Caught in the act

This artist’s conception of the mid-IR flare in Sgr A* captures the variability, or changing intensity, of the flare as the black hole’s magnetic field lines approach each other. The byproduct of this magnetic reconnection is synchrotron emission. The emission seen in the flare intensifies as energized electrons travel along the SMBH’s magnetic field lines at close to the speed of light. Credit: CfA/Mel Weiss

On 6 April 2024, the black hole let out a flare observed in mid-infrared wavelengths, followed by a radio flare counterpart.

Although Sgr A* belches out the occasional flare, this is the first time we've captured it in mid-infrared – one of the missing pieces of the puzzle of the black hole's behavior, according to a team led by astronomer Sebastiano von Fellenberg from the Max Planck Institute for Radio Astronomy in Germany.

"Sgr A*'s flare evolves and changes quickly, in a matter of hours, and not all of these changes can be seen at every wavelength," says astrophysicist Joseph Michail of the Smithsonian Astrophysical Observatory.

"For over 20 years, we've known what happens in the radio and Near-infrared (NIR) ranges, but the connection between them was never 100 percent clear. This new observation in mid-infrared fills in that gap."

Our galaxy's black hole