Zfire: The Beginning Of The End For Massive Galaxies At Z Similar To 2 And Why Environment Matters

We use ZFIRE and ZFOURGE observations with the spectral energy distribution fitting tool PROSPECTOR to reconstruct the star formation histories (SFHs) of protocluster and field galaxies at z similar to 2 and compare our results to the TNG100 run of the IllustrisTNG cosmological simulation suite. In the observations, we find that massive protocluster galaxies ( log[M*/M circle dot] 10.5) form 45% +/- 8% of their total stellar mass in the first 2 Gyr of the universe, compared to 31% +/- 2% formed in the field galaxies. In both observations and simulations, massive protocluster galaxies have a flat/declining SFH with decreasing redshift compared to rising SFH in their field counterparts. Using IllustrisTNG, we find that massive galaxies ( log[M*/M circle dot]>= 10.5 = 9 更多