This book overviews the extensive literature on apparent cosmological and black hole horizons.
In theoretical gravity dynamical situations such as gravitational collapse black hole
evaporation and black holes interacting with non-trivial environments as well as the attempts
to model gravitational waves occurring in highly dynamical astrophysical processes require
that the concept of event horizon be generalized. Inequivalent notions of horizon abound in the
technical literature and are discussed in this manuscript. The book begins with a quick review
of basic material in the first one and a half chapters establishing a unified notation.
Chapter 2 reminds the reader of the basic tools used in the analysis of horizons and reviews
the various definitions of horizons appearing in the literature. Cosmological horizons are the
playground in which one should take baby steps in understanding horizon physics. Chapter 3
analyzes cosmological horizons their proposed thermodynamics and several coordinate systems.
The remaining chapters discuss analytical solutions of the field equations of General
Relativity scalar-tensor and f(R) gravity which exhibit time-varying apparent horizons and
horizons which appear and or disappear in pairs. An extensive bibliography enriches the volume.
The intended audience is master and PhD level students and researchers in theoretical physics
with knowledge of standard gravity.
