A European team of astronomers led by Professor Kalliopi Dasyra of the National and Kapodistrian University of Athens, Greece, under participation of Dr. Thomas Bisbas, University of Cologne modeled several emission lines in Atacama Large Millimeter Array (ALMA) and Very Large Telescope (VLT) observations to measure the gas pressure in both jet-impacted clouds and ambient clouds. With these unprecedented measurements, published recently in Nature Astronomy, they discovered that the jets significantly change the internal and external pressure of molecular clouds in their path.
Depending on which of the two pressures changes the most, both compression of clouds and triggering of star formation and dissipation of clouds and delaying of star formation are possible in the same galaxy. “Our results show that supermassive black holes, even though they are located at the centers of galaxies, could affect star formation in a galaxy-wide manner,” said Professor Dasyra. “Studying the impact of pressure changes in the stability of clouds was key to the success of this project. Once few stars actually form in a wind, it is usually very hard to detect their signal on top of the signal of all other stars in the galaxy hosting the wind.”
It is believed that supermassive black holes lie at the centers of most galaxies in our universe. When particles that were infalling onto these black holes are trapped by magnetic fields, they can be ejected outwards and travel far inside galaxies in the form of enormous and powerful jets of plasma. These jets are often perpendicular to galactic disks. In IC 5,063 however, a galaxy 156 million light years away, the jets are actually propagating within the disk, interacting with cold and dense molecular gas clouds. From this interaction, compression of jet-impacted clouds is theorized to be possible, leading to gravitational instabilities and eventually star formation due to the gas condensation.
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