What finding complicates the simple narrative that massive elliptical galaxies are entirely old?

Answer

The emergence of young stars in some of the oldest and most massive galaxies

Recent findings indicate that even massive galaxies categorized as ellipticals based on shape might have experienced late-stage star formation bursts, perhaps triggered by smaller satellite mergers that delivered fresh gas.

What finding complicates the simple narrative that massive elliptical galaxies are entirely old?
galaxiesastronomystarsstellar evolutiongalaxy types