Complete set of solutions of the geodesic equation in the space-time of a Schwarzschild black hole pierced by a cosmic string

Hackmann, Eva; Hartmann, Betti; Lämmerzahl, Cláus; Sirimachan, Parinya

doi:10.1103/physrevd.81.064016

Cited by 55 publications

(53 citation statements)

References 29 publications

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“…Note that in the space-time of an infinitely thin cosmic string alone no bound orbits exist (see discussion above) and hence it makes no sense to calculate the perihelion shift. On the other hand, the presence of an infinitely thin cosmic string in black hole space-times enhances the (positive) perihelion shift [22]. The fact that the perihelion shift can become negative in the case of finite width cosmic strings is hence related to the fact that the space-time is that of a smoothed cone close to the string axis.…”

Section: A Perihelion Shiftmentioning

confidence: 97%

“…For this particular case, the perihelion shift is negative which means that the test particle moves from the minimal to the maximal radius and returns back to the minimal radius under an angle less than 2π. In asymptotically flat black hole space-times and even asymptotically flat space-times of black holes pierced by infinitely thin cosmic strings (see [22,23]) the perihelion shift is positive. In a Schwarzschild-(Anti)-de Sitter black hole space-time the positive (negative) cosmological constant gives a positive (negative) contribution to the perihelion shift.…”

Section: A Perihelion Shiftmentioning

confidence: 99%

“…There is another way to detect cosmic strings in the universe, namely through the motion of test bodies in such string space-times. The test particle motion in different space-times containing cosmic strings has been investigated in [17][18][19][20][21], while the complete set of orbits of test particles in the space-time of black hole pierced by an infinitely thin cosmic string has been given for a Schwarzschild black hole in [22] and for a Kerr black hole in [23].…”

Section: Introductionmentioning

confidence: 99%

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Detection of cosmic superstrings by geodesic test particle motion

2011

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(p,q)-strings are bound states of p F-strings and q D-strings and are predicted to form at the end of brane inflation. As such these cosmic superstrings should be detectable in the universe. In this paper we argue that they can be detected by the way that massive and massless test particles move in the space-time of these cosmic superstrings, in particular we study solutions to the geodesic equation in the space-time of field theoretical (p,q)-strings. The geodesics can be classified according to the test particle's energy, angular momentum and momentum in the direction of the string axis. We discuss how the change of the magnetic fluxes, the ratio between the symmetry breaking scale and the Planck mass, the Higgs to gauge boson mass ratios and the binding between the F-and D-strings, respectively, influence the motion of the test particles. While massless test particles can only move on escape orbits, a new feature as compared to the infinitely thin string limit is the existence of bound orbits for massive test particles. In particular, we observe that -in contrast to the space-time of a single Abelian-Higgs string -bound orbits for massive test particles in (p,q)-string space-times are possible if the Higgs boson mass is larger than the gauge boson mass. We also compute the effect of the binding between the p-and the q-string on observables such as the light deflection and the perihelion shift. While light deflection can also be caused by other matter distributions, the possibility of a negative perihelion shift seems to be a feature of finite width cosmic strings that could lead to the unmistakable identification of such objects. In Melvin space-times, which are asymptotically non-conical, massive test particles have to move on bound orbits, while massless test particles can only escape to infinity if their angular momentum vanishes.

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Section: A Perihelion Shiftmentioning

confidence: 97%

Section: A Perihelion Shiftmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Detection of cosmic superstrings by geodesic test particle motion

2011

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“…(20) implies that R(r) ≥ 0 is a necessary condition for the existence of a geodesic. We also observe thatr = 0, where the singularity is located, is a zero of R(r) for all values of the parameters.…”

Section: Ther-φ-equationmentioning

confidence: 99%

“…Also these more advanced methods were applied to obtain solutions of the geodesic equations in various spacetimes (see e.g. [18][19][20][21][22][23][24]). …”

Section: Introductionmentioning

confidence: 99%

Analytic treatment of complete geodesics in a static cylindrically symmetric conformal spacetime

et al. 2016

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Can Superconducting Cosmic Strings Piercing Seed Black Holes Generate Supermassive Black Holes in the Early Universe?

Lake

Harkó

2017

Fortschritte der Physik

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The discovery of a large number of supermassive black holes (SMBH) at redshifts z > 6, when the Universe was only 900 million years old, raises the question of how such massive compact objects could form in a cosmologically short time interval. Each of the standard scenarios proposed, involving rapid accretion of seed black holes or black hole mergers, faces severe theoretical difficulties in explaining the short-time formation of supermassive objects. In this work we propose an alternative scenario for the formation of SMBH in the early Universe, in which energy transfer from superconducting cosmic strings piercing small seed black holes is the main physical process leading to rapid mass increase. As a toy model, the accretion rate of a seed black hole pierced by two antipodal strings carrying constant current is considered. Using an effective action approach, which phenomenologically incorporates a large class of superconducting string models, we estimate the minimum current required to form SMBH with masses of order M = 2 × 10 9 M⊙ by z = 7.085. This corresponds to the mass of the central black hole powering the quasar ULAS J112001.48+064124.3 and is taken as a test case scenario for early-epoch SMBH formation. For GUT scale strings, the required fractional increase in the string energy density, due to the presence of the current, is of order 10 −7 , so that their existence remains consistent with current observational bounds on the string tension. In addition, we consider an "exotic" scenario, in which an SMBH is generated when a small seed black hole is pierced by a higher-dimensional F −string, predicted by string theory. We find that both topological defect strings and fundamental strings are able to carry currents large enough to generate early-epoch SMBH via our proposed mechanism.

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Complete set of solutions of the geodesic equation in the space-time of a Schwarzschild black hole pierced by a cosmic string

Cited by 55 publications

References 29 publications

Detection of cosmic superstrings by geodesic test particle motion

Detection of cosmic superstrings by geodesic test particle motion

Analytic treatment of complete geodesics in a static cylindrically symmetric conformal spacetime

Can Superconducting Cosmic Strings Piercing Seed Black Holes Generate Supermassive Black Holes in the Early Universe?

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