The surface geometry and shadow of a Schwarzschild black hole with halo

We investigate the gravitational lensing by spinning Proca stars and the shadows and lensing by Kerr black holes (BHs) with synchronised Proca hair, discussing both theoretical aspects and observational constraints from the Event Horizon Telescope (EHT) M87* and Sgr A* data. On the theoretical side, this family of BHs interpolates between Kerr-like solutions — exhibiting a similar optical appearance to that of Kerr BHs — to very non-Kerr like solutions, exhibiting exotic features such as cuspy shadows, egg-like shadows and ghost shadows. We interpret these features in terms of the structure of the fundamental photon orbits, for which different branches exist, containing both stable and unstable orbits, with some of the latter not being shadow related. On the observational side, we show that current EHT constraints are compatible with all such BHs that could form from the growth of the superradiant instability of Kerr BHs. Unexpectedly, given the (roughly) 10% error bars in the EHT data — and in contrast to their scalar cousin model —, some of the BHs with up to 40% of their energy in their Proca hair are compatible with the current data. We estimate the necessary resolution of future observations to better constrain this model.

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“…This setup has been subsequently widely used e.g [9,32,35,[40][41][42][43][44][45][46][47][48][49][50][51][52][53][54]…”

mentioning

confidence: 99%

Kerr black holes with synchronised Proca hair: lensing, shadows and EHT constraints

Sengo

Cunha

Herdeiro

et al. 2023

J. Cosmol. Astropart. Phys.

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“…[23], we proposed the concept of the curvature radius for the black hole shadow, which is also independent of the location of the center of shadow, while is dependent of the intrinsic properties of the critical curve. On the other hand, the Schwarzschild black hole shadows in an external gravitational field [24], with a cosmological constant [25] and with halos [26] were well studied. Kerr black hole shadows in different backgrounds have also been extensively investigated [23,[27][28][29][30][31][32].…”

Section: Introductionmentioning

confidence: 99%

Optical appearance of Einstein-Æther black hole surrounded by thin disk

Wang¹,

Lin²,

Wei³

2022

Preprint

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In Einstein-AEther theory, the Lorentz symmetry is locally broken in the high-energy regime due to the presence of the AEther field. This shall leave significant imprint on astronomical observation. In this paper, we investigate the optical appearance of two types of the static and spherically symmetric black holes in Einstein-AEther theory. Via Euler-Lagrange equation, we obtain the equations of motion of the photon and calculate the total deflection angle of the photon trajectory around the black hole. By classifying the light rays with the total number of orbits, we study the effects of coupling constants on the direct image, lensing ring, and photon ring. The features of the light trajectories are also investigated by comparing with the Einstein-AEther theory and general relativity. Moreover, we also show the explicit optical appearance of black holes surrounded by thin disk emissions with three characteristic emitted models. The results indicate that the direct image gives the main contribution to the total flux, and the lensing ring just gives a very small contribution, whereas the role of the photon ring is negligible. The optical appearances are also found to significantly rely on these coupling constants.

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“…The presence of black holes is one of the important predictions of general relativity, and this prediction has been proven to be true by the LIGO-Virgo collaborations through the direct observation of gravitational waves [1]. In recent years, there are a large number of works on the study of black holes, such as the black hole shadow, deflection angle, quasinormal modes, thermodynamic phase transitions and other topics [2][3][4][5][6][7][8][9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Dark Information in Black Hole with λφ Fluid

Liu

Wang

et al. 2022

Symmetry

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It has been shown that the nonthermal spectrum of Hawking radiation will lead to information-carrying correlations between emitted particles in the radiation. The mutual information carried by such correlations can not be locally observed and hence is dark. With dark information, the black hole information is conserved. In this paper, we look for the spherically symmetric black hole solution in a λφ fluid model and investigate the radiation spectrum and dark information of the black hole. The spacetime structure of this black hole is similar to that of the Schwarzschild one, while its horizon radius is decreased by the λφ fluid. By using the statistical mechanical method, the nonthermal radiation spectrum is calculated. This radiation spectrum is very different from the Schwarzschild case at its last stage because of the effect of the λφ fluid. The λφ fluid reduces the lifetime of the black hole, but increases the dark information of the Hawking radiation.

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The surface geometry and shadow of a Schwarzschild black hole with halo

Cited by 3 publications

References 17 publications

Kerr black holes with synchronised Proca hair: lensing, shadows and EHT constraints

Kerr black holes with synchronised Proca hair: lensing, shadows and EHT constraints

Optical appearance of Einstein-Æther black hole surrounded by thin disk

Dark Information in Black Hole with λφ Fluid

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