Characterizing the Low-Redshift Intergalactic Medium toward PKS 1302-102
Abstract
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 NH I > 14. Of these, six are associated with at least C III λ977 absorption [log N(C+ +) > 13]; this implies a redshift density dNC III/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 NH I = 17) with associated C III, O VI, and Si 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, dNO VI/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 lesssim [ M/H ] lesssim - 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-175 kpc with L > 0.1L*.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- March 2008
- DOI:
- 10.1086/528704
- arXiv:
- arXiv:0706.1285
- Bibcode:
- 2008ApJ...676..262C
- Keywords:
-
- galaxies: general;
- intergalactic medium;
- quasars: absorption lines;
- quasars: individual: PKS 1302–102;
- techniques: spectroscopic;
- Astrophysics
- E-Print:
- 21 pages in emulatepj form, 24 figures, 10 tables, accepted to ApJ