Starship Asterisk*

Chandra: NASA/CXC/SAO; IXPE: NASA/MSFC/F. Marin et al; Image Processing: L.Frattare, J.Major & K.Arcand;

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These images show X-ray data of the area around the supermassive black hole at the center of the Milky Way galaxy. New data from NASA’s Imaging X-ray Polarimetry Explorer (IXPE) has provided evidence that this black hole — known as Sagittarius A* (Sgr A*) — had an outburst about 200 years ago after devouring gas and dust within its reach.

The IXPE data are shown in the bottom panel (orange) and have been combined with other X-ray data from NASA’s Chandra X-ray Observatory (blue). The top panel is a much wider field-of-view of the center of the Milky Way from Chandra. In this image, low and high-energy X-rays are represented by blue and purple colors.

The IXPE data was obtained in February and March 2022 and shows X-ray emission from clouds of gas (called “molecular clouds”) near Sgr A*. A team of scientists used the IXPE data to conclude that these molecular clouds, which are usually cold and dark, were bright in X-rays because they were reflecting X-rays generated elsewhere in the past — a phenomenon known as a “light echo”.

By combining the IXPE data with data from Chandra and XMM, the researchers were able to isolate the reflected X-ray signal and track down its source. They determined that the light originated from or near Sgr A* during an outburst approximately 200 years ago. If the outburst came from Sgr A* it may have been caused by the black hole abruptly consuming material from the molecular clouds. ...

• Nature (online 21 Jun 2023) DOI: 10.1038/s41586-023-06064-x
• arXiv > astro-ph > arXiv:2304.06967 > 14 Apr 2023