# STU Black Holes and SgrA*

## TL;DR

This paper studies the null geodesics of STU black holes, a family of rotating solutions in supergravity, to test how well the Kerr metric describes the gravitational field near the galactic center, with implications for black hole shadow analysis.

## Contribution

It introduces the integrability of null geodesics in STU black holes and proposes their use as a tool to test the Kerr metric's accuracy in describing astrophysical black holes.

## Key findings

- STU metrics satisfy energy conditions by construction
- Null geodesics are completely integrable in these solutions
- Black hole shadow properties can be straightforwardly calculated

## Abstract

The equations of null geodesics in the STU family of rotating black hole solutions of supergravity theory, which may be considered as deformations of the vacuum Kerr metric, are completely integrable. We propose that they be used as a foil to test, for example, with what precision the gravitational field external to the black hole at the centre of our galaxy is given by the Kerr metric. By contrast with some metrics proposed in the literature, the STU metrics satisfy by construction the dominant and strong energy conditions. Our considerations may be extended to include the effects of a cosmological term. We show that these metrics permit a straightforward calculation of the properties of black hole shadows.