17 research outputs found
Recent Developments
Context. Tracing nuclear inflows and outflows in active galactic nuclei (AGNs), determining the mass of gas involved in them, and their impact on the host galaxy and nuclear black hole requires 3D imaging studies of both the ionized and molecular gas. Aims. We map the distribution and kinematics of molecular and ionized gas in a sample of active galaxies to quantify the nuclear inflows and outflows. Here, we analyze the nuclear kinematics of NGC 1566 via ALMA observations of the CO J:2-1 emission at 24 pc spatial and âŒ2.6 km sâ1 spectral resolution, and Gemini-GMOS/IFU observations of ionized gas emission lines and stellar absorption lines at similar spatial resolution, and 123 km sâ1 of intrinsic spectral resolution. Methods. The morphology and kinematics of stellar, molecular (CO), and ionized ([N II]) emission lines are compared to the expectations from rotation, outflows, and streaming inflows. Results. While both ionized and molecular gas show rotation signatures, there are significant non-circular motions in the innermost 200 pc and along spiral arms in the central kpc (CO). The nucleus shows a double-peaked CO profile (full width at zero intensity of 200 km sâ1), and prominent (âŒ80 km sâ1) blue- and redshifted lobes are found along the minor axis in the inner arcseconds. Perturbations by the large-scale bar can qualitatively explain all features in the observed velocity field. We thus favor the presence of a molecular outflow in the disk with true velocities of âŒ180 km sâ1 in the nucleus and decelerating to 0 by âŒ72 pc. The implied molecular outflow rate is 5.6 Mâ yrâ1, with this gas accumulating in the nuclear 2âł arms. The ionized gas kinematics support an interpretation of a similar but more spherical outflow in the inner 100 pc, with no signs of deceleration. There is some evidence of streaming inflows of âŒ50 km sâ1 along specific spiral arms, and the estimated molecular mass inflow rate, âŒ0.1 Mâ yrâ1, is significantly higher than the SMBH accretion rate (áč = 4.8 Ă 10â5 Mâ yrâ1)
An outflow in the Seyfert ESO 362-G18 revealed by Gemini-GMOS/IFU Observations
We present two-dimensional stellar and gaseous kinematics of the inner 0.7
1.2 kpc of the Seyfert galaxy ESO 362-G18, derived from optical
spectra obtained with the GMOS/IFU on the Gemini South telescope at a spatial
resolution of 170 pc and spectral resolution of 36 km s. ESO
362-G18 is a strongly perturbed galaxy of morphological type Sa or S0/a, with a
minor merger approaching along the NE direction. Previous studies have shown
that the [OIII] emission shows a fan-shaped extension of 10\arcsec\
to the SE. We detect the [OIII] doublet, [NII] and H emission lines
throughout our field of view. The stellar kinematics is dominated by circular
motions in the galaxy plane, with a kinematic position angle of
137. The gas kinematics is also dominated by rotation, with
kinematic position angles ranging from 122 to 139. A
double-Gaussian fit to the [OIII]5007 and H lines, which
have the highest signal to noise ratios of the emission lines, reveal two
kinematic components: (1) a component at lower radial velocities which we
interpret as gas rotating in the galactic disk; and (2) a component with line
of sight velocities 100-250 km s higher than the systemic velocity,
interpreted as originating in the outflowing gas within the AGN ionization
cone. We estimate a mass outflow rate of 7.4 10 M
yr in the SE ionization cone (this rate doubles if we assume a biconical
configuration), and a mass accretion rate on the supermassive black hole (SMBH)
of 2.2 10 M yr. The total ionized gas mass
within 84 pc of the nucleus is 3.3 10 M; infall
velocities of 34 km s in this gas would be required to feed both
the outflow and SMBH accretion.Comment: 18 pages, 14 figure
Signatures of Feedback in the Spectacular Extended Emission Region of NGC 5972
We present Chandra X-ray Observatory observations and Space Telescope Imaging Spectrograph spectra of NGC 5972, one of the 19 âVoorwerpjesâ galaxies. This galaxy contains an extended emission-line region (EELR) and an arcsecond scale nuclear bubble. NGC 5972 is a faded active galactic nucleus (AGN), with EELR luminosity suggesting a 2.1 dex decrease in Lbol in the last âŒ5 Ă104 yr. We investigate the role of AGN feedback in exciting the EELR and bubble given the long-term variability and potential accretion state changes. We detect broad-band (0.3â8 keV) X-ray emission in the near-nuclear regions, coincident with the [O III ] bubble, as well as diffuse soft X-ray emission coincident with the EELR. The soft nuclear (0.5â1.5 keV) emission is spatially extended and the spectra are consistent with two APEC thermal populations ( âŒ0.80 and âŒ0.10 keV). We find a bubble age \u3e 2.2 Myr, suggesting formation before the current variability. We find evidence for efficient feedback with Pkin /Lbol âŒ0.8 per cent, which may be overestimated given the recent Lbol variation. [O III] kinematics show a 300 km sâ1 high-ionization velocity consistent with disturbed rotation or potentially the line-of-sight component of a âŒ780 km sâ1 thermal X-ray outflow capable of driving strong shocks to photoionize the precursor material. We explore possibilities to explain the overall jet, radio lobe and EELR misalignment including evidence for a double supermassive black hole which could support a complex misaligned system
An outflow in the Seyfert ESO 362-G18 revealed by Gemini-GMOS/IFU observations
We present two-dimensional stellar and gaseous kinematics of the inner 0.7 Ă 1.2 kpc2 of the Seyfert 1.5 galaxy ESO 362-G18, derived from optical (4092â7338 Ă
) spectra obtained with the GMOS integral field spectrograph on the Gemini South telescope at a spatial resolution of â170 pc and spectral resolution of 36 km s-Âč. ESO 362-G18 is a strongly perturbed galaxy of morphological type Sa or S0/a, with a minor merger approaching along the NE direction. Previous studies have shown that the [O III] emission shows a fan-shaped extension of â10âČâČ to the SE. We detect the [O III] doublet, [N II] and Hα emission lines throughout our field of view. The stellar kinematics is dominated by circular motions in the galaxy plane, with a kinematic position angle of â137° and is centred approximately on the continuum peak. The gas kinematics is also dominated by rotation, with kinematic position angles ranging from 122° to 139°, projected velocity amplitudes of the order of 100 km s-Âč, and a mean velocity dispersion of 100 km s-Âč. A double-Gaussian fit to the [O III]λ5007 and Hα lines, which have the highest signal to noise ratios of the emission lines, reveal two kinematic components: (1) a component at lower radial velocities which we interpret as gas rotating in the galactic disk; and (2) a component with line of sight velocities 100â250 km s-Âč higher than the systemic velocity, interpreted as originating in the outflowing gas within the AGN ionization cone. We estimate a mass outflow rate of 7.4 Ă 10-ÂČ Mâyr-Âč in the SE ionization cone (this rate doubles if we assume a biconical configuration), and a mass accretion rate on the supermassive black hole (SMBH) of 2.2 Ă 10â2 Mâ yrâ1. The total ionized gas mass within ~84 pc of the nucleus is 3.3 Ă 105 Mâ; infall velocities of ~34 km sâ1 in this gas would be required to feed both the outflow and SMBH accretion
Signatures of Feedback in the Spectacular Extended Emission Region of NGC 5972
We present Chandra X-ray Observatory observations and Space Telescope Imaging Spectrograph spectra of NGC 5972, one of the 19 âVoorwerpjesâ galaxies. This galaxy contains an extended emission-line region (EELR) and an arcsecond scale nuclear bubble. NGC 5972 is a faded active galactic nucleus (AGN), with EELR luminosity suggesting a 2.1 dex decrease in Lbol in the last âŒ5 Ă 104 yr. We investigate the role of AGN feedback in exciting the EELR and bubble given the long-term variability and potential accretion state changes. We detect broad-band (0.3â8 keV) X-ray emission in the near-nuclear regions, coincident with the [O iii] bubble, as well as diffuse soft X-ray emission coincident with the EELR. The soft nuclear (0.5â1.5 keV) emission is spatially extended and the spectra are consistent with two apec thermal populations (âŒ0.80 and âŒ0.10 keV). We find a bubble age >2.2 Myr, suggesting formation before the current variability. We find evidence for efficient feedback with , which may be overestimated given the recent Lbol variation. [O iii] kinematics show a 300 km sâ1 high-ionization velocity consistent with disturbed rotation or potentially the line-of-sight component of a âŒ780 km sâ1 thermal X-ray outflow capable of driving strong shocks to photoionize the precursor material. We explore possibilities to explain the overall jet, radio lobe and EELR misalignment including evidence for a double supermassive black hole which could support a complex misaligned system
The complex jet- and bar- perturbed kinematics in NGC 3393 as revealed with ALMA and GEMINIâGMOS/IFU
NGC 3393, a nearby Seyfert 2 galaxy with nuclear radio jets, large-scale and nuclear bars, and a posited secondary supermassive black hole, provides an interesting laboratory to test the physics of inflows and outflows. Here we present and analyse the molecular gas [ALMA observations of CO J:2-1 emission over a field of view (FOV) of 45 arcsec Ă 45 arcsec, at 0. 56 (143 pc) spatial and 5 kmsâ1 spectral resolution), ionized gas and stars (GEMINIâGMOS/IFU; over an FOV of 4 arcsec Ă 5 arcsec, at 0. 62 (159 pc) spatial and 23 km sâ1 spectral resolution) in NGC 3393. The ionized gas emission, detected over the complete GEMINIâGMOS FOV, has three identifiable kinematic components. A narrow (Ï 115 km sâ1) redshifted component, detected near the NE and SW radio lobes; which we interpret as a radio jet-driven outflow. And a broad (Ï > 115 km sâ1) blueshifted component that shows high velocities in a region perpendicular to the radio jet axis; we interpret this as an equatorial outflow. The CO J:2-1 emission is detected in spiral arms on 5â20 arcsec scales, and in two disturbed circumnuclear regions. The molecular kinematics in the spiral arms can be explained by rotation. The highly disturbed kinematics of the inner region can be explained by perturbations induced by the nuclear bar and interactions with the large scale bar. We find no evidence for, but cannot strongly rule out, the presence of the posited secondary black hole
An outflow in the Seyfert ESO 362-G18 revealed by Gemini-GMOS/IFU observations
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193083.pdf (publisher's version ) (Open Access
The complex jet- and bar- perturbed kinematics in NGC 3393 as revealed with ALMA and GEMINIâGMOS/IFU
NGC 3393, a nearby Seyfert 2 galaxy with nuclear radio jets, large-scale and nuclear bars, and a posited secondary supermassive black hole, provides an interesting laboratory to test the physics of inflows and outflows. Here we present and analyse the molecular gas [ALMA observations of CO J:2-1 emission over a field of view (FOV) of 45 arcsec Ă 45 arcsec, at 0. 56 (143 pc) spatial and 5 kmsâ1 spectral resolution), ionized gas and stars (GEMINIâGMOS/IFU; over an FOV of 4 arcsec Ă 5 arcsec, at 0. 62 (159 pc) spatial and 23 km sâ1 spectral resolution) in NGC 3393. The ionized gas emission, detected over the complete GEMINIâGMOS FOV, has three identifiable kinematic components. A narrow (Ï 115 km sâ1) redshifted component, detected near the NE and SW radio lobes; which we interpret as a radio jet-driven outflow. And a broad (Ï > 115 km sâ1) blueshifted component that shows high velocities in a region perpendicular to the radio jet axis; we interpret this as an equatorial outflow. The CO J:2-1 emission is detected in spiral arms on 5â20 arcsec scales, and in two disturbed circumnuclear regions. The molecular kinematics in the spiral arms can be explained by rotation. The highly disturbed kinematics of the inner region can be explained by perturbations induced by the nuclear bar and interactions with the large scale bar. We find no evidence for, but cannot strongly rule out, the presence of the posited secondary black hole
Outflowing gas in a compact ionization cone in the Seyfert 2 galaxy ESO 153-G20
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208877.pdf (publisher's version ) (Open Access
Detailed Accretion History of the Supermassive Black Hole in NGC 5972 over the Past âł10⎠yr through the Extended Emission-line Region
We present integral field spectroscopic observations of NGC 5972 obtained with the Multi-Unit Spectroscopic Explorer at the Very Large Telescope. NGC 5972 is a nearby galaxy containing both an active galactic nucleus (AGN) and an extended emission-line region (EELR) reaching out to âŒ17 kpc from the nucleus. We analyze the physical conditions of the EELR using spatially resolved spectra, focusing on the radial dependence of ionization state together with the light-travel time distance to probe the variability of the AGN on âł10⎠yr timescales. The kinematic analysis suggests multiple components: (a) a faint component following the rotation of the large-scale disk, (b) a component associated with the EELR suggestive of extraplanar gas connected to tidal tails, and (c) a kinematically decoupled nuclear disk. Both the kinematics and the observed tidal tails suggest a major past interaction event. Emission-line diagnostics along the EELR arms typically evidence Seyfert-like emission, implying that the EELR was primarily ionized by the AGN. We generate a set of photoionization models and fit these to different regions along the EELR. This allows us to estimate the bolometric luminosity required at different radii to excite the gas to the observed state. Our results suggest that NGC 5972 is a fading quasar, showing a steady gradual decrease in intrinsic AGN luminosity, and hence the accretion rate onto the SMBH, by a factor âŒ100 over the past 5 Ă 10⎠yr.ISSN:0004-637XISSN:2041-821