Issue |
A&A
Volume 608, December 2017
The MUSE Hubble Ultra Deep Field Survey
|
|
---|---|---|
Article Number | A5 | |
Number of page(s) | 24 | |
Section | Extragalactic astronomy | |
DOI | https://doi.org/10.1051/0004-6361/201730905 | |
Published online | 29 November 2017 |
The MUSE Hubble Ultra Deep Field Survey
V. Spatially resolved stellar kinematics of galaxies at redshift 0.2 ≲ z ≲ 0.8⋆
1 IRAP, Institut de Recherche en Astrophysique et Planétologie, CNRS, 14 avenue Édouard Belin, 31400 Toulouse, France
2 Université de Toulouse, UPS-OMP, 31400 Toulouse, France
3 European Southern Observatory, Karl-Schwarzschild-Str. 2, 85748 Garching, Germany
4 Leibniz-Institut für Astrophysik Potsdam (AIP), An der Sternwarte 16, 14482 Potsdam, Germany
e-mail: dkrajnovic@aip.de
5 Aix Marseille Université, CNRS, LAM, Laboratoire d’Astrophysique de Marseille, UMR 7326, 13388 Marseille, France
6 Univ. Lyon, Univ. Lyon1, ENS de Lyon, CNRS, Centre de Recherche Astrophysique de Lyon UMR 5574, 69230 Saint-Genis-Laval, France
7 Leiden Observatory, Leiden University, PO Box 9513, 2300 RA Leiden, The Netherlands
8 ETH Zurich, Institute of Astronomy, Wolfgang-Pauli-Str. 27, 8093 Zurich, Switzerland
Received: 31 March 2017
Accepted: 26 June 2017
We present spatially resolved stellar kinematic maps, for the first time, for a sample of 17 intermediate redshift galaxies (0.2 ≲ z ≲ 0.8). We used deep MUSE/VLT integral field spectroscopic observations in the Hubble Deep Field South (HDFS) and Hubble Ultra Deep Field (HUDF), resulting from ≈30 h integration time per field, each covering 1′ × 1′ field of view, with ≈ 0.̋65 spatial resolution. We selected all galaxies brighter than 25 mag in the I band and for which the stellar continuum is detected over an area that is at least two times larger than the spatial resolution. The resulting sample contains mostly late-type disk, main-sequence star-forming galaxies with 108.5 M⊙ ≲ M∗ ≲ 1010.5 M⊙. Using a full-spectrum fitting technique, we derive two-dimensional maps of the stellar and gas kinematics, including the radial velocity V and velocity dispersion σ. We find that most galaxies in the sample are consistent with having rotating stellar disks with roughly constant velocity dispersions and that the second order velocity moments Vrms = √V2+σ2 of the gas and stars, a scaling proxy for the galaxy gravitational potential, compare well to each other. These spatially resolved observations of the stellar kinematics of intermediate redshift galaxies suggest that the regular stellar kinematics of disk galaxies that is observed in the local Universe was already in place 4–7 Gyr ago and that their gas kinematics traces the gravitational potential of the galaxy, thus is not dominated by shocks and turbulent motions. Finally, we build dynamical axisymmetric Jeans models constrained by the derived stellar kinematics for two specific galaxies and derive their dynamical masses. These are in good agreement (within 25%) with those derived from simple exponential disk models based on the gas kinematics. The obtained mass-to-light ratios hint towards dark matter dominated systems within a few effective radii.
Key words: galaxies: formation / galaxies: evolution / galaxies: kinematics and dynamics / galaxies: stellar content
© ESO, 2017
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