Washington: NASA'S Chandra Observatory has found that turbulence might keep the temperature inside cluster galaxies too hot to allow for cooling needed to form stars.
According to the study, the same phenomenon that causes a bumpy airplane ride, turbulence, may be the solution to a long-standing mystery about stars' birth, or the absence of it.
Irina Zhuravleva of Stanford University in Palo Alto, California, who led the study, said that they knew that somehow the gas in clusters is being heated to prevent it cooling and forming stars. They think we may have found evidence that the heat is channeled from turbulent motions, which we identify from signatures recorded in X-ray images.
The latest research by Zhuravleva and her colleagues provides new insight into how energy can be transferred from these cavities to the surrounding gas. The interaction of the cavities with the gas may be generating turbulence, or chaotic motion, which then disperses to keep the gas hot for billions of years.
The evidence for turbulence comes from Chandra data on two enormous galaxy clusters named Perseus and Virgo. By analyzing extended observation data of each cluster, the team was able to measure fluctuations in the density of the gas. This information allowed them to estimate the amount of turbulence in the gas.
These results support the "feedback" model involving supermassive black holes in the centers of galaxy clusters. Gas cools and falls toward the black hole at an accelerating rate, causing the black hole to increase the output of its jets, which produce cavities and drive the turbulence in the gas. This turbulence eventually dissipates and heats the gas.
The study was published online in the journal Nature.