A black hole could have reversed its magnetic field before our eyes.
The story begins with a galaxy known as 1ES 1927+654, which briefly stopped emitting X-rays for a few months, then resumed and increased. So far, possible black hole observations represent a unique situation visible from 236 million light-years away.
“This event marks the first time we’ve seen X-rays completely disappear while other wavelengths light up,” said study lead author Sibasish Laha, a research scientist at the University of Maryland, Baltimore County and the NASA’s Goddard Space Flight Center in Maryland. he said in a NASA statement.
If scientists can confirm that the outburst was due to a supermassive black hole at the heart of the galaxy changing its magnetic field, the event may help astrophysicists understand how that change affects the black hole’s environment, according to the statement.
Related: Eureka! Scientists photograph a black hole for the first time
The Milky Way (and most other large galaxies like it) have a supermassive black hole embedded at their heart; the black hole attracts matter towards its center. Matter first accumulates in an accretion disk surrounding the black hole, then heats up and emits light (in visible, ultraviolet, and X-ray wavelengths) as the matter is pushed inward.
As that matter pushes inward, it forms a cloud of extremely hot particles that scientists call a corona. The new study suggests that changes in the corona are what caused the X-rays streaming from the heart of galaxy 1ES 1927+654 to temporarily disappear.
If a magnetic reversal were to occur causing the north pole to become the south pole and vice versa, visible and ultraviolet light should increase towards the center of the galaxy due to further heating, as the corona begins to wane and the accretion disk becomes more compact. in the middle.
But as the spin evolves, the field weakens so much that the corona can no longer hold on, causing X-ray emissions to cease, the researchers suggested.
That idea matches observations of this galaxy, as the X-ray emissions resurfaced in October 2018, about four months after they disappeared, suggesting a magnetic reversal occurred. The galaxy returned to pre-eruption X-ray emissions in the summer of 2021.
Two space telescopes tracked the changes in ultraviolet and X-rays, including NASA’s Neil Gehrels Swift Observatory and the European Space Agency’s XMM-Newton satellite. Radio and visible light observations were made from various ground-based telescopes in places such as Italy, the Canary Islands, and New Mexico.
A paper based on the research has been accepted for publication in The Astrophysical Journal and is available from the arXiv.org preprint service.