Speaker
Description
Due to an expected progress of observational facilities Zakharov et al. (2005a) proposed to use global and ground – space VLBI observations in mm band to detect a shadow at Sgr A$^*$ as a tool to evaluate a black hole spin and a position angle of distant observer. In particular, it was predicted that the shadow diameter is around 52 μas for the Sgr A$^*$ case and this prediction was remarkably confirmed by the Event Horizon Telescope (EHT) Collaboration on 12 May 2022. Also Zakharov et al. (2005b) showed that a black hole charge can be evaluated from shadow size estimates. Zakharov (2014) generalized these relations for the tidal charge case. In 2019 the EHT Collaboration reconstructed shadows at M87$^*$ in 2019 and at Sgr A$^*$ in 2022. As it was shown by Zakharov (2022) a black hole charge can be found analytically from these observations.
References
Zakharov A. F. et al., New Astronomy 10, 479 (2005a)
Zakharov A. F. et al., A & A 442, 795 (2005b)
Zakharov A. F. , PRD 90, 062007 (2014)
Zakharov A. F. , Universe 8, 141 (2022)
