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Missing Baryons in the Warm-Hot Intergalactic Medium
- Publication Year :
- 2004
- Publisher :
- arXiv, 2004.
-
Abstract
- We briefly review the use of UV absorption lines in the spectra of low-redshift QSOs for the study of the physical conditions, metallicity, and baryonic content of the low-z IGM, with emphasis on the missing baryons problem. Current results on the statistics and baryonic content of intervening, low-z O VI and Lya absorption-line systems are presented with some comments on overlap between these two classes of absorbers and consequent baryon double-counting problems. From observations of a sample of 16 QSOs observed with the E140M echelle mode of STIS, we find 44 intervening O VI absorbers and 14 associated O VI systems [i.e, z(abs) ~ z(QSO)]. The implied number of intervening O VI absorbers per unit redshift is dN/dz(O VI) = 23+/-4 for rest equivalent width > 30 mA. The intervening O VI systems contain at least 7% of the baryons if their typical metallicity is 1/10 solar and the O VI ion fraction is<br />Review paper presented at "Astrophysics in the Far Ultraviolet: Five Years of Discovery with FUSE". 12 pgs, 5 figures. astro-ph version has minor enhancements (e.g., Figures 4a and 4b are larger for better legibility)
Details
- Database :
- OpenAIRE
- Accession number :
- edsair.doi.dedup.....f880169605df07a81187ad9265443767
- Full Text :
- https://doi.org/10.48550/arxiv.astro-ph/0411151