We tend to think of the galactic system occurrences as those that occur uncommonly slowly compared to our short human life. It’s not always the case, though.
Six galaxies have just experienced an enormous transformation in just a matter of months in a moving way. They have moved from relatively peaceful galaxies to active quasars-the brightest of all galaxies, blasting vast quantities of radiation into the Universe.
This is not only incredibly amazing, but these occurrences could assist resolve a long-standing discussion about what generates the light in a specific galaxy type. In reality, they may show a sort of galactic nucleus activity that was earlier unknown.
The six galaxies began as galaxies of the low-ionization nuclear emission-line region (LINER); in terms of brightness, it’s kind of like being a galactic particle.
A third of all known galaxies are brighter than those with dormant supermassive black holes in the center, but not as bright as active galaxies (known as Seyfert galaxies), whose supermassive black holes are cosmic.
Now, the most brilliant of such active galaxies are quasar galaxies; indeed, they are among the most colorful objects in the Universe. The light and radio emissions we see are triggered by black hole material, called an accretion disk.
That disk includes dust and gas swirling at tremendous speeds like water running down a drain, creating enormous friction as it is pulled by the black hole’s substantial gravitational force in the center. This friction generates intense heat and light; large spray tanks emit radio waves from the polar regions of the black hole.
But when a team of astronomers led by the University of Maryland astronomer Sara Frederick walked through the first nine months of automated sky survey information from the Zwicky Transient Facility, they discovered six LINER galaxies doing something strange.
“We first believed we observed a tidal disruption event for one of the six objects, which occurs when a star goes too close to a supermassive black hole and gets shredded,” Frederick said.
Frederick and her colleagues want to understand how a previously quiet galaxy with a calm nucleus can suddenly transition to a bright beacon of galactic radiation. To learn more, they performed follow-up observations on the objects with the Discovery Channel Telescope, which is operated by the Lowell Observatory in partnership with UMD, Boston University, the University of Toledo and Northern Arizona University. These observations helped to clarify aspects of the transitions, including how the rapidly transforming galactic nuclei interacted with their host galaxies.