Gauge Independence of Induced Gravitational Waves
  We study gauge (in)dependence of the gravitational waves (GWs) induced from
curvature perturbations. For the GWs produced in a radiation-dominated era, we
find that the observable (late-time) GWs in the TT gauge and in the Newtonian
gauge are the same in contrast to a claim in the literature. We also mention
the interpretation of the gauge dependence of the tensor perturbations which
appears in the context of the induced GWs.
