Glowing “jellyfish” galaxies have revealed a new way to power some of the most powerful objects in the universe. The same process that feeds the most voracious black holes at the galactic centers may also create dangling “tentacles” of newborn stars, a new study found.
While most galaxies, including the Milky Way, hide massive black holes at their centers, only a few produce enough electromagnetic radiation as they eat to create active galactic nuclei (AGN). AGN shine brilliantly in the universe, and why they form around some black holes and not others has been an ongoing mystery. But jellyfish galaxies may help crack the case.
“When a galaxy enters a galaxy cluster, falling into it at high velocity, the hot, dense gas that fills the cluster — the so-called intracluster gas — acts like a strong wind on the galaxy gas,” Bianca Poggianti, lead author on the new study, told Space.com by email. “It strips it away and creates the tails,” which give the galaxies their “jellyfish” nickname. [When Galaxies Collide: Photos of Great Galactic Crashes]
This same wind that forms the jellyfish galaxies may also feed growing AGNs, she said.
Poggianti, a researcher at the INAF-Astronomical Observatory of Padova in Italy, is part of an international team of scientists using the Multi-Unit Spectroscopic Explorer (MUSE) instrument on the European Space Observatory’s Very Large Telescope (VLT) in Chile to examine jellyfish galaxies. The researchers found that an unexpectedly high fraction of the tentacled galaxies contain AGN.
“Ours is the first study that systematically searches for [jellyfish galaxies] and tries to have a complete census in different regions of the local universe,” Poggianti said.