Accuracy of the Post-Newtonian Approximation for Extreme-Mass Ratio Inspirals from Black-hole Perturbation Approach

Understand

We revisit the accuracy of the post-Newtonian (PN) approximation and its region of validity for quasi-circular orbits of a point particle in the Kerr spacetime, by using an analytically known highest post-Newtonian order gravitational energy flux and accurate numerical results in the black hole perturbation approach.

• It is found that regions of validity become larger for higher PN order results although there are several local maximums in regions of validity for relatively low-PN order results.
• This might imply that higher PN order calculations are also encouraged for comparable-mass binaries.