Erratum: Comparative studies of lensing methods [Phys. Rev. D<b>62</b>, 024025 (2000)]

Kling, Thomas; Newman, Ezra T.; Pérez, Alejandro

doi:10.1103/physrevd.62.109901

Cited by 10 publications

(30 citation statements)

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“…It has been realised [1][2][3][4] in the recent past that the physics of the region x > 0.5 is quite different from that in the x < 0.5 for the 3D manganites and one has to look at the heavily doped (x > 0.5) manganites from a different perspective. A similar situation prevails [5] in the bilayer manganites (e.g., La 2−2x Sr 1+2x Mn 2 O 7 ), the n = 2 member of the Ruddelsden-Popper series (R, A) n+1 Mn n O 3n+1 (where R and A are rare-earth and alkaline-earth ions, respectively) as well. These layered systems also show large magnetoresistance (MR) and a sequence of magnetic phases [6,7] like their 3D counterparts.…”

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confidence: 57%

Magnetic and orbital order in overdoped bilayer manganites

Maitra

Taraphder

2004

Europhys. Lett.

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The magnetic and orbital orders for the bilayer manganites in the doping region 0.5 < x < 1.0 have been investigated from a model that incorporates the two e g orbitals at each Mn site, the inter-orbital Coulomb interaction and lattice distortions. The usual double exchange operates via the e g orbitals. It is shown that such a model reproduces much of the phase diagram recently obtained for the bilayer systems in this range of doping. The C-type phase with (π, 0, π) spin order seen by Ling et al. appears as a natural consequence of the layered geometry and is stabilised by the static distortions of the system. The orbital order is shown to drive the magnetic order while the anisotropic hopping across the e g orbitals, layered nature of the underlying structure and associated static distortions largely determine the orbital arrangements.

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confidence: 57%

Magnetic and orbital order in overdoped bilayer manganites

Maitra

Taraphder

2004

Europhys. Lett.

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“…Ten years ago this was essentially true. However, the current speed and memory capacity of even small workstations removes this argument against using the general relativistic equations instead of the thin-lens method or other higher order approximations such as those proposed by Pyne & Birkinshaw (1993) or Kling et al (2000a).…”

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confidence: 99%

“…In the work of Pyne & Birkinshaw (1993), higher order lens equations in cosmological backgrounds are developed. A different style of approximation, which correctly utilizes the thin-lens paths as the zeroth-order path, is introduced in Kling et al (2000aKling et al ( , 2000b.…”

Section: Introductionmentioning

confidence: 99%

Study of Errors in Strong Gravitational Lensing

Kling

Frittelli

2008

ApJ

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We examine the accuracy of strong gravitational lensing determinations of the mass of galaxy clusters by comparing the conventional approach with the numerical integration of the fully relativistic null geodesic equations in the case of weak gravitational perturbations on Robertson-Walker metrics. In particular, we study spherically symmetric, three-dimensional singular isothermal sphere models and the three-dimensional matter distribution of Navarro and coworkers which are both commonly used in gravitational lensing studies. In both cases we study two different methods for mass-density truncation along the line of sight: hard truncation and conventional (no truncation). We find that the relative error introduced in the total mass by the thin-lens approximation alone is less than 0.3% in the singular isothermal sphere model and less than 2% in the model of Navarro and coworkers. The removal of hard truncation introduces an additional error of the same order of magnitude in the best case and up to an order of magnitude larger in the worst case studied. Our results ensure that the future generation of precision cosmology experiments based on lensing studies will not require the removal of the thin-lens assumption, but they may require a careful handling of truncation.

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“…On the other hand, the strongly naked singularities have qualitatively different lensing features, i.e., they give rise to two or none Einstein rings and one radial critical curve. After publication of these results [4,5,6,7], there has been a growing curiosity in black hole lensing and many interesting papers have appeared in last few years (see [8,9,10,11,12,13,14,15,16,17,18,19] and references therein).…”

Section: Introductionmentioning

confidence: 99%

Time delay and magnification centroid due to gravitational lensing by black holes and naked singularities

2008

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We model the massive dark object at the center of the Galaxy as a Schwarzschild black hole as well as Janis-Newman-Winicour naked singularities, characterized by the mass and scalar charge parameters, and study gravitational lensing (particularly time delay, magnification centroid, and total magnification) by them. We find that the lensing features are qualitatively similar (though quantitatively different) for Schwarzschild black holes, weakly naked, and marginally strongly naked singularities. However, the lensing characteristics of strongly naked singularities are qualitatively very different from those due to Schwarzschild black holes. The images produced by Schwarzschild black hole lenses and weakly naked and marginally strongly naked singularity lenses always have positive time delays. On the other hand, strongly naked singularity lenses can give rise to images with positive, zero, or negative time delays. In particular, for a large angular source position the direct image (the outermost image on the same side as the source) due to strongly naked singularity lensing always has a negative time delay. We also found that the scalar field decreases the time delay and increases the total magnification of images; this result could have important implications for cosmology. As the Janis-Newman-Winicour metric also describes the exterior gravitational field of a scalar star, naked singularities as well as scalar star lenses, if these exist in nature, will serve as more efficient cosmic telescopes than regular gravitational lenses.

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Erratum: Comparative studies of lensing methods [Phys. Rev. D62, 024025 (2000)]

Cited by 10 publications

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Magnetic and orbital order in overdoped bilayer manganites

Magnetic and orbital order in overdoped bilayer manganites

Study of Errors in Strong Gravitational Lensing

Time delay and magnification centroid due to gravitational lensing by black holes and naked singularities

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