Scalar absorption cross section of rotating black holes with tidal charge

Abstract

The absorption cross section of rotating black holes in the Randall-Sundrum brane-world scenario for massless scalar waves is obtained via the partial-wave method. A variety of incidence directions with respect to the black hole rotation axis is considered. Special attention is given to near-extreme black holes, in which cases the absorption cross section increases as the tidal charge becomes more negative. It is shown that black holes with different configurations can present capture cross sections/shadows of same size. However, in such cases, the absorption spectra are different mainly for small frequencies. Numeric results are compared with the capture cross sections in the high-frequency limit, and with the black hole area in the low-frequency limit showing good agreement.

Geodesics and optical properties of rotating black hole in Randall-Sundrum brane with a cosmological constant

“…From the numerical investigation, we have observed that in response to the dragging effect, BH's rotation elongates its image toward the rotational axis. While the negative value of tidal charge and cosmological constant contributes to the shadow area, which is consistent with the exploration of Oliveira [53]. On the other hand, their positive values result in diminishing the shadow radius analogously to the findings of Banerjee et.…”