Astronomers studying the motions of molecular gas in the milky way and another nearby galaxy and found that at different scales, fluctuations in its velocity exhibit a similar structure. While the formation of stars and planets — a local process, it is controlled by mechanisms originating at the galactic level, reported in an article published in the journal Nature Astronomy.
In the galaxies the gas are distributed unevenly, there are areas where the density of matter in the hundreds or even thousands of times higher than the average, and that is where stars are born. On the occurrence of clumps of a substance can affect different physical processes by which gas is driven from galactic rotation to the supernova explosions. However, to establish the exact mechanisms leading to the emergence of a star “cradles”, it is quite difficult from a technical point of view, as you first need to study the motion of gas on different scales, and then to establish a link with known structures and astronomical objects.
A team of astronomers under the leadership of Jonathan Henshaw (Henshaw, Jonathan D.) from the Institute of astronomy, max Planck Society decided to perform such work based on the milky way and the nearby galaxy NGC 4321 obtained by ALMA telescope (Atacama Large Millimeter/submillimeter Array). The researchers tracked how the gas is moving in different scales (from 0.1 to parsec thousand parsec) to change the apparent frequency of the radiation, a phenomenon called the Doppler effect. Researchers software has analyzed millions of such measurements and visualized the interstellar medium, building a map that shows the position of gas in two-dimensional space and its radial velocity (position-position-velocity).
As expected, the scientists recorded in a cold molecular gas velocity variations, which can be likened to waves in the ocean. However, it turned out that these fluctuations are common and have a similar structure as the scale of the galaxy and the scale of individual clouds.
To better understand the nature of the gas flows, the group’s Henshaw have selected a few individual regions for more detailed study. Applying statistical analysis and other techniques, astronomers have identified three gas filament in which, despite the study on a different scale, it was observed equidistant “clumps” resembling strung on a rope of beads, whether that’s the spiral arm of the galaxy or the formation of individual stars.