In this letter we report the detection of a strong and extremely blueshifted X–ray absorption feature in the 1 Ms Chandra spectrum of CXO CDFS J033260.0-274748 , a quasar at z = 2.579 with L _ { 2 - 10 keV } \sim 4 \times 10 ^ { 44 } ergs s ^ { -1 } .
The broad absorption feature at \sim 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 \xi \sim 10 ^ { 4 } , and a high column density N _ { H } > 5 \times 10 ^ { 23 } cm ^ { -2 } .
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 jet-like outflow with bulk velocity of \sim 0.7 - 0.8 c .
Similar relativistic outflows have been reported in the X–ray spectra of several other AGNs in the past few years .