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.
The IXPE team plans to continue its observations of Sgr A*, which will help provide a better understanding of how active the Milky Way’s supermassive black hole was in the past. They are eager to learn the history of such outbursts and whether these are typical events or unique and rare.
These results appear in a paper published in the current issue of the journal Nature by Frederic Marin and colleagues. In addition, a new sonification of these data are being released simultaneously, which translates these new X-ray data from IXPE and Chandra into sounds. This sonification is available at: https://chandra.si.edu/photo/2023/gcenter/animations.html
IXPE is a collaboration between NASA and the Italian Space Agency with partners and science collaborators in 12 countries. IXPE is led by Marshall. Ball Aerospace, headquartered in Broomfield, Colorado, manages spacecraft operations together with the University of Colorado's Laboratory for Atmospheric and Space Physics in Boulder.
NASA's Marshall Space Flight Center manages the Chandra program. The Smithsonian Astrophysical Observatory's Chandra X-ray Center controls science operations from Cambridge, Massachusetts, and flight operations from Burlington, Massachusetts.
This release features multiple images and sonifications, each focused on molecular clouds near the black hole known as Sagittarius A*.
The primary image features a top panel and a bottom panel. The top panel offers an image of the Milky Way's core, courtesy of Chandra’s X-ray Observatory. In this rendering, the Milky Way resembles layers of neon pink and dark blue clouds, dotted with specks of light in similar colors. Two bright spots in light blue glow to our left of center.
The bottom panel offers a close-up image of the space between the glowing light blue spots, courtesy of Chandra and NASA's Imaging X-ray Polarimetry Explorer (IXPE). Thin white lines layered onto the top panel frame the area being highlighted, and indicate that the perspective in the bottom panel has been rotated approximately 45 degrees to our right. In the bottom panel, dappled orange mist overlaps with cloudy indigo veins, and light purple specks. These patches of veiny mist are molecular clouds. By combining data from IXPE and Chandra, researchers have determined that the X-ray light in the clouds originated from Sagittarius A* during an outburst approximately 200 years ago.
This lower panel image is used in a sonification of the same data sets. In the sonification, an arched line ripples across the image, beginning at our lower right hand corner. As it passes over the dappled orange mist representing IXPE data, sounds like digital winds are triggered. When the mist is bright, the whooshing sounds grow more intense. When the arching line passes the indigo veins and specks representing Chandra data, notes are played resembling steel drums. The brighter the light, the louder the sound.