In this paper , we provide new 1 Ms Chandra ACIS spectra of two quasars in the Chandra Deep Field South ( CDF-S ) , which were previously reported to show strong and extremely blueshifted X-ray emission/absorption line features in previous 1 Ms spectra , with outflowing bulk velocity v \sim 0.65-0.84c .
In the new 1 Ms spectra , the relativistic blueshifted line feature is solidly confirmed in CXO CDFS J033225.3-274219 ( CDFS 46 , z = 1.617 ) , and marginally visible in CXO CDFS J033260.0-274748 ( CDFS 11 , z = 2.579 ) , probably due to the increased Chandra ACIS background in the new 1 Ms exposure .
The new data rule out the possibility ( though very tiny already based on the old 1Ms data ) that the two sources were selected to be unusual due to noise spikes in the spectra .
The only likely interpretation is extremely blueshifted iron absorption/emission line or absorption edge due to relativistic outflow .
We find that the rest frame emission line center in CDFS 46 marginally decreased from 16.2 keV to 15.2 keV after 7 years .
The line shift can be due to either decreasing outflowing velocity or lower ionization level .
Including the two quasars reported in this paper , we collect from literature a total of 7 quasars showing blueshifted emission or absorption line feature with v \geq 0.4 c in X-ray spectra , and discuss its connection to jet and/or BAL ( broad absorption line ) outflow .