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 -