EVIDENCE FOR AN OBSCURED QUASAR IN THE GIANT RADIO GALAXY PKS 0634 - 205

摘要

We report on optical and near-infrared imaging and spectroscopy of the giant radio galaxy PKS 0634-205. The images longward of 2 μm reveal the presence of an extremely red compact source coincident with the nucleus, which is not detected at shorter wavelengths. The observed K - L color of this source, the [O III] λ5007 flux and the soft X-ray flux, are consistent with the spectral energy distribution of a typical quasar observed through a visual extinction A_v ～ 30 magnitudes. Our 2 μm spectrum shows strong narrow Paα, but has insufficient sensitivity and wavelength coverage to reveal broad Paα from the putative quasar at the predicted level.