What can a relatively low metallicity in some massive ellipticals suggest about their formation history?

Answer

The star formation was rapid and short-lived, expelling metal-rich hot gas before enrichment stabilized.

A lower-than-expected metallicity can imply that a massive early starburst expelled its metal-rich, hot gas phase before multiple generations of supernovae could fully enrich the galaxy, leaving a metal-poor stellar population.

What can a relatively low metallicity in some massive ellipticals suggest about their formation history?
galaxiesastronomystar formationelliptical galaxiesgalaxy evolution