BASS. XLII. The Relation between the Covering Factor of Dusty Gas and the Eddington Ratio in Nearby Active Galactic Nuclei

Ricci, C.; Ichikawa, K.; Stalevski, M.; Kawamuro, T.; Yamada, S.; Ueda, Y.; Mushotzky, R.; Privon, G. C.; Koss, M. J.; Trakhtenbrot, B.; Fabian, A. C.; Ho, L. C.; Asmus, D.; Bauer, F. E.; Chang, C. S.; Gupta, K. K.; Oh, K.; Powell, M.; Pfeifle, R. W.; Rojas, A.; Ricci, F.; Temple, M. J.; Toba, Y.; Tortosa, A.; Treister, E.; Harrison, F.; Stern, D.; Urry, C. M.

doi:10.3847/1538-4357/ad0733

“…The difference in the distributions of Swift/BAT AGNs and buried AGNs on the N H -λ Edd plane may originate in the difference in the amount of material supplied from the host galaxies. The circumnuclear material in Swift/BAT AGNs, most of which are nonmergers, is mostly surrounded by obscurers with N H 10 22 cm −2 , which would be blown away at log 2 Edd l - (e.g., Ricci et al 2022Ricci et al , 2023, whereas the circumnuclear material in buried AGNs in late mergers may be shrouded in CT obscurers, which can be blown away at a higher threshold λ Edd of −1. In fact, a dramatic variability of N H has been discovered in an AGN with λ Edd ∼ −0.7 (stage D merger IRAS F05189−2524); its column density varied between non-CT (N H ∼ 8 × 10 22 cm −2 ) and CT (>2.3 × 10 24 cm −2 ) within ∼10 yr (see Figure 12 in Yamada et al 2021).…”

Section: N H -λ Edd Diagrammentioning

confidence: 99%

[O iv]- and [Ne v]-weak Active Galactic Nuclei Hidden by Compton-thick Material in Late Mergers

Yamada,

Ueda,

Kawamuro

et al. 2024

ApJ

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We study “buried” active galactic nuclei (AGNs) almost fully covered by circumnuclear material in ultra/luminous infrared galaxies (U/LIRGs), which show weak ionized lines from narrow-line regions. Employing an indicator of a [O iv] 25.89 or [Ne v] 14.32 μm line to 12 μm AGN luminosity ratio, we find 17 buried AGN candidates that are [O iv]-weak (L [O IV]/L 12,AGN ≤ −3.0) or [Ne v]-weak (L [Ne V]/L 12,AGN ≤ −3.4) among 30 AGNs in local U/LIRGs. For the [O iv]-weak AGNs, we estimate their covering fractions of Compton-thick (CT; N H ≥ 1024 cm−2) material with an X-ray clumpy torus model to be f CT ( spec ) = 0.55 ± 0.19 on average. This value is consistent with the fraction of CT AGNs ( f CT ( stat ) = 53 % ± 12 % ) among the [O iv]-weak AGNs in U/LIRGs and much larger than that in Swift/Burst Alert Telescope (BAT) AGNs (23% ± 6%). The fraction of [O iv]-weak AGNs increases from 27 − 10 + 13 % (early) to 66 − 12 + 10 % (late mergers). Similar results are obtained with the [Ne v] line. The [O iv]- or [Ne v]-weak AGNs in late mergers show larger N H and Eddington ratios (λ Edd) than those of the Swift/BAT AGNs, and the largest N H is ≳1025 cm−2 at log λ Edd ∼ − 1 , close to the effective Eddington limit for CT material. These suggest that (1) the circumnuclear material in buried AGNs is regulated by the radiation force from high-λ Edd AGNs on the CT obscurers, and (2) their dense material with large f CT ( spec ) (∼0.5 ± 0.1) in U/LIRGs is a likely cause of a unique structure of buried AGNs, whose amount of material may be maintained through merger-induced supply from their host galaxies.

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AGN populations in the local Universe: Their alignment with the main sequence, stellar population characteristics, accretion efficiency, and the impact of AGN feedback

Mountrichas,

Ruiz,

Georgantopoulos

et al. 2024

A&A

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In this study, we used a sample of 338 galaxies ---within the redshift range of $ 0.02<z<0.1$ drawn from the Sloan Digital Sky Survey (SDSS)--- for which there are available classifications based on their emission line ratios. We identified and selected Compton-thick (CT) AGN through the use of X-ray and infrared luminosities at $12\ m$. We constructed the spectral energy distributions (SEDs) for all sources and fit them using the CIGALE code to derive properties related to both the AGN and host galaxies. Employing stringent criteria to ensure the reliability of SED measurements, our final sample comprises 14 CT AGN, 118 Seyfert 2 (Sy2), 82 composite, and 124 low-ionization nuclear emission-line regions (LINER) galaxies. Our analysis reveals that, irrespective of their classification, the majority of the sources lie below the star-forming main sequence (MS). Additionally, a lower level of AGN activity is associated with a closer positioning to the MS. Using the D$_n$4000 spectral index as a proxy for the age of stellar populations, we observe that, compared to other AGN classes, LINERs exhibit the oldest stellar populations. Conversely, CT sources are situated in galaxies with the youngest stellar populations. Furthermore, LINER and composite galaxies tend to show the lowest accretion efficiency, while CT AGN, on average, display the most efficient accretion among the four AGN populations. Our findings are consistent with a scenario in which the different AGN populations might not originate from the same AGN activity burst. Early triggers in gas-rich environments can create high-accretion-rate supermassive black holes (SMBHs), leading to a progression from CT to Sy2, while later triggers in gas-poor stages result in low-accretion-rate SMBHs like those found in LINERs.

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Deciphering the imprint of active galactic nucleus feedback in Seyfert galaxies

García-Burillo,

Hicks,

Alonso-Herrero

et al. 2024

A&A

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We study the distribution of cold molecular gas in the circumunuclear disks (CND; $r pc) of a sample of 64 nearby L $=7-45 Mpc) disk galaxies ---including 45 active galactic nuclei (AGN) and 19 nonAGN--- for which high-spatial-resolution (median value $ pc) multiline CO interferometer observations have been obtained at millimeter wavelengths with the Atacama Large Millimeter Array (ALMA) and/or Plateau de Bure Interferometer (PdBI). We decipher whether or not the concentration and normalized radial distribution of cold molecular gas change as a function of X-ray luminosity in the 2--10 keV range X $) in order to analyze the imprint left by AGN feedback. We also look for similar trends in the concentration and normalized radial distribution of the hot molecular gas and in the hot-to-cold-molecular gas mass ratio in a subset of 35 galaxies using near-infrared (NIR) integral field spectroscopy data obtained for the H$_2$ 1-0 S(1) line. We find a significant turnover in the distribution of the cold molecular gas concentration as a function of X-ray luminosity with a breakpoint that divides the sample into two branches: (1) the `AGN build-up branch'' ($L_ X pm0.3 $erg s$^ $) and (2) the ``AGN feedback branch'' ($L_ X pm0.3 $erg s$^ $) . Lower-luminosity AGN and nonAGN of the AGN build-up branch show high cold molecular gas concentrations and centrally peaked radial profiles on nuclear ($r pc) scales. Higher-luminosity AGN of the AGN feedback branch show a sharp decrease in the concentration of molecular gas and flat or inverted radial profiles. The cold molecular gas concentration index ($CCI$) --- defined as the ratio of surface densities at $r pc ($ gas $) and $r pc $( gas $), namely $CCI gas gas $)--- spans a 0.63 dex range, equivalent to a factor simeq 4-5, between the galaxies lying at the high end of the AGN build-up branch and the galaxies showing the most extreme nuclear-scale molecular gas deficits in the AGN feedback branch. The concentration and radial distributions of the hot molecular gas in our sample follow qualitatively similar but less extreme trends as a function of X-ray luminosity. As a result, we find higher values of hot-to-cold molecular gas mass ratios on nuclear scales in the highest luminosity AGN sources of the AGN feedback branch. These observations confirm ---with a three times larger sample--- previous evidence found in the context of the Galaxy Activity Torus and Outflow Survey (GATOS) that the imprint of AGN feedback on the CND-scale distribution of molecular gas is more extreme in higher luminosity Seyfert galaxies of the local Universe.

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BASS. XLII. The Relation between the Covering Factor of Dusty Gas and the Eddington Ratio in Nearby Active Galactic Nuclei

Cited by 5 publications

References 166 publications

[O iv]- and [Ne v]-weak Active Galactic Nuclei Hidden by Compton-thick Material in Late Mergers

[O iv]- and [Ne v]-weak Active Galactic Nuclei Hidden by Compton-thick Material in Late Mergers

AGN populations in the local Universe: Their alignment with the main sequence, stellar population characteristics, accretion efficiency, and the impact of AGN feedback

Deciphering the imprint of active galactic nucleus feedback in Seyfert galaxies

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