KMOS{sup 3D} Reveals Low-level Star Formation Activity in Massive Quiescent Galaxies at 0.7 < z < 2.7

Journal Article · Sat May 20 00:00:00 EDT 2017 · Astrophysical Journal Letters

DOI:https://doi.org/10.3847/2041-8213/AA70E5· OSTI ID:22654475

Belli, Sirio; Genzel, Reinhard; Förster Schreiber, Natascha M.; Wisnioski, Emily; Wilman, David J.; Mendel, J. Trevor; Beifiori, Alessandra; Bender, Ralf; Burkert, Andreas; Chan, Jeffrey; Davies, Rebecca L.; Davies, Ric; Fabricius, Maximilian; Fossati, Matteo; Galametz, Audrey; Lang, Philipp; Lutz, Dieter ^[1]; Wuyts, Stijn ^[2]; Brammer, Gabriel B.; Momcheva, Ivelina G. ^[3] ; others, and

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1. Max-Planck-Institut für Extraterrestrische Physik (MPE), Giessenbachstr. 1, D-85748 Garching (Germany)
2. Department of Physics, University of Bath, Claverton Down, Bath, BA2 7AY (United Kingdom)
3. Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)

We explore the H α emission in the massive quiescent galaxies observed by the KMOS{sup 3D} survey at 0.7 < z < 2.7. The H α line is robustly detected in 20 out of 120 UVJ -selected quiescent galaxies, and we classify the emission mechanism using the H α line width and the [N ii]/H α line ratio. We find that AGNs 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. The H α kinematics reveal rotating disks in five of the nine galaxies. The dust-corrected H α star formation rates are low (0.2–7 M {sub ⊙} yr{sup −1}), and place these systems significantly below the main sequence. The 24 μ m-based, infrared luminosities, instead, overestimate the star formation rates. These galaxies present a lower gas-phase metallicity compared to star-forming objects with similar stellar mass, and many of them have close companions. We therefore conclude that the low-level star formation activity in these nine quiescent galaxies is likely to be fueled by inflowing gas or minor mergers, and could be a sign of rejuvenation events.

• OSTI ID: 22654475
• Journal Information: Astrophysical Journal Letters, Vol. 841, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 2041-8205
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
BALMER LINES
COMPARATIVE EVALUATIONS
EMISSION
EVOLUTION
GALAXIES
LINE WIDTHS
LUMINOSITY
MASS
METALLICITY
RED SHIFT
STARS