scholarly journals Orbits of the Magellanic Clouds

1991 ◽  
Vol 148 ◽  
pp. 475-477
Author(s):  
Slobodan Ninkovic ◽  
Miroslav Filipovic

We use a simple, spherically symmetric model for the Galaxy based on the rotation curve for the inner parts. We extrapolate beyond the rotation curve boundary, assuming a dark corona whose total mass is a model parameter. For each mass value assume we calculate the allowed angular-momentum interval for which a cloud is neither tidally disrupted, nor escapes. On the basis of this investigation we reach a conclusion about the expected mass of the Galaxy.

1970 ◽  
Vol 38 ◽  
pp. 51-60
Author(s):  
J. Einasto ◽  
U. Rümmel

A model for the Andromeda galaxy, M 31, has been derived from the available radio, photometric, and spectroscopic data. The model consists of four components – the nucleus, the bulge, the disc, and the flat component.For all components the following functions have been found: the mass density; the mass-to-light ratio; the velocity dispersions in three perpendicular directions (for the plane of symmetry and the axis of the galaxy); the deviation angle of the major axis of the velocity ellipsoid from the plane of symmetry; the centroid velocity (for the plane of symmetry).Our model differs in two points from the models obtained by other authors: the central concentration of mass is higher (in the nucleus the mass-to-light ratio is about 170), and the total mass of the galaxy (200 × 109 solar masses) is smaller. The differences can be explained by different rotation curves adopted, and by attributing more weight to photometric and spectroscopic data in the case of our model.


2012 ◽  
Vol 27 (40) ◽  
pp. 1250231 ◽  
Author(s):  
HÜSNÜ BAYSAL

We have calculated the total energy–momentum distribution associated with (n+2)-dimensional spherically symmetric model of the universe by using the Møller energy–momentum definition in general relativity (GR). We have found that components of Møller energy and momentum tensor for given spacetimes are different from zero. Also, we are able to get energy and momentum density of various well-known wormholes and black hole models by using the (n+2)-dimensional spherically symmetric metric. Also, our results have been discussed and compared with the results for four-dimensional spacetimes in literature.


1998 ◽  
Vol 57 (10) ◽  
pp. 6094-6103 ◽  
Author(s):  
Masaaki Morita ◽  
Kouji Nakamura ◽  
Masumi Kasai

1996 ◽  
Vol 169 ◽  
pp. 703-706
Author(s):  
D. M. Peterson ◽  
D. Slowik

The Galactic rotation law provides critical information for estimating the distribution of mass in the Galaxy, for tying the distance of the Sun from the Galactic center to local distance scales, and, if determined over large enough distances, for estimating the total mass of the system and the amount of nonluminous matter present. Interior to the Sun velocities are well defined by observations of the ISM, particularly HI. These techniques are not available for points exterior to the Sun and we must rely on observations of velocities of objects whose distances can be estimated. Notable among these are the Cepheids (Pont et al 1994) and the combination of CO velocities and OB cluster distances (Brand & Blitz 1993) where the two are found to coexist. Adding a new class of objects, particularly bright, relatively common objects to this effort is of importance.


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