In this talk, I explore the determination of an event horizon candidate for slowly evolving dynamical black holes (BHs). Such a candidate has been termed as a slowly evolving null surface (SENS). Such surfaces are of interest because they coincide with the event horizon and are causal, unlike apparent horizons. Moreover, known laws of BH mechanics can be established for these slowly evolving...
In this talk, I will define the photon surface conditions using Cartan scalars within an invariant spin frame which offers a comprehensive description of the local spacetime geometry. By employing this approach, one can gain novel insights into the geometry and dynamics of photon surfaces, independent of the global spacetime structure. I will first discuss the photon surface conditions in a...