TY - JOUR

T1 - Spherical collapse in quintessence models with zero speed of sound

AU - Creminelli, Paolo

AU - D'Amico, Guido

AU - Norẽa, Jorge

AU - Senatore, Leonardo

AU - Vernizzi, Filippo

PY - 2010

Y1 - 2010

N2 - 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 Q/Ω m. This gives a distinctive modification of the total mass function at low redshift.

AB - 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 Q/Ω m. This gives a distinctive modification of the total mass function at low redshift.

KW - Cluster counts

KW - Dark energy theory

UR - http://www.scopus.com/inward/record.url?scp=77950289447&partnerID=8YFLogxK

U2 - 10.1088/1475-7516/2010/03/027

DO - 10.1088/1475-7516/2010/03/027

M3 - Article

AN - SCOPUS:77950289447

VL - 2010

JO - Journal of Cosmology and Astroparticle Physics

JF - Journal of Cosmology and Astroparticle Physics

SN - 1475-7516

IS - 3

M1 - 027

ER -