The SINS/zC-SINF survey of z ∼ 2 galaxy kinematics: Evidence for gravitational quenching
- Max-Planck-Institut für Extraterrestrische Physik (MPE), Giessenbachstr.1, D-85748 Garching (Germany)
- Institute for Astronomy, Department of Physics, Eidgenössische Technische Hochschule, ETH Zürich, 8093-CH (Switzerland)
- Istituto Nazionale di Astrofisica—Osservatorio Astronomico di Arcetri, Largo Enrico Fermi 5, I-50125 Firenze (Italy)
- Department of Physics and Astronomy, University of Alaska Anchorage, 3211 Providence Drive, Anchorage, AK 99507 (United States)
- Osservatorio Astronomico di Padova, Vicolo dell'Osservatorio 5, I-35122 Padova (Italy)
- Max-Planck Institute for Astrophysics, Karl Schwarzschildstrasse 1, D-85748 Garching (Germany)
As part of the SINS/zC-SINF surveys of high-z galaxy kinematics, we derive the radial distributions of Hα surface brightness, stellar mass surface density, and dynamical mass at ∼2 kpc resolution in 19 z ∼ 2 star-forming disks with deep SINFONI adaptive optics spectroscopy at the ESO Very Large Telescope. From these data we infer the radial distribution of the Toomre Q-parameter for these main-sequence star-forming galaxies (SFGs), covering almost two decades of stellar mass (10{sup 9.6}-10{sup 11.5} M {sub ☉}). In more than half of our SFGs, the Hα distributions cannot be fit by a centrally peaked distribution, such as an exponential, but are better described by a ring, or the combination of a ring and an exponential. At the same time the kinematic data indicate the presence of a mass distribution more centrally concentrated than a single exponential distribution for 5 of the 19 galaxies. The resulting Q-distributions are centrally peaked for all, and significantly exceed unity there for three-quarters of the SFGs. The occurrence of Hα rings and of large nuclear Q-values appears to be more common for the more massive SFGs. While our sample is small and biased to larger SFGs, and there remain uncertainties and caveats, our observations are consistent with a scenario in which cloud fragmentation and global star formation are secularly suppressed in gas-rich high-z disks from the inside out, as the central stellar mass density of the disks grows.
- OSTI ID:
- 22357139
- Journal Information:
- Astrophysical Journal, Vol. 785, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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