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

Kathy L. Cooksey, Jason X. Prochaska, Hsiao Wen Chen, John S. Mulchaey, Benjamin J. Weiner

Research output: Contribution to journalArticlepeer-review

54 Scopus citations


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 (zQSO = 0.2784). We supplement the archive data with CLOUDY ionization models and a survey of galaxies in the quasar field. There are 15 strong Lyα absorbers with column densities log NHI > 14. Of these, six are associated with at least C III λ977 absorption [log N(C++) > 13]; this implies a redshift density dNcIII/dz = 36-9+13 (68% confidence limits) for the five detections with rest equivalent width Wr > 50 mÅ. Two systems show O VI λλ1031, 1037 absorption in addition to C III [log N(O+5) > 14]. One is a partial Lyman limit system (log NHI = 17) with associated C III, O VI, and Si m III λ1206 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 σ with Wr > 50 mÅ, dNOVI/dz = 7-4 +9. We also search for O VI doublets without Lyα absorption but identify none. From CLOUDY modeling, these metal-line systems have metallicities spanning the range -4 ≲ [M/H] ≲ -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 h75-1 kpc with L > 0.1L*.

Original languageEnglish (US)
Pages (from-to)262-285
Number of pages24
JournalAstrophysical Journal
Issue number1
StatePublished - Mar 20 2008


  • Galaxies: general
  • Intergalactic medium
  • Quasars: absorption lines
  • Quasars: individual (PKS 1302-102)
  • Techniques: Spectroscopic

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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