摘要:

AbstractThe evolution of small‐scale density perturbations on the background of increasing large‐scale perturbations of supercluster size will be considered. In the case that the characteristic length scales of both perturbation modes differ significantly, the interaction between both modes has to be taken into account already within lowest order of approximation. It will be shown that in this case an effective amplification for the smaller‐scale perturbations occurs. For these perturbations the characteristic times of evolution decreases in dependence on the considered mass‐scales more or less rapidly. Therefore, the growth of adiabatic density perturbations on mass‐scales up to galaxy masses seems to be triggered by the density evolution of superclusters which the smaller‐mass perturbations are embedded in. A model for the formation of observed condensed matter distribution will

ISSN:0004-6337    

DOI:10.1002/asna.2113080102

出版商:WILEY‐VCH Verlag    

年代:1987

数据来源: WILEY

ISSN:0004-6337    

DOI:10.1002/asna.2113080103

出版商:WILEY‐VCH Verlag    

年代:1987

数据来源: WILEY

摘要:

AbstractZunächst wird die mathematisch‐physikalische Bedeutung kovarianter Greenscher Funktionen im relativistischen Gravitationsfeld‐gemäß EINSTEIN: auf gekrümmter Raum‐Zeit‐in Verbindung mit ihrer Konstruktion nach HADAMARD erörtert. Sodann werden für den Fall einer allgemeinen statischkugelsymmetrischen Raum‐Zeit die Konstruktionsgleichungen für eine skalare Greensche Funktion in symmetrieangepaßte Form gebracht, was einen günstigen Ausgangspunkt zur expliziten Berechnung der Hadamard‐Bauelemente gibt. Bei Anwendung der so gewonnenen Grundgleichungen auf eine spezielle einparametrige Schar von Modell‐Metriken gelingt es, bis zur expliziten strengen Berechnung von Schweifterm‐Koeffizienten einer masselosen Greenschen Funktion vorzudringen; sie sind zugleich Koeffizienten in der Schwinger‐DeWitt‐Entwicklung des Feynman‐Propagators zur entsprechenden Ruhmasse enthaltenden Klein‐Gordon‐

ISSN:0004-6337    

DOI:10.1002/asna.2113080104

出版商:WILEY‐VCH Verlag    

年代:1987

数据来源: WILEY

摘要:

AbstractIn an earlier paper the evolution of a magnetic field was considered which permeates an electrically conducting fluid and its non‐conducting surroundings. It was shown how the tensorial Green's function of the initial value problem posed by the governing equations can be constructed. The present paper gives a more detailed analysis of the case where the fluid occupies the interior of a sphere. The construction is carried out for arbitrary motions of the fluid. More special results are derived for differential rotation with angular velocity depending only on the radius, and explicit expressions of Green's functions are given for rigid body rotatio

ISSN:0004-6337    

DOI:10.1002/asna.2113080105

出版商:WILEY‐VCH Verlag    

年代:1987

数据来源: WILEY

ISSN:0004-6337    

DOI:10.1002/asna.2113080107

出版商:WILEY‐VCH Verlag    

年代:1987

数据来源: WILEY

摘要:

AbstractUsing the data obtained with the ultraviolet photometer in the Astronomical Netherlands Satellite the equivalent widths of the interstellar 217 nm band as well as other parameters characterizing the behaviour of the continuous interstellar extinction in the wavelength region of the band have been derived for 790 O, B stars with colour excesses E(B ‐ V) ≥ 0·4

ISSN:0004-6337    

DOI:10.1002/asna.2113080108

出版商:WILEY‐VCH Verlag    

年代:1987

数据来源: WILEY

ISSN:0004-6337    

DOI:10.1002/asna.2113080110

出版商:WILEY‐VCH Verlag    

年代:1987

数据来源: WILEY

摘要:

AbstractFrom observations published in Smithsonian Astrophysical Observatory and MPC circulars corrected orbits of 30 comets have been calculated.

ISSN:0004-6337    

DOI:10.1002/asna.2113080111

出版商:WILEY‐VCH Verlag    

年代:1987

数据来源: WILEY

ISSN:0004-6337    

DOI:10.1002/asna.2113080113

出版商:WILEY‐VCH Verlag    

年代:1987

数据来源: WILEY

摘要:

AbstractThe major principles of establishing a statistical model for plates of the Tautenburg Schmidt telescope (134/200/400) are described. The model is intended to be used for the Monte Carlo simulation of the determination of coordinates and proper motions. It has been tested with orthogonal polynomials by determining positions of stars. Under certain conditions linear equations are sufficient for the reduction of measured to standard coordinates when using the AGK3 as the reference system.

ISSN:0004-6337    

DOI:10.1002/asna.2113080114

出版商:WILEY‐VCH Verlag    

年代:1987

数据来源: WILEY