BS2 - Scalar fields in cosmology |
|
Speaker |
Guzman, Francisco S. |
|
Coauthors |
|
| Talk Title |
Galactic structures in the Gross-Pitaevskii regime of ultralight scalar field dark matter |
|
Abstract |
The Gross-Pitaevskii-Poisson (GPP) system of equations is appropriate to model the dynamics of Bose Condensate dark matter made of ultralight bosons in the non-linear regime of structure evolution. In this scenario the trap of the condensate is the gravitational potential generated by the mass density of the condensate itself. The GPP system of equations has stationary, spherically symmetric solutions called equilibrium configurations. Using numerical simulations we show these solutions are not only stable, but also late-time attractors. This means that despite the initial profile of a condensate dark matter structure -either spherically symmetric or not- after the turn-around of a cosmic fluctuation, the system relaxes through the gravitational cooling process and approaches a virialized state within a time scale , whereas the density profile tends toward one of the equilibrium configurations of the GPP system. Within the Bose condensate dark matter model, the clumpy density distributions of the condensate, in particular equilibrium configurations, are therefore assumed to be dark matter galactic halos. Then we construct the rotation curves of these equilibrium solutions and use them to fit observations using only the central density as a free parameter. We enrich the variety of rotation curves by numerically adding angular momentum to these solutions and show that the central density of the configuration together with its angular momentum suffice to parametrize a rotation curve. With this result we imply there is no need to use the self-interaction of bosons and the boson mass as free parameters to fit rotation curves as current analyses suggest. Going further in the analysis of the dynamics, we present the collision between two condensate halos and show there are solitonic and merger regimes. By carrying out sufficiently long simulations, we track the density of the long-term configuration resulting from a merger and construct a universal core-tail halo profile that can be contrasted with halo mass functions extracted from structure formation simulations. |
|
Talk view |
|
|
|
|