NuSTAR Reveals the Comptonizing Corona of the Broad-Line Radio Galaxy 3C
  382
  Broad-line radio galaxies (BLRGs) are active galactic nuclei that produce
powerful, large-scale radio jets, but appear as Seyfert 1 galaxies in their
optical spectra. In the X-ray band, BLRGs also appear like Seyfert galaxies,
but with flatter spectra and weaker reflection features. One explanation for
these properties is that the X-ray continuum is diluted by emission from the
jet. Here, we present two NuSTAR observations of the BLRG 3C 382 that show
clear evidence that the continuum of this source is dominated by thermal
Comptonization, as in Seyfert 1 galaxies. The two observations were separated
by over a year and found 3C 382 in different states separated by a factor of
1.7 in flux. The lower flux spectrum has a photon-index of
$\Gamma=1.68^{+0.03}_{-0.02}$, while the photon-index of the higher flux
spectrum is $\Gamma=1.78^{+0.02}_{-0.03}$. Thermal and anisotropic
Comptonization models provide an excellent fit to both spectra and show that
the coronal plasma cooled from $kT_e=330\pm 30$ keV in the low flux data to
$231^{+50}_{-88}$ keV in the high flux observation. This cooling behavior is
typical of Comptonizing corona in Seyfert galaxies and is distinct from the
variations observed in jet-dominated sources. In the high flux observation,
simultaneous Swift data are leveraged to obtain a broadband spectral energy
distribution and indicates that the corona intercepts $\sim 10$% of the optical
and ultraviolet emitting accretion disk. 3C 382 exhibits very weak reflection
features, with no detectable relativistic Fe K$\alpha$ line, that may be best
explained by an outflowing corona combined with an ionized inner accretion
disk.
