Bibcode
DOI
Arribas, S.; Mediavilla, E.; Garcia-Lorenzo, B.; del Burgo, C.
Referencia bibliográfica
Astrophysical Journal v.490, p.227
Fecha de publicación:
11
1997
Número de citas
47
Número de citas referidas
41
Descripción
We present bidimensional spectroscopy of the central region (9."4 x
12."2) of the Seyfert galaxy NGC 3516 in the two spectral ranges
4186-5839 A and 6110-7890 A. The data (95 x 2 spectra) were
simultaneously obtained with an optical fibre system (2D-FIS). The
two-dimensional velocity map of the stellar component was obtained from
the Mg I b absorption lines. The kinematic axes of this stellar velocity
field agree very well with the geometrical axes determined from the
outer isophotes. In consequence, despite the existence of an outer ring
and a bar, the stars in the circumnuclear region rotate regularly. New
accurate value for the systemic velocity (2593 +/- 15 km s-1), the
orientation of the line of nodes (53 deg +/- 5 deg), and the amplitude
of the velocity field (~80 km s-1) are presented. The center of rotation
has also been determined and could be spatially displaced with respect
to the active nucleus. We have performed an emission-line profile
decomposition and identified several components. In addition to the
component responsible for the Z-shaped morphology of the line-emission
region, gaseous systems showing large widths (FWHM ~ 10-20 A) and
extreme blueshift (-900 km s-1) have been found. The comparison between
the stellar and ionized-gas velocity maps favors the precessing twin-jet
model over the bent-outflow hypothesis to explain the Z-shaped
morphology and two-dimensional kinematics of the line-emission region.