Star formation in z~1.5 quiescent galaxies

The targets were initially observed with VIMOS on the VLT to facilitate the calibration of the photometric redshifts of massive galaxies at z>~1.5. Here we describe the reduction and analysis of the data, and the spectrophotometric properties of these pBzK galaxies.

In particular, using a spatially resolved median 2D spectrum, we find that the fraction of stellar populations with ages <1Gyr is at least 3 times higher in the outer regions of the pBzK galaxies than in their cores. This results in a mild age gradient of {DELTA}age<=0.4Gyr over ~6kpc and suggests either the occurrence of widespread rejuvenation episodes or that inside-out quenching played a role in the passivization of this galaxy population.