We report the detection with Chandra of a Low-Luminosity AGN ( LLAGN ) in the Low Ionization Emission Line Region ( LINER ) hosted by Hydra A , a nearby ( z =0.0537 ) powerful FR I radio galaxy with complex radio and optical morphology .
In a 20 ks ACIS-S exposure during the calibration phase of the instrument , a point source is detected at energies \gtrsim 2 keV at the position of the compact radio core , embedded in diffuse thermal X-ray emission ( kT \sim 1 keV ) at softer energies .
The spectrum of the point source is well fitted by a heavily absorbed power law with intrinsic column density N _ { H } ^ { int } \sim 3 \times 10 ^ { 22 } cm ^ { -2 } and photon index \Gamma \sim 1.7 .
The intrinsic ( absorption-corrected ) luminosity is L _ { 2 - 10 ~ { } keV } \sim 1.3 \times 10 ^ { 42 } erg s ^ { -1 } .
These results provide strong evidence that an obscured AGN is present in the nuclear region of Hydra A .
We infer that the optical/UV emission of the AGN is mostly hidden by the heavy intrinsic reddening .
In order to balance the photon budget of the nebula , we must either postulate that the ionizing spectrum includes a UV bump or invoke and additional power source ( shocks in the cooling flow or interaction with the radio jets ) .
Using an indirect estimate of the black hole mass and the X-ray luminosity , we infer that the accretion rate is low , suggesting that the accretion flow is advection dominated .
Finally , our results support current unification schemes for radio-loud sources , in particular the presence of the putative molecular torus in FR Is .
These observations underscore the power of the X-rays and of Chandra in the quest for black holes .