XRISM X-Ray Observations Reveal Historical Flares from Milky Way's Supermassive Black Hole

The Japanese-European-American XRISM spacecraft has uncovered a thousand-year history of violent flares from the Milky Way's central black hole, challenging assumptions about its quiescence.

By analyzing X-ray echoes reflected off a molecular cloud near the galactic center, researchers have reconstructed Sgr A eruptive activity over the past millennium.

XRISM's 2023 launch enabled precise measurement of X-ray energy and shape, allowing scientists to rule out cosmic ray explanations for the observed signals.

Stephen DiKerby of Michigan State University described the findings as "nothing in my professional training...had prepared me for something like this." The molecular cloud acted as a 'cosmic mirror,' reflecting X-rays from historical flares that would otherwise remain undetectable.

Sgr A, estimated to contain 4 million solar masses, was previously thought to emit minimal flares. The new study, published in The Astrophysical Journal Letters, contrasts this prior understanding with evidence of recurrent high-energy eruptions.

The collaboration between NASA, JAXA, and ESA enabled the mission's technical capabilities to distinguish between transient and historical X-ray signatures.