We study the gravitational clustering of spherically symmetric overdensities and the statistics of the resulting dark matter halos in the "symmetron model," in which a new long range force is mediated by a Z2 symmetric scalar field. Depending on the initial radius of the overdensity, we identify two distinct regimes: for small initial radii the symmetron mediated force affects the spherical collapse at all redshifts; for initial radii larger than some critical size this force vanishes before collapse because of the symmetron screening mechanism. As a consequence, halos with initial radii smaller than some critical value collapse earlier than in the ΛCDM and statistically tend to form more massive dark matter halos. Regarding the halo mass function of these objects, we observe departures from standard ΛCDM predictions at the few percent level. The formalism developed here can be easily applied to other models where fifth forces participate to the dynamics of the gravitational collapse. © 2014 American Physical Society.

Spherical collapse and halo mass function in the symmetron model / Taddei, Laura; Catena, Riccardo; Pietroni, Massimo. - In: PHYSICAL REVIEW D, PARTICLES, FIELDS, GRAVITATION, AND COSMOLOGY. - ISSN 1550-7998. - 89:2(2014). [10.1103/PhysRevD.89.023523]

Spherical collapse and halo mass function in the symmetron model

TADDEI, Laura;CATENA, RICCARDO;PIETRONI, MASSIMO
2014

Abstract

We study the gravitational clustering of spherically symmetric overdensities and the statistics of the resulting dark matter halos in the "symmetron model," in which a new long range force is mediated by a Z2 symmetric scalar field. Depending on the initial radius of the overdensity, we identify two distinct regimes: for small initial radii the symmetron mediated force affects the spherical collapse at all redshifts; for initial radii larger than some critical size this force vanishes before collapse because of the symmetron screening mechanism. As a consequence, halos with initial radii smaller than some critical value collapse earlier than in the ΛCDM and statistically tend to form more massive dark matter halos. Regarding the halo mass function of these objects, we observe departures from standard ΛCDM predictions at the few percent level. The formalism developed here can be easily applied to other models where fifth forces participate to the dynamics of the gravitational collapse. © 2014 American Physical Society.
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11381/2815950
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 18
  • ???jsp.display-item.citation.isi??? 17
social impact