The most general bound binary black hole (BBH) system has an eccentric orbit and precessing spins. Detecting a BBH with significant eccentricity near merger would be a clear signature of dynamical formation, while the spin–orbit misalignment angles (spin tilts) provide a powerful probe of different astrophysical formation channels. We have developed publicly available codes that evolve...
The Kiselev metric has gained increasing relevance in recent years due to its ability to model a variety of physical systems. It describes a black hole influenced by the presence of an anisotropic fluid—composed of the superposition of a perfect fluid, an electromagnetic field, and a scalar field. Depending on the equation of state parameter $\omega$, this metric can model dispersed gases in...
Current waveform models of binary black hole mergers incorporate a large amount of analytical information during the inspiral phase. On the other hand, post-merger templates use a phenomenological ansatz informed by numerical simulations, with the quasinormal frequencies as the only analytical input.
Working in the perturbative limit, we develop the first analytical model predicting the...
Black Hole Perturbation Theory (BHPT) has been shown to be very successful in describing physical processes around BHs. In particular, the scattering of electromagnetic and gravitational waves (and other physical fields) and the so-called quasinormal mode (QNM) oscillations, the damped BH oscillations that dominate the ringdown phase of binary BH (BBH) coalescences.
A key feature of BHPT is...
We evolve for the first time in full GR a small, collisional N-body black hole cluster of arbitrary total mass M. The bound cluster is initially compact (radius R/M≈10), stable, and consists of 25 equal-mass, nonspinning black holes. The dynamical interactions of compact objects in N-body clusters is of great interest for the formation of black holes in the upper mass gap as well as...
Recent millimeter-wavelength observations of the near-horizon regions of
M87 and Sgr A by the Event Horizon Telescope have significantly advanced our understanding of gravity and astrophysics under extreme conditions. A key goal for future observations, with improved angular resolution and sensitivity, is the detection of the photon ring in these black holes. For Kerr black holes, photon...
