ABSTRACT
Coronal-line forest (CLiF) active galactic nuclei (AGNs) are characterized by strong high-ionization lines, which contrasts with what is found in most AGNs. Here, we carry out a ...multiwavelength analysis aimed at understanding the physical processes in the narrow-line region (NLR) of these objects, and at discovering whether they are indeed a special class of AGNs. By comparing coronal emission-line ratios we conclude that there are no differences between CLiF and non-CLiF AGNs. We derive physical conditions of the NLR gas and we find electron densities in the range of 3.6 × 102 to 1.7 × 104 cm−3 and temperatures of 3.7 × 103 to 6.3 × 104 K, suggesting that the ionization mechanism is associated primarily with photoionization by the AGN. We suggest an NLR dominated by matter-bounded clouds to explain the high-ionization line spectrum observed. The mass of the central black hole, derived from the stellar velocity dispersion, shows that most of the objects have values in the interval 107–108 M⊙. Our results imply that CLiF AGNs are not in a separate category of AGNs. In all optical/near-infrared emission-line properties analysed, they represent an extension to the low/high ends of the distribution within the AGN class.
Abstract
We present and characterize a sample of 20 nearby Seyfert galaxies selected for having BAT 14–195 keV luminosities LX ≥ 1041.5 erg s−1, redshift z ≤ 0.015, being accessible for observations ...with the Gemini Near-Infrared Field Spectrograph (NIFS) and showing extended O iiiλ5007 emission. Our goal is to study Active Galactic Nucleus (AGN) feeding and feedback processes from near-infrared integral-field spectra, which include both ionized (H ii) and hot molecular (H2) emission. This sample is complemented by other nine Seyfert galaxies previously observed with NIFS. We show that the host galaxy properties (absolute magnitudes MB, MH, central stellar velocity dispersion and axial ratio) show a similar distribution to those of the 69 BAT AGN. For the 20 galaxies already observed, we present surface mass density (Σ) profiles for H ii and H2 in their inner ∼500 pc, showing that H ii emission presents a steeper radial gradient than H2. This can be attributed to the different excitation mechanisms: ionization by AGN radiation for H ii and heating by X-rays for H2. The mean surface mass densities are in the range (0.2 ≤ ΣH ii ≤ 35.9) M⊙ pc−2, and (0.2 ≤ ΣH2 ≤ 13.9)× 10−3 M⊙ pc−2, while the ratios between the H ii and H2 masses range between ∼200 and 8000. The sample presented here will be used in future papers to map AGN gas excitation and kinematics, providing a census of the mass inflow and outflow rates and power as well as their relation with the AGN luminosity.
ABSTRACT
Coronal-Line Forest Active Galactic Nuclei (CLiF AGN) are characterized by strong, high-ionization lines, which are in contrast to what is found in typical AGNs. Here, we carry out an ...infrared analysis aimed at understanding the spectral energy distribution (SED) of six sources from this group. In this work, the properties of the dusty torus for these objects are analysed. To this purpose, we infer the physical and geometrical properties of the dust structure that surrounds the central region by fitting with models, the SED of CLiF AGNs in the infrared. For this analysis, we compare the results of three models: clumpy, skirtor, and cat3d-wind. Using the Bayesian information criterion, skirtor was found to have the most robust fit to the SEDs in five out of six galaxies. The remaining object was best fitted with clumpy. The results indicate that these objects are preferentially Type I sources, supporting the detection of broad components in the permitted lines, likely associated with the broad-line region in the near-infrared spectra. The best SED fitting indicates that the line of sight gives access to the view of the central source for these objects, but the amount of dusty clouds in the same direction is high, suggesting the hypothesis that they obscure the emission of the continuum produced by the central source and that the obscuration makes the coronal lines to not overlap with the continuum.
ABSTRACT
We study the gas distribution and kinematics of the inner kpc of six moderately luminous (43.43 ≤ log Lbol ≤ 44.83) nearby (0.004 ≤ z ≤ 0.014) Seyfert galaxies observed with the ...Near-infrared Integral Field Spectrograph (NIFS) in the J ($1.25\,\mu$m) and K ($2.2\,\mu$m) bands. We analyse the most intense emission lines detected on these spectral wavebands: Fe ii $1.2570\, \mu$m and Paβ, which trace the ionized gas in the partially and fully ionized regions, and $\mathrm{ H}_2 \ 2.1218\, \mu$m, which traces the hot (∼2000 K) molecular gas. The dominant kinematic component is rotation in the disc of the galaxies, except for the ionized gas in NGC 5899 that shows only weak signatures of a disc component. We find ionized gas outflow in four galaxies, while signatures of H2 outflows are seen in three galaxies. The ionized gas outflows display velocities of a few hundred km s−1, and their mass outflow rates are in the range 0.005–12.49 M⊙ yr−1. Their kinetic powers correspond to 0.005–0.7 per cent of the active galactic nuclei (AGN) bolometric luminosities. Besides rotation and outflows signatures in some cases, the H2 kinematics also reveals inflows in three galaxies. The inflow velocities are 50–80 km s−1 and the mass inflow rates are in the range 1–9 × 10−4 M⊙ yr−1 for hot molecular gas. These inflows might be only the hot skin of the total inflowing gas, which is expected to be dominated by colder gas. The mass inflow rates are lower than the current accretion rates to the AGN, and the ionized outflows are apparently disturbing the gas in the inner kpc.
ABSTRACT
We study the ionized and highly ionized gas phases in the Seyfert 2 galaxy IC 5063 by means of the Very Large Telescope (VLT)/Multi-Unit Spectroscopic Explorer (MUSE) integral field ...spectroscopy. Our analysis allowed us to detect a high-ionization gas outflow traced by the coronal lines Fe vii λ6087 and Fe x λ6375. Both emissions are found to be extended. The former up to 1.2 kpc and 700 pc north-west (NW) and south-east (SE) from the nucleus, respectively. The latter reaches 700 pc NW of the nucleus. This is the first time that Fe x emission is observed at such distances from the central engine in an active galactic nucleus. The Fe vii λ6087 emission peaks at the nucleus, with two secondary peaks at the position of the NW and SE radio lobes. The gas kinematics is complex, with the coronal emission displaying split line profiles along the radio jet and line widths of several hundred km s−1. Velocity shifts of up to 600 km s−1 in excess of the systemic velocity of the galaxy are found very close to the radio lobes and along the jet propagation. The extended coronal gas is characterized by temperatures reaching 20 000 K and electron densities >102 cm−3, with the larger values associated with the regions of larger turbulence, likely due to the passage of the radio jet. This hypothesis is supported by photoionization models that combine the effects of the central engine and shocks. Our work highlights the strong relationship between extended coronal emission and the radio jet, with the former suitably tracing the latter, which in the case of IC 5063, propagates very close to the galaxy disc.
ABSTRACT
We present the hot molecular and warm ionized gas kinematics for 33 nearby (0.001 ≲ z ≲ 0.056) X-ray selected active galaxies using the H$_2\, 2.1218\, \mu$m and Br γ emission lines observed ...in the K band with the Gemini near-infrared integral field spectrograph. The observations cover the inner 0.04–2 kpc of each active galactic nucleus at spatial resolutions of 4–250 pc with a velocity resolution of σinst ≈ 20 ${\rm km\, s^{-1}}$. We find that 31 objects (94 per cent) present a kinematically disturbed region (KDR) seen in ionized gas, while such regions are observed in hot molecular gas for 25 galaxies (76 per cent). We interpret the KDR as being due to outflows with masses of 102–107 and 100–104 M⊙ for the ionized and hot molecular gas, respectively. The ranges of mass-outflow rates ($\dot{M}_{\rm out}$) and kinetic power ($\dot{E}_{\rm K}$) of the outflows are 10−3–101 M⊙ yr−1 and ∼1037–1043 erg s−1 for the ionized gas outflows, and 10−5–10−2 M⊙ yr−1 and 1035–1039 erg s−1 for the hot molecular gas outflows. The median coupling efficiency in our sample is $\dot{E}_{\mathrm{K}}/L_{\rm bol}\approx 1.8\times 10^{-3}$ and the estimated momentum fluxes of the outflows suggest they are produced by radiation-pressure in low-density environment, with possible contribution from shocks.
ABSTRACT
We use the Gemini NIFS instrument to map the H$_2\, 2.1218\, \mu$m and Brγ flux distributions in the inner 0.04–2 kpc of a sample of 36 nearby active galaxies (0.001 ≲ z ≲ 0.056) at spatial ...resolutions from 4 to 250 pc. We find extended emission in 34 galaxies. In ∼55 per cent of them, the emission in both lines is most extended along the galaxy major axis, while in the other 45 per cent the extent follows a distinct orientation. The emission of H2 is less concentrated than that of Brγ, presenting a radius that contains half of the flux 60 per cent greater, on average. The H2 emission is driven by thermal processes – X-ray heating and shocks – at most locations for all galaxies, where $0.4\lt \rm H_2/Br\gamma \lt 6$. For regions where H2/Brγ > 6 (seen in 40 per cent of the galaxies), shocks are the main H2 excitation mechanism, while in regions with H2/Brγ < 0.4 (25 per cent of the sample) the H2 emission is produced by fluorescence. The only difference we found between type 1 and type 2 active galactic nucleus (AGN) was in the nuclear emission-line equivalent widths that are smaller in type 1 than in type 2 due to a larger contribution to the continuum from the hot dusty torus in the former. The gas masses in the inner 125 pc radius are in the range 101−104 M⊙ for the hot H2 and 103−106 M⊙ for the ionized gas and would be enough to power the AGN in our sample for 105−108 yr at their current accretion rates.
ABSTRACT
In modern models and simulations of galactic evolution, the star formation in massive galaxies is regulated by an ad hoc active galactic nuclei (AGN) feedback process. However, the physics ...and the extension of such effects on the star formation history of galaxies is matter of vivid debate. In order to shed some light in the AGN effects over the star formation, we analysed the inner 500 × 500 pc of a sample of 14 Seyfert galaxies using GMOS and MUSE integral field spectroscopy. We fitted the continuum spectra in order to derive stellar age, metallicity, velocity, and velocity dispersion maps in each source. After stacking our sample and averaging their properties, we found that the contribution of young SP, as well as that of AGN featureless continuum both peak at the nucleus. The fraction of intermediate-age SPs is smaller in the nucleus if compared to outer regions, and the contribution of old SPs vary very little within our field of view (FoV). We also found no variation of velocity dispersion or metallicity within our FoV. Lastly, we detected an increase in the dust reddening towards the center of the galaxies. These results lead us to conclude that AGN phenomenon is usually related to a recent star formation episode in the circumnuclear region.
ABSTRACT
We map the optical and near-infrared (NIR) emission-line flux distributions and kinematics of the inner 320 × 535 pc2 of the elliptical galaxy NGC 1052. 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 arcsec in the optical and NIR, respectively. We detect five kinematic components: (1) and (2) two spatially unresolved components: a broad-line region visible in H α, with a full width at half-maximum (FWHM) of ∼3200 km s−1, and an intermediate broad component seen in the O iii λλ4959,5007 doublet; (3) an extended intermediate-width component with 280 km s−1 < FWHM < 450 km s−1 and centroid velocities up to 400 km s−1, which dominates the flux in our data, attributed either to a bipolar outflow related to the jets, rotation in an eccentric disc or to a combination of a disc and large-scale gas bubbles; (4) and (5) two narrow (FWHM < 150 km s−1) components, one visible in O iii, and another 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.
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