The supermassive black hole (SMBH) in the middle of our Milky Way galaxy, Sagittarius A *, is by far the closest such object to us, only about 25 thousand light years away. While it's not nearly active or luminous like other SMBHs, its relative proximity gives astronomers a unique opportunity to explore what's happening close to the "edge" of a black hole. Monitored in the radio since its discovery and recently in infrared and x-ray, Sgr A * seems to be accreting material at a very low speed, only a few hundredths of a soil mass per year. Its X-ray emission is sustained, probably due to the rapid movement of electrons in the hot accretion current associated with the black hole. Once a day there are also flares of emissions that are very variable; they occur more often in infrared than in x-rays. Some submillimeter wavelength glare is also gently associated with IR flares, although their timing seems to be delayed in infrared events. Despite these intensive observation efforts, the physical mechanisms that produce flaring around this SMBH are still unknown and are subject to intense theoretical modeling.
CfA astronomers Steve Willner, Joe Hora, Giovanni Fazio and Howard Smith joined their colleagues for a systematic campaign of simultaneous multiwavelength observations of flaring in SagA * by Spitzer and Chandra observatories (Submillimeter Array was also used in some series ). In over 1
Remarkable glare from the galactic center
H. Boyce et al. Simultaneous X-ray and infrared observations of Sagittarius A * s Variability, The Astrophysical Journal (2019). DOI: 10.3847 / 1538-4357 / aaf71f