Probing Cosmic Reionization with Neutral Hydrogen 21cm Line<\/p>\n\n\n\n
Keitaro Takahashi (Kumamoto University)<\/p>\n\n\n\n
\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\nCosmic reionization is\nan important era in the history of the universe, when intergalactic neutral\nhydrogen was ionized by radiation from high-redshift galaxies. So far, cosmic\nreionization has been observationally studied mainly by galaxy surveys and\ncosmic microwave background observation and it is well known that cosmic\nreionization was completed at around z~6. However, its beginning and evolution,\nand the source of ionizing photons are still unknown. These problems are deeply\nrelated to the formation and properties of first stars, first galaxies and\nfirst supermassive black holes so that cosmic reionization has attracted much\nattention of broad astronomical community. One of the most powerful probes\nof cosmic reionization is 21cm radiation from neutral hydrogen, from which we\ncan obtain information on the spatial distribution of intergalactic neutral\nhydrogen and its time evolution. However, the 21cm signal has never been\ndetected yet, due to the weakness of the signal, presence of huge foreground\nand difficulty of precise calibration. In this talk, I will review\ntheoretical and observational studies of 21cm line radiation from cosmic\nreionization. Especially, I focus on several ongoing projects which are aiming\nto detect 21cm line radiation such as MWA, LOFAR and HERA, and a\nnext-generation project SKA.\n\n\n\n<\/p>\n","protected":false},"excerpt":{"rendered":"