Non-linear Structure Formation in Modified Gravity Theories
Fabian Schmidt (Caltech) - Nov 30, 2009 at 12:10 pm
Instead of adding another dark component to the energy budget of the
Universe, one can ask whether the observed accelerated expansion might
in fact be due to the behavior of gravity itself on the largest scales.
In this talk, we will consider two popular modified gravity theories
which realize this scenario: f(R) gravity and the DGP model. While these
models yield an accelerated expansion, they also affect the formation of
structure on much smaller scales. We have studied this with cosmological
N-body simulations which consistently solve for the modified
gravitational force. We will discuss the effects of modified gravity on
dark matter halo properties as well as cosmological observables. Using
observables in the non-linear regime to probe modified gravity allows
for much tighter constraints. In case of f(R) gravity, our first
simulation-calibrated constraints from the observed abundance of massive
clusters improve on previous constraints from the CMB and ISW by a
factor of ~1000.
The seminar will be held in 544 Campbell Hall.
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