Infrared Spectral Energy Distribution and Variability of Active Galactic Nuclei: Clues to the Structure of Circumnuclear Material

Lyu, Jianwei; Rieke, G. H.

doi:10.3390/universe8060304

Cited by 25 publications

(22 citation statements)

References 334 publications

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“…9 Our templates have been optimized to minimize the number of free parameters while preserving an adequate description of the modeled behavior. Further discussion of their applicability can be found in Lyu & Rieke (2022). In addition, no energy balance between the stellar extinction and galaxy IR emission is introduced because of the strong anisotropy of extinction in typical disk galaxies and the uncertain effects on the extinction behavior caused by the introduction of an AGN.…”

Section: The Fitting Toolmentioning

confidence: 99%

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AGN Selection and Demographics in GOODS-S/HUDF from X-Ray to Radio

Lyu

Alberts

Rieke

et al. 2022

ApJ

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We present a comprehensive census of the active galactic nuclei (AGNs) in the GOODS-S/HUDF region from the X-ray to the radio, covering both the obscured and unobscured populations. This work includes a robust analysis of the source optical to mid-IR spectral energy distributions (SEDs) featuring (semi)empirical AGN and galaxy dust emission models and Bayesian fitting techniques, ultra-deep Very Large Array 3 and 6 GHz observations, and an integrated analysis of various AGN selection techniques, including X-ray properties, UV to mid-IR SED analysis, optical spectral features, mid-IR colors, radio-loudness and spectral slope, and AGN variability. In total, we report ∼900 AGNs over the ∼170 arcmin2 3D-HST GOODS-S footprint, which has doubled the AGN number identified in the previous X-ray sample, with ∼26% of our sample undetected in the deepest Chandra image. With a summary of AGN demographics from different selection methods, we find that no one single band or technique comes close to selecting a complete AGN sample despite the great depth of the data in GOODS-S/HUDF. We estimate the yields of various approaches and explore the reasons for incompleteness. We characterize the statistical properties, such as source number density, obscuration fraction, and luminosity function of the AGN sample in this field, and discuss their immediate implications. We also provide some qualitative predictions of the AGN sample that might be discovered by the upcoming JWST surveys.

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Section: The Fitting Toolmentioning

confidence: 99%

“…There have been many previous efforts to identify complete samples of AGNs. A comprehensive review can be found in Lyu & Rieke (2022). Our approach represents an advance because of the depth of the observational database and the breadth of the methods employed.…”

Section: Comparison With Other Workmentioning

confidence: 99%

AGN Selection and Demographics in GOODS-S/HUDF from X-Ray to Radio

Lyu

Alberts

Rieke

et al. 2022

ApJ

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“…This central dusty structure is commonly assumed to be optically thick and to have a toroidal geometry that is aligned with the plane of the accretion disk. The latter requirement was mainly derived from the need for an equatorial obscurer in AGNs, in order to account for the observations of broad emission lines in the polarized scattered light of many type 2 AGNs and the relative numbers of type 1 and type 2 AGNs in complete samples (see the reviews by Lawrence 1987;Antonucci 1993;Netzer 2015;Lyu & Rieke 2022a). A warped dusty disk could be a viable alternative to the dusty torus, as first proposed by Phinney (1989).…”

Section: Introductionmentioning

confidence: 99%

A Complex Dust Morphology in the High-luminosity AGN Mrk 876

Landt

Mitchell

Ward

et al. 2023

ApJ

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Recent models for the inner structures of active galactic nuclei (AGNs) advocate the presence of a radiatively accelerated dusty outflow launched from the outer regions of the accretion disk. Here, we present the first near-IR variable (rms) spectrum for the high-luminosity nearby AGN Mrk 876. We find that it tracks the accretion disk spectrum out to longer wavelengths than the mean spectrum, due to a reduced dust emission. The implied outer accretion disk radius is consistent with the IR results predicted by a contemporaneous optical accretion disk reverberation mapping campaign, and much larger than the self-gravity radius. The reduced flux variability of the hot dust could either be due to the presence of a secondary constant dust component in the mean spectrum or be introduced by the destructive superposition of the dust and accretion disk variability signals, or be some combination of the two. Assuming thermal equilibrium for optically thin dust, we derive the luminosity-based dust radii for different grain properties, using our measurement of the temperature. We find that in all the cases considered, the values are significantly larger than the dust response time measured by IR photometric monitoring campaigns, with the least discrepancy present relative to the result for a wavelength-independent dust emissivity law, i.e., a blackbody, which is appropriate for large grain sizes. This result can be well explained by assuming a flared disk-like structure for the hot dust.

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“…The average quasar SEDs derived in the literature show similar dust continua that are described by the normal template and have little evolution with redshift (e.g., see review by Lyu & Rieke 2022). Given the discussion in the preceding paragraph, this suggests that a large fraction of quasars have a moderate level of polar dust emission.…”

Section: Quasar Ir Sedsmentioning

confidence: 87%

Polar Dust Emission in Quasar IR SEDs and Its Correlation with Narrow-line Regions

Lyu

Rieke

2022

ApJL

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Polar dust has been found to play an important role in the mid-infrared emission of nearby Seyfert nuclei. If and how often polar dust exists among the quasar population is unknown due to the lack of spatially resolved observations. In this Letter, we report correlations between the prominence of active galactic nucleus (AGN) forbidden line emission (commonly associated with the narrow-line region) and the dust mid-IR energy output among the archetypal Palomar-Green quasar sample and other bright type-1 AGNs drawn from the Sloan Digital Sky Survey, Spitzer, and Wide-field Infrared Survey Explorer (WISE) archives. The AGN mid-IR color differences traced by WISE W2 (∼4.6 μm)−W3 (∼12 μm) and W2 (∼4.6 μm)−W4 (∼22 μm), and near-IR to mid-IR spectral energy distributions (SEDs) constrained with the Two Micron All Sky Survey, WISE, and Spitzer data have clear trends with the relative strength of the forbidden line regions traced by the optical [O iii] and mid-IR [O iv] emission lines. These observations indicate that, where the lines are strong, a large fraction of the AGN emission at λ ≳ 5 μm comes from dust in the forbidden line regions. We find that the widely quoted universal AGN template is a result of averaging quasar SEDs with different levels of polar dust emission above the torus output and that the typical intrinsic IR SED of compact torus dust emission alone falls with increasing wavelength past 5 μm (in νF ν ). In addition, the association of polar dust with the forbidden lines suggests an alternative to the receding torus hypothesis for the decrease in infrared output with increasing AGN luminosity.

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Infrared Spectral Energy Distribution and Variability of Active Galactic Nuclei: Clues to the Structure of Circumnuclear Material

Cited by 25 publications

References 334 publications

AGN Selection and Demographics in GOODS-S/HUDF from X-Ray to Radio

AGN Selection and Demographics in GOODS-S/HUDF from X-Ray to Radio

A Complex Dust Morphology in the High-luminosity AGN Mrk 876

Polar Dust Emission in Quasar IR SEDs and Its Correlation with Narrow-line Regions

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