The time delay in strong gravitational lensing with Gauss-Bonnet correction

Abstract

The time delay between two relativistic images in the strong gravitational lensing governed by Gauss-Bonnet gravity is studied. We derive and calculate the expression of time delay due to the Gauss-Bonnet coupling. It is shown that the time delay for two images with larger space each other is longer. We also find that the ratio of

Photon spheres in Einstein and Einstein-Gauss-Bonnet theories and circular null geodesics in axially-symmetric spacetimes

“…Similarly from ( 27), (30) and the condition of nonpositive trace T ≤ 0 , we see that P ′ (r H ≤ r < r γ ) ≤ 0. From this last condition and (31) we have…”

“…Even without these Gauss-Bonnet corrections, the ndimensional version of GR is usually studied in astrophysical and theoretical contexts, and in general it is also the case using other alternative gravitational theories. For some works on these topics in EGB or pure GR see [11,26,[28][29][30].…”

Strong deflection gravitational lensing by a modified Hayward black hole

“…These strong deflection lensing can be used to determine different black holes [88][89][90][91][92], naked singularities [93][94][95][96] and wormholes [97][98][99][100][101] as well as test gravity [102,103]. If the source of light has time signals, time delays between the relativistic images can also reveal some information about the lens [104][105][106][107]. Reviews of strong deflection lensing can be found in [108,109].…”

Time delay of photons coupled to Weyl tensor in a regular phantom black hole

“…In the present work, in order to obtain a more comprehensive picture of the photons coupled to the Weyl tensor in the regular phantom black hole, we investigate its time delay in both weak and strong deflection gravitational lensing, which is absent in the previous work [88]. These time-domain signals are important for determining the properties of black holes [89][90][91][92][93][94] and probing new physics [95][96][97][98][99][100][101][102].…”