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We present a survey of extremely high-velocity outflows (EHVOs) in quasars,defined by speeds between 0.1c and 0.2c. This region of the parameter space hasnot been included in previous surveys, but it might present the biggestchallenge for theoretical models and it might be a large contributor tofeedback due to the outflows' potentially large kinetic power. Using the SloanDigital Sky Survey, we find 40 quasar spectra with broad EHVO CIV absorption,10 times more than the number of previously known cases. We characterize theEHVO absorption and find that in 26 cases, CIV is accompanied by NV and/or OVIabsorption. We find that EHVO quasars lack HeII emission and have overalllarger bolometric luminosities and black hole masses than those of their parentsample and BALQSOs, while we do not find significant differences in theirEddington ratios. We also report a trend toward larger black hole masses as thevelocity of the outflowing gas increases in the BALQSOs in our sample. Theoverall larger Lbol and lack of HeII emission of EHVO quasars suggest thatradiation is likely driving these outflows. We find a potential evolutionaryeffect as EHVO quasars seem to be more predominant at large redshifts. Weestimate that the kinetic power of these outflows may be similar to or evenlarger than that of the outflows from BALQSOs as the velocity factor increasesthis parameter by 1-2.5 orders of magnitude. Further study of EHVO quasars willhelp improve our understanding of quasar physics.

Survey of Extremely High-velocity Outflows in Sloan Digital Sky Survey Quasars