Bibcode
Fathi, Kambiz; van de Ven, Glenn; Peletier, Reynier F.; Emsellem, Eric; Falcón-Barroso, Jesús; Cappellari, Michele; de Zeeuw, Tim
Referencia bibliográfica
Monthly Notices of the Royal Astronomical Society, Volume 364, Issue 3, pp. 773-782.
Fecha de publicación:
12
2005
Número de citas
55
Número de citas referidas
49
Descripción
We analyse Spectrographic Areal Unit for Research on Optical Nebulae
(SAURON) kinematic maps of the inner kiloparsec of the early-type (Sa)
barred spiral galaxy NGC 5448. The observed morphology and kinematics of
the emission-line gas is patchy and perturbed, indicating clear
departures from circular motion. The kinematics of the stars is more
regular, and display a small inner disc-like system embedded in a
large-scale rotating structure. We focus on the [OIII] gas, and use a
harmonic decomposition formalism to analyse the gas velocity field. The
higher order harmonic terms and the main kinematic features of the
observed data are consistent with an analytically constructed simple bar
model. The bar model is derived using linear theory, considering an m= 2
perturbation mode, and with bar parameters that are consistent with the
large-scale bar detected via imaging. We also study optical and near
infrared images to reveal the asymmetric extinction in NGC 5448, and we
recognize that some of the deviations between the data and the
analytical bar model may be due to these complex dust features. Our
study illustrates how the harmonic decomposition formalism can be used
as a powerful tool to quantify non-circular motions in observed gas
velocity fields.