In 2019, the supermassive black hole at the center of our galaxy woke up and emitted a series of burps. A new study now examines what meal may have led to this indigestion.
Artist’s impression of the dramatic outflows from an active galaxy’s nucleus. The Milky Way’s supermassive black hole, in contrast, is very quiet. [NASA/SOFIA/Lynette Cook]
Waking Up for a Snack
Sgr A*, the 4.6-million-solar-mass black hole that lies at the center of the Milky Way, is normally a fairly quiet beast. The black hole slowly feeds on accreting material in the galactic center — but this food source is sparse, and Sgr A*’s accretion doesn’t produce anything like the fireworks we associate with supermassive black holes in active galaxies.
In May 2019, however, Sgr A* suddenly became substantially more active than usual, producing an unprecedented bright, near-infrared flare that lasted roughly 2.5 hours. This flare was more than 100 times brighter than the typical emission from Sgr A*’s casual accretion, and more than twice as bright as the brightest flare we’ve ever measured from our neighborhood monster.
The May 2019 flare marked the start of prolonged increased activity — an unusual number of strong flares that continued at ...