Résumé / Abstract Journal-club_Doctorants

Journal-club Doctorants / Journal-club PhD students

« Analytic description of dark matter clustering: beyond the perfect fluid approximation »

Giulia Cusin
Dept. Physique Théorique, Univ. Genève (Genève, Suisse)

According to the standard paradigm for structure formation, barionic matter has clustered in the dark matter (DM) potential wells. Depending on the prevalence of cold or warm dark matter, we have different scenarios for the formation of structures. Observations seem to indicate that structure formed with a bottom-up scenario and that the dominant component of DM is made of cold particle species.

Cold dark matter is usually described as a perfect fluid with zero temperature. In this scenario a rotational component of the fluid velocity field (i.e. vorticity) can not be generated, as a consequence of the Helmotz's theorem. On the other hand, we see that barionic matter has non vanishing vorticity (i.e. galaxies rotate ect). Therefore, we want to go beyond the standard description of dark matter as a perfect fluid. In our model cold dark matter is described as a viscous fluid with finite temperature. We study the resulting dynamics of the fluid and we compute the vorticity field induced by the presence of viscosity. We compare our result with the output of N-body simulations.
mercredi 15 février 2017 - 17:00
Salle Entresol Daniel Chalonge, Institut d'Astrophysique
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