Scientists have used a groundbreaking X-ray technique to reveal the three-dimensional structure of the molecular cloud at the center of the Milky Way. These cosmic clouds are critical to star formation, and they are illuminated by past outbursts from the supermassive black hole Sagittarius A*. By analyzing how X-ray flares interact with these clouds, astronomers have pieced together a detailed map of the universe that reveals the Milky Way's turbulent core.
This image shows a study using decades of data to explore the three-dimensional structure of the molecular cloud at the center of the Milky Way. The panorama combines several types of observational data: radio data from the Submillimeter Array (green), infrared data from the Herschel Space Telescope (red) and Spitzer Space Telescope (blue), and X-ray data from NASA's Chandra X-ray Observatory.
For the first time, researchers have mapped three-dimensional molecular clouds in the Milky Way's most extreme environments - dense regions of star formation. They studied past flare events from Sagittarius A* (SgrA*), the Milky Way's supermassive black hole located at the center of the Milky Way. This region is highly turbulent, and the gas temperature, density, and motion intensity are ten times higher than elsewhere in the Milky Way. Occasionally, incoming gas is pulled into SgrA*, triggering powerful X-ray flares that radiate outward.
These X-ray flares interact with molecular clouds through a process called fluorescence. As X-ray light moves through space, it illuminates different layers of clouds over time, much like an X-ray scan, revealing their hidden structures.
The research team developed a new X-ray tomography method and produced two three-dimensional maps of the molecular clouds at the center of the Milky Way, known as the "stone" cloud and the "stick" cloud. These maps are the first three-dimensional representation of the molecular cloud at the center of the Milky Way. They used two decades of data from Chandra to create three-dimensional models of "stone" and "stick" molecular clouds.
Astronomers typically see only two spatial dimensions of objects in space, but X-ray tomography can measure the third dimension of clouds because X-rays illuminate individual slices of the cloud over time.
The researchers also used data from the Submillimeter Array and the Herschel Space Observatory to compare the structures seen in the X-ray echoes with those seen at other wavelengths. Because the X-ray data is not collected continuously, some structures seen in the submillimeter band are not visible in X-rays. However, these "missing" structures allowed the researchers to limit the duration of the X-ray flare events that illuminated the stone clouds. They determined that the X-ray flare would last no longer than four to five months.
Danya Alboslani (University of Connecticut) presented these results at the 245th Meeting of the American Astronomical Society in National Harbor, Maryland.
Compiled from /ScitechDaily