Imprints of local lightcone projection effects on the galaxy bispectrum
  IV: Second-order vector and tensor contributions
  The galaxy bispectrum on scales around and above the equality scale receives
contributions from relativistic effects. Some of these arise from lightcone
deformation effects, which come from local and line-of-sight integrated
contributions. Here we calculate the local contributions from the generated
vector and tensor background which is formed as scalar modes couple and enter
the horizon. We show that these modes are sub-dominant when compared with other
relativistic contributions.
