Cosmological constraints on axionic dark radiation from axion-photon conversion in the early Universe

Tetsutaro Higaki, Kazunori Nakayama, Fuminobu Takahashi

Research output: Contribution to journalArticle

12 Citations (Scopus)


Axions seem ubiquitous in string theories and some of them may be produced non-thermally by heavy scalar decays, contributing to dark radiation. We study various cosmological effects of photons produced from the axionic dark radiation through axion-photon conversion in the presence of primordial magnetic fields, and derive tight constraints on the combination of the axion-photon coupling and the primordial magnetic field.

Original languageEnglish
Article number030
JournalJournal of Cosmology and Astroparticle Physics
Issue number9
Publication statusPublished - 2013 Sep 1



  • axions
  • particle physics - cosmology connection
  • physics of the early universe

ASJC Scopus subject areas

  • Astronomy and Astrophysics

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