Speaker
Takuya Okawa
Description
Photons with a frequency equivalent to one-half of the axion mass can induce its decay into two photons. Half of the produced photons generate a potentially detectable 'gegenschein' radio signal traveling in the opposite direction. We take into account that, in addition to a smooth halo distribution, a fraction of the axionic dark matter might be in the form of compact objects known as axion stars. We discuss how, as a result, the gegenschein signal might be enhanced.
