Gravitational time advancement and its possible detection

Bhadra, Arunava; Nandi, K. K.

doi:10.1007/s10714-009-0842-6

Cited by 19 publications

(15 citation statements)

References 11 publications

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“…The gravitational time advancement effect takes place when the observer is situated at a stronger gravitational field with respect to the gravitational field encountered by the photon while traversing a certain path [55]. We found that dark energy and dark matter do affect the gravitational time advancement and though the magnitude of the effect is small, it induces an interesting observational consequence, at least in principle.…”

Section: Introductionmentioning

confidence: 82%

“…The general perception as regards the gravitational time delay is that due to the influence of a gravitating object the average global speed of light is reduced from its special-relativistic value c 0 and hence the signal always suffers an additional time delay. But depending upon the position of the observer, the delay can as well be negative, which was called a gravitational time advancement [55]. To exemplify the effect let us consider light propagating in a gravitational field between two points A and B.…”

Section: Gravitational Time Advancementmentioning

confidence: 99%

“…Now let us consider the case that the observer is at the point B instead of the point A. In that case the proper time between transmission and the reception of the signal to be measured by the observer will be [55] …”

Section: Gravitational Time Advancementmentioning

confidence: 99%

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Influences of dark energy and dark matter on gravitational time advancement

Ghosh

Bhadra

2015

Eur. Phys. J. C

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The effect of dark matter/energy on the gravitational time advancement (negative effective time delay) has been investigated considering a few dark energy/matter models including cosmological constant. It is found that dark energy gives only a (positive) gravitational time delay, irrespective of the position of the observer, whereas a pure Schwarzschild geometry leads to a gravitational time advancement when the observer is situated at a relatively stronger gravitational field point in the light trajectory. Consequently, there will be no time advancement effect at all at radial distances where the gravitational field due to dark energy is stronger than the gravitational field of the Schwarzschild geometry.

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Section: Introductionmentioning

confidence: 82%

Section: Gravitational Time Advancementmentioning

confidence: 99%

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Influences of dark energy and dark matter on gravitational time advancement

Ghosh

Bhadra

2015

Eur. Phys. J. C

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“…2 Interestingly, there is also an effect of gravitational time advancement in Schwarzschild gravity, which is largely due to differing clock rates [19]. However, the delay in Eq.…”

Section: Johannsen Metric and Relative Time Delaymentioning

confidence: 99%

“…Inserting the expressions for 1/r in Eq. (19) for the relevant segments and carrying out the angular integrations on the co-rotating and counter-rotating sides using…”

mentioning

confidence: 99%

Relative time delay in a spinning black hole as a diagnostic for no-hair theorem

Izmailov¹,

Zhdanov²,

Bhadra

et al. 2019

Eur. Phys. J. C

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The spinning regular black hole (spin a) metric proposed by Johannsen shares the Kerr horizon but contains independent dimensionless parameters marking deviation from the Kerr metric. Non-zero value of any of the parameters would indicate violation of the no-hair theorem. We shall find the influence of these parameters on the relative time delay (not Shapiro time delay) treated here as a diagnostic for no-hair theorem using aligned, finite, thinlens approximation in realistic spinning astrophysical configurations. Precise measurement of this delay would then help us determine, from observational perspective, whether or not any of the parameters is really non-zero. We shall also point out that the aligned spinning lens is completely equivalent to a "static" lens with a fictitious lens geometry, which would enable us to re-express the relative time delay components in terms of the spin a. Numerical values are tabulated for three astrophysical lens systems. The advantage of the present treatment is that it can accommodate a variety of spinning lens systems that are likely to be detected in the near future.

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Probing dark matter and dark energy through gravitational time advancement

2019

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The expression of gravitational time advancement (negative time delay) for particles with non-zero mass in Schwarzschild geometry has been obtained. The influences of the gravitational field that describes the observed rotation curves of spiral galaxies and that of dark energy (in the form of cosmological constant) on time advancement of particles have also been studied. The present findings suggest that in presence of dark matter gravitational field the time advancement may take place irrespective of gravitational field of the observer, unlike the case of pure Schwarzschild geometry where gravitational time advancement takes place only when the observer is situated at stronger gravitational field compare to the gravitational field encountered by the particle during its journey. When applied to the well known case of SN 1987a, it is found that the net time delay of a photon/gravitational wave is much smaller than quoted in the literature. In the presence of dark matter field, the photon and neutrinos from SN 1987a should have been suffered gravitational time advancement rather than the delay.

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Gravitational time advancement and its possible detection

Cited by 19 publications

References 11 publications

Influences of dark energy and dark matter on gravitational time advancement

Influences of dark energy and dark matter on gravitational time advancement

Relative time delay in a spinning black hole as a diagnostic for no-hair theorem

Probing dark matter and dark energy through gravitational time advancement

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