Confirmation of Sgr A* Using the Event Horizon Telescope Data as Extreme Binary of the Supermassive Black Holes Concluded by Decameter Radio Wave Pulse Observations

Abstract

Hiroshi Oya

We analyzed the time variation of the visibilities in the publicly released event horizon telescope (EHT) data provided by the EHT Collaboration, who carried out observations of Sgr A* on April 6 and 7, 2017. The EHT consists of the 1.3 mm wavelength very long baseline interferometry (VLBI) system associated with globally distributed six stations with eight antennas. The analyses were not intended to make image of Sgr A*; instead, we searched for periodic time variations in the observed individual baseline data of the EHT by applying a method to compare with the model visibility, for 1.3 mm VLBI detection that was constructed to reflect the effects of the supermassive black hole binary (SMBHB) concluded from the study on the observation of the decameter radio wave pulses from Sgr A*. The SMBHB, orbiting with a period of 2200 ± 50 sec and an orbit size of 4.1×107 km, is observable with an observation angle width of 32.6 μas in a plane nearly parallel to the Galactic equatorial plane. After confirming the possible correspondence between the visibilities of EHT data and constructed model via direct comparison in real-time space, we applied the modified Fourier transformation to confirm the coincidence between observation data and model visibilities. The modified Fourier transformation was uniquely restructured in this paper to eliminate the artificially modulated data sampling time interval by utilizing Fourier transformation of the random noises distributed over time synchronized with data sample timing of the EHT data. We identified significant periodic time variations in the radiation within a range below 70 μas with an orbiting period of 2193.3±27.5 sec that is associated with an eclipse cycle period of 1096.5 sec caused by the SMBHB orbiting motion.

PDF