The reionization history in the lognormal model
文献类型：期刊论文
| 作者 | Fang, LZ; Feng, LL; Liu, JR ; Bi, HG
|
| 刊名 | ASTROPHYSICAL JOURNAL
 |
| 出版日期 | 2004-04-20 |
| 卷号 | 605期号:2页码:591-598 |
| 关键词 | Cosmology : Theory Early Universe Large-scale Structure Of Universe |
| 英文摘要 | We study the evolution of baryonic gas before reionization in the lognormal (LN) model of cosmic clustering. We show that the thermal history of the universe around reionization can roughly be divided into three epochs: (1) a cold dark age z > z(r), in which the baryon gas is neutral and opaque to Lyalpha photons; (2) a hot dark age z(r) > z > z(GP), in which a predominant part of the baryon gas is ionized and hot but is still opaque to Lyalpha photons; and (3) a bright age z < z(GP), in which the universe is ionized enough to be transparent to Lyα photons. In the flat cold dark matter cosmological models given by WMAP and COBE, the difference of the two redshifts z(r) - z(GP) is found to be as large as &SIM;10, with z(r) &SIM; 17 and z(GP) &SIM; 7. This reionization history naturally yields a high optical depth of the CMB τ(e) &SIME; 0.12-0.19, which is observed in the TE polarization in the WMAP data, and a low redshift z(GP) for the appearance of the Lyα Gunn-Peterson trough, z(GP) &SIME; 6-8, in QSO absorption spectra. The universe stays so long in an ionized, yet Lyα opaque, stage because the first photoionization heats the inter-galactic gas effectively and balances the gravitational clustering for a long period of time. Therefore, a high τ(e) and low z(GP) is a result of all the considered models. Besides the cosmological parameters, the only free parameter we used in the calculation is N-ion, the mean number of ionization photons produced by each baryon in collapsed objects. We take it to be 40-80 in the calculations. |
| 语种 | 英语 |
| WOS记录号 | WOS:000220801900002 |
| 源URL | [http://ir.bao.ac.cn/handle/114a11/8924]  |
| 专题 | 国家天文台_星系宇宙学研究部 |
| 作者单位 | 1.Chinese Acad Sci, Natl Astron Observ, Beijing 100012, Peoples R China 2.Univ Sci & Technol China, Ctr Astrophys, Anhua 230026, Peoples R China 3.Univ Arizona, Dept Phys, Tucson, AZ 85721 USA |
| 推荐引用方式 GB/T 7714 | Fang, LZ,Feng, LL,Liu, JR,et al. The reionization history in the lognormal model[J]. ASTROPHYSICAL JOURNAL,2004,605(2):591-598. |
| APA | Fang, LZ,Feng, LL,Liu, JR,&Bi, HG.(2004).The reionization history in the lognormal model.ASTROPHYSICAL JOURNAL,605(2),591-598. |
| MLA | Fang, LZ,et al."The reionization history in the lognormal model".ASTROPHYSICAL JOURNAL 605.2(2004):591-598. |
入库方式： OAI收割
来源：国家天文台
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