Year: 2014
Type: article
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 ${Z}_{2}$ 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 $\mathrm{\ensuremath{\Lambda}}\mathrm{CDM}$ and statistically tend to form more massive dark matter halos. Regarding the halo mass function of these objects, we observe departures from standard $\mathrm{\ensuremath{\Lambda}}\mathrm{CDM}$ 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.
Institutions: University of Parma, University of Göttingen
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W2092919265