Abstract

Title of Abstract
Spherical collapse model for adiabatic fast transition models
Session
Cosmology Beyond the Standard Model
Author
Francesco Pace
Co-Authors
Daniele Bertacca (Bonn), Richard Battye (Manchester), Marco Bruni (Portsmouth)
Institution
University of Manchester
Summary (maximum 250 words)
Dark matter and dark energy are usually considered to be two separate components in the energy budget of the Universe. A simple extension to this hypothesis is to consider that they could be different aspects of a single component. This class of models is hence dubbed Unified Dark Matter (UDM) models.

UDM models could cluster and hence give origin to cosmic structures if the adiabatic sound speed of the fluid is small enough, but this is achieved only with a severe fine-tuning of the parameters.

A particularly interesting sub-class of UDM models solving this issue is characterised by a fast transition between a standard matter-like era and a late epoch with accelerated expansion (cosmological constant or dark energy). In addition these models can avoid the problems affecting the Chaplygin gas models.

An important point lacking in literature is a rigorous analysis of structure formation in adiabatic fast transition models, clearly defining the equation of motions of the clustering part of the fluid.
I will show results of structure formation in UDM fast transition models within the framework of the spherical collapse model and a comparison with the standard approach for LCDM and dark energy models.
Attachment

Schedule

Session Time
16:30 - 18:00
Talk start
17:15
Day
Tuesday

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