Photon surfaces, shadows and accretion disks in gravity with minimally coupled scalar field

Understand

In this article, we conduct a sequential study of possible observable images of black hole simulators described by two recently obtained rotating geometries in Einstein gravity, minimally coupled to a scalar field.

• One of them, "Kerr-like" (KL), can be seen as a legitimate alternative to the rotating Fisher-Janis-Newman-Winicour (FJNW) solution, and the other (TSL) is a scalar generalization of the Tomimatsu-Sato solution.
• Unlike the previous version of the rotating FJNW, these solutions do indeed satisfy the system's equations of motion.
• Our study includes both analytical and numerical calculations of equatorial circular orbits, photon regions, gravitational shadows, and radiation from thin accretion disks for various values of the object's angular momentum and scalar charge.