astrophysical twin universe and cosmology Ghost matter astrophysical matter. 5 : Results of 2D numerical simulations. VLS. About a possible scheme for galaxy formation. (p5)
...Now, dealing with two species (matter plus ghost matter), if Vthr << Vth cr, we get two clumps, whose distance corresponds to antipodality and maximum distance between them. See figure 14.
** ** Fig. 14 :** Schematic result of joint gravitational instability** **matter plus ghost matter, when **Vthr << Vth cr (initially cold medium)
...If Vthr >> Vth cr the system remains uniform and the two species remain strongly mixed. For Vthr » Vth cr, we get long duration emulsion-like patterns, see figure 15 (this result was presented in a previous paper [1]).
Fig. 15 : Emulsion pattern for Vth = Vth cr
...We have used two sets of 5000 interacting mass points. As we can see, the result is similar to that of figure 11 bis. The same method could be extended to 3D systems (which is far beyond the possibilities of our system). Although 3D systems differ from 2D systems, we can expect 3D simulations to produce similar long duration 3D emulsions. The theory of joint instabilities (coupled Jeans equations) is presented in section 11.
- The problem of the very large structure of the Universe
...We take initial conditions with uniform mass distributions for normal matter (that we call simply matter) and ghost matter. r being the mass density of the matter and r* the mass distribution of the ghost matter, we choose for initial conditions ro* = 64 ro. At this level, just see what happens. We have performed 2D numerical simulations with two sets of 5000 mass points, that are supposed to represent some clusters of matter and ghost matter, with masses M and M*, which means that M* = 64 M. We give these two sets Maxwellian distributions of 2D thermal velocities with <V*> = 4 < V >. We neglect the expansion phenomena (it would be very difficult to deal with, for we do not know how to describe gravitational force in an expanding universe). The results are the following. The more massive population, the ghost matter one, whose Jeans time is eight times shorter than the other one's, takes over and forms clumps, through gravitational instability, that repel and confine the other population in the remaining place. We get a 2D cellular structure. The characteristic birth time of the whole structure is close to the Jeans time of the heavier population, of the ghost matter.
. Fig. 16 :** Results of simulations performed by F. Lansheat.** Left : ghost matter clumps. Right : matter structure. . Fig. 17 : Superposition of the two. ...The general pattern depends on the initial conditions. In a previous paper [6], bigger clumps of ghost matter were obtained, with a more regular cellular structure for normal matter, due to the choice of a higher initial ghost matter temperature. This approach, aiming at a modeling of the very large scale structure of the Universe, is fundamentally different from the classical approaches based on dark matter. In classical matter-dark matter systems, stability is problematic: gravitational instability, by increasing the density locally, increases the thermal velocities and makes the observed structures disappear over time. The system with two repelling populations is qualitatively different, each population creating a potential barrier for the other one. This explains the great stability in time and space: the cells of matter keep the clumps of ghost matter in place, and vice versa. 