4 research outputs found
Gemini NIFS survey of feeding and feedback processes in nearby Active Galaxies: I - Stellar kinematics
We use the Gemini Near-Infrared Integral Field Spectrograph (NIFS) to map the
stellar kinematics of the inner few hundred parsecs of a sample of 16 nearby
Seyfert galaxies, at a spatial resolution of tens of parsecs and spectral
resolution of 40 km/s. We find that the line-of-sight (LOS) velocity fields for
most galaxies are well reproduced by rotating disk models. The kinematic
position angle (PA) derived for the LOS velocity field is consistent with the
large scale photometric PA. The residual velocities are correlated with the
hard X-ray luminosity, suggesting that more luminous AGN have a larger impact
in the surrounding stellar dynamics. The central velocity dispersion values are
usually higher than the rotation velocity amplitude, what we attribute to the
strong contribution of bulge kinematics in these inner regions. For 50% of the
galaxies, we find an inverse correlation between the velocities and the
Gauss-Hermitte moment, implying red wings in the blueshifted side and blue
wings in the redshifted side of the velocity field, attributed to the movement
of the bulge stars lagging the rotation. Two of the 16 galaxies (NGC 5899 and
Mrk 1066) show an S-shape zero velocity line, attributed to the gravitational
potential of a nuclear bar. Velocity dispersion maps show rings of low-
values (50-80 km/s) for 4 objects and "patches" of low-sigma for 6 galaxies at
150-250 pc from the nucleus, attributed to young/ intermediate age stellar
populations.Comment: To be published in MNRA
Gemini NIFS survey of feeding and feedback in nearbyActive Galaxies - III. Ionized versus warm molecular gasmasses and distributions
We have used the Gemini Near-Infrared Integral Field Spectrograph (NIFS) in
the J and K bands to map the distribution, excitation and kinematics of the
ionized HII and warm molecular gas H, in the inner few 100 pc of 6 nearby
active galaxies: NGC 788, Mrk 607, NGC 3227, NGC 3516, NGC 5506, NGC 5899. {For
most galaxies, this is the first time that such maps have been obtained}. The
ionized and H gas show distinct kinematics: while the H gas is mostly
rotating in the galaxy plane with low velocity dispersion (), the
ionized gas usually shows signatures of outflows associated with higher
values, most clearly seen in the [FeII] emission line. These two gas
species also present distinct flux distributions: the H is more uniformly
spread over the whole galaxy plane, while the ionized gas is more concentrated
around the nucleus and/or collimated along the ionization axis of its Active
Galactic Nucleus (AGN), presenting a steeper gradient in the average surface
mass density profile than the H gas. The total HII masses cover the range
M, with surface mass densities in the range
3-150 M pc, while for the warm H the values are 10
times lower. We estimate that the available gas reservoir is at least
100 times more massive than needed to power the AGN. If this gas form new stars
the star-formation rates, obtained from the Kennicutt-schmidt scalling
relation, are in the range 1-260 10 M yr. But
the gas will also - at least in part - be ejected in the form of the observed
otflows
A panchromatic spatially resolved study of the inner 500pc of NGC1052 -- II: Gas excitation and kinematics
We map the optical and near-infrared (NIR) emission-line flux distributions
and kinematics of the inner 320535pc of the elliptical galaxy
NGC1052. The integral field spectra were obtained with the Gemini Telescope
using the GMOS-IFU and NIFS instruments, with angular resolutions of 0''88 and
0''1 in the optical and NIR, respectively. We detect five kinematic components:
(1 and 2) Two spatially unresolved components, being a broad line region
visible in H, with a FWHM of 3200km s and an
intermediate-broad component seen in the [OIII]4959,5007
doublet; (3) an extended intermediate-width component with 280<FWHM<450km
s and centroid velocities up to 400km s, which dominates the flux
in our data, attributed either to a bipolar outflow related to the jets,
rotation in an eccentric disc or a combination of a disc and large-scale gas
bubbles; (4 and 5) two narrow (FWHM<150km s) components, one visible in
[OIII], and one visible in the other emission lines, extending beyond the
field-of-view of our data, which is attributed to large-scale shocks. Our
results suggest that the ionization within the observed field of view cannot be
explained by a single mechanism, with photoionization being the dominant
mechanism in the nucleus with a combination of shocks and photoionization
responsible for the extended ionization.Comment: Accepted at MNRAS. 17 pages, 17 figure