A very close binary black hole in a giant elliptical galaxy 3C 66B and its black hole merger.
IGUCHI S., OKUDA T. and SUDOU H.
Abstract (from CDS):
Recent observational results provide possible evidence that binary black holes (BBHs) exist in the center of giant galaxies and may merge to form a supermassive black hole in the process of their evolution. We first detected a periodic flux variation on a cycle of 93±1 days from the 3 mm monitor observations of a giant elliptical galaxy 3C 66B for which an orbital motion with a period of 1.05±0.03 yr had been already observed. The detected signal period being shorter than the orbital period can be explained by taking into consideration the Doppler-shifted modulation due to the orbital motion of a BBH. Assuming that the BBH has a circular orbit and that the jet axis is parallel to the binary angular momentum, our observational results demonstrate the presence of a very close BBH that has a binary orbit with an orbital period of 1.05±0.03 yr, an orbital radius of (3.9±1.0)x10–3 pc, an orbital separation of (6.1+1.0–0.9)x10–3 pc, a larger black hole mass of (1.2+0.5–0.2)x109 M☉, and a smaller black hole mass of (7.0+4.7–6.4)x108 M☉. The BBH decay time of (5.1+60.5–2.5)x102 yr provides evidence for the occurrence of black hole mergers. This Letter will demonstrate the interesting possibility of black hole collisions to form a supermassive black hole in the process of evolution, one of the most spectacular natural phenomena in the universe.
black hole physics - galaxies: active - galaxies: elliptical and lenticular, cD - galaxies: formation - galaxies: individual: 3C 66B