![Lookback time to formation for the individual galaxies](https://noirlab.edu/public/media/archives/images/thumb700x/geminiann06013b.jpg)
International Gemini Observatory/NOIRLab/NSF/AURA
Lookback time to formation for the individual galaxies
The lookback time to formation for the individual galaxies in the sample versus the galaxy masses. Field galaxies at redshifts z∼1 - black and blue points, cluster galaxies at redshifts 0.8-0.9 - red points.