Nonlinear evolution of initially biased tracers in modified gravity
  In this work we extend the perturbation theory for modified gravity (MG) in
two main aspects. First, the construction of matter overdensities from
Lagrangian displacement fields is shown to hold in a general framework,
allowing us to find Standard Perturbation Theory (SPT) kernels from known
Lagrangian Perturbation Theory (LPT) kernels. We then develop a theory of
biased tracers for generalized cosmologies, extending already existing
formalisms for $\Lambda$CDM. We present the correlation function in
Convolution-LPT and the power spectrum in SPT for $\Lambda$CDM, $f(R)$
Hu-Sawicky, and DGP braneworld models. Our formalism can be applied to many
generalized cosmologies and to facilitate it, we are making public a code to
compute these statistics. We further study the relaxation of bias with the use
of a simple model and of excursion set theory, showing that in general the bias
parameters have smaller values in MG than in General Relativity.
