Effects of dark matter on shadows and rings of Brane-World black holes illuminated by various accretions
Abstract
In this study, by taking the accretions into account, the observed shadows and rings cast by the Brane-World black hole were numerically investigated when the observer was located at the cosmological horizon. The results showed that the radius rp of the photon sphere increased with the cosmological parameter α and dark matter parameter β, while the impact parameter bp decreased with α and increased with β. For thin disk accretion, the total observed intensity is mainly composed of direct emission. Simultaneously, the lensing ring and photon ring have only small and negligible contributions, respectively. We also found that shadows and rings exhibit different and exciting features when the disk is located at different positions. For static and infalling spherical accretions, it is evident that the size of shadows is always the same for both accretions. This implies that shadows are only related to space-time geometry in this case. The luminosity of the shadow and photon sphere is closely associated with the Doppler effect and the emissivity per unit volume j(ve). In addition, the influence of dark matter and cosmological constant on the observed intensity of shadows and rings is carefully emphasized throughout this paper. Finally, we obtained the burring images of shadows and rings using the nominal resolution of the event horizon telescope. We also studied the upper limits of the X-clod dark matter parameter β using the data of the shadow of M87.
- Publication:
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Science China Physics, Mechanics, and Astronomy
- Pub Date:
- September 2022
- DOI:
- 10.1007/s11433-022-1896-0
- Bibcode:
- 2022SCPMA..6590411Z
- Keywords:
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- 04.20.Bw;
- 04.50.Kd;
- 95.35.+d