Spherical collapse in quintessence models with zero speed of sound
- Abdus Salam International Centre for Theoretical Physics Strada Costiera 11, 34151, Trieste (Italy)
- SISSA, via Beirut 2-4, 34151, Trieste (Italy)
- School of Sciences, Institute for Advanced Study, Olden Lane, Princeton, NJ 08540 (United States)
- CEA, IPhT, 91191 Gif-sur-Yvette cédex (France)
We study the spherical collapse model in the presence of quintessence with negligible speed of sound. This case is particularly motivated for w < −1 as it is required by stability. As pressure gradients are negligible, quintessence follows dark matter during the collapse. The spherical overdensity behaves as a separate closed FLRW universe, so that its evolution can be studied exactly. We derive the critical overdensity for collapse and we use the extended Press-Schechter theory to study how the clustering of quintessence affects the dark matter mass function. The effect is dominated by the modification of the linear dark matter growth function. A larger effect occurs on the total mass function, which includes the quintessence overdensities. Indeed, here quintessence constitutes a third component of virialized objects, together with baryons and dark matter, and contributes to the total halo mass by a fraction ∼ (1+w)Ω{sub Q}/Ω{sub m}. This gives a distinctive modification of the total mass function at low redshift.
- OSTI ID:
- 22273025
- Journal Information:
- Journal of Cosmology and Astroparticle Physics, Vol. 2010, Issue 03; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 1475-7516
- Country of Publication:
- United States
- Language:
- English
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