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 significantly weaker reflection features. One possible 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 seperated 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 Γ=1.68^+0.03_-0.02, while the photon-index of the higher flux spectrum is Γ=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=228± 19 keV in the low flux data to 158⁺³⁵_-76 keV in the high flux observation (assuming a slab geometry). These are precisely the characteristics of a Comptonizing corona, and are distinct from those found in jet-dominated sources. 3C 382 exhibits very weak reflection features, which may be best explained by an outflowing corona combined with an ionized inner accretion disk.