NuSTAR Observations of 52 Compton-thick Active Galactic Nuclei Selected
  by the Swift/BAT All-sky Hard X-Ray Survey
  We present the systematic broadband X-ray spectral analysis of 52
Compton-thick ($24 \leq \log N_{\mathrm{H}}^{\mathrm{LOS}}/\mathrm{cm}^{-2}$)
active galactic nucleus (CTAGN) candidates selected by the Swift/BAT all-sky
hard X-ray survey observed with Chandra, XMM--Newton, Swift/XRT, Suzaku, and
NuSTAR. The XMM--Newton data of 10 objects and the NuSTAR data of 15 objects
are published for the first time. We use an X-ray spectral model from a clumpy
torus (XClumpy) to determine the torus properties. As a result, the hydrogen
column density along the line of sight $N_{\mathrm{H}}^{\mathrm{LOS}}$ obtained
from the XClumpy model indicate that 24 objects are Compton-thin AGNs and 28
objects are Compton-thick AGNs in the 90\% confidence interval. The main reason
is the difference in the torus model applied. The hydrogen column density along
the equatorial direction $N_{\mathrm{H}}^{\mathrm{Equ}}$ of CTAGNs inferred
from the XClumpy model is larger than that of less obscured AGNs. The
Compton-thin torus covering factor $C_{22}$ obtained from the XClumpy model is
consistent with that of Ricci et al. (2017) in the low Eddington ratio ($\log
R_{\mathrm{Edd}} \leq -1.0$), whereas $C_{22}$ inferred from the XClumpy model
is larger than that of Ricci et al. (2017) in the high Eddington ratio ($-1.0
\leq \log R_{\mathrm{Edd}}$). The average value of the Compton-thick torus
covering factor $C_{24}$ obtained from the XClumpy model is $36_{-4}^{+4}$\%.
This value is larger than that of Ricci et al. (2015) ($C_{24} \simeq
27_{-4}^{+4}$\%) based on the assumption that all AGNs have intrinsically the
same torus structure. These results suggest that the structure of CTAGN may be
intrinsically different from that of less obscured AGN.
