Shadow of a regular black hole in scalar-tensor-vector gravity theory
Abstract
We investigate the shadow cast by a regular black hole in scalar-tensor-vector modified gravity theory. This black hole differs from a Schwarzschild-Kerr black hole by the dimensionless parameter $\ensuremath{\beta}$. The size of the shadow depends on this parameter. Increasing the value of the parameter $\ensuremath{\beta}$ shrinks the shadow. A critical value of the parameter $\ensuremath{\beta}$ is found to be ${\ensuremath{\beta}}_{\mathrm{crit}}=0.40263$. The shadow for the horizonless dark compact object has been analyzed for the static, spherically symmetric case and compared with M87* and Sgr A* data. Shadow observables have been determined in the context of the regular black hole and used for obtaining the energy emission rate. The peak of the energy emission rate shifts to lower frequency for the increasing value of the parameter $\ensuremath{\beta}$.