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21 cm signals from early ionizing sources
Liu, Jiren; Qiu, Jing-Mei; Feng, Long-Long; Shu, Chi-Wang; Fang, Li-Zhi
2007-07-01
发表期刊ASTROPHYSICAL JOURNAL
卷号663期号:1页码:1-9
摘要We investigate the 21 cm signals from the UV ionizing sources in the reionization epoch. The formation and evolution of 21 cm signals depend essentially on the kinetics of photons in the physical and frequency spaces, and we use the weighted essentially nonoscillatory algorithm to solve the radiative transfer equation. We show that a spherical shell of 21 cm signal will develop around a point source once the speed of the ionization front (I-front) is significantly lower than the speed of light. The 21 cm shell extends from the I-front to the front of light; its inner part is the emission region, and its outer part is the absorption region. The 21 cm emission region depends strongly on the intensity, frequency spectrum, and lifetime of the ionizing source. At redshift 1 + z = 20, for an ionizing source with intensity. E similar or equal to 10(45) ergs s(-1) and a power-law spectrum nu(-alpha) with alpha = 2, the emission region has a comoving size of 1-3 Mpc at time similar or equal to 2 Myr. Nevertheless, the emission region is very small if the intensity is less than. E similar or equal to 10(43) ergs s(-1), the spectrum is thermal at temperature T similar or equal to 10(5) K, or the spectral index alpha >= 3, while the 21 cm absorption region is prominent in all these cases. For a source of short lifetime, no 21 cm emission region can develop if the source dies out before the I-front speed is significantly lower than the speed of light. Yet, a 21 cm absorption region can form even after the emission of the source ceases.
文章类型Article
关键词Cosmology : Theory Intergalactic Medium Methods : Numerical Radiative Transfer
WOS标题词Science & Technology ; Physical Sciences
关键词[WOS]LY-ALPHA FOREST ; INTERGALACTIC MEDIUM ; HIGH-REDSHIFT ; RADIATIVE-TRANSFER ; IONIZATION FRONTS ; WENO ALGORITHM ; 21-CM EMISSION ; 1ST GALAXIES ; POINT-SOURCE ; DARK-AGES
收录类别SCI
语种英语
WOS研究方向Astronomy & Astrophysics
WOS类目Astronomy & Astrophysics
WOS记录号WOS:000247542700001
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文献类型期刊论文
条目标识符http://libir.pmo.ac.cn/handle/332002/15849
专题南极天文中心
作者单位1.Univ Arizona, Dept Phys, Tucson, AZ 85721 USA
2.Brown Univ, Div Appl Math, Providence, RI 02912 USA
3.Acad Sinica, Purple Mt Observ, Nanjing 210008, Peoples R China
4.Chinese Acad Sci, Natl Astron Observ, Beijing 100012, Peoples R China
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GB/T 7714
Liu, Jiren,Qiu, Jing-Mei,Feng, Long-Long,et al. 21 cm signals from early ionizing sources[J]. ASTROPHYSICAL JOURNAL,2007,663(1):1-9.
APA Liu, Jiren,Qiu, Jing-Mei,Feng, Long-Long,Shu, Chi-Wang,&Fang, Li-Zhi.(2007).21 cm signals from early ionizing sources.ASTROPHYSICAL JOURNAL,663(1),1-9.
MLA Liu, Jiren,et al."21 cm signals from early ionizing sources".ASTROPHYSICAL JOURNAL 663.1(2007):1-9.
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