Tuesday, July 16, 2013

1307.3584 (Soma De et al.)

Polarization of 21cm lines from the epoch of reionization as seen through the Milky Way    [PDF]

Soma De, Hiroyuki Tashiro
Redshifted 21 cm signal from neutral hydrogen is one of the most competitive probes of the epoch of reionization (EoR). Unpolarized 21 cm radiation acquires a certain level of linear polarization during the EoR due to Thompson scattering. This linear polarization, if measured, could probe important information about the EoR. We study the effect of Faraday rotation (FR) due to the Milky way which is one of the most dominant foregrounds in the detection of polarization of 21 cm radiation. We show that FR modifies the initial E-mode signal carried by 21 cm photons in its entirety. A 99 % accuracy on rotation measure (RM) data is necessary to recover the initial E-mode signal. We conclude that, given the current status of RM observations, it is not possible to retrieve the initial polarization signal of 21 cm from the EoR. However, we are optimistic that it may be possible from the next generation radio surveys.
View original: http://arxiv.org/abs/1307.3584

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