OASIS integral-field spectroscopy of the central kpc in 11 Seyfert 2 galaxies
Stoklasová, I.; Ferruit, P.; Emsellem, E.;Jungwiert, B.; Pécontal, E.; Sánchez, S. F.. OASIS integral-field spectroscopy of the central kpc in 11 Seyfert 2 galaxies. Astronomy and Astrophysics. 2009, Vol. Volume 500, Issue 3, 2009, pp.1287-1325, p. -2009.
Aims. We examine the physical conditions of ionised gas in the central
kiloparsec(s) of nearby Seyfert galaxies. Our aim is a detailed
two-dimensional mapping of optical spectroscopic properties, searching
for features in the emission structure and in gas kinematics which would
be common to all the active galactic nuclei (AGN) or their class, and
which would help us to understand the origin and nature of the
circumnuclear gas, and its role in the AGN. Methods: We map narrow-line
regions (NLRs) of 11 nearby Seyfert 2 galaxies with the optical
integral-field spectrograph OASIS mounted at CFHT. We model
emission-line profiles of 5 forbidden-line doublets and 2 Balmer lines,
correcting for the underlying stellar absorption by reconstructing
stellar spectra with synthetic evolutionary stellar population models.
Results: For each of the 11 targets, we present 2D maps of surface
brightness in the observed emission lines, diagnostic line intensity
ratios, gas kinematics (mean line-of-sight velocity and velocity
dispersion), electron density, and interstellar reddening, and we plot
spatially resolved spectral-diagnostic diagrams. The stellar data are
represented by maps of mean line-of-sight (LOS) velocities and of the
relative mass fractions of the young stellar populations. The gas
velocity fields in 80% of the sample exhibit twisted S-shaped
isovelocity contours, which are signatures of non-circular orbits and
indicate non-axisymmetric gravitational potentials, gas motions out of
the galactic plane, or possible outflows and inflows. Based on the
kinematic measurements, we identified a possible nuclear ring or radial
gas flow in NGC 262 (Mrk 348), not reported before. Eight of the eleven
observed objects exhibit strongly asymmetric or multi-component
emission-line profiles, in most cases confined to an elongated region
passing through the galactic centre, perpendicular to the major axis of
emission.
Aims. We examine the physical conditions of ionised gas in the central
kiloparsec(s) of nearby Seyfert galaxies. Our aim is a detailed
two-dimensional mapping of optical spectroscopic properties, searching
for features in the emission structure and in gas kinematics which would
be common to all the active galactic nuclei (AGN) or their class, and
which would help us to understand the origin and nature of the
circumnuclear gas, and its role in the AGN. Methods: We map narrow-line
regions (NLRs) of 11 nearby Seyfert 2 galaxies with the optical
integral-field spectrograph OASIS mounted at CFHT. We model
emission-line profiles of 5 forbidden-line doublets and 2 Balmer lines,
correcting for the underlying stellar absorption by reconstructing
stellar spectra with synthetic evolutionary stellar population models.
Results: For each of the 11 targets, we present 2D maps of surface
brightness in the observed emission lines, diagnostic line intensity
ratios, gas kinematics (mean line-of-sight velocity and velocity
dispersion), electron density, and interstellar reddening, and we plot
spatially resolved spectral-diagnostic diagrams. The stellar data are
represented by maps of mean line-of-sight (LOS) velocities and of the
relative mass fractions of the young stellar populations. The gas
velocity fields in 80% of the sample exhibit twisted S-shaped
isovelocity contours, which are signatures of non-circular orbits and
indicate non-axisymmetric gravitational potentials, gas motions out of
the galactic plane, or possible outflows and inflows. Based on the
kinematic measurements, we identified a possible nuclear ring or radial
gas flow in NGC 262 (Mrk 348), not reported before. Eight of the eleven
observed objects exhibit strongly asymmetric or multi-component
emission-line profiles, in most cases confined to an elongated region
passing through the galactic centre, perpendicular to the major axis of
emission.