Hawking radiation inside a rotating black hole

Understand

In semiclassical gravity, the vacuum expectation value ${\langle\hat{N}\rangle}$ of the particle number operator for a quantum field gives rise to the perception of thermal radiation in the vicinity of a black hole.

• This Hawking effect has been examined only for observers asymptotically far from a Kerr black hole; here we generalize the analysis to various classes of freely falling observers both outside and inside the Kerr event horizon.
• Of note, we find that the effective temperature of the ${\langle\hat{N}\rangle}$ distribution remains regular for observers at the event horizon but becomes negative and divergent for observers reaching the inner Cauchy horizon.
• Furthermore, the perception of Hawking radiation varies greatly for different classes of observers, though the spectrum is generally a graybody that decreases in intensity with black hole spin and increases in temperature when looking toward the edges of the black hole shadow.