What happens if you mix gas and dust clouds with energetic shock waves in the core of the Milky Way Galaxy? Space tornados. At least in this way, researchers who use the Atacama Large millimeter array (Alma) in Chile to examine the heart of the galaxy what they found.
An international team of astronomers under the direction of Kai Yang from Shanghai Jiao Tong University focused on a region called Central Molecular Zone (CMZ). This region of the Milky Way occupies several hundred parsec of the room around the Sagittarius A*. It has an irregular shape with a diameter of up to 1900 light years.
The CMZ is a fairly extreme environment that is full of shock waves. It has a star formation activity that creates small drains. The region receives material from the rest of the galaxy when the gas is inserted over the central rod. Gas in the CMZ is much denser, hotter and more turbulated than molecular clouds in the rest of the disc. There are stronger magnetic fields and increased cosmic rays. Various regions in the zone have a high level of emission level of interstellar molecules, including silicon oxide (SIO). These emissions are displayed in spectral images of millimeter wavelengths and look like “slim filaments”. They are not to be dealt with in the region.
Tracing activity in CMZ
Yangs team used Alma to calculate the spectral lines of Si0 and other molecules from which the filaments consist of. They found some unexpected characteristics. “When we checked the Alma pictures that show the drains, we noticed these long and narrow filaments that were spatially compensated for by all star-forming regions. In contrast to objects we know, these filaments really surprised us. Since then, we have thought about what they are,” said Yang.
Slim filaments in the CMZ. Panel A is a meaner view in 1.28 GHz radio emission of the SGR A region. Blue boxes mark zoom-in regions in which slim filaments are recognized. With kind permission: Yang et al. You can find a more detailed description in the work below.
These “slim filaments” are located in the emission lines of SIO and eight other molecules and are not structures that we see in visible light. Since they are not necessarily connected to stubborn activities and are not to be associated with emissions from heated dust, the team checks the dynamics of the region to explain their cause.
“The high angle resolution and the extraordinary sensitivity of Alma were essential to recognize these molecular line emissions connected to the slim filaments and to confirm that there is no connection between these structures with dust emissions,” said Yichen Zhang, professor at Shanghai Jiao Tong University. “Our discovery marks a significant progress by recognizing these filaments on a much finer parsec scale of 0.01 to mark the work surface of these shocks.”
Name Tornados
Let's look at several important features of these filaments. Rotation transitions from SIO 5-4 can be clearly observed in Alma observations. Basically, the molecule changes from a higher energy state to a lower one. This changes its rotary energy and can be seen in the spectral pictures. The team also noticed the presence of CH3OH masons, which are structures that create microwave emissions. The filaments are also rich in complex organic molecules.
Each of the spectral filaments shows a unique morphology (or form). They also have different speed structures and molecular frequencies. In an article in which the work of the team is described, the authors say: “We speculate that these slim filaments represent a certain class as dense gas filaments that are typically observed in nearby molecular clouds, and they can result from interactions between shocks and molecular clouds.”
“We can imagine these as space cornados: they are violent gas flows, they released themselves and distribute materials efficiently into the environment,” said Xing LU, a research professor at the astronomical observatory of Shanghai and co-author on a paper via the filaments.
What's next?
The groundbreaking discovery of the team offers a window in the processes that occur in the CMZ and its cyclical nature. In order to resume what you know so far, shocks slim filaments, the Silicon Sio and the organic molecules Ch3oh, CH3CN and HC3N release. They freeze on dust grains. After a while the filaments dissolve. So that the widespread, releasing, releasing material in the CMZ reproduces and the molecular exhaustion and the possible supplies balance.
Future observations in other wavelengths should help astronomers to understand the evolutionary nature of the filaments and the events that encourage their education and derivations.
More information
Discover astronomers “space tornados” in the core of the Milky Way
Alma observations of massive clouds in the central molecular zone: slim filaments pursue shocks on the parse scale
3-D CMZ I: Overview of the central molecular zone
