The dependence is less steep for the solids which may be due to relatively pronounced backscattering properties in case of comet P/Halley. During one night (1985 Dec. 22/23) intensity profiles along three sections through the coma of comet P/Halley were measured. Compared with theoretical profiles they show a global anisotropy of the coma and possibly local structure.
Mesures micrometriques d'etoiles doubles visuelles (3me liste)
Authors: Scardia M.
Published: July 2007

The results of 521 micrometric measurements of 140 binary stars are given. The measurements have been made at Brera‐Merate and Collurania (Teramo) observatories during the period February 1984‐December 1985 with two refractors of 23 cm and 40 cm, respectively.
Binary star statistics: the mass ratio distribution for very wide systems
Authors: Trimble V.
Published: July 2007

The distribution of mass ratios for a sample of common proper motion (CPM) binaries is determined and compared with that of 798 visual binaries (VB's) studied earlier, in hopes of answering the question: Can the member stars of these systems have been drawn at random from the normal initial mass function for single stars? The observed distributions peak strongly toward q = 1·0 for both kinds of systems, but less strongly for the CPM's than for the VB's. Due allowance having been made for assorted observational selection effects, it seems quite probable that the CPM's represent the observed part of a population drawn at random from the normal IMF, while the VB's are much more difficult to interpret that way and could, perhaps, result from a formation mechanism that somewhat favors systems with roughly equal components.
Isotropization by scalar field driven inflation and the cosmological quantum boundary
Authors: Lukash V. N. , Schmidt H.‐J.
Published: July 2007

We derive the Wheeler‐de Witt equation for the scalar field of mass m > 0 in a Bianchi‐type I universe. We argue that classical trajectories become possible at h2 ⩽ αtp‐2, h being the mean Hubble value and tp the Planck time. We feel justified to set the numerical constant α ≈︁ 1. We discuss this condition in geometrically invariant quantities and compare it with ⩽tp‐4. The proposed quantum boundary of classical trajectories represents a 3‐dimensional sphere in the 4‐space of the dynamical system. Equipartition of the initial energy over field (m < mp) and shear variables at the quantum boundary will cause inflation with a probability p of the order p = 1 ‐ m/mp thus, p = 1 ‐ 10‐4 for m taken from GUT. In the course of the inflationary stage the initially arbitrarily large shear‐anisotropy exponentially decays.
MV Lyrae: Entering the period gap?
Authors: Andronov I. L. , Fuhrmann B. , Wenzel W.
Published: July 2007

MV Lyrae was studied on about 2000 photographic plates of the Moscow, Odessa and Sonneberg collections. A brief review of these results in comparison with literature data is given. The object might be a unique system, entering the period gap. Outbursts are observed in the minimum state, which may be possibly explained by the trigger mechanism for the radiation‐induced mass outflow from the secondary, underfilling its Roche lobe.
Model calculations of the degree of polarization of solar S‐coniponent emission at millimetre waves
Authors: KrÜger A. , Hildebrandt J.
Published: July 2007

Model calculations of the S‐component accounting for the emission from uniform sunspot and inhomogeneous plage regions are applied to a prediction of the spectral distribution of the degree of circular polarization at millimetre waves. The results are compared with observations adopted from the literature and a sufficient agreement between model computation and measurement can be slated. However, observations with higher spatial resolution than presently available are needed in order to check the predicted fine structures and to verify details of the applied model.
Beobachtungen Kleiner Planeten. VII
Authors: BÖrngen F.
Published: July 2007

Es wird eine Übersicht über die im Jahr 1986 auf Tautenburger Schmidtplatten gefundenen Kleinen Planeten gegeben. Es wurden 129 Objekte entdeckt und für sie 312 Positionen gerechnet. Es handelt sich um 29 numenerte Objekte und 100 Planetoiden mit provisorischer Bezeichnung, von denen sechs keine neue Bezeichnung haben. Für fünf im Berichtszeitraum numerierte Planeten haben Tautenburger Beobachtungen einen Beitrag geleistet. Darunter ist der in Tautenburg entdeckte Planetoid 1981 VW1, der die Nummer (3499) und den Namen Hoppe erhielt.
Investigation of clusters of galaxies II. A two colour photometry for the cluster Abell 1795
Authors: Baier F. W. , Ziener R.
Published: July 2007

A photographic photometry in B and V was performed for the cD cluster of galaxies A 1795 which is located near the north galactic pole. Our catalogue contains 721 galaxies in a field of 1.6 ° around the cluster center.
Analysis of the light curve of the magnetic CP star HD 56022
Authors: Hempelmann A. , Sch;Öneich W.
Published: July 2007

An examination of the published observational data concerning the light curves of magnetic CP stars has shown that only one star — HD 56022 — shows a light curve with a very long phase interval of light constancy. Only for this type of variability it is imaginable that the equatorial symmetry of the surface brightness distribution could be excluded. However, the analysis of the light curve of HD 56022 in the colour u of the Strömgren system has indicated that the possibly equatorial position of the small bright spot is not in contradiction to this observed curve.

From the analysis in u the maximum amplitude of a light curve at another wavelength, where the curve is in counterphase to the light curve in u, can be predicted. The amplitude of such a light curve must be much smaller than 0.1 mag. From unpublished observations of HD 56022 by the satellites TD‐1 A and ANS we have determined the amplitude at $LD = 155 nm, where the light curve is in counterphase to that in u, to be 0.2 mag.

The consequences from the contradiction between the model and the observations in UV are discussed.
Radiation pressure — a stabilizing agent of dust clouds in comets?
Authors: Fr$Ouhlich H.‐E. , Notni P.
Published: July 2007

The internal dynamics of an illuminated dust cloud of finite optical thickness is investigated. The dependence of the radiation pressure on the optical depth makes the individual particles oscillate, in one dimension, around the accelerated centre of gravity of the cloud. The cloud moves as an entity, irrespectively of the velocity dispersion of the particles and their efficiency for radiation pressure. If the optical depth does not change, i.e. if the cloud does not expand laterally, its lifetime is unlimited. A contraction caused by energy dissipation in mechanical collissions between the dust particles is expected.

The range of particle sizes which can be transported by such a “coherent cloud” is estimated, as well as the acceleration of the whole cloud. The structure of the cloud in real space and in velocity space is investigated. A comparison with the “striae” observed in the dust tails of great comets shows that the parent clouds of these striae may have been of the kind considered.
Runaway instabilities in geometrically thin accretion disks around Kerr black holes
Authors: Elstner D. , Paul H. G.
Published: July 2007

The stability of the innermost disk region orbiting a Kerr black hole is investigated for geometrically thin accretion disks. The infalling matter transports mass and angular momentum into the Kerr hole. This affects the inner disk boundary and leads to runaway instabilities in some cases.
Laws of motion for interacting Yang‐Mills particles
Authors: Fuchs H.
Published: July 2007

Our recent Lagrangian approach to the equations of motion for test particles with internal structure can be enlarged to the laws of motion for interacting particles, at least in principle. As an example we consider the interaction of point particles endowed with a pole‐dipole structure of the non‐abelian charge.
Alternative theories of gravitation in the framework of Riemannian geometry
Authors: Goenner H. F. M.
Published: July 2007

In the framework of Riemannian geometry alternative theories of gravitation with field equations differing from Einstein's are discussed. Examples of physically acceptable alternative theories with second, third or fourth‐order field equations and without or with an additional coupling constant are given.
Harmonic maps from spacetimes and their coupling to gravitation
Authors: Schimming R. , Hirschmann T.
Published: July 2007

The paper focusses on harmonic maps f from an m‐dimensional space‐time or Lorentzian manifold into an n‐dimensional properly Riemannian field manifold: the energy‐momenturn tensor of f, the coupling of f to a gravitational field, and the Cauchy problem to the harmonic map equations are studied.
On the universality of initial mass function of open star clusters
Authors: Zakharova P. E.
Published: July 2007

Our photometric investigation of a number of open clusters with age younger than 109 years confirms the hypothesis of the universality of the zero‐age luminosity function of open clusters.
Die Entdeckung eines neuen Asteroiden (1988BJ) vom “Hungaria”‐Typ
Authors: Elst E. W. , Goffin E.
Published: July 2007

Während eines Asteroiden‐Beobachtungsprogramms in Haute Provence (Frankreich) wurde am 22. Januar 1988 ein Asteroid 17. Größe entdeckt (Elst 1988). Weitere Beobachtungen an der Europäischen Südsternwarte (ESO) und eine vorläufige Bahnbestimmung ergaben, daß der Asteroid zur “Hungaria”‐Familie (Resonanzgruppe) gehört.
On the cosmological evolution of the quasar population
Authors: Boller T. H. , Lorenz H. , Afanas'Ev V. L. , Dodonov S. N. , Yu. Terebizh V.
Published: July 2007

Two selected fields (south east of the galaxie M 82 and in SA 57) are completely spectroscopically searched for quasars. The (N — m) relation is enlarged by 0.4 and 1.6 magnitudes with regard to the value determined by KRON and CHIU (1981). Consequences for models of the evolution of the luminosity function are discussed.
A geometric method to determine the distances of galaxies
Authors: Issa I. A.
Published: July 2007

We consider the possibility to use the size distribution function of globular clusters to determine the distance of galaxies.
Properties of the process of massive star formation
Authors: Kravchuk S.G. , Kolesnik I.G.
Published: July 2007

The dynamics of protostellar envelopes around forming massive stars is analysed and the main stages of the process of massive star formation are identified. It is shown that massive stars can be formed in the outer layers of giant molecular cloud cores. Special conditions are necessary for the formation of massive stars.
Possibilities of investigation of interstellar matter by radio recombination lines (Review)
Authors: Sorochenko R.L.
Published: July 2007

Radio recombination lines (RRL) discovered about 25 years ago became a very effective tool for the investigation of interstellar matter (ISM). These lines are unique by the number of transitions and the spectral range observed: from 2 mm to 20 m wavelength. This allows to study the ISM under variety of physical conditions which differ by 7 to 8 orders of magnitude in density and 3 orders of magnitude in temperature.

RRL allow to determine the main physical conditions in HII and HI‐CII regions, to map the galactic distribution of ionized hydrogen, and to obtain the helium abundance of the ISM. Furthermore, the information contained in the RRL allows to estimate the intensity of cosmic rays and to draw conclusions on the galactic evolution.

The physical properties of the RRL and the results obtained by observations of RRLs are reviewed.
Physical processes in the interstellar matter determining parameters of radio recombination lines in meter and decameter ranges
Authors: Bochkarev N.G.
Published: July 2007

We give a review of problems connected with the interpretation of meter and decameter carbon radiolines. The lines are formed inside clumps of molecular clouds in layers with a column density N ≈ 6 · 1021 cm−2. These clumps are very typical structures. The distribution of physical parameters (number density, temperature, etc.) inside the clumps is poorly known. The most difficult and important question is the penetration of subcosmic rays into the clumps. Observations show that the ionization rate is ζ = (1–7) · 10−17 s−1 inside molecular clouds and significantly greater in the diffuse gas. Long‐wave radio recombination lines can probably be used for the analysis of the distribution of subcosmic rays inside molecular clouds. The interpretation is complicated by the influence of low‐temperature dielectron recombination and poorl known variations of carbon depletion in the clumps.
On the problem of H2 formation
Authors: Klose S.
Published: July 2007

In the first part of the paper the framework for theoretical studies of the H2 formation on interstellar grains will be shortly considered. In the second part the chemisorption of a hydrogen atom at a carbon grain will be examined and results of an ab initio perturbational approach are presented.
Three‐dimensional distribution of high‐velocity stars
Authors: Greiner J.
Published: July 2007

Numerical calculations support the conjecture that high velocity stars born in or near the rotating disk are not distributed spherically throughout the galaxy. Instead an empty funnel region forms around the rotation axis of the galaxy, where no stars reside. The funnel appears only for high velocity stars, such as old pulsars. Within about 50 kpc distance from the galactic center the funnel shape is almost not dependent on the existence of a massive corona.
A survey of the peculiar radio emission of the solar behind‐limb event on 16th February 1984
Authors: Chertok I. M. , Fomichev V. V. , Gorgutsa R. V. , Markeev A. K. , Podstrigach T. S. , Aurass H. , Hildebrandt J. , Kliem B. , Krüger A. , Kurths J. , KarlickýA M. , Tlamicha A. , Urbarz H. W. , Zlobec P.
Published: July 2007

Basing on radio measurements from different stations the paper presents a compilation of observations and resultinng questions concerning the interpretation of some remarkable features of the solar behind‐limb event on 16th February 1984. The event was related to a very strong relativistic particle emission. Attention is paid to the related microwave radiation stimulating a discussion of the discrimination between plasma and gyromagnetic radiation being important for plasma diagnostics. Another outstanding feature is the occurrence of a spectacular multi‐band U‐shaped type II burst pattern challenging a discussion of possible higher harmonic plasma radiation.
The massive scalar field in a closed Friedmann universe model — new rigorous results
Authors: Schmidt H.‐J.
Published: July 2007

For the minimally coupled scalar field in Einstein's theory of gravitation we look for the space of solutions within the class of closed Friedmann universe models. We prove D ≥ 1, where D ≥ is the dimension of the set of solutions which can be integrated up to t → ∞ (D > 0 was conjectured by PAGE (1984)). We discuss concepts like “the probability of the appearance of a sufficiently long inflationary phase” and argue that it is primarily a probability measure μ in the space V of solutions (and not in the space of initial conditions) which has to be applied. μ is naturally defined for Bianchi‐type I cosmological models because V is a compact cube. The problems with the closed Friedmann model (which led to controversial claims in the literature) will be shown to originate from the fact that V has a complicated non‐compact non‐Hausdorff Geroch topology: no natural definition of μ can be given.

We conclude: the present state of our universe can be explained by models of the type discussed, but thereby the anthropic principle cannot be fully circumvented.
New solutions in linearized R+R2 gravity
Authors: Teyssandier P.
Published: July 2007

A general method is proposed to solve in the linear approximation the fourth‐order gravitational equations, which stem from Lagrangians \documentclass{article}\pagestyle{empty}\begin{document}$ \text{Q} = 1 ‐ g\left( {R + \frac{1}{2}aR^2 + bR_{av} R^{av} } \right) ‐ x\text{Q}. $\end{document} The metric of a static spherically symmetric body and the metric of a straight infinitely thin cosmic string are given.
Electromagnetism and gravito‐inertial behaviour in Einstein's unified field theory
Authors: Antoci S.
Published: July 2007

Sources are added to the field equations of Einstein's unified field theory and a purely electromagnetic model of matter is proposed, in which all the properties of the material sources ultimately depend on one four‐current. Examples show that between charged matter built in this way electrodynamic interactions only arise when there is true scope for them, i.e., when the previously mentioned current deviates from geodesic flow.
Topological approach to nonlinear models of molecular electronics: Topological solitons, phenomenology, and compactification
Authors: Nikolaenko V. M. , Rambidi N. G.
Published: July 2007

The U(1) × SO(1,1)‐gauge field model of gravitating topological solitons is considered for the physical construction of information logic devices at the molecular level. It is of interest due to stability both from the energetical and the topological point of view. Coupled to the Weinberg‐Salam theory of electroweak interactions, the gravitating solition may be stable in the case of the negative curvature. The case of positive curvature leads to a radius over 10−11 cm.
Magnetic field topology of an active region
Authors: Linke J. , Ioshpa B. A. , Selivanov V. L.
Published: July 2007

The global 3‐dimensional topology of the magnetic field of the weakly flaring active region AR 5420 in the early phase has been estimated using a series of photospheric longitudinal and vector magnetogams together with Hα filtergrams and white‐light images. As a physical model for this task, we have used the assumption ofa force‐free magnetic field character. An arcade‐like structure of the magnetic field has been identified in the preflare phase with an apparent sheared configuration already present in the current‐free field case. This system might have been an important source of generation of a field‐aligned current system for the eruptions that followed. That was, in particular, suggeted by a significant extension of the active region area in the observation period from June 22 to 25, 1984, that resulted in a stronger shear of the detected arcade‐like system. The atmospheric electric currents generated in such a way and the transition triggered by a large‐amplitude perturbation generated by new flux emergences on June 23 at this place together might be the reason of the sequence of flares observed. Despite the changes in the Hα structure, the global force‐free character of the field did not change significantly over the time of observations. The invariance (in the first order) of the force‐free (nearly current‐free) character of the magnetic field is consistent with the occurrence of relatively small flares only.
Fragmentary energy release due to tearing and coalescence in coronal current sheets
Authors: Kliem B.
Published: July 2007

The internal dynamics of current sheets in the solar corona is shown to provide a basis for understanding fragmentary energy release.
On gravitational instability in a multi‐component cosmological medium
Authors: Haubold H.J. , Mathai A.M. , Mücket J.P.
Published: July 2007

The paper presents results for deriving analytic solutions of the non‐relativistic linear perturbation equations, which govern the evolution of inhomogeneities in a homogeneous spatially flat multi‐component cosmological model. The multi‐component dark matter problem is reviewed.
Evolution of a magnetic blob in a helical flow
Authors: Reshetnyak M. , Sokoloff D. , Shukurov A.
Published: July 2007

An intermediate stage of magnetic field evolution in kinematic dynamo systems, during which the growing field does not coincide with the leading eigensolution, can be physically important in those cases, if the difference of the growth rates of individual dynamo eigenfunctions is small in comparison with the growth rates themselves. The eigenvalue problem is also insufficient for complete analysis of evolution of an initial distribution of magnetic field which is initially concentrated within a small portion of the dynamo volume. In this case there arise magnetic fronts which spread over the whole volume. Here we solve the Cauchy problem, which describes such situations, for the case of helical axisymmetric flow, the screw dynamo.

We consider evolution of an initially small magnetized region (called here a “blob” or “magnetic packet”) embedded in the axisymmetric helical flow. A prototype of such flow is a helical flow in a tube or a swirling jet. As shown below, the group velocity of such magnetic packet is equal to the fluid velocity at the radius where the eigenfunction concentrates which has the maximal growth rate. The field within the packet grows at this rate. On the contrary, the growth rate of the field outside the packet (within the jet) grows at another rate given by the growth rate of the eigenfunction which has the minimal oscillation frequency v, i.e. dv/dk = 0, where k is the longitudinal wave number. If the latter growth rate is negative, the field within the jet decays and the growing magnetic packet moves through the jet leaving it unmagnetized.
Entropy generation in a ten‐dimensional cosmological model admitting decompressive forces
Authors: Wolf C.
Published: July 2007

By allowing the equation of state for matter to be of a decompressive nature we study the effect on entropy generation in a ten‐dimensional cosmological model. We study the three cases when bulk viscosity is constant, depends on the energy density, and lastly, on the square of the curvature.
On the discovery of the Trojan object 4060 = 1987 YT1 = Deipylos
Authors: Elst E.W. , Debehogne H.
Published: July 2007

During an extensive search in 1987 for new Trojan objects with the ESO Schmidt telescope, two new Trojans were discovered. One of these objects, 1987 YT1, was recovered at the subsequent dark run at ESO by DEBEHOGNE with the GPO instrument used in the astrographic mode.

New observations in 1989 by ELST at the GPO and ESO Schmidt led to definite numbering (4060) and naming (Deipylos) of this Trojan object. The orbit is calculated starting from the discovery 1987/88 observations using a classic Gaussian procedure. The orbit is subsequently improved by the method of the variation of the geocentric distances. These orbital elements are compared with the osculating elements which have been obtained from orbit calculation using all available observations (1942–1989).
Helium surface distribution on He‐peculiar stars
Authors: Vetö B. , Hempelmann A. , Schöneich W. , Stahlberg J.
Published: July 2007

A method has been developed to determine the geometrical parameters of surface distributions of chemical elements on a spotted rotator from observations of variable line strengths. On the basis of simple assumptions for spot geometry and limb darkening this problem has been traced back to the same inverse problem as the determination of surface brightness parameters from photometric observations. The method was applied to eight He‐peculiar (CP4) stars (HR 1441, HR 1890, HR 1932, HD 37776, HR 2509, HR 3089, HR 5387 and HR 7129) to derive the He surface distribution of these He‐rich and He‐weak stars from the line strength variation of the HeI λ 4026 line. The result and a discussion of the analysis is given.
On star formation in cooling flows of clusters of galaxies
Authors: Schmidt K.‐H.
Published: July 2007

A correlation between the masses of cooling flows in clusters of galaxies and the absolute magnitudes of the central parts of the brightest galaxies of the clusters is detected. This correlation is consistent with star formation in the cooling flows according to an initial mass function of stars truncated at stellar masses corresponding to absolute magnitudes in the most probable cases between +7 and +2.
A coarse analysis of Seyfert‐I narrow‐line properties
Authors: Rafanelli P. , Schulz H.
Published: July 2007

Medium‐resolution spectrophotometry of 19 Seyfert‐I galaxies with Mv between ‐20m and ‐24m is presented. Balmer line broad and narrow components are decomposed and relative narrow‐line intensities are compared with a grid of power law photoionization models. Diagrams displaying ratios of strong forbidden lines are devised which allow to read power law indices α and ionization parameters U for individual objects. On the average, α‐values derived from [O I]/[O III] versus [N II]/[O III] are in good agreement with power‐law slope indices αux derived from continuum measurements at 1450 Å (U) and 0.7 keV (X). However, for the same parameters, the theoretical [S II]/[O III] values appear to be 40% too large. Based on trends in current photoionization models we suggest that this discrepancy might be removed by including a black‐body component in the ionizing continuum and a high‐density component in the narrow‐line region. Mkn 1044 has been isolated as an unusual object whose strong [S II] λλ4068,4076 feature suggests that its NLR emission is dominated by a high‐density zone with Ne ∼ 107 cm‐3.
Synthetic curves of some observational properties of contact binary asteroids
Authors: Hoffmann Martin
Published: July 2007

The shape of some asteroids may be deduced by other ground based means than rotation light curves or advanced techniques like speckle imaging or radar observations: the analysis of high precision astrometry and lunar occultation light curves. Calculations of the phenomena among the cosmogonically interesting case of a double asteroid configuration, when the objects are in contact with each other, are presented with special emphasis on the involved shadow phenomena.
FÖPPL's negative gravity masses and the repulsive cosmos
Authors: Treder H.‐J.
Published: July 2007

FÖPPL (1897) distincts between the positive inertial masses and gravity masses which may have positive and negative signes. FÖPPL has proved the masses with opposite signes of gravity each other repel. For our normal matter the principle of equivalence is valid. Our “world island” is built by masses with positive gravity only and repels each body with negative gravity.
Image detection and separation on Tautenburg Schmidt plates with the ASAG program package
Authors: Lange M. , Richter G.M. , Scholz R.‐D.
Published: July 2007

The Babelsberg image processing system which will be used for the new automated measuring machine ASAG (Astronomisches Auswertegerät) includes as special feature an adaptive filtering technique. This technique allows a reduction of noise and the determination of the background in astronomical pictures and has already been used for the surface photometry of galaxies on Schmidt plates. For astrometric purposes a method of detecting and separating images in two‐dimensional measuring rasters was developed within the frame of the ASAG software and algorithms.
Radio signature and Hα limb features of the 1979 March 9 and 1982 July 9 flares
Authors: Aurass H. , Krüger A. , Rompolt B. , Garczynska I. , Fomichev V.V. , Chertok I.M. , Ishkov V.N. , Urbarz H.
Published: July 2007

We present a comprehensive compilation of data for both events. Some typical Hα limb and type IV radio spectrogram features are found to be associated. The escape of matter out of loops visible in Hα via blob ejection or loop eruption is associated with fast drift burst signatures resp. early flare continuum (FCE) emission in radio spectra and pulses in HXR. The comparison of both events reveals that the metric radio‐HXR association is essentially a matter of particle escape conditions into the corona.
Relative motions between the inner core and the Earth's mantle due to attractions of the Sun and the Moon
Authors: Jochmann H.
Published: July 2007

The response of the inner core motion with respect to the mantle due to the attraction of the Sun and the Moon is studied. It could be shown that some periodic constituents of polar motion and the dipole part of the geomagnetic westward drift, which correspond with astronomical nutation periods, are in accordance with the applied hypothesis of a relative precession and nutation of the inner core.
ASCHOT — Astrophysical Schmidt Orbital Telescope
Authors: Tovmasyan H.M. , Lorenz H. , Priebe A. , Richter G.M. , Schmidt K.‐H. , Khodzhayants Y.M. , Krmoyan M.N. , Isajanyan R.V. , Zakharyan A.Z.
Published: July 2007

The necessity for a wide‐angle UV space telescope for astrophysical investigations is outlined. Some of the main scientific goals such as full sky survey and massive study of UV emission of extragalactic and galactic objects, which may be achieved by the use of the Astrophysical Schmidt Orbital Telescope ASCHOT, are presented.

The concept of the telescope design, its optical system, and its system of guidance are described. Electronic devices which may be used as detectors of UV emission in the telescope are considered. The limiting sensitivity of the telescope is estimated: it is about 24m for stellar objects at 1500 Å. The control system of the telescope is brieffy described. At the end the organizations which take part in designing and manufacturing the telescope are listed.
Small waves in UT1 caused by the inequality of the equatorial moments of inertia A and B of the Earth
Authors: Wünsch J.
Published: July 2007

A number of semidiurnal terms in UT1 arising from the inequality of the two equatorial moments of inertia A and B of the Earth are studied. Amplitudes are given using coefficients from Vondrák (1984). The most important waves correspond to the M2, S2, N2 and K2 tidal frequencies. At present, these are below the detection limit of geodetic VLBI experiments.
Aerodynamic drag perturbations in artificial satellite nodal period
Authors: Mioc V. , Radu E.
Published: July 2007

The difference caused by the atmospheric drag between the nodal period of artificial satellites and the corresponding Keplerian period is analytically studied for orbits with small eccentricities. Considering various effects in the distribution of the upper atmospheric density (described by the Total Density thermospheric model) and the atmospheric rotation as well, an analytic expression for the mentioned difference is established. Some particular cases are discussed.
Speckle‐interferometry and provisional orbit of BU 738
Authors: Scardia M. , Neri R. , Grewing M.
Published: July 2007

Three different orbits of BU 738 ‐ WDS 02189 S 3019, a close visual binary, have been proposed up to now: Finsen (1969, elliptic orbit), Finsen (1969, parabolic orbit) and Heintz (1984, elliptic). In the last few years, three micrometric observations [MS] and a single speckle‐interferometric observation [RN and MG] have been independently carried out with the ESO/GPO 38 cm astrograph and ESO/MPI 2.2 m telescope. From these measurements and a list of observations of C. E. Worley of the Naval Observatory a new provisional orbit is proposed. Whereas new observations will improve the presented solution, the validity of the first two orbits suggested by Finsen has definitively to be ruled out. The masses of the two components are estimated as MA = 1·09 MȮ and MB = 1·01MȮ, respectively.
Determination of absolute proper motions in the main meridional section of the Galaxy
Authors: Schilbach E. , Scholz R.–D.
Published: July 2007

In two fields of the programme of the main meridional section of the Galaxy (MEGA) the proper motions for several thousands of stars were obtained in respect to a frame of background galaxies. An average proper motion accuracy of about 6 milliarcseconds per year was achieved from an analyses of MAMA measurements of Tautenburg Schmidt plates. The tautenburg and Lick mean proper motions for stars in the same magnitude range (15 < B < 17) and in the same galactic latitude zone (40° < b < 50°) show good agreement within the error bars.
Breitenänderungen der Station Potsdam
Authors: Meinig M.
Published: July 2007

Die Breitenbestimmungen mit dem photographischen Zenitteleskop PZT 2 des geodätisch‐astronomischen Observatoriums Potsdam, wurden für den Zeitraum von 1981‐90 analysiert mit dem Ziel, Aussagen über das Langzeitverhalten abzuleiten. Die Ausgangsdaten wurden wegen der Polbewegung korrigiert. Der Verlauf der korrigierten Breitenwerte zeigt neben einem signifikanten linearen Trend jahreszeitliche Schwankungen mit zeitlich veränderlichen Parametern. Vergleichende Untersuchungen für die tschechoslowakische Station Ondrejov führen zu ähnlichen Ergebnissen. Als Ursache für die erhaltenen Breitenänderungen könnten systematische Fehler der Eigenbewegungen der beobachteten Sterne in Frage kommen.