Boosted black string bombs

Sep, 2012
14 pages
Published in:
  • JHEP 02 (2013) 014
e-Print:
Report number:
  • EDINBURGH-2012-18

Citations per year

2012201520182021202401234567
Abstract: (Springer)
We study the formation of superradiant bound states for massive scalar fields in five-dimensional rotating black string geometries with a non-vanishing Kaluza-Klein momentum along the compact direction. Even though all Kaluza-Klein modes may form bound states in this geometry, in realistic extra-dimensional models and astrophysical black holes only the zero-mode is sufficiently light for superradiant instabilities to develop, provided the field has a small but non-vanishing mass, as for example for axion-like particles. We use analytical and numerical methods to show that, although the Kaluza-Klein momentum decreases the upper bound on the field mass for an instability to develop, it may enhance its maximum growth rate by more than 50%, thus boosting the black hole bomb mechanism. We discuss the possible observational consequences of this result and its potential as an astrophysical probe of non-trivial extra-dimensional compactifications.
Note:
  • 15 pages, 6 figures; revised version published in JHEP
  • Kaluza-Klein
  • black hole
  • black string: rotation
  • bound state
  • compactification
  • dimension: 5
  • superradiance
  • zero mode