  We analyze the dynamics of Bose polarons in the vicinity of a Feshbach
resonance between the impurity and host atoms. We compute the radio-frequency
absorption spectra for the case when the initial state of the impurity is
non-interacting and the final state is strongly interacting. We compare results
of different theoretical approaches including a single excitation expansion, a
self-consistent T-matrix method, and a time-dependent coherent state approach.
Our analysis reveals sharp spectral features arising from metastable states
with several Bogoliubov excitations bound to the impurity atom. This surprising
result of the interplay of many-body and few-body Efimov type bound state
physics can only be obtained by going beyond the commonly used Fr\"ohlich model
and including quasiparticle scattering processes. Close to the resonance we
find that strong fluctuations lead to a broad, incoherent absorption spectrum
where no quasi-particle peak can be assigned.
