Observational Features of Nonsingular Rotating Black Holes in the Dark-Energy Dominated Universe

@misc{torres2026observational,
  title = {{Observational Features of Nonsingular Rotating Black Holes in the Dark-Energy Dominated Universe}},
  author = {Ramon Torres},
  howpublished = {arXiv},
  year = {2026},
  month = sep,
  doi = {10.48550/arxiv.2609.24926},
  eprint = {2609.24926},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2609.24926},
}

TY  - UNPB
TI  - Observational Features of Nonsingular Rotating Black Holes in the Dark-Energy Dominated Universe
AU  - Ramon Torres
PY  - 2026
DA  - 2026/09/21
PB  - arXiv
DO  - 10.48550/arxiv.2609.24926
UR  - https://arxiv.org/abs/2609.24926
AB  - Recent DESI baryon acoustic oscillation measurements, combined with cosmic microwave background and type-Ia supernova data, suggest that dark energy may evolve with cosmic time. Along a cosmological background, an evolving dark-energy density can be expressed locally as a function of a monotonic curvature invariant, motivating an effective curvature-dependent cosmological term. Moreover, quantum field theory in curved spacetime and approaches to quantum gravity with running gravitational couplings provide complementary motivations for exploring such a term. Here we study how the phenomenology of nonsingular rotating black holes embedded in a Universe dominated by dark energy can differ substantially from that of the Kerr and Kerr--de Sitter geometries. The problem is directly formulated in phase space using a null geodesic super-Hamiltonian and a Mino-type parameter. The shadows of the black holes are calculated by backward ray tracing from a zero-angular-momentum observer. We define and analyze a comprehensive set of standard shadow observables, characterizing the size, shape, and displacement of the shadow. We show that the area of the shadow and its vertical diameter provide particularly clear signatures of a running cosmological term. In this way, joint analyses of multiple strong-field observables and of several black holes with different masses and spins could provide a realistic route to tightly constraining, or potentially measuring, the effective regularization scale behind the running of the cosmological term and statistically distinguishing the non-singular black hole geometry from Kerr/Kerr-dS solutions.
ER  -