The local Lyα forest:: Absorbers in galaxy voids

被引:28
作者
McLin, KM
Stocke, JT
Weymann, RJ
Penton, SV
Shull, JM
机构
[1] Univ Colorado, Ctr Astrophys & Space Astron, Boulder, CO 80309 USA
[2] Univ Colorado, Dept Astrophys & Planetary Sci, Boulder, CO 80309 USA
[3] Carnegie Inst Washington Observ, Pasadena, CA 91101 USA
[4] Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA
[5] Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA
关键词
galaxies : halos; intergalactic medium; large-scale structure of universe; quasars : absorption lines;
D O I
10.1086/342419
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
We have conducted pointed redshift surveys for galaxies in the direction of bright active galactic nuclei whose Hubble Space Telescope far-UV spectra contain nearby (czless than or similar to30,000 km s(-1)), low column density [12.5 less than or equal to log N-H I (cm(-2)) less than or equal to 14.5] Lyalpha forest absorption systems. Here we present results for four lines of sight that contain nearby (czless than or similar to3000 km s(-1)) Lyalpha absorbers in galaxy voids. Although our data go quite deep [-13 less than or equal to M-B (limit) less than or equal to -14] out to impact parameters of rho less than or similar to 100-250 h(70)(-1) kpc, these absorbers remain isolated and thus appear to be truly intergalactic, rather than part of galaxies or their halos. Since we and others have discovered no galaxies in voids, the only baryons detected in the voids are in the Lyalpha "clouds." Using a photoionization model for these clouds, the total baryonic content of the voids is 4.5%+/-1.5% of the mean baryon density.
引用
收藏
页码:L115 / L118
页数:4
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