KMOS-3D Reveals Low-Level Star Formation Activity in Massive Quiescent Galaxies at 0.7 < z < 2.7

Understand

We explore the H-alpha emission in the massive quiescent galaxies observed by the KMOS-3D survey at 0.7 < z < 2.7.

• The H-alpha line is robustly detected in 20 out of 120 UVJ-selected quiescent galaxies, and we classify the emission mechanism using the H-alpha line width and the [NII]/H-alpha line ratio.
• We find that AGN are likely to be responsible for the line emission in more than half of the cases.
• We also find robust evidence for star formation activity in nine quiescent galaxies, which we explore in detail.