Near-Horizon Metric

1. Nov 14, 2008

vizart

It seems to be obvious, but I cant see the reason behind the statement that authors make after Equation 4.2 that "As the horizon is approached, the right-hand side of (4.2) approaches zero."
I would be appreciative if somebody could help me with this issue.

2. Nov 14, 2008

Naty1

You might try Wikipedia for a clue,,,
Kerr Solution or Kerr Neumann Metric..

3. Nov 15, 2008

vizart

thank you for the tip but if you look at the Boyer-Lindquist form #(4.1), you see that it is quite general and i think their statement is somehow related to the fact that the horizon is a null hypersurface. yet i dont know the 'how' part :)

4. Nov 15, 2008

stevebd1

5. Nov 19, 2008

vizart

I must be hanged for not seeing the simple fact that when the metric has the given Lewis form (4.1) if you move to the rotating reference frame, then the near-horizon condition "RHS of Eqn. 4.2 approaches zero" will be obvious.