X-Ray echo suggests our galaxy was "active" (quasar-like) just 200 years ago - Nature
X-Ray echo suggests our galaxy was "active" (quasar-like) just 200 years ago - Nature

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X-ray polarization evidence for a 200-year-old flare of Sgr A* - Nature

Well, from the perspective of Earth. Obviously there's a big delay on the way here, which is kind of the entire idea of the technique used.
Plus, without reading the paper I'm not sure what "briefly" means. Even if it was a short spurt this is crazy, though.