scholarly journals New evidence for the ubiquity of prominent polar dust emission in AGN on tens of parsec scales

2019 ◽  
Vol 489 (2) ◽  
pp. 2177-2188 ◽  
Author(s):  
D Asmus
Keyword(s):  
Active Galactic Nuclei ◽  
Dust Emission ◽  
Galactic Nuclei ◽  
Large Telescope ◽  
Mid Infrared ◽  
Bolometric Luminosity ◽  
Very Large Telescope ◽  
Lower Limits ◽  
New Evidence ◽  
Small Dispersion

ABSTRACT The key ingredient of active galactic nuclei (AGN) unification, the dusty obscuring torus was so far held responsible for the observed mid-infrared (MIR) emission of AGN. However, the best studied objects with Very Large Telescope Interferometer (VLTI)/MID-infrared Interferometric instrument (MIDI) show that instead a polar dusty wind is dominating these wavelengths, leaving little room for a torus contribution. But is this wind a ubiquitous part of the AGN? To test this, we conducted a straightforward detection experiment, using the upgraded Very Large Telescope (VLT)/VLT Imager and Spectrometer for mid-InfraRed (VISIR) for deep subarcsecond resolution MIR imaging of a sample of nine [O iv]-bright, obscured AGN, all of which were predicted to have detectable polar emission. Indeed, the new data reveal such emission in all objects but one. We further estimate lower limits on the extent of the polar dust and show that the polar dust emission is dominating the total MIR emission of the AGN. These findings support the scenario that polar dust is not only ubiquitous in AGN but also an integral part of its structure, processing a significant part of the primary radiation. The polar dust has to be optically thin on average, which explains e.g. the small dispersion in the observed MIR–X-ray luminosity correlation. At the same time, it has to be taken into account when deriving covering factors of obscuring material from MIR to bolometric luminosity ratios. Finally, we find a new tentative trend of increasing MIR emission size with increasing Eddington ratio.

scholarly journals High-Ionization Mid-Infrared Lines as Black Hole Mass and Bolometric Luminosity Indicators in Active Galactic Nuclei

2008 ◽  
Vol 674 (1) ◽  
pp. L9-L12 ◽  
Author(s):  
K. M. Dasyra ◽  
L. C. Ho ◽  
L. Armus ◽  
P. Ogle ◽  
G. Helou ◽  
...  
Keyword(s):  
Black Hole ◽  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Black Hole Mass ◽  
Mid Infrared ◽  
Bolometric Luminosity ◽  
High Ionization

scholarly journals Towards a new paradigm of dust structure in AGN: Dissecting the mid-IR emission of Circinus galaxy

2019 ◽  
Vol 15 (S356) ◽  
pp. 50-55
Author(s):  
Marko Stalevski ◽  
Daniel Asmus ◽  
Konrad R. W. Tristram
Keyword(s):  
Active Galactic Nuclei ◽  
Large Scale ◽  
Dust Emission ◽  
Galactic Nuclei ◽  
Polar Regions ◽  
New Paradigm ◽  
Mid Infrared ◽  
Small Scales ◽  
Ir Emission ◽  
Dusty Torus

AbstractRecent mid-infrared (MIR) observations of nearby active galactic nuclei (AGN), revealed that their dust emission appears prominently extended in the polar direction, at odds with the expectations from the canonical dusty torus. This polar dust, tentatively associated with dusty winds driven by radiation pressure, is found to have a major contribution to the MIR flux from a few to hundreds of parsecs. One such source with a clear detection of polar dust is a nearby, well-known AGN in the Circinus galaxy. We proposed a phenomenological model consisting of a compact, thin dusty disk and a large-scale polar outflow in the form of a hyperboloid shell and demonstrated that such a model is able to explain the peculiar MIR morphology on large scales seen by VLT/VISIR and the interferometric data from VLTI/MIDI that probe the small scales. Our results call for caution when attributing dust emission of unresolved sources entirely to the torus and warrant further investigation of the MIR emission in the polar regions of AGN.

scholarly journals Resolving the Nucleus of Centaurus A at Mid-Infrared Wavelengths

2010 ◽  
Vol 27 (4) ◽  
pp. 490-495 ◽  
Author(s):  
Leonard Burtscher ◽  
Klaus Meisenheimer ◽  
Walter Jaffe ◽  
Konrad R. W. Tristram ◽  
Huub J. A. Rottgering
Keyword(s):  
Dust Emission ◽  
Galactic Nuclei ◽  
Major Axis ◽  
Seyfert Galaxies ◽  
Position Angle ◽  
Small Scale ◽  
Mid Infrared ◽  
Very Large Telescope ◽  
Infrared Wavelengths ◽  
Centaurus A

AbstractWe have observed Centaurus A with the Mid-Infrared Interferometric Instrument (MIDI) at the Very Large Telescope Interferometer at resolutions of 7–15 mas (at 12.5 μm) and filled gaps in the (u, v) coverage in comparison to earlier measurements. We are now able to describe the nuclear emission in terms of geometric components and derive their parameters by fitting models to the interferometric data. With simple geometrical models, the best fit is achieved for an elongated disk with flat intensity profile with diameter 76 ± 9 × 35 ± 2 mas (1.41 ± 0.17 × 0.65 ± 0.03 pc) whose major axis is oriented at a position angle (PA) of 10.1 ± 2.2° east of north. A point source contributes 47 ± 11% of the nuclear emission at 12.5 μm. There is also evidence that neither such a uniform nor a Gaussian disk are good fits to the data. This indicates that we are resolving more complicated small-scale structure in active galactic nuclei with MIDI, as has been seen in Seyfert galaxies previously observed with MIDI. The PA and inferred inclination i = of the dust emission are compared with observations of gas and dust at larger scales.

scholarly journals Jet-Induced Feedback in the [O III] Lines of Early Evolution Stage Active Galactic Nuclei

Universe ◽  
2021 ◽  
Vol 7 (6) ◽  
pp. 188
Author(s):  
Marco Berton ◽  
Emilia Järvelä
Keyword(s):  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Plasma Jets ◽  
Early Evolution ◽  
Host Galaxy ◽  
Bolometric Luminosity ◽  
Radio Imaging ◽  
Strong Relation ◽  
Evolution Stage ◽  
Good Proxy

It is well known that active galactic nuclei (AGN) show various forms of interaction with their host galaxy, in a number of phenomena generally called AGN feedback. In particular, the relativistic plasma jets launched by a fraction of AGN can strongly affect their environment. We present here a study of the [O III] λλ4959,5007 lines in a diverse sample of early evolution stage AGN–specifically narrow-line Seyfert 1 galaxies. Radio imaging observations of all of the sources enable a division to jetted and non-jetted sources, and exploiting this we show that the ionized gas properties are significantly influenced by the presence of the jets, as we often find the [O III] lines (blue-)shifted with respect to their restframe wavelength. We also show how the radio morphology and the radio spectral index do not seem to play a role in the origin of the [O III] shifts, thus suggesting that the source inclination is not relevant to the lines displacement. We do not find a strong relation between the [O III] line properties and the bolometric luminosity, suggesting that within our sample radiatively driven outflows do not seem to have a significant contribution to the [O III] line kinematics. We finally suggest that [O III] shifts may be a good proxy to identify the presence of relativistic jets. Additional studies, especially with integral-field spectroscopy, will provide a deeper insight into the relation between jets and their environment in early evolution stage AGN.

scholarly journals MID-INFRARED SPECTROSCOPY OF CANDIDATE ACTIVE GALACTIC NUCLEI-DOMINATED SUBMILLIMETER GALAXIES

2010 ◽  
Vol 713 (1) ◽  
pp. 503-519 ◽  
Author(s):  
K. Coppin ◽  
A. Pope ◽  
K. Menéndez-Delmestre ◽  
D. M. Alexander ◽  
J. S. Dunlop ◽  
...  
Keyword(s):  
Infrared Spectroscopy ◽  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Mid Infrared ◽  
Mid Infrared Spectroscopy ◽  
Submillimeter Galaxies

scholarly journals STAR FORMATION RATES FROM [C II] 158 μm AND MID-INFRARED EMISSION LINES FOR STARBURSTS AND ACTIVE GALACTIC NUCLEI

2014 ◽  
Vol 790 (1) ◽  
pp. 15 ◽  
Author(s):  
L. Sargsyan ◽  
A. Samsonyan ◽  
V. Lebouteiller ◽  
D. Weedman ◽  
D. Barry ◽  
...  
Keyword(s):  
Star Formation ◽  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Infrared Emission ◽  
Emission Lines ◽  
Mid Infrared

scholarly journals The infrared view of dust and molecules around V4334 Sgr (Sakurai’s object): a 20-yr retrospective

2020 ◽  
Vol 493 (1) ◽  
pp. 1277-1291 ◽  
Author(s):  
A Evans ◽  
R D Gehrz ◽  
C E Woodward ◽  
D P K Banerjee ◽  
T R Geballe ◽  
...  
Keyword(s):  
Amorphous Carbon ◽  
Near Infrared ◽  
Dust Emission ◽  
Infrared Excess ◽  
Object A ◽  
Bolometric Luminosity ◽  
Dust Mass ◽  
Mass Ejection ◽  
Lower Limits ◽  
Hydrogenated Amorphous

ABSTRACT We present an analysis of the evolution of circumstellar dust and molecules in the environment of the very late thermal pulse object V4334 Sgr (Sakurai’s object) over an ∼20-yr period, drawing on ground-, airborne-, and space-based infrared photometry and spectroscopy. The dust emission, which started in 1997, resembles a blackbody that cooled from ∼1200 K in 1998 August to ∼180 K in 2016 July. The dust mass, assuming amorphous carbon, was ∼5 × 10−10 M⊙ in 1998 August, and we estimate that the total dust mass was ∼2 × 10−5 M⊙ by ∼2016. The appearance of a near-infrared excess in 2008 suggests that a new episode of (or renewed) mass-loss began then. We infer lower limits on the bolometric luminosity of the embedded star from that of the dust shell, which rose to ∼16 000 L⊙ before declining to ∼3000 L⊙. There is evidence for weak 6–7 μm absorption, which we attribute to hydrogenated amorphous carbon formed in material ejected by Sakurai’s object during a mass ejection phase that preceded the 1997 event. We detect small hydrocarbon and other molecules in the spectra, and trace the column densities in hydrogen cyanide (HCN) and acetylene (C2H2). We use the former to determine the 12C/13C ratio to be 6.4 ± 0.7, 14 times smaller than the Solar system value.

scholarly journals IDENTIFICATION OF 1.4 MILLION ACTIVE GALACTIC NUCLEI IN THE MID-INFRARED USING WISE DATA

2015 ◽  
Vol 221 (1) ◽  
pp. 12 ◽  
Author(s):  
N. J. Secrest ◽  
R. P. Dudik ◽  
B. N. Dorland ◽  
N. Zacharias ◽  
V. Makarov ◽  
...  
Keyword(s):  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Mid Infrared
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