Have you tried making a family tree? It can be fun tracing your roots and family history. It is like looking back in time to find some interesting facts about your origins. Now imagine if we took this activity a cosmic step further to trace how galaxies, like our Milky Way, form and grow up.

An international team of researchers have been studying a peculiar region in our Universe known as the ‘Spiderweb protocluster’ using the Subaru Telescope. The Spiderweb protocluster is a busy ‘cosmic city’ that contains groups of massive galaxies that started to come together when our Universe was much younger, more than 10 billion years ago.

The Subaru team has been studying the supercluster for over 10 years. They found that some galaxies in this protocluster were still teeming with star formation, while others seemed to have all but entirely halted their production of stars.  Some have even started to grow into giant elliptical galaxies . The Subaru team also knew that about half of the galaxies in the Spiderweb had supermassive black holes — hungry ones! “I get really hangry if I don’t get my daily dose of high energy matter ”, quotes one of the supermassive black holes.

Now this made the team even more curious: could there be a connection between black holes' diet and star formation in these galaxies? To solve this puzzle, researchers needed a detailed map of the galaxies containing important data. “To the rescue, here I come”, sang the James Webb Space Telescope (JWST). And Voila!

Using maps from JWST, the team found that galaxies with active supermassive black holes have stopped forming new stars, while galaxies without hangry big black holes are still forming new stars. This theory supports the team's findings using the Subaru Telescope. Subaru and JWST hi5s!
 

Image: The Spiderweb protocluster captured by JWST Credits: Shimakawa et al.