Detection of Decameter Radio Wave Pulses from the Center Part of Our Galaxy Suggesting Sources at Rotating Super Massive Black Hole Binary
Citation: Oya, H. (2019), Detection of decameter radio wave pulses from the center part of our Galaxy suggesting sources at rotating super massive black hole binary, TERRAPUB. Abstract By using the long baseline interferometer for the decameter wavelength radio waves at Tohoku University operated at 21.86 MHz, we observed decameter radio wave pulses from our Galaxy center mainly in June 2016 and June 2017. Due to the extremely low S/N (signal to noise ratio), where the noise is from 300 to 500
... is from 300 to 500 times larger than the signal level, the observed interferometer data are uniquely analyzed to detect the source direction. Separation of the signal from the high background noise is accomplished by applying the Interferometer Fringe Function Correlation Method (IFFCM) where the aperture synthesis method of the interferometer data that utilizes the Earth's rotation is modified to eliminate any ambiguity of phase shifts in the system. Pulse forms in the signal are confirmed in the Fourier transformed domain by applying FFT operations to the time series data of the IFFCM; by taking an average of the FFT results over 2016 independent sets, the pulse frequencies are separated from the background white noise. The resulting signals indicate a source direction identified to be at Sgr A* within ±6 arc minutes. The signals are characterized by an ensemble of pulses with fundamental periods of (173 ± 1) sec and (148 ± 1) sec corresponding to the spin periods of two sources which we call Gaa and Gab, respectively, whose frequencies periodically vary with a common period of (2200 ± 50) sec. We suggest being based on Kerr black hole theory that Gaa and Gab are super massive Kerr black holes, with masses of (2.27 ± 0.02) × 10 6 M and (1.94 ± 0.01) × 10 6 M , respectively, and with a total mass of (4.22 ± 0.03) × 10 6 M form a binary system orbiting at 2200 ± 50 sec. Keywords: Center of our Galaxy, decameter radio wave, interferometer observations, black hole binary.