Characterizing the low-redshift intergalactic medium toward PKS 1302-102

We present a detailed analysis of the intergalactic metal-line absorption systems in the archival HST STIS and FUSE ultraviolet spectra of the low-redshift quasar PKS 1302 - 102 ( z(QSO) 0: 2784). We supplement the archive data with CLOUDY ionization models and a survey of galaxies in the quasar field. There are 15 strong Ly proportional to absorbers with column densities log N-H (I) > 14. Of these, six are associated with at least C III lambda 977 absorption [ log N( C++) > 13]; this implies a redshift density dN(CIII) / dz = 36(-9)(+13) (68% confidence limits) for the five detections with rest equivalent width W-r > 50 m angstrom. Two systems show O VI lambda lambda 1031, 1037 absorption in addition to C III [log N(O+5) > 14]. One is a partial Lyman limit system (log N-HI = 17) with associated C III, O VI, andSi III lambda 1206 absorption. There are three tentative O VI systems that do not have C III detected. For one O VI doublet with both lines detected at 3 sigma withW(r) > 50m angstrom, dN(O) (VI) /dz = 7(-4)(.)(+9) We also search for O VI doublets without Ly alpha absorption but identify none. From CLOUDY modeling, these metal- line systems have metallicities spanning the range - 4 less than or similar to[M/H] less than or similar to - 0.3. The two O vi systems with associated C III absorption cannot be single- phase, collisionally ionized media based on the relative abundances of the metals and kinematic arguments. From the galaxy survey, we discover that the absorption systems are in a diverse set of galactic environments. Each metal- line system has at least one galaxy within 500 km s(-1) and 600 h(75)(-1) kpc with L > 0.1L(*).