Scientists were surprised by a strange pulse emitted from the massive black hole at the center of the Milky Way Galaxy, known as Sagittarius A. Physicists Gustavo Magallanes Joykhoun and Sergio Mendoza from the National Autonomous University of Mexico revealed fluctuations in the gamma-ray flux of Sagittarius A every 76 minutes.
According to the research team, published on the arXiv website, this periodicity resembles variations in the radio and X-ray emissions from the black hole, indicating the presence of an orbital motion around the black hole.
As per “Science Alert,” black holes themselves do not emit radiation that we can currently detect, but the surrounding space is a different matter. In extreme gravity conditions outside the event horizon of a black hole, a lot can happen.
Light emanates from the Sagittarius A region in various wavelength ranges, and the intensity of this light changes significantly over time. Astronomers have discovered a pattern in some of these wavelength ranges, at least.
Radio waves fluctuate on a timescale of about 70 minutes or so, according to a research paper published in 2022. However, recently, specifically in 2021, gamma-ray radiation has been linked to Sagittarius A.
Magallanes Joykhoun and Mendoza believe that there may be some hidden secrets in the gamma-ray data, so they began analyzing it. They took the publicly available data recorded by the Fermi Gamma-ray Space Telescope between June and December 2022, processed it, and conducted a search for periodic patterns.
They found that every 76.32 minutes, Sagittarius A emits a gamma-ray burst, which is the most active wavelength range of light in the universe.
The similarity to the frequency of radio and X-ray bursts suggests a common underlying cause. The research team states that the radio burst has a periodicity almost identical to the gamma-ray burst itself. The X-ray burst, at 149 minutes, has a multiple periodicity, and this is unlikely to be a mere coincidence, indicating that its periodicity is concordant with both gamma rays and radio bursts.
Since the black hole itself does not emit any radiation, and this regular and recurring periodicity often indicates orbital motion, the likely explanation lies in the physical mechanism of what is orbiting around the black hole.