The Suzaku View of the Disk-Jet Connection in the Low-excitation Radio Galaxy NGC 6251
Abstract
We present results from an 87 ks Suzaku observation of the canonical low-excitation radio galaxy (LERG) NGC 6251. We have previously suggested that LERGs violate conventional active galactic nucleus unification schemes: they may lack an obscuring torus and are likely to accrete in a radiatively inefficient manner, with almost all of the energy released by the accretion process being channeled into powerful jets. We model the 0.5-20 keV Suzaku spectrum with a single power law of photon index Γ = 1.82+0.04 - 0.05, together with two collisionally ionized plasma models whose parameters are consistent with the known galaxy- and group-scale thermal emission. Our observations confirm that there are no signatures of obscured, accretion-related X-ray emission in NGC 6251, and we show that the luminosity of any such component must be substantially sub-Eddington in nature.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- November 2011
- DOI:
- arXiv:
- arXiv:1109.6584
- Bibcode:
- 2011ApJ...741L...4E
- Keywords:
-
- galaxies: active;
- galaxies: individual: NGC 6251;
- galaxies: jets;
- X-rays: galaxies;
- Astrophysics - High Energy Astrophysical Phenomena;
- Astrophysics - Cosmology and Nongalactic Astrophysics
- E-Print:
- 5 pages, 3 figures, 2 tables. Accepted for publication in ApJ Letters