Probing the Lorentz Symmetry Violation Using the First Image of Sagittarius A*: Constraints on Standard-Model Extension Coefficients

Abstract

Thanks to unparalleled near-horizon images of the shadows of Messier 87* (M87*) and Sagittarius A* (Sgr A*) delivered by the Event Horizon Telescope (EHT), two amazing windows opened up to us for the strong-field test of the gravity theories as well as fundamental physics. Information recently published from EHT about the Sgr A*'s shadow lets us have a novel exploration of Lorentz symmetry violation (LSV) within the Standard-Model Extension (SME) framework. Despite the agreement between the shadow image of Sgr A* and the prediction of the general theory of relativity, there is still a slight difference which is expected to be fixed by taking some fundamental corrections into account. We bring up the idea that the recent inferred shadow image of Sgr A* is explicable by a minimal SME-inspired Schwarzschild metric containing the Lorentz violating (LV) terms obtained from the post-Newtonian approximation. The LV terms embedded in Schwarzschild metric are dimensionless spatial coefficients sjk associated with the field responsible for the LSV in the gravitational sector of minimal SME theory. In this way, one can control the Lorentz invariance violation in the allowed sensitivity level of the first shadow image of Sgr A*. Actually, using the bounds released within 1σ uncertainty for the shadow size of Sgr A* and whose fractional deviation from standard Schwarzschild, we set upper limits for the two different combinations of spatial diagonal coefficients of SME and time-time coefficient, as well. The best upper limit is at the 10 −3 level, consistent with the value already extracted from Gravity Probe B for the combination of temporal and spatial coefficients of SME.

Spontaneous Lorentz symmetry breaking effects on GRBs jets arising from neutrino pair annihilation process near a black hole

“…Namely, the LSB parameter l can be limited, via constraints imposed on Lorentz violating coefficients of the SME, to find most of the upper bounds extracted on the different combinations of s μν (see the review paper [88]). In the recent paper [89] there is a summarized list of the most important physical frameworks to derive upper bounds on the s μν . Moreover, stringent constraints on l have been directly inferred in Refs.…”

Spontaneous Lorentz symmetry breaking effects on GRBs jets arising from neutrino pair annihilation process near a black hole

“…Namely, the LSB parameter l can be limited, via constraints imposed on Lorentz violating coefficients of the SME, to find most of the upper bounds extracted on the different combinations of s µν (see the review paper [88]). In the recent paper [89] there is a summarized list of the most important physical frameworks to a Note to this point is essential that the shadow of BG with Kerr-like black hole solution introduced in [24] is not distinguishable from its standard counterpart, see [90] for more details.…”

Asymptotically‐Flat Black Hole Solutions in Symmergent Gravity

“…[18,19] We can gather data to derive these characteristics by studying black hole shadows, which are essentially dark representations of their event horizon, and photon rings, which are dazzling images formed by photons circling around black holes, [20][21][22] which are especially noteworthy since they provide accurate gravity constraints in the strong-field regime. [21, These discrepancies could be caused by many reasons linked with several alternative theories of gravity [54][55][56][57][58][59][60][61][62][63][64][65][66][67][68] or the surrounding astrophysical conditions in which the black hole is located. [69][70][71][72][73][74][75][76] Therefore, it becomes crucial to investigate modified gravity theories and establish constraints by utilizing the black hole's shadow alongside astrophysical data, such as observations from telescopes like EHT.…”