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Title: The Compton-thick AGN population and the N H distribution of low-mass AGN in our cosmic backyard
ABSTRACT We present a census of the Compton-thick (CT) active galactic nucleus (AGN) population and the column density ($$N_{\rm {H}}$$) distribution of AGN in our cosmic backyard using a mid-infrared selected AGN sample within 15 Mpc. The column densities are measured from broad-band X-ray spectral analysis, mainly using data from Chandra and NuSTAR. Our sample probes AGN with intrinsic 2–10 keV luminosities of $$L_{\rm 2-10, int} = 10^{37}$$-$$10^{43}$$ erg s$$^{-1}$$, reaching a parameter space inaccessible to more distant samples. We directly measure a 32$$^{+30}_{-18}\, \rm per\, cent$$ CT AGN fraction and obtain an $$N_{\rm {H}}$$ distribution that agrees with that inferred by the Swift-BAT survey. Restricting the sample to the largely unexplored domain of low-luminosity AGN with $$L_{2-10,\mathrm{int}} \le 10^{42} \, \mathrm{erg} \, \mathrm{s}^{-1}$$, we found a CT fraction of $$19^{+30}_{-14}\, \rm per\, cent$$, consistent with those observed at higher luminosities. Comparing the host-galaxy properties between the two samples, we find consistent star formation rates, though the majority of our galaxy have lower stellar masses (by $$\approx 0.3$$ dex). In contrast, the two samples have very different black hole mass ($$M_{\rm BH}$$) distributions, with our sample having $$\approx$$1.5 dex lower mean mass ($$M_{\rm BH}$$  $$\sim$$ 10$$^{6} \, \rm M_\odot$$). Additionally, our sample contains a significantly higher number of LINERs and H ii-type nuclei. The Eddington ratio range probed by our sample, however, is the same as Swift-BAT, although the latter dominates at higher accretion rates, and our sample is more evenly distributed. The majority of our sample with $$\lambda _{\rm Edd} \ge$$ 10$$^{-3}$$ tend to be CT, while those with $$\lambda _{\rm Edd} <$$ 10$$^{-3}$$ are mostly unobscured or mildly obscured.  more » « less
Award ID(s):
2407089
PAR ID:
10688962
Author(s) / Creator(s):
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; more » ; ; ; ; « less
Publisher / Repository:
Monthly Notices of the Royal Astronomical Society
Date Published:
Journal Name:
Monthly Notices of the Royal Astronomical Society
Volume:
540
Issue:
4
ISSN:
0035-8711
Page Range / eLocation ID:
3827 to 3849
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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