Timing the earliest quenching events with a robust sample of massive quiescent galaxies at 2 < z < 5

Understand

We present a sample of 151 massive ($M_* > 10^{10}\mathrm{M_\odot}$) quiescent galaxies at $2 < z < 5$, based on a sophisticated Bayesian spectral energy distribution fitting analysis of the CANDELS UDS and GOODS-South fields.

• Our sample includes a robust sub-sample of 61 objects for which we confidently exclude low-redshift and star-forming solutions.
• We identify 10 robust objects at $z>3$, of which 2 are at $z>4$.
• We report formation redshifts, demonstrating that the oldest objects formed at $z > 6$, however individual ages from our photometric data have significant uncertainties, typically $\sim0.5$ Gyr.