Cosmological expansion and local systems: a Lema\^{i}tre-Tolman-Bondi   model
  We propose a Lema\^{i}tre-Tolman-Bondi system mimicking a two-body system to address the problem of the cosmological expansion versus local dynamics. This system is strongly bound but participates in the cosmic expansion and is exactly comoving with the cosmic substratum. 
Ivana Bochicchio and Valerio Faraoni
gr-qc