We report our Keck/MOSFIRE and Magellan/LDSS3 spectroscopy for an [ Oii ] Blob , Oii B 10 , that is a high- z galaxy with spatially extended [ Oii ] \lambda \lambda 3726 , 3729 emission over 30 kpc recently identified by a Subaru large-area narrowband survey .
The systemic redshift of Oii B 10 is z = 1.18 securely determined with [ Oiii ] \lambda \lambda 4959 , 5007 and H \beta emission lines .
We identify Fe ii \lambda 2587 and Mg ii \lambda \lambda 2796,2804 absorption lines blueshifted from the systemic redshift by 80 \pm 50 and 260 \pm 40 km s ^ { -1 } , respectively , which indicate gas outflow from Oii B 10 with the velocity of \sim 80 - 260 km s ^ { -1 } .
This outflow velocity is comparable with the escape velocity , 250 \pm 140 km s ^ { -1 } , estimated under the assumption of a singular isothermal halo potential profile .
Some fraction of the outflowing gas could escape from the halo of Oii B 10 , suppressing Oii B 10 ’ s star-formation activity .
We estimate a mass loading factor , \eta , that is a ratio of mass outflow rate to star-formation rate , and obtain \eta > 0.8 \pm 0.1 which is relatively high compared with low- z starbursts including U/LIRGs and AGNs .
The major energy source of the outflow is unclear with the available data .
Although no signature of AGN is found in the X-ray data , Oii B 10 falls in the AGN/star-forming composite region in the line diagnostic diagrams .
It is possible that the outflow is powered by star formation and a type-2 AGN with narrow FWHM emission line widths of 70 - 130 km s ^ { -1 } .
This is the first detailed spectroscopic study of oxygen-line blobs , which includes the analyses of the escape velocity , the mass loading factor , and the presence of an AGN , and a significant step to understanding the nature of oxygen-line blobs and the relation with gas outflow and star-formation quenching at high redshift .