2010A&A...515A..23H


C.D.S. - SIMBAD4 rel 1.7 - 2021.01.24CET00:42:20

2010A&A...515A..23H - Astronomy and Astrophysics, volume 515, A23-23 (2010/6-1)

The dusty heart of nearby active galaxies. I. High-spatial resolution mid-IR spectro-photometry of Seyfert galaxies.

HOENIG S.F., KISHIMOTO M., GANDHI P., SMETTE A., ASMUS D., DUSCHL W., POLLETTA M. and WEIGELT G.

Abstract (from CDS):

In a series of papers, we aim at stepping towards characterizing physical properties of the AGN dust torus by combining IR high-spatial resolution observations with 3D clumpy torus models. In this first paper, we present mid-IR imaging and 8-13µm low-resolution spectroscopy of nine type 1 and ten type 2 AGN. The observations were carried out with the VLT/VISIR mid-IR imager and spectrograph and can be considered the largest currently available mid-infrared spectro-photometric data set of AGN at spatial resolution ≲100pc. These data resolve scales at which the emission from the dust torus dominates the overall flux, and emission from the host galaxy (e.g. star-formation) is resolved out in most cases. The silicate absorption features are moderately deep and emission features, if seen at all, are shallow. The strongest silicate emission feature in our sample shows some notable shift of the central wavelength from the expected 9.7µm (based on ISM extinction curves) to ∼10.5µm. We compare the observed mid-IR luminosities of our objects to AGN luminosity tracers (X-ray, optical and [OIII] luminosities) and find that the mid-IR radiation is emitted quite isotropically. In two cases, IC 5063 and MCG-3-34-64, we find evidence for extended dust emission in the narrow-line region. We confirm the correlation between observed silicate feature strength and Hydrogen column density, which was recently found in Spitzer data at lower spatial resolution. In a further step, our 3D clumpy torus model has been used to interpret the data. We show that the strength of the silicate feature and the mid-IR spectral index α can be used to get reasonable constraints on the radial dust distribution of the torus and the average number of clouds N0 along an equatorial line-of-sight in clumpy torus models. The mid-IR spectral index α is almost exclusively determined by the radial dust distribution power-law index a, while the silicate feature depth mostly depends on N0 and the torus inclination. A comparison of model predictions to our type 1 and type 2 AGN reveals that average parameters of a=-1.0±0.5 and N0=5-8 are typically seen in the presented sample, which means that the radial dust distribution is rather shallow. As a proof-of-concept of this method, we compared the model parameters derived from α and the silicate feature strength to more detailed studies of full IR SEDs and interferometry and found that the constraints on a and N0 are consistent. Finally, we may have found evidence that the radial structure of the torus changes from low to high AGN luminosities towards steeper dust distributions, and we discuss implications for the IR size-luminosity relation.

Abstract Copyright:

Journal keyword(s): galaxies: Seyfert - galaxies: nuclei - galaxies: active - infrared: galaxies - X-rays: galaxies

Simbad objects: 22

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Number of rows : 22

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2021
#notes
1 M 77 GiP 02 42 40.771 -00 00 47.84 9.70 9.61 8.87 10.1 9.9 ~ 4162 2
2 NGC 2110 Sy2 05 52 11.3760694860 -07 27 22.489931610   14.77 13.51 11.86   ~ 598 1
3 ESO 428-14 Sy2 07 16 31.2067043371 -29 19 28.898984517   13.28 13.52 11.61   ~ 222 4
4 ESO 434-40 Sy2 09 47 40.1345889569 -30 56 55.959492708   14.10 13.69 12.44   ~ 494 0
5 M 82 IG 09 55 52.430 +69 40 46.93 9.61 9.30 8.41     ~ 5410 6
6 NGC 3227 GiP 10 23 30.57 +19 51 54.3   12.61 11.79     ~ 1556 2
7 NGC 3783 Sy1 11 39 01.7095761008 -37 44 19.008597647   12.46 13.43 11.33 12.1 ~ 1498 0
8 PB 3894 Sy1 12 14 17.6737003918 +14 03 13.182526431   14.46 14.19     ~ 753 0
9 NGC 4507 Sy2 12 35 36.6328010225 -39 54 33.661858548   12.95 13.54 11.70 12.4 ~ 445 0
10 NGC 4593 Sy1 12 39 39.4435521178 -05 20 39.035028119   13.95 13.15     ~ 968 0
11 ESO 323-77 Sy2 13 06 26.1213873662 -40 24 52.594127368   13.58 13.42 12.01   ~ 197 0
12 MCG-03-34-064 Sy2 13 22 24.485 -16 43 42.09   14   13.16   ~ 267 2
13 ESO 383-35 Sy1 13 35 53.7686909139 -34 17 44.139127597   13.89 13.61 8.9   ~ 1395 0
14 ESO 445-50 Sy1 13 49 19.2607281800 -30 18 34.224136831   13.81 13.66 12.18   ~ 739 0
15 NGC 5643 Sy2 14 32 40.778 -44 10 28.60   11.03 13.60 9.92 10.6 ~ 469 0
16 NGC 5995 Sy2 15 48 24.9486951203 -13 45 27.258674402   14.66 13.69 13.17   ~ 132 0
17 Mrk 509 Sy1 20 44 09.7504131334 -10 43 24.724854084   13.35 13.12 10.7   ~ 1146 0
18 IC 5063 Sy2 20 52 02.329 -57 04 07.60   12.92 13.60 11.30   ~ 559 1
19 NGC 7213 Sy1 22 09 16.2106632887 -47 10 00.082166299   10.97 12.08 10.50 10.6 ~ 605 0
20 NGC 7469 Sy1 23 03 15.674 +08 52 25.28 12.60 13.00 12.34     ~ 1915 3
21 NGC 7582 GiP 23 18 23.621 -42 22 14.06 11.62 10.92 10.62     ~ 819 2
22 NGC 7674 Sy2 23 27 56.6974755223 +08 46 44.238278540 13.84 13.92 13.23 12.64   ~ 646 4

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2021.01.24-00:42:20

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