The story begins with a galaxy known as 1ES 1927+654, which briefly ceased X-ray emissions for a few months, then resumed and increased. So far, the potential 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 dropping out completely while the other wavelengths brighten,” study lead author Sibasish Laha, a research scientist at the University of Maryland, Baltimore County, and NASA’s Goddard Space Flight Center in Maryland, said in a NASA statement.
The Milky Way (and most other large galaxies like it) have a supermassive black hole embedded at its heart; the black hole pulls matter in toward its center. The matter first collects in an accretion disc surrounding the black hole, then heats up and emits light (in visible, ultraviolet, and X-ray wavelengths) as the matter is pushed inward.
If a magnetic reversal took place, causing the north pole to become the south pole and vice versa, visible and UV light should increase toward the center of the galaxy due to more heating as the corona begins to diminish and the accretion disk grows more compact in the center.
But as the flip evolves, the field weakens so much that the corona cannot be supported at all anymore, causing the X-ray emissions to cease, researchers, suggested.
That idea matches observations of this galaxy, as the X-ray emissions re-emerged in October 2018, roughly four months after they disappeared, suggesting a magnetic reversal took place. The galaxy returned to pre-eruption X-ray emissions in summer 2021.