Localized Objects Formed by Self-Trapped Gravitational Waves

Geons are localized horizonless objects formed by gravitational waves, held together by the gravitational attraction of their own field energy. In many respects they are similar to scalar field pulson/oscillon configurations, which were found numerically in 1976 by Kudryavtsev, Bogolyubskii, and Makhankov. If there is a negative cosmological constant, the spacetime of geons asymptotically approaches the anti-de Sitter (AdS) metric. AdS geons are time-periodic regular localized vacuum solutions without any radiation loss at infinity. A higher order perturbative construction in terms of an amplitude parameter shows that there are one-parameter families of AdS geon solutions emerging from combinations of identical-frequency linear modes of the system.