Fausto Kuhn Berenguer Barbosa

Gemini/GMOS Integral Field Unit stellar kinematics of the nuclear region of six nearby active galaxies

We present two-dimensional (2D) mapping of the stellar velocity field within the inner 5 arcsec of six nearby active galaxies, using spectra obtained with the Integral Field Unit of the GMOS instrument at the Gemini North telescope. The spatial resolution range from 20 to about 180 pc, and the observed field of view covers a few hundred parsecs around the nuclei. The Calcium II triplet absorption features at ~ 8500 A were used to measure the stellar radial velocities and velocity dispersions (sigma). A simple kinematical model assuming a purely rotating system with circular orbits in a plane was fitted to the radial velocity data. The turnover of the rotation curve is at only ~ 50 pc for NGC 4051 and between 200 and 700 pc for the other 5 galaxies. The sigma maps show the largest values at the centre. In the cases of NGC 2273 and NGC 3227, there is a decrease to sigma ~ 70-80 km/s at ~ 200-300 pc from the nucleus, delineating partial rings of low sigma values. A similar broken ring seems to be present at ~ 400 pc from the nucleus also in NGC 4593. We interpret these low sigma rings as traces of recently formed stars that partially keep the cold kinematics of the original gas from which they have formed. The main novelty of the present work is the unprecedented spatial resolution reached by a 2D study of stellar kinematics of Seyfert galaxies using an IFU. The few similar IFU studies available in the literature for Seyfert galaxies have a much poorer spatial resolution and/or are restricted to the study of emission line kinematics.

Gemini/GMOS IFU stellar kinematics of the nuclear region of six nearby active galaxies

We present two-dimensional (2D) mapping of the stellar velocity field within the inner 5 arcsec of six nearby active galaxies, using spectra obtained with the Integral Field Unit of the GMOS instrument at the Gemini North telescope. The spatial resolution range from 20 to about 180 pc, and the observed field of view covers a few hundred parsecs around the nuclei. The Calcium II triplet absorption features at ~ 8500 A were used to measure the stellar radial velocities and velocity dispersions (sigma). A simple kinematical model assuming a purely rotating system with circular orbits in a plane was fitted to the radial velocity data. The turnover of the rotation curve is at only ~ 50 pc for NGC 4051 and between 200 and 700 pc for the other 5 galaxies. The sigma maps show the largest values at the centre. In the cases of NGC 2273 and NGC 3227, there is a decrease to sigma ~ 70-80 km/s at ~ 200-300 pc from the nucleus, delineating partial rings of low sigma values. A similar broken ring seems to be present at ~ 400 pc from the nucleus also in NGC 4593. We interpret these low sigma rings as traces of recently formed stars that partially keep the cold kinematics of the original gas from which they have formed. The main novelty of the present work is the unprecedented spatial resolution reached by a 2D study of stellar kinematics of Seyfert galaxies using an IFU. The few similar IFU studies available in the literature for Seyfert galaxies have a much poorer spatial resolution and/or are restricted to the study of emission line kinematics.

Hubble Space Telescope Imaging of the Circinus Galaxy

We present a Hubble Space Telescope imaging study of the nearby (4 Mpc distant) Circinus galaxy, which contains the nearest type 2 Seyfert nucleus and prominent circumnuclear star formation. Images have been obtained in the [O III] ?5007, H?, and H2 v = 1?0 S(1) emission lines, and in the green (5470 ?), red (8140 ?), and near-infrared (2.04 and 2.15 ?m) continua. An image in the [Fe II] ?1.644 ?m line has been taken with a ground-based telescope. The [O III] and H? images reveal the detailed structure of the complex of streamers and knots of high-excitation gas, which extends out of the galaxy disk. The morphology some 250 pc from the nucleus strongly suggests that the high-excitation gas is concentrated on the surface of a hollow cone with apex close to the nucleus. Such a structure may result through entrainment of dense gas from a circumnuclear torus in the galaxy disk by a low-density, outflowing wind or jet. Within 40 pc of the nucleus, the high-excitation gas takes the form of a striking, filled V-shaped structure extending in the same direction as the larger scale high-excitation emission. This V can be described as an ionization cone, though a matter-bounded structure is also possible. The implied collimation of the ionizing photons or gaseous outflow must occur within 2 pc of the apex of the cone, presumed to be the location of the nucleus. The H? image shows a complex structure of H II regions, including the well-known starburst ring of radius 150?270 pc. In addition, there is a more compact (40 pc radius), elliptical ring of H II regions around the ionization cone. We argue that this latter ring, which we call the nuclear ring, is intrinsically circular and located in the plane of the galaxy disk. Much of the [Fe II] emission is associated with this nuclear, star-forming ring and is presumably powered by supernova remnants. Hot molecular hydrogen extends to within 10 pc of the nucleus, and possibly closer. The intrinsic infrared?optical continuum colors in the inner regions of the Circinus galaxy are, in many locations, bluer than is typical of bulges, indicating a relatively young stellar population is present. We confirm the presence of a compact (<2 pc), very red nuclear source in the K band. Its properties are consistent with a type 1 Seyfert nucleus viewed through an obscuration of AV = 28 ? 7 mag.

Modelling the [Fe II] λ1.644 μm outflow and comparison with H2 and H+ kinematics in the inner 200 pc of NGC 1068

We map the kinematics of the inner (200 pc) narrow-line region (NLR) of the Seyfert 2 galaxy NGC 1068 using the instrument NIFS and adaptative optics at the Gemini North Telescope. Channel maps and position-velocity diagrams are presented at a spatial resolution of

Two-dimensional kinematics of the circumnuclear region of Seyfert galaxies using GMOS-IFU

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Gemini/GMOS IFU gas velocity 'tomography' of the narrow line region of nearby active galaxies

10 pc and spectral resolution

Gemini near-infrared integral field spectroscopy of the narrow-line region of ESO 428−G14: kinematics, excitation and the role of the radio jet

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Near-IR integral field spectroscopy of the NLR of ESO428-G14: the role of the radio jet

5300 in the emission lines [Fe II] {\lambda} 1.644 {\mu}m, H

1.17–1.34μ IFU observations of nearby AGN with Gemini South

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Anlise cinemtica bi-dimensional dos ncleos de NGC 4051 e NGC 4941

{\lambda} 2.122 {\mu}m and Br{\gamma}. The [Fe II] emission line provides a better coverage of the NLR outflow than the previously used [O III] {\lambda} 5007 emission line, extending beyond the area of the bi-polar cone observed in Br{\gamma} and [O III]. This is mainly due to the contribution of the redshifted channels to the NE of the nucleus, supporting its origin in a partial ionized zone with additional contribution from shocks of the outflowing gas with the galactic disc. We modeled the kinematics and geometry of the [Fe II] emitting gas finding good agreement with the data for outflow models with conical and lemniscate (or hourglass) geometry. We calculate a mass outflow rate