Searching for the earliest galaxies in the 21cm forest  

作　　者：Andrea FERRARA Francisco S. KITAURA 

机构地区：[1]Scuola Normale Superiore,Piazza dei Cavalieri 7,56126 Pisa,Italy

出　　处：《Science China(Physics,Mechanics & Astronomy)》2010年第6期1124-1129,共6页中国科学：物理学、力学、天文学（英文版）

基　　金：was supported in part by a scholarship from the China Scholarship Council;a research training fellowship from SISSA astrophysics sector;the National Natural Science Foundation of China (Grant Nos. 10373001,10533010,10525314,and 10773001);the Knowledge Innovation Program of Chinese Academy of Sciences (Grant No. KJCX3- SYW-N2);the National Basic Research Program of China (Grant No. 2007CB8125401)

摘　　要：We use a model developed by Xu,Ferrara,and Chen(Mon Not Roy Astron Soc,submitted) to compute the 21 cm line absorption signatures imprinted by star-forming dwarf galaxies(DGs) and starless minihalos(MHs). The method,based on a statistical comparison of the equivalent width(W ν ) distribution and flux correlation function,allows us to derive a simple selection criteria for candidate DGs at very high(z ≤ 8) redshift. We find that ≈18% of the total number of DGs along a line of sight to a target radio source(GRB or quasar) can be identified by the condition W ν【0; these objects correspond to the high-mass tail of the DG distribution at high redshift,and are embedded in large HII regions. The criterion W ν】0.37 kHz instead selects ≈11% of MHs. Selected candidate DGs could later be re-observed in the near-IR by the JWST with high efficiency,thus providing a direct probe of the most likely reionization sources.We use a model developed by Xu,Ferrara,and Chen(Mon Not Roy Astron Soc,submitted) to compute the 21 cm line absorption signatures imprinted by star-forming dwarf galaxies(DGs) and starless minihalos(MHs). The method,based on a statistical comparison of the equivalent width(W ν ) distribution and flux correlation function,allows us to derive a simple selection criteria for candidate DGs at very high(z ≤ 8) redshift. We find that ≈18% of the total number of DGs along a line of sight to a target radio source(GRB or quasar) can be identified by the condition W ν<0; these objects correspond to the high-mass tail of the DG distribution at high redshift,and are embedded in large HII regions. The criterion W ν>0.37 kHz instead selects ≈11% of MHs. Selected candidate DGs could later be re-observed in the near-IR by the JWST with high efficiency,thus providing a direct probe of the most likely reionization sources.

关 键 词：COSMOLOGY DWARF GALAXIES HIGH-REDSHIFT GALAXIES radio absorption lines 

分 类 号：P152[天文地球—天文学]