Black holes, which we can call extremely powerful ‘cosmic engines’, are among the most mysterious cosmic objects that people are most curious about. These extremely powerful structures provide the energy behind quasars and other active galactic nuclei (AGNs) due to matter’s interaction with its strong gravitational and magnetic fields.
Technically speaking, black holes do not have a magnetic field of their own, while the dense plasma surrounding the black hole is known to have a magnetic field. This plasma, rotating around the black hole, creates an electric current and magnetic field thanks to the charged particles inside. The fact that the direction of the plasma flow does not change by itself means that the magnetic field is extremely stable. However, according to the latest information discovered, it seems that astronomers may have found evidence of the existence of a supermassive black hole that can reverse its entire magnetic field.
Astronomers have noticed that a galaxy hundreds of millions of light-years away is suddenly ‘brightening’
Recently, the world of astronomers has pointed to the existence of a black hole reversing its magnetic field. Shocked by the evidence.
Basically, you can think of a magnetic field as the magnetic field in a simple magnet with a north and south pole. A magnetic reversal can be defined as a reversal of the direction of this imaginary pole and a change of direction of the magnetic field. This effect is quite common among stars. For example, the Sun, the main star of the Solar System of which our planet is a part, reverses its magnetic field every 11 years. Even the Earth undergoes magnetic reversal every few hundred thousand years.
However, this was thought to be unlikely for supermassive black holes. At least until now. An automated survey of the sky detected a sudden change in a galaxy 239 million light-years away in 2018. Known as 1ES 1927+654, the galaxy was 100 times brighter in visible light than before. Shortly after its discovery, the Swift Observatory captured the galaxy’s light with X-rays and ultraviolet. Archival observations of the region revealed that the galaxy actually began to light up towards the end of 2017.
Early evidence that black holes can reverse their magnetic field
At the time, it was thought that a star passing near the galaxy’s supermassive black hole was causing the flash. . In theory, such a close encounter should shatter the star and cause a tidal perturbation that would disrupt the gas flow in the black hole’s accretion disk. But the new study in question shows that the situation may be much different than that.
The research team studied observations of galactic flare across the entire light spectrum, from radio to X-rays. One of the things that caught the team’s attention during this review was that the intensity of the X-rays dropped very quickly. Considering that X-rays are usually produced by charged particles spiraling in intense magnetic fields, this suggested that there may have been a sudden change in the magnetic field around the black hole.
However, the team also observed that the intensity of visible and ultraviolet light in the galaxy increased. This indicates that parts of the black hole’s accretion disk are getting hotter; however, none of the effects we have mentioned are the ones expected to be experienced as a result of a tidal interruption event as predicted.
Judging by the available data, astronomers think that the magnetic reversal theory is much more appropriate for this situation. According to the team’s statements on the subject, if there is a reversal in the magnetic field of a black hole accretion disk, the field should first weaken at the outer edges of the accretion disk. As a result, the disc can heat up more efficiently. In addition, a weaker magnetic field means less X-rays are produced by the charged particles. After the magnetic field reversal completes, the disk returns to its original state.
This evidence stands out as the first observations to show that a galactic black hole can be magnetically reversible. While it is now known that this is possible, it is not yet known how often it occurs. Researchers say that much more detailed observations are needed to understand how many times a galaxy can reverse the magnetic field of its black hole.
7999
