Resolving the Hot Dust Disk of ESO323-G77 Leftley, James H.; Tristram, Konrad R. W.; Hönig, Sebastian F. ...
The Astrophysical journal,
05/2021, Volume:
912, Issue:
2
Journal Article
Peer reviewed
Open access
Abstract
Infrared interferometry has led to a paradigm shift in our understanding of the dusty structure in the central parsecs of active galactic nuclei (AGNs). The dust is now thought to comprise a ...hot (∼1000 K) equatorial disk, some of which is blown into a cooler (∼300 K) polar dusty wind by radiation pressure. In this paper, we utilize the new near-IR interferometer GRAVITY on the Very Large Telescope Interferometer (VLTI) to study a Type 1.2 AGNs hosted in the nearby Seyfert galaxy ESO 323-G77. By modeling the squared visibility and closure phase, we find that the hot dust is equatorially extended, consistent with the idea of a disk, and shows signs of asymmetry in the same direction. Furthermore, the data is fully consistent with the hot dust size determined by
K
-band reverberation mapping as well as the predicted size from a CAT3D-WIND model created in previous work using the spectral energy distribution of ESO 323-G77 and observations in the mid-IR from VLTI/MID-infrared Interferometric instrument).
Abstract
Infrared interferometry of Seyfert galaxies has revealed that their warm (300–400 K) dust emission originates primarily from polar regions instead of from an equatorial dust torus as ...predicted by the classic AGN unification scheme. We present new data for the type 1.2 object ESO 323-G77 obtained with the MID-infrared interferometric Instrument and a new detailed morphological study of its warm dust. The partially resolved emission on scales between 5 and 50 mas (1.6–16 pc) is decomposed into a resolved and an unresolved source. Approximately 65% of the correlated flux between 8 and 13
μ
m is unresolved at all available baseline lengths. The remaining 35% is partially resolved and shows angular structure. From geometric modeling, we find that the emission is elongated along a position angle of 155° ± 14° with an axis ratio (major/minor) of 2.9 ± 0.3. Because the system axis is oriented in the position angle 174° ± 2°, we conclude that the dust emission of this object is also polar extended. A
CAT3D-WIND
radiative transfer model of a dusty disk and a dusty wind with a half opening angle of 30° can reproduce both the interferometric data and the SED, while a classical torus model is unable to fit the interferometric data. We interpret this as further evidence that a polar dust component is required even for low-inclination type 1 sources.
Abstract
Infrared interferometry of the local active galactic nucleus (AGN) has revealed a warm (∼300–400 K) polar dust structure that cannot be trivially explained by the putative dust torus of the ...unified model. This led to the development of the disk+wind scenario which comprises a hot (∼1000 K) compact equatorial dust disk and a polar dust wind. This wind is assumed to be driven by radiation pressure and, therefore, we would expect that long-term variation in radiation pressure would influence the dust distribution. In this paper we attempt to quantify if and how the dust distribution changes with radiation pressure. We analyze so far unpublished Very Large Telescope Interferometer (VLTI)/MID-infrared Interferometer (MIDI) data on 8 AGN and use previous results on 25 more to create a sample of 33 AGN. This sample comprises all AGN successfully observed with VLTI/MIDI. For each AGN, we calculate the Eddington ratio, using the intrinsic 2–10 keV X-ray luminosity and black hole mass, and compare this to the resolved dust emission fraction as seen by MIDI. We tentatively conclude that there is more dust in the wind at higher Eddington ratios, at least in type 2 AGN where such an effect is expected to be more easily visible.
ABSTRACT
Single dish observations of NGC 1068 have shown the presence of a 3.4 μm aliphatic hydrocarbon absorption feature similar to diffuse lines of sight towards the Galactic Centre. Both, the ...single dish spectra and the correlated fluxes obtained by MATISSE, present a broad absorption profile in the L band as well, that vary from baseline to baseline. A new CRIRES spectrum with a slit width comparable to the MATISSE aperture also reveals a wide feature around 3.4 μm. We aim to analyse these features to learn about their origin and the distribution of the carriers across the source. We argue that all these features are caused by absorption of aliphatic hydrocarbons. The 3.4 μm absorption features in the interferometric MATISSE correlated fluxes vary in optical depth over scales of 0.2-1.4 parsec in the plane of the sky, although probably placed at a larger distance from the AGN along the line of sight. The absorption in the extended areas seems to peak in the direction of the inner jet, close to the center of the ionization cone. These results support the theory of a clumpy torus. In comparing our results to the N-band surface density previously reported, we have discovered a mass ratio of carbonaceous to silicate olivine dust at ∼2 - 3.6 per cent, which is similar to those found in several lines of sight in the diffuse interstellar medium of our Galaxy.
Infrared interferometry of the local active galactic nucleus (AGN) has revealed a warm (∼300-400 K) polar dust structure that cannot be trivially explained by the putative dust torus of the unified ...model. This led to the development of the disk+wind scenario which comprises a hot (∼1000 K) compact equatorial dust disk and a polar dust wind. This wind is assumed to be driven by radiation pressure and, therefore, we would expect that long-term variation in radiation pressure would influence the dust distribution. In this paper we attempt to quantify if and how the dust distribution changes with radiation pressure. We analyze so far unpublished Very Large Telescope Interferometer (VLTI)/MID-infrared Interferometer (MIDI) data on 8 AGN and use previous results on 25 more to create a sample of 33 AGN. This sample comprises all AGN successfully observed with VLTI/MIDI. For each AGN, we calculate the Eddington ratio, using the intrinsic 2-10 keV X-ray luminosity and black hole mass, and compare this to the resolved dust emission fraction as seen by MIDI. We tentatively conclude that there is more dust in the wind at higher Eddington ratios, at least in type 2 AGN where such an effect is expected to be more easily visible.
Infrared interferometry of Seyfert galaxies has revealed that their warm (300-400 K) dust emission originates primarily from polar regions instead of from an equatorial dust torus as predicted by the ...classic AGN unification scheme. We present new data for the type 1.2 object ESO 323-G77 obtained with the MID-infrared interferometric Instrument and a new detailed morphological study of its warm dust. The partially resolved emission on scales between 5 and 50 mas (1.6-16 pc) is decomposed into a resolved and an unresolved source. Approximately 65% of the correlated flux between 8 and 13 m is unresolved at all available baseline lengths. The remaining 35% is partially resolved and shows angular structure. From geometric modeling, we find that the emission is elongated along a position angle of 155° 14° with an axis ratio (major/minor) of 2.9 0.3. Because the system axis is oriented in the position angle 174° 2°, we conclude that the dust emission of this object is also polar extended. A CAT3D-WIND radiative transfer model of a dusty disk and a dusty wind with a half opening angle of 30° can reproduce both the interferometric data and the SED, while a classical torus model is unable to fit the interferometric data. We interpret this as further evidence that a polar dust component is required even for low-inclination type 1 sources.
The physical link between AGN activity and the suppression of star formation
in their host galaxies is one of the major open questions of AGN feedback. The
Spitzer space mission revealed a subset of ...nearby radio galaxies with unusually
bright line emission from warm ($T\ge 100$ K) H$_2$, while typical
star-formation tracers were exceptionally faint or undetected. We present JWST
NIRSpec and MIRI IFU observations of 3C 326 N at z=0.09 and identify 19
ro-vibrational H$_2$ emission lines that probe hot ($T\sim 1000$ K) gas as well
as the rotational lines of H$_2$ 0--0 S(3), S(5), and S(6) which probe most of
the $2\times 10^9$ M$_\odot$ of warm H$_2$ in this galaxy. CO band heads show a
stellar component consistent with a "slow-rotator", typical of a massive
$3\times10^{11}$ M$_\odot$ galaxy, and provide us with a reliable redshift of
$z=0.08979\pm 0.0003$. Extended line emission shows a bipolar bubble expanding
through the molecular disk at velocities of up to 380 km s$^{-1}$, delineated
by several bright clumps along the Northern outer rim, potentially from gas
fragmentation. Throughout the disk, the H$_2$ is very broad, FWHM ~100-1300 km
s$^{-1}$, and shows dual-component Gaussian line profiles. FeII$\lambda$1.644
and Pa$\alpha$ follow the same morphology, however NeIII$\lambda$15.56 is
more symmetric about the nucleus. We show that the gas, with the exception of
NeIII$\lambda$15.56, is predominantly heated by shocks driven by the radio
jet and that the accompanying line broadening is sufficient to suppress star
formation. We also compare the rotational and ro-vibrational lines, finding
that the latter can be a good proxy to the global morphology and kinematic
properties of the former in strongly turbulent environments. This enables
studies of turbulence in galaxies at intermediate and high redshifts while most
rotational lines are redshifted out of the MIRI bandpass for $z$>1.5.
Infrared interferometry has fuelled a paradigm shift in our understanding of the dusty structure in the central parsecs of Active Galactic Nuclei (AGN). The dust is now thought to comprise of a hot ...(\(\sim1000\,\)K) equatorial disk, some of which is blown into a cooler (\(\sim300\,\)K) polar dusty wind by radiation pressure. In this paper, we utilise the new near-IR interferometer GRAVITY on the Very Large Telescope Interferometer (VLTI) to study a Type 1.2 AGN hosted in the nearby Seyfert galaxy ESO323-G77. By modelling the squared visibility and closure phase, we find that the hot dust is equatorially extended, consistent with the idea of a disk, and shows signs of asymmetry in the same direction. Furthermore, the data is fully consistent with the hot dust size determined by K band reverberation mapping as well as the predicted size from a CAT3D-WIND model created in previous work using the SED of ESO323-G77 and observations in the mid-IR from VLTI/MIDI.
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