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The earliest galaxies seen in 21 cm line absorption
Xu, Yidong1,2,3; Ferrara, Andrea4; Chen, Xuelei3,5
2011-02-01
Source PublicationMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
Volume410Issue:3Pages:2025-2042
AbstractWe investigate the 21 cm absorption lines produced by non-linear structures during the early stage of reionization, i.e. the starless minihaloes and the dwarf galaxies. After a detailed modelling of their properties, with particular attention to the coupling physics, we determine their 21 cm absorption line profiles. The infalling gas velocity around minihaloes/dwarf galaxies strongly affects the line shape and, with the low spin temperatures outside the virial radii of the systems, gives rise to horn-like line profiles. The optical depth of a dwarf galaxy is reduced for lines of sight penetrating through its H ii region and, especially, a large H ii region created by a dwarf galaxy with higher stellar mass and/or a top-heavy initial mass function results in an optical depth trough rather than an absorption line. We compute synthetic spectra of 21 cm forest for both high-redshift quasars and radio afterglows of gamma-ray bursts (GRBs). Even with the planned Square Kilometre Array (SKA), radio afterglows of most if not all GRBs would still be too dim to be the background sources for high-resolution (1 kHz) observations, but absorption lines can be easily detected towards a high-z quasar. Broadband observation against GRB afterglows can also be used to reveal the evolving 21 cm signal from both minihaloes and dwarf galaxies if there was no X-ray background or it was extremely weak, but it becomes difficult if an early X-ray background existed. Hence, the 21 cm absorption could be a powerful probe of the presence/intensity of the X-ray background and the thermal history of the early Universe.
KeywordLine: Profiles Galaxies: Dwarf Galaxies: High-redshift Cosmology: Theory
DOI10.1111/j.1365-2966.2010.17579.x
Indexed BySCI
Language英语
WOS IDWOS:000286004300001
Citation statistics
Cited Times:14[WOS]   [WOS Record]     [Related Records in WOS]
Document Type期刊论文
Identifierhttp://ir.bao.ac.cn/handle/114a11/8035
Collection星系宇宙学研究部
Affiliation1.Peking Univ, Dept Astron, Sch Phys, Beijing 100871, Peoples R China
2.SISSA Int Sch Adv Studies, I-34014 Trieste, Italy
3.Chinese Acad Sci, Natl Astron Observ, Beijing 100012, Peoples R China
4.Scuola Normale Super Pisa, I-56126 Pisa, Italy
5.Peking Univ, Ctr High Energy Phys, Beijing 100871, Peoples R China
Recommended Citation
GB/T 7714
Xu, Yidong,Ferrara, Andrea,Chen, Xuelei. The earliest galaxies seen in 21 cm line absorption[J]. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY,2011,410(3):2025-2042.
APA Xu, Yidong,Ferrara, Andrea,&Chen, Xuelei.(2011).The earliest galaxies seen in 21 cm line absorption.MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY,410(3),2025-2042.
MLA Xu, Yidong,et al."The earliest galaxies seen in 21 cm line absorption".MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 410.3(2011):2025-2042.
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