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OATS-DAUT SEMINAR
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Speaker: Paolo Creminelli (ICTP)
Title: The collapse of dark energy
Date: Wednesday, February 10th, 2010
Time: 12:00
Venue: Villa Bazzoni
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Abstract: I will present a study of a generic single-field
dark energy model.
One finds no general pathology associated to an equation of state w < -1.
Stability requires that the w < -1 side of dark energy behaves, on cosmological scales, as a fluid with virtually zero speed of sound: clustering quintessence.
Focussing on this particular scenario, I will study the spherical collapse
model.
The spherical overdensity behaves as a separate closed FLRW universe,
so that its evolution can be studied exactly. One can thus derive the critical
overdensity for collapse and use the Press-Shechter theory to study
how the clustering of quintessence affects the mass function.
A novel feature is that quintessence contributes to the mass of virialiazed
object at low redhsift.
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contact: Matteo Viel (OATS)