Extended X-Ray Emission around 4C 41.17 at z = 3.8

We present sensitive, high-resolution, X-ray imaging from Chandra of the high-redshift radio galaxy 4C 41.17 (z = 3.8). Our 150 ks Chandra exposure detects strong X-ray emission from a point source coincident with the nucleus of the radio galaxy. In addition, we identify extended X-ray emission with a luminosity of ~10⁴⁵ ergs s^-1 covering a 100 kpc (15'') diameter region around the radio galaxy. The extended X-ray emission follows the general distribution of radio emission in the radio lobes of this source and the distribution of a giant Lyα emission-line halo, while the spectrum of the X-ray emission is nonthermal and has a power-law index consistent with that of the radio synchrotron. We conclude that the X-ray emission is most likely inverse Compton scattering of far-infrared photons from a relativistic electron population probably associated with past and current activity from the central object. Assuming an equipartition magnetic field, the cosmic microwave background energy density at z = 3.8 can account for at most only 40% of the inverse Compton emission. Published submillimeter maps of 4C 41.17 have detected an apparently extended and extremely luminous far-infrared emission around the radio galaxy. We demonstrate that this photon component and its spatial distribution, in combination with the cosmic microwave background, can reproduce the observed X-ray luminosity. We propose that photoionization by these inverse Compton X-ray photons plays a significant role in this system and provides a new physical feedback mechanism to preferentially affect the gas within the most massive halos at high redshift. This is the highest redshift example of extended X-ray emission around a radio galaxy currently known and points toward an extraordinary halo around such systems, where cool dust, relativistic electrons, neutral and ionized gas, and intense infrared and X-ray radiation all appear to coexist.