scholarly journals SUPERMASSIVE BLACK HOLES OR BOSON STARS? HAIR COUNTING WITH GRAVITATIONAL WAVE DETECTORS

2006 ◽  
Vol 15 (12) ◽  
pp. 2209-2216 ◽  
Author(s):  
EMANUELE BERTI ◽  
VITOR CARDOSO
Keyword(s):  
Black Holes ◽  
Laser Interferometer ◽  
Kerr Black Hole ◽  
Space Time ◽  
Multipole Moments ◽  
Boson Stars ◽  
Laser Interferometer Space Antenna ◽  
Kerr Space ◽  
Oscillation Frequencies ◽  
Rule Out

The evidence for supermassive Kerr black holes in galactic centers is strong and growing, but only the detection of gravitational waves will convincingly rule out other possibilities to explain the observations. The Kerr space–time is completely specified by the first two multipole moments: mass and angular momentum. This is usually referred to as the "no-hair theorem," but it is really a "two-hair" theorem. If general relativity is the correct theory of gravity, the most plausible alternative to a supermassive Kerr black hole is a rotating boson star. Numerical calculations indicate that the space–time of rotating boson stars is determined by the first three multipole moments ("three-hair theorem"). The Laser Interferometer Space Antenna (LISA) could accurately measure the oscillation frequencies of these supermassive objects. We propose to use these measurements to "count their hair," unambiguously determining their nature and properties.

The gravitational perturbations of the Kerr black hole IV. The completion of the solutiont

1980 ◽  
Vol 372 (1751) ◽  
pp. 475-484 ◽  
Keyword(s):  
Black Hole ◽  
Kerr Black Hole ◽  
Space Time ◽  
Gravitational Perturbations ◽  
Kerr Space ◽  
The One

This paper eliminates the last remaining lacuna in the information that was needed to make the solution for the perturbations in the metric coefficients of the Kerr space-time fully explicit. The requisite information is obtained from a pair of equations which is complementary to the one considered in paper III; and the solution of the Newman-Penrose equations governing the perturbations is, thus, completed.

scholarly journals A pseudo-Newtonian description of any stationary space-time

2016 ◽  
Vol 12 (S324) ◽  
pp. 45-46
Author(s):  
Vojtěch Witzany ◽  
Claus Lämmerzahl
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Strong Field ◽  
Kerr Black Hole ◽  
Space Time ◽  
Schwarzschild Black Hole ◽  
Test Particles ◽  
Kerr Field ◽  
Alternative Gravity Theories ◽  
Static Space

AbstractSince the first investigations into accretion onto black holes, astrophysicists have proposed effective Newtonian-like potentials to mimic the strong-field behavior of matter near a Schwarzschild or Kerr black hole. On the other hand, the fields of neutron stars or black holes in many of the alternative gravity theories differ from the idealized Schwarzschild or Kerr field which would require a number of new potentials. To resolve this, we give a Newtonian-like Hamiltonian which almost perfectly mimics the behavior of test particles in any given stationary space-time. The properties of the Hamiltonian are excellent in static space-times such as the Schwarzschild black hole, but become worse for space-times with gravito-magnetic or dragging effects such as near the Kerr black hole.

scholarly journals Kerr–Bolt black hole entropy and soft hair

2020 ◽  
Vol 35 (25) ◽  
pp. 2050156
Author(s):  
M. R. Setare ◽  
A. Jalali
Keyword(s):  
Black Holes ◽  
Phase Space ◽  
Central Charge ◽  
Black Hole Entropy ◽  
Space Time ◽  
Limiting Behavior ◽  
Virasoro Symmetry ◽  
Kerr Space ◽  
Space Formalism ◽  
Good Agreement

Recently it has been speculated that a set of infinitesimal [Formula: see text] diffeomorphisms exist which act nontrivially on the horizon of some black holes such as Kerr and Kerr–Newman black holes.[Formula: see text] Having applied this symmetry in covariant phase space formalism, one can obtain Virasoro charges as surface integrals on the horizon. Kerr–Bolt space–time is well known for its asymptotically topology and has been studied widely in recent years. In this work, we are interested to find conserved charge associated to the Virasoro symmetry of Kerr–Bolt geometry using covariant phase space formalism. We will show right and left central charge are [Formula: see text], respectively. Our results also show good agreement with Kerr space–time in the limiting behavior.

scholarly journals Discovering intermediate massive black holes through tidally disrupted stars

2019 ◽  
Vol 28 (14) ◽  
pp. 1944015
Author(s):  
Martina Toscani ◽  
Giuseppe Lodato ◽  
Elena Maria Rossi
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Laser Interferometer ◽  
Point Of View ◽  
Frequency Range ◽  
Tidal Disruption ◽  
Massive Black Holes ◽  
Binding Force ◽  
Laser Interferometer Space Antenna ◽  
Self Gravity

Stars are spheres of gas held together by self-gravity. When flying by a black hole, however, the star self-binding force can be overwhelmed by the black hole tides and the star can be torn apart. This is a physically rich and fascinating event which will be described by first introducing the concept of black hole from a mathematical point of view. We will then dive into the physics of the tidal disruption and proceed describing the accompanying electromagnetic flare and gravitational wave burst in the frequency range of the Laser Interferometer Space Antenna. This empowers such events to discover the elusive black holes with mass intermediate between the solar and the million/billion solar masses.

scholarly journals NOTES ON FIVE-DIMENSIONAL KERR BLACK HOLES

2006 ◽  
Vol 21 (11) ◽  
pp. 2331-2352 ◽  
Author(s):  
MAKOTO SAKAGUCHI ◽  
YUKINORI YASUI
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Kerr Black Hole ◽  
Weyl Curvature ◽  
Null Geodesics ◽  
Ricci Flat ◽  
Space Star ◽  
Kerr Space ◽  
Kerr Black Holes

The geometry of five-dimensional Kerr black holes is discussed based on geodesics and Weyl curvatures. Kerr-Star space, Star-Kerr space and Kruskal space are naturally introduced by using special null geodesics. We show that the geodesics of AdS Kerr black hole are integrable, which generalizes the result of Frolov and Stojkovic. We also show that five-dimensional AdS Kerr black holes are isospectrum deformations of Ricci-flat Kerr black holes in the sense that the eigenvalues of the Weyl curvature are preserved.

Gauge invariant perturbations of black holes. II. Kerr space–time

1997 ◽  
Vol 38 (1) ◽  
pp. 330-349 ◽  
Author(s):  
Joe F. Q. Fernandes ◽  
Anthony W. C. Lun
Keyword(s):  
Black Holes ◽  
Space Time ◽  
Gauge Invariant ◽  
Kerr Space

scholarly journals Time-delay interferometry

2020 ◽  
Vol 24 (1) ◽  
Author(s):  
Massimo Tinto ◽  
Sanjeev V. Dhurandhar
Keyword(s):  
Time Delay ◽  
Laser Interferometer ◽  
Laser Light ◽  
Space Antenna ◽  
Phase Measurements ◽  
Laser Noise ◽  
Future Space ◽  
Laser Interferometer Space Antenna ◽  
Overall Performance ◽  
Mathematical Foundations

AbstractEqual-arm detectors of gravitational radiation allow phase measurements many orders of magnitude below the intrinsic phase stability of the laser injecting light into their arms. This is because the noise in the laser light is common to both arms, experiencing exactly the same delay, and thus cancels when it is differenced at the photo detector. In this situation, much lower level secondary noises then set the overall performance. If, however, the two arms have different lengths (as will necessarily be the case with space-borne interferometers), the laser noise experiences different delays in the two arms and will hence not directly cancel at the photo detector. To solve this problem, a technique involving heterodyne interferometry with unequal arm lengths and independent phase-difference readouts has been proposed. It relies on properly time-shifting and linearly combining independent Doppler measurements, and for this reason it has been called time-delay interferometry (TDI). This article provides an overview of the theory, mathematical foundations, and experimental aspects associated with the implementation of TDI. Although emphasis on the application of TDI to the Laser Interferometer Space Antenna mission appears throughout this article, TDI can be incorporated into the design of any future space-based mission aiming to search for gravitational waves via interferometric measurements. We have purposely left out all theoretical aspects that data analysts will need to account for when analyzing the TDI data combinations.

scholarly journals GENERALIZED W3-STRINGS FROM FREE FIELDS

1995 ◽  
Vol 10 (06) ◽  
pp. 515-524 ◽  
Author(s):  
J. M. FIGUEROA-O'FARRILL ◽  
C. M. HULL ◽  
L. PALACIOS ◽  
E. RAMOS
Keyword(s):  
Bosonic Strings ◽  
Free Field ◽  
Space Time ◽  
General Construction ◽  
Special Cases ◽  
Free Fields ◽  
Rule Out ◽  
General Conditions ◽  
String Theories

The conventional quantization of w3-strings gives theories which are equivalent to special cases of bosonic strings. We explore whether a more general quantization can lead to new generalized W3-string theories by seeking to construct quantum BRST charges directly without requiring the existence of a quantum W3-algebra. We study W3-like strings with a direct space-time interpretation — that is, with matter given by explicit free field realizations. Special emphasis is placed on the attempt to construct a quantum W-string associated with the magic realizations of the classical w3-algebra. We give the general conditions for the existence of W3-like strings, and comment on how the known results fit into our general construction. Our results are negative: we find no new consistent string theories, and in particular rule out the possibility of critical strings based on the magic realizations.

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