Formation of dynamically transversely trapping surfaces and the stretched hoop conjecture. (15th May 2020)

• Record Type: Journal Article
• Authors: Yoshino, Hirotaka; Izumi, Keisuke; Shiromizu, Tetsuya; Tomikawa, Yoshimune
• Is Part Of: Progress of theoretical and experimental physics. Volume 2020:Number 5(2020)
• Publication Date: 2020-05-15
• Subjects: A13 -- E00 -- E31; Physics -- Periodicals; Mathematical physics -- Periodicals; 530.05
• DOI: 10.1093/ptep/ptaa050
• Languages: English
• ISSNs: 2050-3911

Abstract

Abstract: A dynamically transversely trapping surface (DTTS) is a new concept for an extension of a photon sphere that appropriately represents a strong gravity region and has close analogy with a trapped surface. We study formation of a marginally DTTS in time-symmetric, conformally flat initial data with two black holes, with a spindle-shaped source, and with a ring-shaped source, and clarify that $\mathcal{C}\lesssim 6\pi GM$ describes the condition for the DTTS formation well, where $\mathcal{C}$ is the circumference and $M$ is the mass of the system. This indicates that an understanding analogous to the hoop conjecture for the horizon formation is possible. Exploring the ring system further, we find configurations where a marginally DTTS with the torus topology forms inside a marginally DTTS with the spherical topology, without being hidden by an apparent horizon. There also exist configurations where a marginally trapped surface with the torus topology forms inside a marginally trapped surface with the spherical topology, showing a further similarity between DTTSs and trapped surfaces.