A galactic tapestry in the center of the Milky Way

Structures at the center of the Milky Way seen by Chandra and MeerKAT
An article published in the journal “Monthly Notices of the Royal Astronomical Society” reports a study of the center of the Milky Way that reveals the presence of superheated gas threads and magnetic fields. Astronomer Q. Daniel Wang of the University of Massachusetts at Amherst combined the results of 370 observations of various parts of that area conducted with NASA’s Chandra X-ray Observatory adding observations conducted using the MeerKAT radio telescope. The results suggest the possibility of ongoing processes that could be due to an unknown energy source in the galactic center.

Q. Daniel Wang defined the galaxy as an ecosystem and explained that the central areas of galaxies play huge roles in their evolution. However, these are areas full of gas and dust that make observations very difficult, as those materials block many electromagnetic frequencies. For this reason, the author of this new study exploited instruments that detect emissions in the bands that pass through those materials such as X-rays and radio waves.

NASA’s Chandra X-ray Observatory made it possible to obtain excellent images of the central area of ​​the Milky Way where the various X-ray bands are shown in orange, green, and purple in the image (Credit: X-ray: NASA/CXC/UMass/Q.D. Wang; Radio: NRF/SARAO/MeerKAT). The green circles indicate very bright X-ray sources. Purple circles and ellipses indicate objects of other types such as star clusters and molecular complexes. The MeerKAT radio telescope is one of the precursors of the SKA, the next-generation radio telescope, and made it possible to detect radio emissions shown in gray in the image.

Various studies are trying to understand the influence of supermassive black holes on their host galaxies. In the Milky Way’s case, the supermassive black hole is referred to as Sagittarius A* but this study shows other phenomena that generate X-ray emissions.

One discovery is the clearest image obtained so far of a pair of X-ray emitting plumes emerging from the region close to Sagittarius A*. The superheated gas threads present near the galactic center are also interesting, and this study allowed to discover another one under the southern plume, cataloged as G0.17-0.41.

Q. Daniel Wang explained that the presence of the G0.17-0.41 thread reveals a magnetic reconnection event. This process occurs when two opposing magnetic fields break and combine causing the release of a huge amount of energy. Those are processes at the center of other types of astronomical studies because they also generate solar flares that have consequences on Earth too such as the northern lights. Scientists now think that magnetic reconnection may also occur in interstellar space and that it tends to occur at the outer boundaries of the outward-expanding plumes of the galactic center.

For Q. Daniel Wang, the questions regarding the production and transport of energy flows from the galactic center and their effects on what he called the galactic ecosystem are crucial to understanding the Milky Way’s history. The author of this study is the first to highlight the questions that still await answers and to stress the importance of the multiband approach to offer more comprehensive information on the galactic center. In his study, he used X-ray and radio wave observations obtained using two of the best instruments and we can see the results. Now other researchers will also be able to conduct follow-up research in the most interesting areas of the center of the Milky Way looking for more answers.

The G0.17-0.41 thread (Image X-ray: NASA/CXC/UMass/Q.D. Wang; Radio: NRF/SARAO/MeerKAT)
The G0.17-0.41 thread (Image X-ray: NASA/CXC/UMass/Q.D. Wang; Radio: NRF/SARAO/MeerKAT)

Leave a Reply

Your email address will not be published. Required fields are marked *