scholarly journals Tidally induced multipole moments of a nonrotating black hole vanish to all post-Newtonian orders

2021 ◽  
Vol 104 (10) ◽  
Author(s):  
Eric Poisson
Keyword(s):  
Black Hole ◽  
Multipole Moments

The interaction between a rotating, spherical shell of matter and a central black hole

1978 ◽  
Vol 362 (1711) ◽  
pp. 469-492
Keyword(s):  
Black Hole ◽  
Spherical Shell ◽  
Energy Momentum Tensor ◽  
Momentum Tensor ◽  
Leading Order ◽  
Multipole Moments ◽  
Matter Distribution ◽  
Central Black Hole ◽  
Magnetic Components ◽  
Axis Of Rotation

A method due to Chrzanowski, involving horizon multipole moments, is applied to the problem of a black hole perturbed by an enclosing, distant, spinning, spherical shell of matter. The hole, of mass M and angular momentum J = aM , is at the centre of the shell, their respective axes of rotation differing by an angle ξ. The matter-distribution on the shell is axisymmetric about its axis of rotation, but otherwise arbitrary, except that the total mass of the shell is small in comparison with M . The energy-momentum tensor of such a shell has been previously found by Bass & Pirani. Using their expression, we calculate the spin-down law for the black hole, correct to leading order in the inverse of the shell’s radius, and to second order in its angular velocity. The solution may be expressed in terms of the ‘electric’ and ‘magnetic’ components E αβ and B αβ of the Weyl tensor C ijkl , as calculated at the centre of the shell, in the absence of the black hole. For, denoting by J ∥ and J ⊥ the components of J parallel and perpendicular, respectively, to the direction of spin of the shell, we have always d J ∥ /d t = 0 and 1/ J ⊥ d J ⊥ /d t =–4/15 M 3 ( E αβ E αβ + B αβ B αβ ) (1–3/4ã 2 +15/4ã 2 sin 2 ξ), where ã = a / M . This law is of theoretical interest. It shows points both of similarity to, and of difference from, the known laws describing the response of a black hole to (uniform) scalar and electromagnetic fields.

scholarly journals A New Solution of the Einstein-Maxwell Equations for a System with Mass, Magnetic Moment, Charge, and Angular momentum

1974 ◽  
Vol 64 ◽  
pp. 192-192
Author(s):  
Louis Witten
Keyword(s):  
Black Hole ◽  
Angular Momentum ◽  
Magnetic Dipole ◽  
Electric Charge ◽  
Magnetic Moment ◽  
Maxwell Equations ◽  
Black Hole Physics ◽  
Red Shift ◽  
Multipole Moments ◽  
Asymptotically Flat

A five parameter solution of the combined Einstein-Maxwell equations is given which describes a source containing mass, electric charge, magnetic dipole, higher multipole moments of all three kinds, and angular momentum. The solution is asymptotically flat and has a singular infinite red shift surface. Possible relevance of the solution to black hole physics is discussed.

scholarly journals Effect of Multipole Moments in the Weak Field Limit of a Black Hole Plus Halo Potential

2021 ◽  
Vol 908 (1) ◽  
pp. 74
Author(s):  
Fredy L. Dubeibe ◽  
Tareq Saeed ◽  
Euaggelos E. Zotos
Keyword(s):  
Black Hole ◽  
Weak Field ◽  
Multipole Moments ◽  
Field Limit ◽  
Weak Field Limit

scholarly journals Delaying the inevitable: tidal disruption in microstate geometries

2021 ◽  
Vol 2021 (2) ◽  
Author(s):  
Iosif Bena ◽  
Anthony Houppe ◽  
Nicholas P. Warner
Keyword(s):  
Black Hole ◽  
String Theory ◽  
Large Distance ◽  
Black Hole Horizon ◽  
Multipole Moments ◽  
Tidal Effects ◽  
Tidal Disruption ◽  
Tidal Deformations ◽  
Significant Distance

Abstract Microstate geometries in string theory replace the black-hole horizon with a smooth geometric “cap” at the horizon scale. In geometries constructed using superstratum technology, this cap has the somewhat surprising property that induces very large tidal deformations on infalling observers that are far away from it. We find that this large-distance amplification of the tidal effects is also present in horizonless microstate geometries constructed as bubbling solutions, but can be tamed by suitably arranging the bubbles to reduce the strength of some of the gravitational multipole moments. However, despite this taming, these tidal effects still become large at a significant distance from the microstructure. This result suggests that an observer will not fall unharmed into the structure replacing the black hole horizon.

scholarly journals The multipolar structure of fuzzballs

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Massimo Bianchi ◽  
Dario Consoli ◽  
Alfredo Grillo ◽  
Josè Francisco Morales ◽  
Paolo Pani ◽  
...  
Keyword(s):  
Black Hole ◽  
Angular Momentum ◽  
Global Minimum ◽  
Kerr Black Hole ◽  
Large Family ◽  
Compact Objects ◽  
Multipole Moments ◽  
Abelian Gauge ◽  
Dimensional Parameter ◽  
General Method

Abstract We extend and refine a general method to extract the multipole moments of arbitrary stationary spacetimes and apply it to the study of a large family of regular horizonless solutions to $$ \mathcal{N} $$ N = 2 four-dimensional supergravity coupled to four Abelian gauge fields. These microstate geometries can carry angular momentum and have a much richer multipolar structure than the Kerr black hole. In particular they break the axial and equatorial symmetry, giving rise to a large number of nontrivial multipole moments. After studying some analytical examples, we explore the four-dimensional parameter space of this family with a statistical analysis. We find that microstate mass and spin multipole moments are typically (but not always) larger that those of a Kerr black hole with the same mass and angular momentum. Furthermore, we find numerical evidence that some invariants associated with the (dimensionless) moments of these microstates grow monotonically with the microstate size and display a global minimum at the black-hole limit, obtained when all centers collide. Our analysis is relevant in the context of measurements of the multipole moments of dark compact objects with electromagnetic and gravitational-wave probes, and for observational tests to distinguish fuzzballs from classical black holes.

Sign in / Sign up

Export Citation Format

Share Document