Eight examples of jellyfish galaxies. Images like these are presented to the participants of the new Zooniverse project for classification. IllustrisTNG collaboration
Galaxies come in all shapes and sizes, and we still have a lot to learn about how they form and grow. An open puzzle is the formation of jellyfish galaxies, which got their name because of their long gas tails that look like trailing jellyfish tentacles. Now a new project invites the public to support research into these cosmic jellyfish by identifying targets for further study.
Jellyfish galaxies form in galaxy clusters, these are groups of galaxies that also have hot gas in the space between them. It is this hot intergalactic dust that creates a “headwind” when traversing a fast-moving galaxy, which causes the galaxy to leave a gas trail as it moves. But there are many unknowns about these galaxies, such as how quickly the tails form and how long they take, or how big a cluster needs to be to carry them.
To answer these questions, researchers at the Max Planck Institute for Astronomy used computers to simulate a virtual universe as part of their Cosmological Jellyfish project in order to view galaxies on a very large scale. But before they can study the jellyfish galaxies in their simulations, they have to identify them – which is easy for a human, but difficult for a computer. Humans are excellent at pattern recognition so they can easily identify things that look like jellyfish, and the researchers hope to use public input to help them identify and label their galaxies.
“There is nothing better than the human eye for recognizing unique shapes,” said one of the researchers on the project website. “We hope that you will join us in this attempt to look for jellyfish galaxies so that we can better understand them!”
The project consists of 38,000 images that need to be searched for jellyfish. Volunteers can use the Zooniverse platform to view images of galaxies which they then display or not display as a jellyfish galaxy. Each image is classified by at least twenty participants in order to obtain the most consistent results possible, then the researchers know which galaxies to focus their study on.
To participate, visit the Zooniverse website, take a tutorial, and then start classifying.