We detect high-velocity absorbing gas using Hubble Space Telescope and Far Ultraviolet Spectroscopic Explorer medium resolution spectroscopy along two high-latitude AGN sight lines ( Mrk 1383 and PKS 2005–489 ) above and below the Galactic Center ( GC ) .
These absorptions are most straightforwardly interpreted as a wind emanating from the GC which does not escape from the Galaxy ’ s gravitational potential .
Spectra of four comparison B stars are used to identify and remove foreground velocity components from the absorption-line profiles of O vi , N v , C ii , C iii , C iv , Si ii , Si iii , and Si iv .
Two high-velocity ( HV ) absorption components are detected along each AGN sight line , three redshifted and one blueshifted .
Assuming that the four HV features trace a large-scale Galactic wind emanating from the GC , the blueshifted absorber is falling toward the GC at a velocity of 250 \pm 20 km s ^ { -1 } , which can be explained by ” Galactic fountain ” material that originated in a bound Galactic wind .
The other three absorbers represent outflowing material ; the largest derived outflow velocity is +250 \pm 20 km s ^ { -1 } , which is only 45 % of the velocity necessary for the absorber to escape from its current position in the Galactic gravitational potential .
All four HV absorbers are found to reach the same maximum height above the Galactic plane ( |z _ { max } | = 12 \pm 1 kpc ) , implying that they were all ejected from the GC with the same initial velocity .
The derived metallicity limits of \gtrsim 10 –20 % Solar are lower than expected for material recently ejected from the GC unless these absorbers also contain significant amounts of hotter gas in unseen ionization stages .