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J/ApJ/822/109    MIR view of polar dust emission in local AGNs    (Asmus+, 2016)

The subarcsecond mid-infrared view of local active galactic nuclei. III. Polar dust emission. Asmus D., Honig S.F., Gandhi P. <Astrophys. J., 822, 109-109 (2016)> =2016ApJ...822..109A (SIMBAD/NED BibCode)
ADC_Keywords: Active gal. nuclei ; Galaxies, Seyfert ; Infrared sources ; Morphology Keywords: accretion, accretion disks - galaxies: active - galaxies: nuclei - infrared: galaxies - X-rays: galaxies Abstract: Recent mid-infrared (MIR) interferometric observations have shown that in a few active galactic nuclei (AGNs) the bulk of the infrared emission originates from the polar region above the putative torus, where only a little dust should be present. Here, we investigate whether such strong polar dust emission is common in AGNs. Out of 149 Seyferts in the MIR atlas of local AGNs, 21 show extended MIR emission on single-dish images. In 18 objects, the extended MIR emission aligns with the position angle (PA) of the system axis, established by [O III], radio, polarization, and maser-based PA measurements. The relative amount of resolved MIR emission is at least 40% and scales with the [O IV] fluxes, implying a strong connection between the extended continuum and [O IV] emitters. These results together with the radio-quiet nature of the Seyferts support the scenario that the bulk of MIR emission is emitted by dust in the polar region and not by the torus, which would demand a new paradigm for the infrared emission structure in AGNs. The current low detection rate of polar dust in the AGNs of the MIR atlas is explained by the lack of sufficient high-quality MIR data and the requirements on the orientation, strength of narrow-line region, and distance of the AGNs. The James Webb Space Telescope will enable much deeper nuclear MIR studies with comparable angular resolution, allowing us to resolve the polar emission and surroundings in most of the nearby AGNs. Description: The parent sample for this work is the AGN MIR atlas of 253 objects (Asmus et al. 2014, J/MNRAS/439/1648). The optical classifications and distances (using the same cosmology) are adopted from that work. We furthermore use the nuclear MIR flux measurements from Asmus et al. (2014, J/MNRAS/439/1648). These are extracted from ground-based multi-filter photometry obtained with the instruments VLT/VISIR (Lagage et al. 2004Msngr.117...12L), Gemini/T-ReCS (Telesco et al. 1998SPIE.3354..534T), Gemini/Michelle (Glasse et al. 1997SPIE.2871.1197G), and Subaru/COMICS (Kataza et al. 2000SPIE.4008.1144K), with an angular resolution of the order of 0.35" or 120 pc for the median sample distance of 72 Mpc at 12 µm. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1.dat 138 149 Properties of the Seyfert Sample refs.dat 85 133 References
See also: J/ApJS/133/77 : VLA radio continuum survey of Seyfert galaxies (Ho+, 2001) J/ApJ/705/14 : Seyfert galaxies in the mid-IR (Deo+, 2009) J/ApJ/725/2270 : Mid-IR emission lines in AGNs (Pereira-Santaella+, 2010) J/ApJS/208/24 : Spitzer MIR AGN survey. I. (Lacy+, 2013) J/MNRAS/439/1648 : Subarcsecond mid-infrared atlas of local AGN (Asmus+, 2014) J/MNRAS/454/766 : Mid-infrared-X-ray correlation for local AGNs (Asmus+, 2015) Byte-by-byte Description of file: table1.dat
Bytes Format Units Label Explanations
1- 23 A23 --- Name Seyfert galaxy name 25- 29 F5.1 Mpc Dist [3.8/807] Distance 31- 37 A7 --- Class Optical Seyfert classification (1) 39 A1 --- Ext [npuy] Nuclear MIR extension from Asmus et al. (2014, J/MNRAS/439/1648) (2) 41- 44 F4.2 --- Ratio [0.01/2.59]? Ratio of relative extended to nuclear emission at 12µm (Rnucext=FνGau/FνPSF-1) 46- 48 I3 deg PA-MIR [1/210] Mean nuclear MIR position angle from the individual images from Asmus et al. (2014, J/MNRAS/439/1648) (3) 50- 51 I2 deg e_PA-MIR [3/89]? Uncertainty in PA-MIR (4) 53- 55 I3 deg PA-NLR [-17/215]? Position angle of the narrow-line region (NLR) major axis, mostly from [O III] images 57- 71 A15 --- r_PA-NLR Reference for PA-NLR (see refs.dat file) 73- 75 I3 deg PA-Rad [-20/245]? Position angle of the nuclear radio morphology 77- 87 A11 --- r_PA-Rad Reference for PA-Rad (see refs.dat file) 89- 91 I3 deg PA-Pol [-45/150]? Position angle of polarized broad lines 93- 95 I3 --- r_PA-Pol ? Reference for PA-Pol (see refs.dat file) 97- 99 I3 deg PA-Mas [-34/155]? Maser position angle 101-111 A11 --- r_PA-Mas Reference for PA-Mas (see refs.dat file) 113-115 I3 deg PA-SA [-41/245]? Mean system axis position angle 117-118 I2 deg e_PA-SA [1/53]? Uncertainty in PA-SA (if multiple PAs are used) (4) 120-122 I3 deg PA-Host [-60/290]? Host inner structure position angle 124-125 I2 --- r_PA-Host ? Reference for PA-Host (see refs.dat file) 127-128 A2 --- l_logF [≤ ] Limit flag on logF 129-134 F6.2 10-3W/m2 logF [-14.52/-10.72]? The [O IV] 25.89µm line flux (in erg/s/cm2) 136-138 I3 --- r_logF ? Reference for logF (see refs.dat file)
Note (1): Adopted from Asmus et al. 2014, J/MNRAS/439/1648. Note (2): Extension as follows: n = Not resolved; p = Possibly extended; u = Unknown extension; y = Extended. Note (3): Note that this value can be unreliable if the object was not classified as extended. Note (4): Standard deviation in the case of multiple measurements available.
Byte-by-byte Description of file: refs.dat
Bytes Format Units Label Explanations
1- 3 I3 --- Ref [1/133] Reference code 5- 37 A33 --- Aut Author's name(s) 39- 57 A19 --- BibCode BibCode 59- 85 A27 --- Com Comment on reference
History: From electronic version of the journal References: Asmus et al. Paper I. 2014MNRAS.439.1648A, Cat. J/MNRAS/439/1648 Asmus et al. Paper II. 2015MNRAS.454..766A
(End) Tiphaine Pouvreau [CDS] 14-Feb-2018
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