Year: 2011
Type: article
Abstract: We have studied the properties of giant star-forming clumps in five z ∼ 2 star-forming disks with deep SINFONI AO spectroscopy at the ESO VLT. The clumps reside in disk regions where the Toomre Q -parameter is below unity, consistent with their being bound and having formed from gravitational instability. Broad Hα/[N ii ] line wings demonstrate that the clumps are launching sites of powerful outflows. The inferred outflow rates are comparable to or exceed the star formation rates, in one case by a factor of eight. Typical clumps may lose a fraction of their original gas by feedback in a few hundred million years, allowing them to migrate into the center. The most active clumps may lose much of their mass and disrupt in the disk. The clumps leave a modest imprint on the gas kinematics. Velocity gradients across the clumps are 10–40 km s −1 kpc −1 , similar to the galactic rotation gradients. Given beam smearing and clump sizes, these gradients may be consistent with significant rotational support in typical clumps. Extreme clumps may not be rotationally supported; either they are not virialized or they are predominantly pressure supported. The velocity dispersion is spatially rather constant and increases only weakly with star formation surface density. The large velocity dispersions may be driven by the release of gravitational energy, either at the outer disk/accreting streams interface, and/or by the clump migration within the disk. Spatial variations in the inferred gas phase oxygen abundance are broadly consistent with inside-out growing disks, and/or with inward migration of the clumps.
Source: The Astrophysical Journal
Authors: R. Genzel, S. Newman, T. Jones, N. M. Förster Schreiber, K. Shapiro, S. Genel, S. J. Lilly, A. Renzini, L. J. Tacconi, N. Bouché, A. Burkert, G. Cresci, P. Buschkamp, C. M. Carollo, D. Ceverino, R. Davies, A. Dekel, F. Eisenhauer, E. Hicks, J. Kurk, D. Lutz, C. Mancini, T. Naab, Y. Peng, A. Sternberg, D. Vergani, G. Zamorani
Institutions: Max Planck Institute for Extraterrestrial Physics, University of California, Berkeley, Northrop Grumman (United States), ETH Zurich, Osservatorio Astronomico di Padova, University of California, Santa Barbara, Ludwig-Maximilians-Universität München, Arcetri Astrophysical Observatory, National Institute for Astrophysics, Hebrew University of Jerusalem, University of Washington, Max Planck Institute for Astrophysics, Tel Aviv University, Osservatorio astronomico di Bologna
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: bronze
Funder: European Commission
OpenAlex ID: W2068007459