Infrared and X-ray flaring of the Galactic Centre supermassive black hole Sgr A*

Image

The accretion flow onto the 4 million solar mass black hole Sgr A* is fed by the winds of massive stars in the central few parsecs of the Galaxy. As the captured material flows towards the event horizon it emits across the electromagnetic spectrum from radio and sub-millimetre through infrared into X-rays. The emission is variable on time scales from minutes to years (and longer), providing valuable information on the physical processes at work in the accretion flow. JWST observations of SgrA* at several epochs in 2023 and 2024 have yielded simultaneous light curves at 2.1 and 4.8 micron with unprecedented sensitivity, allowing accurate characterisation of the spectral evolution during flaring events in the infrared. In addition NuSTAR observed a very bright X-ray flare simultaneous with flaring observed in the infrared by JWST. I shall present these new observations and the implications for models of the accretion flow.

Image: Mark Wardle https://web.science.mq.edu.au/~wardle/