Radio/X-ray monitoring of the broad-line radio galaxy 3C 382. High-energy view with XMM-Newton and NuSTAR

TL;DR

This study analyzes five joint XMM-Newton and NuSTAR observations of the broad-line radio galaxy 3C 382, revealing spectral features and a two-corona accretion scenario similar to radio-quiet Seyferts.

Contribution

First detailed joint X-ray analysis of 3C 382 showing a two-corona accretion model, bridging radio-loud and radio-quiet AGN behaviors.

Findings

Presence of warm absorber and iron Kα line without Compton hump

Detection of a variable soft excess modeled by thermal Comptonization

Spectral similarities to radio-quiet Seyfert galaxies

Abstract

We present the analysis of five joint XMM-Newton/NuSTAR observations, 20 ks each and separated by 12 days, of the broad-line radio galaxy 3C 382. The data were obtained as part of a campaign performed in September-October 2016 simultaneously with VLBA. The radio data and their relation with the X-ray ones will be discussed in a following paper. The source exhibits a moderate flux variability in the UV/X-ray bands, and a limited spectral variability especially in the soft X-ray band. In agreement with past observations, we find the presence of a warm absorber, an iron K$\alpha$ line with no associated Compton reflection hump, and a variable soft excess well described by a thermal Comptonization component. The data are consistent with a "two-corona" scenario, in which the UV emission and soft excess are produced by a warm ($kT \simeq 0.6$ keV), optically thick ($\tau \simeq 20$) corona consistent with being a slab fully covering a nearly passive accretion disc, while the hard X-ray emission is due to a hot corona intercepting roughly 10 per cent of the soft emission. These results are remarkably similar to those generally found in radio-quiet Seyferts, thus suggesting a common accretion mechanism.