2D velocity fields of simulated interacting disc galaxies
1
Institut für Astro- und Teilchenphysik, Universität Innsbruck, Technikerstr. 25, 6020 Innsbruck, Austria e-mail: Thomas.Kronberger@uibk.ac.at
2
Institut für Astrophysik, Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
3
Argelander-Institut für Astronomie, Universität Bonn, Auf dem Hügel 71, 53121 Bonn, Germany
Received:
23
April
2007
Accepted:
11
July
2007
We investigate distortions in the velocity fields of disc
galaxies and their use in revealing the dynamical state of
interacting galaxies at different redshifts. We model disc galaxies
in combined N-body/hydrodynamic simulations. 2D velocity fields of
the gas are extracted, which we place at different redshifts from
to 
to investigate resolution effects on the properties
of the velocity field. To quantify the structure of the velocity
field we also perform a kinemetry analysis. If the galaxy is
undisturbed we find that the rotation curve extracted from the 2D
field agrees well with long-slit rotation curves. This is not true
for interacting systems, as the kinematic axis is not well defined
and in general does not coincide with the photometric axis of the
system. For large (Milky way type) galaxies we find that distortions
are still visible at intermediate redshifts but are partly smeared
out. Thus a careful analysis of the velocity field is necessary
before using it for a Tully-Fisher study. For small galaxies (disc
scale length ~2 kpc) even strong distortions are not visible
in the velocity field at 
with currently available
angular resolution. Therefore we conclude that current distant
Tully-Fisher studies cannot give reliable results for low-mass
systems. Additionally we confirm the power of near-infrared integral
field spectrometers in combination with adaptive optics (such as
SINFONI) to study velocity fields of galaxies at high redshift
(
).
Key words: galaxies: kinematics and dynamics / galaxies: interactions / methods: numerical
© ESO, 2007