2005ApJ...631L..33W

In this Letter we report the detection of a strong and extremely blueshifted X-ray absorption feature in the 1 Ms Chandra spectrum of CXOCDFS J033260.0-274748, a quasar at z=2.579 with L_2–10keV∼4x10⁴⁴ ergs/s. The broad absorption feature at ∼6.3 keV in the observed frame can be fitted either as an absorption edge at 20.9 keV or as a broad absorption line at 22.2 keV rest frame. The absorber has to be extremely ionized with an ionization parameter ξ∼10⁴, and a high column density, N_H>5x10²³/cm2. We reject the possibility of a statistical or instrumental artifact. The most likely interpretation is an extremely blueshifted broad absorption line or absorption edge, due to H or He-like iron in a relativistic jetlike outflow with bulk velocity of ∼0.7c-0.8c. Similar relativistic outflows have been reported in the X-ray spectra of several other AGNs in the past few years.