84 citations · 429 across the 17 of their papers we have counts for
17 papers
Relativistic disks by Appell-ring convolutions
David Kofroň, Petr Kotlařík, Oldřich Semerák
We present a new method for generating the gravitational field of thin disks within the Weyl class of static and axially symmetric spacetimes. Such a gravitational field is describ…
The exterior gravitational potential of toroids
J. -M. Huré, B. Basillais, V. Karas +2
We perform a bivariate Taylor expansion of the axisymmetric Green function in order to determine the exterior potential of a static thin toroidal shell having a circular section, a…
Free motion around black holes with discs or rings: between integrability and chaos -- VI. The Melnikov method
L. Polcar, O. Semerák
Motivated by black holes surrounded by accretion structures, we consider in this series static and axially symmetric black holes "perturbed" gravitationally as being encircled by a…
Free motion around black holes with discs or rings: between integrability and chaos -- V
L. Polcar, P. Suková, O. Semerák
Complete integrability of geodesic motion, the well known feature of the fields of isolated stationary black holes, can easily be "spoilt" by the presence of some additional source…
Schwarzschild binary supported by an Appell ring
O. Semerák, M. Basovník, P. Kotlařík
We continue to study black holes subjected to strong sources of gravity, again paying special attention to the behaviour of geometry in the black-hole interior. After examining, in…
Schwarzschild black hole encircled by a rotating thin disc: Properties of perturbative solution
P. Kotlařík, O. Semerák, P. Čížek
In ApJ (1974), Will solved the perturbation of a Schwarzschild black hole due to a slowly rotating light concentric thin ring, using Green's functions expressed as infinite-sum exp…
Spinning particles in general relativity: Momentum-velocity relation for the Mathisson-Pirani spin condition
L. Filipe O. Costa, Georgios Lukes-Gerakopoulos, Oldřich Semerák
The Mathisson-Papapetrou-Dixon (MPD) equations, providing the "pole-dipole" description of spinning test particles in general relativity, have to be supplemented by a condition spe…
Perturbation of a Schwarzschild black hole due to a rotating thin disc
P. Čížek, O. Semerák
Will (1974) treated the perturbation of a Schwarzschild black hole due to a slowly rotating light concentric thin ring by solving the perturbation equations in terms of a multipole…
Static axisymmetric rings in general relativity: How diverse they are
O. Semerák
Three static and axially symmetric (Weyl-type) ring singularities -- the Majumdar-Papapetrou--type (extremally charged) ring, the Bach-Weyl ring and the Appell ring -- are studied…
On geometry of deformed black holes: II. Schwarzschild hole surrounded by a Bach-Weyl ring
M. Basovník, O. Semerák
We continue to study the response of black-hole space-times on the presence of additional strong sources of gravity. Restricting ourselves to static and axially symmetric (electro-…
On geometry of deformed black holes: I. Majumdar-Papapetrou binary
O. Semerák, M. Basovník
Although black holes are eminent manifestations of very strong gravity, the geometry of space-time around and even inside them can be significantly affected by additional bodies pr…
On geodesic dynamics in deformed black-hole fields
Oldřich Semerák, Petra Suková
"Almost all" seems to be known about isolated stationary black holes in asymptotically flat space-times and about the behaviour of {\em test} matter and fields in their backgrounds…
Spinning particles in vacuum spacetimes of different curvature types
O. Semerák, M. Šrámek
We consider the motion of spinning test particles with nonzero rest mass in the "pole-dipole" approximation, as described by the Mathisson-Papapetrou-Dixon (MPD) equations, and exa…
Free motion around black holes with discs or rings: between integrability and chaos -- IV
V. Witzany, O. Semerak, P. Sukova
The dynamical system studied in previous papers of this series, namely a bound time-like geodesic motion in the exact static and axially symmetric space-time of an (originally) Sch…
Free motion around black holes with discs or rings: between integrability and chaos - III
P. Suková, O. Semerák
We continue the study of time-like geodesic dynamics in exact static, axially and reflection symmetric space-times describing the fields of a Schwarzschild black hole surrounded by…
Free motion around black holes with discs or rings: between integrability and chaos - II
O. Semerák, P. Suková
We continue the study of time-like geodesic dynamics in exact static, axially and reflection symmetric space-times describing the fields of a Schwarzschild black hole surrounded by…
Free motion around black holes with discs or rings: between integrability and chaos - I
O. Semerák, P. Suková
Geodesic dynamics is regular in the fields of isolated stationary black holes. However, due to the presence of unstable periodic orbits, it easily becomes chaotic under various per…