Early reionization with primordial magnetic fields |
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| Authors: | Hiroyuki Tashiro Naoshi Sugiyama |
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| Institution: | Department of Physics, Kyoto University, Kyoto 606-8502, Japan;Division of Theoretical Astronomy, National Astronomical Observatory, Japan, Mitaka, Tokyo 181-8588, Japan |
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| Abstract: | Early reionization of the intergalactic medium (IGM), which is favoured from the WMAP temperature–polarization cross-correlations, contests the validity of the standard scenario of structure formation in the cold dark matter (CDM) cosmogony. It is difficult to achieve early enough star formation without rather extreme assumptions such as a very high escape fraction of ionizing photons from protogalaxies or a top-heavy initial mass function (IMF). Here, we propose an alternative scenario that additional fluctuations on small scales induced by primordial magnetic fields trigger early structure formation. We found that ionizing photons from Population III stars formed in dark haloes can easily reionize the Universe by z ≃ 15 if the strength of primordial magnetic fields is between 0.7 and 1.5 × 10−9 G . |
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| Keywords: | magnetic fields stars: formation galaxies: formation cosmology: theory large-scale structure of Universe |
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