A Long Hard-X-Ray Look at the Dual Active Galactic Nuclei of M51 with NuSTAR

We present a broadband X-ray spectral analysis of the M51 system, including the dual active galactic nuclei (AGNs) and several off-nuclear point sources. Using a deep observation by NuSTAR, new high-resolution coverage of M51b by Chandra, and the latest X-ray torus models, we measure the intrinsic X-ray luminosities of the AGNs in these galaxies. The AGN of M51a is found to be Compton-thick, and both AGNs have very low accretion rates (λ_Edd) 10^(-39) erg s^(−1) and find that a spectral turnover is present below 10 keV in most such sources, in line with recent results on ultraluminous X-ray sources.