| タイトル | Baryonic Content in the Warm-Hot IGM at Low Redshift |
| 著者（英） | Sonneborn, George; Danforth, C.; Moos, W.; Shull, M. |
| 著者所属（英） | NASA Goddard Space Flight Center |
| 発行日 | 2007-08-23 |
| 言語 | eng |
| 内容記述 | Baryons are 4.5% of the universe's mass/energy density; only 10% of these are in stars, galaxies, and clusters. At low-redshift 90% of baryons are in the IGM, 30% in Ly-alpha forest, but most are in hot gas (10(exp 5-7) K) produced by shocks during structure formation. O VI 1032-38 A are the best tracers of this gas. The distribution of O VI absorbers observed by FUSE rises as N(sup -2+/-0.2, down to 10(exp 13)/sq cm. Integrated to logN=13, 7% of baryons reside in the O VI-bearing IGM at 10% solar metallicity, T approx. 10(exp 5.5) K. At redshift z<0.1 metals have been transported less than 800/h kpc from L* galaxies and 200/h kpc from 0.1 L* galaxies. The steepness of dN/dz means that low-N absorbers contribute an equal mass of hot IGM as higher N gas. The total mass of O VI-bearing gas in the IGM depends on determining the turnover in dN/dz at low N(O VI). Future observations by FUSE are needed to reach lower N and to reduce the uncertainty in the dN/dz power law. |
| NASA分類 | Astrophysics |
| 権利 | Copyright |
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