We present new GALEX images and optical spectroscopy of J1229+02 , a dwarf post-starburst galaxy located 81 kpc from the 1585 { km s } ^ { -1 } absorber in the 3C 273 sight line .
The absence of { H } \alpha emission and the faint GALEX UV fluxes confirm that the galaxy ’ s recent star formation rate is < 10 ^ { -3 } ~ { } M _ { \sun } { yr ^ { -1 } } .
Absorption-line strengths and the UV-optical SED give similar estimates of the acceptable model parameters for its youngest stellar population where f _ { m } < 60 % of its total stars ( by mass ) formed in a burst t _ { sb } = 0.7 –3.4 Gyr ago with a stellar metallicity of -1.7 < { [ Fe / H ] } < +0.2 ; we also estimate the stellar mass of J1229+02 to be 7.3 < \log { ( M _ { * } / M _ { \sun } ) } < 7.8 .
Our previous study of J1229+02 found that a supernova-driven wind was capable of expelling all of the gas from the galaxy ( none is observed today ) and could by itself plausibly create the nearby absorber .
But , using new data , we find a significantly higher galaxy/absorber velocity difference , a younger starburst age , and a smaller starburst mass than previously reported .
Simple energy-conserving wind models for J1229+02 using fiducial values of f _ { m } \sim 0.1 , t _ { sb } \sim 2 Gyr , and \log { ( M _ { * } / M _ { \sun } ) } \sim 7.5 allow us to conclude that the galaxy alone can not produce the observed QSO absorber ; i.e. , any putative ejecta must interact with ambient gas from outside J1229+02 .
Because J1229+02 is located in the southern extension of the Virgo cluster ample potential sources of this ambient gas exist .
Based on the two nearest examples of strong metal-line absorbers discovered serendipitously ( the current one and the 1700 { km s } ^ { -1 } metal-line absorber in the nearby Q1230+0115 sight line ) , we conclude that absorbers with 10 ^ { 14 } < N _ { H I } < 10 ^ { 16 } ~ { } { cm ^ { -2 } } at impact parameters \gtrsim 1 R _ { vir } are likely intergalactic systems and can not be identified unambiguously as the circumgalactic material of any one individual galaxy .