Polar Dust, Nuclear Obscuration, and IR SED Diversity in Type-1 AGNs*

Lyu, Jianwei; Rieke, G. H.

doi:10.3847/1538-4357/aae075

Cited by 72 publications

(103 citation statements)

References 206 publications

(287 reference statements)

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“…The recent high spatial resolution MIR interferometric observations of the polar dust region often reveal a weak silicate feature (e.g., Hönig et al 2012;Burtscher et al 2013) as well as SED decomposition of the dusty polar region (Lyu & Rieke 2018); these observations are consistent with our results suggesting that only large-sized dust grains can survive in such a region. 4.3.…”

Section: Implications For the Silicate Feature Of Agns In The Mirsupporting

confidence: 92%

Dust Destruction by Drift-induced Sputtering in Active Galactic Nuclei

Tazaki

Ichikawa

2020

ApJ

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Recent mid-infrared high spatial resolution observations have revealed that active galactic nuclei (AGNs) may host a polar dust region with the size of several pc, and such dust may be carried by radiation from the central engine. The polar dust emission often exhibits very weak or absence of the silicate 10-µm emission feature. A possible explanation is that the polar dust is dominated by micronsized large grains because these grains do not show the silicate feature, while it remains unclear how large grains are preferentially supplied to the polar region. We here propose a new scenario describing the prevalence of large grains at the polar region. We show that grains are accelerated to the hypersonic drift velocity by the radiation pressure from AGN, and the hypersonic drift results in dust destruction via kinetic sputtering. Sputtering destroys small grains faster than the large ones, and thus larger grains will be preferentially blown over longer distance. Although the hypersonic drift, or kinetic sputtering, tends to be suppressed for very small grains due to the Coulomb drag, they might also be disrupted by Coulomb explosion. Removal of small grains and/or survival of large grains may explain the lack of a silicate 10-µm emission feature in polar dust emission.

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Section: Implications For the Silicate Feature Of Agns In The Mirsupporting

confidence: 92%

Dust Destruction by Drift-induced Sputtering in Active Galactic Nuclei

Tazaki

Ichikawa

2020

ApJ

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“…However their significance in the samples studied by us is rather minor: in the MIR band -because SFRs are predicted to produce much redder MIR spectra than observed in the objects of our sample (e.g. Ichikawa et al 2017;Lyu & Rieke 2018); and in the UV band only in Type 2 AGN -otherwise domination of UV radiation by SFR should be similar in Type 1 and Type 2 AGN, whereas our Type 1 objects are more UV luminous than Type 2 objects (see Fig. 6 and 7).…”

Section: Sed / Multi-band Spectramentioning

confidence: 72%

Comparison of SEDs of very massive radio-loud and radio-quiet AGN

Gupta

Sikora

Rusinek

2019

Monthly Notices of the Royal Astronomical Society

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The main objective of this work is to establish and interpret the dominant spectral components and their differences in radio-loud (RL) and radio-quiet (RQ) AGN with very massive black holes, and accreting at moderate rates. Such a sample is selected from the Swift/BAT catalogue of AGN having determined optical spectra types and hosting black holes with masses > 10 8.5 M . We confirm our previous results, that radio loudness distribution of Swift/BAT AGN is bimodal and that radio galaxies are about two times X-ray louder than their radio-quiet counterparts. We show that the average X-ray loudness (defined as a ratio of luminosity in the 14 − 195 keV band to that at 12 µm) of Type 1 and Type 2 AGN is very similar. This similarity holds for both RL and RQ subsamples and indicates negligible dependence of the observed X-ray luminosities on the inclination angle in both populations.In both the radiative output is dominated by mid-IR and hard X-ray components, and relatively weak UV luminosities indicate large amounts of dust in polar regions.

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“…Costamante et al (2018) showed that in the vast majority of the Fermi FSRQs, the γ-ray emission appears to originate outside the BLR. Moreover, recent findings support a torus geometry that deviates significantly from the standard picture of a "donut"-like structure (Carilli et al 2019;Asmus 2019;Lyu & Rieke 2018;Hönig & Beckert 2007). The torus is likely to be rather clumpy, with polar molecular clouds providing an even richer photon field available for EC scattering.…”

Section: Location Of the Gamma-ray Emissionmentioning

confidence: 90%

Localizing the γ-ray emitting region in the blazar TXS 2013+370

Traianou

Krichbaum

Boccardi

et al. 2020

A&A

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Aims. The γ-ray production mechanism and its localization in blazars are still a matter of debate. The main goal of this paper is to constrain the location of the high-energy emission in the blazar TXS 2013+370 and to study the physical and geometrical properties of the inner jet region on sub-pc scales. Methods. TXS 2013+370 was monitored during 2002-2013 with VLBI at 15, 22, 43, and 86 GHz, which allowed us to image the jet base with an angular resolution of ≥ 0.4 pc. By employing CLEAN imaging and Gaussian model-fitting, we performed a thorough kinematic analysis at multiple frequencies, which provided estimates of the jet speed, orientation, and component ejection times. Additionally, we studied the jet expansion profile and used the information on the jet geometry to estimate the location of the jet apex. VLBI data were combined with single-dish measurements to search for correlated activity between the radio, mm, and γ-ray emission. For this purpose, we employed a cross-correlation analysis, supported by several significance tests. Results. The high-resolution VLBI imaging revealed the existence of a spatially bent jet, described by co-existing moving emission features and stationary features. New jet features, labeled as A1, N, and N1, are observed to emerge from the core, accompanied by flaring activity in radio/mm-bands and γ rays. The analysis of the transverse jet width profile constrains the location of the mm core to lie ≤2 pc downstream of the jet apex, and also reveals the existence of a transition from parabolic to conical jet expansion at a distance of ∼54 pc from the core, corresponding to ∼1.5 × 10 6 Schwarzschild radii. The cross-correlation analysis of the broad-band variability reveals a strong correlation between the radio-mm and γ-ray data, with the 1 mm emission lagging ∼ 49 days behind the γ rays. Based on this, we infer that the high energy emission is produced at a distance of the order of ∼1 pc from the jet apex, suggesting that the seed photon fields for the external Compton mechanism originate either in the dusty torus or in the broad-line region.

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Polar Dust, Nuclear Obscuration, and IR SED Diversity in Type-1 AGNs*

Cited by 72 publications

References 206 publications

Dust Destruction by Drift-induced Sputtering in Active Galactic Nuclei

Dust Destruction by Drift-induced Sputtering in Active Galactic Nuclei

Comparison of SEDs of very massive radio-loud and radio-quiet AGN

Localizing the γ-ray emitting region in the blazar TXS 2013+370

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