Spherical Collapse in f(R) Gravity

Understand

We use 1-dimensional numerical simulations to study spherical collapse in the f(R) gravity models.

• We include the nonlinear coupling of the gravitational potential to the scalar field in the theory and use a relaxation scheme to follow the collapse.
• We find an unusual enhancement in density near the virial radius which may provide observable tests of gravity.
• We also use the estimated collapse time to calculate the critical overdensity $\delta_c$ used in calculating the mass function and bias of halos.