Determining the Redshift of Reionization From the Spectra of High-Redshift Sources
Determining the Redshift of Reionization From the Spectra of High-Redshift Sources
复制标题
从高红移源的光谱确定再电离的红移
DOI：
10.1086/307393
复制
发表时间：
1998
期刊：
影响因子：
--
通讯作者：
A. Loeb
中科院分区：
文献类型：
--
作者：
Z. Haiman;A. Loeb
宇宙再电离时的红移目前还不清楚。我们研究的最佳策略提取这种红移，zreion，从早期来源的光谱。对于一个位于红移zs以上但接近再电离红移的源，（1 + zreion）<（1 + zs）< 32/27（1 + zreion），冈恩-彼得森槽分裂成不相交的Lyα，Lyβ，以及可能更高的莱曼系列槽，在这些槽之间有一些透射通量。我们发现，虽然在高红移时，透过的通量被稠密的Lyα森林大大抑制，但只要zreion = 1.8，它仍然可以被探测到。如果电离源是明亮的并且具有短的占空比（例如，如果它们是寿命为106年的小型类星体或星暴，那么在它们周围的H II区重叠后不久就会发生突破，透射的通量提供了对zreion的测量。下一代太空望远镜将达到这种测量所需的光谱灵敏度。
The redshift at which the universe was reionized is currently unknown. We examine the optimal strategy for extracting this redshift, zreion, from the spectra of early sources. For a source located at a redshift zs beyond but close to the reionization redshift, (1 + zreion) < (1 + zs) < 32/27(1 + zreion), the Gunn-Peterson trough splits into disjoint Lyα, Lyβ, and possibly higher Lyman series troughs, with some transmitted flux between these troughs. We show that although the transmitted flux is suppressed considerably by the dense Lyα forest at high redshifts, it could still be detectable as long as zreion ≲ 8. If the ionizing sources are bright and have a short duty cycle (e.g., if they are miniquasars or starbursts with a lifetime ≲106 yr), then breakthrough occurs shortly after the H II regions around them overlap, and the transmitted flux provides a measurement of zreion. The Next Generation Space Telescope will reach the spectroscopic sensitivity required for such a measurement.