Accretion and Outflow in the Active Galactic Nucleus and Starburst of NGC 5135

Abstract

Observations of the Seyfert 2 and starburst galaxy NGC 5135 with the Chandra X-Ray Observatory demonstrate that both of these phenomena contribute significantly to its X-ray emission. We spatially isolate the active galactic nucleus (AGN) and demonstrate that it is entirely obscured by column density N_H>10²⁴ cm^-2, detectable in the Chandra bandpass only as a strongly reprocessed weak continuum and a prominent iron Kα emission line with equivalent width of 2.4 keV. Most of the soft X-ray emission, both near the AGN and extending over spatial scales of several kpc, is collisionally excited plasma. We attribute this thermal emission to stellar processes. The AGN dominates the X-ray emission only at energies above 4 keV. In the spectral energy distribution that extends to far-infrared wavelengths, nearly all the emergent luminosity below 10 keV is attributable to star formation, not the AGN.