• Corpus ID: 249926380

Conformally Schwarzschild cosmological black holes

@inproceedings{Sato2022ConformallySC,
  title={Conformally Schwarzschild cosmological black holes},
  author={Takuma Sato and Hideki Maeda and Tomohiro Harada},
  year={2022}
}

• Takuma Sato, H. Maeda, T. Harada
• Published 22 June 2022
• Physics

We thoroughly investigate conformally Schwarzschild spacetimes in different coordinate systems to seek for physically reasonable models of a cosmological black hole. We assume that a conformal factor depends only on the time coordinate and the spacetime is asymptotically flat Friedmann-Lemâıtre-RobertsonWalker universe filled by a perfect fluid obeying a linear equation state p = wρ with w > −1/3. In this class of spacetimes, the McClure-Dyer spacetime, constructed in terms of the isotropic coordinates, and the Thakurta spacetime, constructed in terms of the standard Schwarzschild coordinates, are identical and do not describe a cosmological black hole. In contrast, the Sultana-Dyer class of spacetimes, constructed in terms of the Kerr-Schild coordinates, describe a cosmological black hole and the corresponding matter field can be interpreted as a combination of a homogeneous perfect fluid and an inhomogeneous null fluid, which is valid everywhere in the spacetime unlike Sultana and Dyer’s interpretation. The Culetu spacetime, constructed in terms of the Painlevé-Gullstrand coordinates, also describes a cosmological black hole and the corresponding matter field can be interpreted as a combination of a homogeneous perfect fluid and an inhomogeneous anisotropic fluid. It turns out, however, that in both the Sultana-Dyer and Culetu spacetimes, the total energy-momentum tensor violates all the standard energy conditions at a finite value of the radial coordinate in sufficiently late times.