The University of Southampton
University of Southampton Institutional Repository

New evidence for the dusty wind model: Polar dust and a hot core in the type-1 Seyfert ESO 323-G77

New evidence for the dusty wind model: Polar dust and a hot core in the type-1 Seyfert ESO 323-G77
New evidence for the dusty wind model: Polar dust and a hot core in the type-1 Seyfert ESO 323-G77

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 μm 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.

galaxies: active, galaxies: individual (ESO 323-G77), galaxies: nuclei, galaxies: Seyfert, infrared: galaxies, instrumentation: interferometers
0004-637X
Leftley, James H.
4eb054bd-32d4-428d-8979-84f3b3854785
Tristram, Konrad R.W.
37fab926-5cfc-4c23-8f75-52fafaa518b6
Hönig, Sebastian F.
be0bb8bc-bdac-4442-8edc-f735834f3917
Kishimoto, Makoto
ffd0231d-af4a-467e-b693-82905e0ca7f3
Asmus, Daniel
f783516a-c74c-4912-b68e-4e896e4317b2
Gandhi, Poshak
5bc3b5af-42b0-4dd8-8f1f-f74048d4d4a9
Leftley, James H.
4eb054bd-32d4-428d-8979-84f3b3854785
Tristram, Konrad R.W.
37fab926-5cfc-4c23-8f75-52fafaa518b6
Hönig, Sebastian F.
be0bb8bc-bdac-4442-8edc-f735834f3917
Kishimoto, Makoto
ffd0231d-af4a-467e-b693-82905e0ca7f3
Asmus, Daniel
f783516a-c74c-4912-b68e-4e896e4317b2
Gandhi, Poshak
5bc3b5af-42b0-4dd8-8f1f-f74048d4d4a9

Leftley, James H., Tristram, Konrad R.W., Hönig, Sebastian F., Kishimoto, Makoto, Asmus, Daniel and Gandhi, Poshak (2018) New evidence for the dusty wind model: Polar dust and a hot core in the type-1 Seyfert ESO 323-G77. The Astrophysical Journal, 862 (17), [17]. (doi:10.3847/1538-4357/aac8e5).

Record type: Article

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 μm 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.

Text
1806.01863 - Accepted Manuscript
Download (2MB)

More information

Accepted/In Press date: 28 May 2018
e-pub ahead of print date: 18 July 2018
Published date: 20 July 2018
Keywords: galaxies: active, galaxies: individual (ESO 323-G77), galaxies: nuclei, galaxies: Seyfert, infrared: galaxies, instrumentation: interferometers

Identifiers

Local EPrints ID: 425325
URI: http://eprints.soton.ac.uk/id/eprint/425325
ISSN: 0004-637X
PURE UUID: e31e0728-8cec-430c-9934-07480775badc
ORCID for James H. Leftley: ORCID iD orcid.org/0000-0001-6009-1803
ORCID for Poshak Gandhi: ORCID iD orcid.org/0000-0003-3105-2615

Catalogue record

Date deposited: 12 Oct 2018 16:30
Last modified: 17 Dec 2019 01:34

Export record

Altmetrics

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×