Pantheon SEMPARIS Le serveur des séminaires parisiens Paris

Statut Confirmé
Série APC-TH
Domaines hep-th
Date Mardi 7 Avril 2015
Heure 14:00
Institut APC
Salle 483A Malevitch
Nom de l'orateur Musco
Prenom de l'orateur Ilia
Addresse email de l'orateur
Institution de l'orateur LUTH
Titre Gravitational collapse, primordial black hole formation and quasi static solutions of compact objects in Chameleon Models
Résumé Gravitational collapse is the main mechanism leading to structure formation of different types in the Universe. The phenomenology depends on the characteristics of the matter involved, with there being a crucial distinction between zero and non-zero rest-mass particles. In the very early universe, when the matter is characterised by a barotropic equation of state (pressure proportional to the energy density), only black holes could have been formed. I the first part of the talk I will explain the mechanism of formation of these objects, called primordial black holes. They be can be considered as interesting sources of different signals due to black hole evaporation, as also being the seeds of the very massive black holes that we think are in the centre of galaxies like the Milky Way. In the second part I will move to a different problem, analyzing quasi-static spherically symmetric solutions in presence of scalar fields, to understand the screening mechanism, known as Chameleon. Considering objects such as standard stars and more compact objects like white dwarfs and neutron stars, I am solving the Tolman- Oppenheimer-Volkoff equations coupled with the Klein-Gordon equation in a quasi static regime, keeping into account the background expansion without needing to introduce an artificial cosmic matter that corresponds to a non-spatially flat metric. The interior of the star is solved using a polytropic equation of state matching the solution outside onto the cosmic density of an expanding spatially flat background.
Numéro de preprint arXiv
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