The Australian info A new image of our galaxy’s central black hole reveals the magnetic field surrounding the object in polarized light. The image reveals how gas and superheated matter in the immediate vicinity of the black hole move around it. But aside from that, it’s a great way to visualize the extreme physics happening at the center of our galaxy.
The Milky Way’s supermassive black hole is named Sagittarius A*. It’s about four million times the mass of the Sun and was first imaged by the Event Horizon Telescope (EHT) Collaborationin 2022. The collaboration imaged its first black hole three years earlier, an even more massive behemoth at the heart of the M87 galaxy (it’s a whopper at 6.5-billion-solar-masses).
Famously, nothing—not even light—can escape the event horizon of a black hole, so these images really show the black holes’ shadows; that is, the regions of space where the black holes reside. But the immediate environment around a black hole is a different story. These regions emit an extraordinary range of brightness, spanning from radio waves to X-rays. This luminosity is due to the heating of matter and gas that surround black holes and make up their accretion disks, resulting in the emission of light across various wavelengths.
Some of this light is polarized—its wavelengths are oscillating in a specific way that reveals aspects of the physical universe that our naked eyes cannot see. In two papers published today in The Astrophysical Journal Letters, scientists affiliated with the EHT revealed an image of Sagittarius Athat showcases the magnetic fields surrounding the black hole, as revealed by polarized light from its accretion disc.
The first paper includes the image and an overview of the team’s observations and data, while the second paper unpacks the physical structure of the ring and the theoretical models that explain the team’s observations.
“Because Sgr Amoves around while we try to take its picture, it was difficult to construct even the unpolarised image,” said Geoffrey Bow
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