According to astronomers’ best models of black hole evolution, the magnetic fields in the accretion disk need to be strong enough to push the accreting plasma around. The new results from Sagittarius A*, the 4.3-million-solar-mass black hole that resides at the center of the Milky Way Galaxy, and those from its much larger cousin M87* previously, provide the first direct observational evidence to support those models.
In 2022, astronomers from the EHT Collaboration unveiled the first image of Sagittarius A*, which is approximately 27,000 light-years away from Earth, revealing that while the Milky Way’s supermassive black hole is more than a thousand times smaller and less massive than M87’s, it looks remarkably similar.
This made the scientists wonder whether the two shared common traits outside of their looks. To find out, they decided to study Sagittarius A* in polarized light.
Previous studies of light around M87* revealed that the magnetic fields around the black hole giant allowed it to launch powerful jets of material back into the surrounding environment.
Building on this work, the new EHT images revealed that the same may be true for Sagittarius A*.
“What we’re seeing now is that there are strong, twisted, and organised magnetic fields near the black hole at the center of the Milky Way Galaxy,” said Dr. Sara Issaoun, an astronomer at the Harvard & Smithsonian’s Center for Astrophysics.
“Along with Sagittarius A* having a strikingly similar polarisation structure to that seen in the much larger and more powerful M87* black hole, we’ve learned that strong and ordered magnetic fields are critical to how black holes interact with the gas and matter around them.”
Light is an oscillating, or moving, electromagnetic wave that allows us to see objects. Sometimes, light oscillates in a preferred orientation, and scientists call it polarized.
Although polarized light surrounds us, to human eyes it is indistinguishable from…
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