Gravitational lensing by cosmic string loops

Laix, Andrew A. de; Vachaspati, Tanmay

doi:10.1103/physrevd.54.4780

Cited by 41 publications

(61 citation statements)

References 18 publications

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“…A time dependence of the deflecting potential which is of particular interest for string type lenses (because they are expected to move with relativistic velocities) is that of an oscillating loop. For this scenario the deflection of light passing sufficiently far outside the loop has been found to be identical to that of a point mass source (see [21,22] for details). In contrast, the linear motion studied in this work gives rise to a vector perturbation of the metric, which manifests itself in the dt dz cross term of the boosted line element (12).…”

Section: Rigidly Moving Lensesmentioning

confidence: 99%

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Deflection of light and particles by moving gravitational lenses

2004

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Various authors have investigated the problem of light deflection by radially moving gravitational lenses, but the results presented so far do not appear to agree on the expected deflection angles. Some publications claim a scaling of deflection angles with 1 − v to first order in the radial lens velocity v, while others obtained a scaling with 1 − 2v. In this paper we generalize the calculations for arbitrary lens velocities and show that the first result is the correct one. We discuss the seeming inconsistency of relativistic light deflection with the classical picture of moving test particles by generalizing the lens effect to test particles of arbitrary velocity, including light as a limiting case. We show that the effect of radial motion of the lens is very different for slowly moving test particles and light and that a critical test particle velocity exists for which the motion of the lens has no effect on the deflection angle to first order. An interesting and not immediately intuitive result is obtained in the limit of a highly relativistic motion of the lens towards the observer, where the deflection angle of light reduces to zero. This phenomenon is elucidated in terms of moving refractive media. Furthermore, we discuss the dragging of inertial frames in the field of a moving lens and the corresponding Lense-Thirring precession, in order to shed more light on the geometrical effects in the surroundings of a moving mass. In a second part we discuss the effect of transversal motion on the observed redshift of lensed sources. We demonstrate how a simple kinematic calculation explains the effects for arbitrary velocities of the lens and test particles. Additionally we include the transversal motion of the source and observer to show that all three velocities can be combined into an effective relative transversal velocity similar to the approach used in microlensing studies.

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Section: Rigidly Moving Lensesmentioning

confidence: 99%

“…Of most interest in the context of our work is the study of moving cosmic strings (see, for example, de Laix and Vachaspati [21] and Uzan and Bernardeau [22]). Below we will discuss the similarities and differences arising from such different types of lenses and motions.…”

Section: Introductionmentioning

confidence: 99%

Deflection of light and particles by moving gravitational lenses

2004

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“…The analysis of the WMAP CMBR data by [9][10][11][12] provides us with an upper limit to the linear density of a cosmic string.…”

Section: Cosmic Strings: Generalities and Their Role In Particle Physicsmentioning

confidence: 99%

Gravitational Lens Images Generated by Cosmic Strings

Sazhin¹,

Sazhina²,

Capaccioli³

et al. 2010

TOAAJ

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Abstract:In this review paper the current understanding on the properties of cosmic strings is shortly outlined with special emphasis on the observational signatures which can be expected both in the optical, through gravitational lensing, and in the radio, through anisotropies in the cosmic microwave background. The experience gathered during the long term investigation of the former candidate CSL-1 is also shortly summarized.Keywords: Cosmology, cosmic string, quasars, gravitational lensing, the CMBR anisotropy. COSMIC STRINGS: GENERALITIES AND THEIR ROLE IN PARTICLE PHYSICSThe topological defects of space-time known as cosmic strings were introduced in the late seventies by Kibble [1] and have been extensively discussed over the past decades by several authors [2,3].Their existence finds support in a large class of early Universe models based on the superstring theory [4][5][6]. Cosmic strings are in fact predicted by compactification models, in theories with extended additional dimensions, and are easily justified within the current inflationary scenarios. It is important to stress that in comparision with other topological defects such as monopoles, domain walls, textures, etc., cosmic strings are the most likely to exist.Nowadays, inflation finds a widespread consensus within the cosmological community and is in good agreement with observational astronomical data. On the other end, the braneantibrane inflationary mechanism is the most natural model arising from superstring theories (being one of the most promising to achieve a full description of the Universe at Planckian time-scales) theory tells us that, within this mechanism, inflation ends when the brane and the antibrane annihilate. This process is likely to generate an extremely rich spectrum of post-inflationary remnants. Cosmic strings are among the most likely remnants with a rather rich spectrum.Without any doubt, the discovery of any of such objects would lead to a quantum leap in many fields of fundamental physics and, more specifically, in understanding the rules of GUT and the processes occurring in the pre-inflationary Universe. The linear density of a string (or its tension) *Address correspondence to this author at the Sternberg Astronomical Institute, Moscow State University, University pr. 13, Moscow, Russia; Tel: +7 495 939 50 06; Fax: +7 495 932 88 41; E-mail: miksazhin@yandex.ru depends in fact on the symmetry breaking scale. The specific equation which links these two values depends both on the model of phase transition and on the specific form of the scalar field potential. In the case of a global U(1) string (i.e. the simplest case with winding number n = 1), the equation is, [7]:where vac is the energy density of the false vacuum and H is the Compton wavelenght of the Higgs boson. Here μ has dimension of linear density.The most relevant and, what is more important, model independent feature of cosmic strings is that they are one dimensional objects with diameter of the order of Planckian size of 10 33 cm. The microscopic charact...

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“…We build on previous work (e.g. [7,8,9,10,11,12,13]) and revisit estimates of probability of lensing by a cosmic string. In particular, we identify simple yet effective strategies for confirming or refuting the string hypothesis, given one putative lens.…”

Section: Introductionmentioning

confidence: 99%

Gravitational lensing by cosmic strings in the era of wide-field surveys

Huterer

Vachaspati

2003

Phys. Rev. D

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Motivated by the recent claim for gravitational lensing by a cosmic string, we reinvestigate the probability of finding such an event with upcoming wide-field surveys. If an observed lensing event is suspected to be due to a string, observations of the vicinity of the event in a circle of diameter L centered on the observed lens should reveal several additional lensing events. For a string located nearby (z < ∼ 0.5), we find that observations in a region of size ≈ 1 arcmin 2 will see ∼ 100 objects, of which ∼ 5 would be lensed by the string, compared to ∼ 0.1 lensed by conventional sources.

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Gravitational lensing by cosmic string loops

Cited by 41 publications

References 18 publications

Deflection of light and particles by moving gravitational lenses

Deflection of light and particles by moving gravitational lenses

Gravitational Lens Images Generated by Cosmic Strings

Gravitational lensing by cosmic strings in the era of wide-field surveys

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