Sagitario A* sopla una brisa caliente, resolviendo un misterio de agujero negro de 50 años

Sagittarius A*, the black hole at the center of our galaxy, weighs 1.3 trillion Earth masses and is packed into a region barely 2,000 times our planet's diameter. After 50 years of staring, we finally caught it blowing a hot breeze.

Elena Murchikova and Mark Gorski at Northwestern University published the detection in the Astrophysical Journal Letters today. They stacked five years of observations from the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile to image the cold molecular gas surrounding Sgr A*. Once they subtracted the blinding radio glow near the black hole, a cone-shaped cavity emerged — nearly three light-years long. The same void showed up in archival Chandra X-ray data.

The Cone That Gave It Away

That cavity is the signature of a steady wind. Here's the mechanism: gas drifting close enough to feel Sgr A*'s gravity heats up and forms a flattened accretion disk, whipping around at near light speed. But not all of that gas makes it into the black hole. Radiation pressure from the inner disk — plus small eruptions — flings hot material outward. Murchikova puts it bluntly: "In fact, more of the gas is ejected than falls into the black hole." If a strong magnetic field is present, that wide cone would narrow into a jet; here, the field is weak, so we get a diffuse breeze.

Why This Wind Matters

For decades, every other supermassive black hole we've studied seems to blow something out — jets, winds, some kind of feedback. Our own black hole was the glaring exception. "The lack of winds from it was one of the most obviously uncomfortable facts," Murchikova said. That missing piece made it hard to test models of black-hole feeding and galactic evolution. Now we have direct evidence that Sgr A* is not a silent loner; it's quietly dumping energy into its surroundings without violent outbursts.

This opens a new window. With a measurable breeze, we can start calibrating accretion physics at the closest possible range — something no other supermassive black hole offers. The next step is to map the wind's velocity and composition, then ask how it shapes the interstellar medium in the galactic center. For a black hole that's been sitting there quietly for 50 years of scrutiny, it's finally starting to talk.

Source: Astronomers just solved a 50-year-old mystery about the Milky Way's black hole
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