Resolving galactic-scale obscuration of X-ray AGN at $zgtrsim1$ with COSMOS-Web

Kavli Affiliate: John D. Silverman

| First 5 Authors: John D. Silverman, Vincenzo Mainieri, Xuheng Ding, Daizhong Liu, Knud Jahnke

| Summary:

A large fraction of the accreting supermassive black hole population is
shrouded by copious amounts of gas and dust, particularly in the distant
($zgtrsim1$) Universe. While much of the obscuration is attributed to a
parsec-scale torus, there is a known contribution from the larger-scale host
galaxy. Using JWST/NIRCam imaging from the COSMOS-Web survey, we probe the
galaxy-wide dust distribution in X-ray selected AGN up to $zsim2$. Here, we
focus on a sample of three AGNs with their host galaxies exhibiting prominent
dust lanes, potentially due to their edge-on alignment. These represent 27% (3
out of 11 with early NIRCam data) of the heavily obscured ($N_H>10^{23}$
cm$^{-2}$) AGN population. With limited signs of a central AGN in the optical
and near-infrared, the NIRCam images are used to produce reddening maps
$E(B-V)$ of the host galaxies. We compare the mean central value of $E(B-V)$ to
the X-ray obscuring column density along the line-of-sight to the AGN
($N_Hsim10^{23-23.5}$ cm$^{-2}$). We find that the extinction due to the host
galaxy is present ($0.6lesssim E(B-V) lesssim 0.9$; $1.9 lesssim A_V
lesssim 2.8$) and significantly contributes to the X-ray obscuration at a
level of $N_Hsim10^{22.5}$ cm$^{-2}$ assuming an SMC gas-to-dust ratio which
amounts to $lesssim$30% of the total obscuring column density. These early
results, including three additional cases from CEERS, demonstrate the ability
to resolve such dust structures with JWST and separate the different
circumnuclear and galaxy-scale obscuring structures.

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