We present a complete catalogue of 27 O vi absorbers at low redshift ( 0.12 < z < 0.5 ) from a blind survey of 16 QSO echelle spectra in the HST/STIS data archive .
These absorbers are identified based only upon matching line profiles and the expected doublet ratio between the \lambda \lambda 1031 , 1037 transitions .
Subsequent searches are carried out to identify their associated transitions .
Here we present all relevant absorption properties .
By considering absorption components of different species which are well-aligned in velocity-space , we derive gas temperatures and non-thermal broadening values , b _ { \mathrm { n } t } .
We show that in all 16 cases considered the observed line width is dominated by non-thermal motion and that gas temperatures are well below those expected for { \mathrm { O } } ^ { 5 + } in collisional ionization equilibrium .
This result reaffirms previous findings from studies of individual lines of sight , but are at odds with expectations for a WHIM origin .
At least half of the absorbers can be explained by a simple photoionization model .
In addition , in some absorbers we find evidence for large variation in gas density/metallicity across components in individual absorbers .
Comparisons of multiple associated metal species further show that under the assumption of the gas being photoionized by the metagalacitic background radiation field , the absorbing clouds have gas densities < n _ { \mathrm { H } } > < -2.9 and sizes L > 1 \mbox { kpc } .
Finally , we compare our absorber selection with the results of other independent studies .