English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

We explore the origin of mid-infrared (mid-IR) dust extinction in all 20nearby (z < 0.05) bona-fide Compton-thick (N_H > 1.5 x 10^24 cm^-2) AGN withhard energy (E > 10 keV) X-ray spectral measurements. We accurately measure thesilicate absorption features at lambda~9.7um in archival low-resolution(R~57-127) Spitzer Infrared Spectrograph (IRS) spectroscopy, and show that onlya minority (~45%) of nearby Compton-thick AGN have strong Si-absorptionfeatures (S_9.7 = ln(f_{int}/f_{obs}) > 0.5) which would indicate significantdust attenuation. The majority (~60%) are star-formation dominated (AGN:SB<0.5)at mid-IR wavelengths and lack the spectral signatures of AGN activity atoptical wavelengths, most likely because the AGN emission-lines areoptically-extinguished. Those Compton-thick AGN hosted in low-inclination anglegalaxies exhibit a narrow-range in Si-absorption (S_9.7 ~ 0-0.3), which isconsistent with that predicted by clumpy-torus models. However, on the basis ofthe IR spectra and additional lines of evidence, we conclude that the dominantcontribution to the observed mid-IR dust extinction is dust located in the hostgalaxy (i.e., due to disturbed morphologies; dust-lanes; galaxy inclinationangles) and not necessarily a compact obscuring torus surrounding the centralengine.

Deep Silicate absorption features in Compton-thick AGN predominantly arise due to dust in the host galaxy