Shadow casted by a Konoplya-Zhidenko rotating non-Kerr black hole

TL;DR

This paper explores how a deformation parameter in a Konoplya-Zhidenko rotating non-Kerr black hole influences its shadow's size and shape, revealing new patterns such as cusp shapes and D-shapes depending on parameters.

Contribution

It provides a detailed analysis of the black hole shadow affected by the deformation parameter, highlighting novel shadow shapes and their dependence on black hole parameters.

Findings

Shadow size increases with the deformation parameter.

D-shape shadow appears for certain rotation and deformation parameters.

Shadow becomes less cuspidal as deformation increases.

Abstract

We have investigated the shadow of a Konoplya-Zhidenko rotating non-Kerr black hole with an extra deformation parameter. The spacetime structure arising from the deformed parameter affects sharply the black hole shadow. With the increase of the deformation parameter, the size of the shadow of black hole increase and its shape becomes more rounded for arbitrary rotation parameter. The D-shape shadow of black hole emerges only in the case $a<\frac{2\sqrt{3}}{3}M$ with the proper deformation parameter. Especially, the black hole shadow possesses a cusp shape with small eye lashes in the cases with $a>M$, and the shadow becomes less cuspidal with the increase of the deformation parameter. Our result show that the presence of the deformation parameter yields a series of significant patterns for the shadow casted by a Konoplya-Zhidenko rotating non-Kerr black hole.