http://arxiv.org/abs/1402.7068
Stellar coronae have been invoked to explain the apparently extragalactic dispersion measures observed in Fast radio bursts (Loeb, Shvartzvald & Maoz 2014). This paper demonstrates that the suggested plasma densities would lead to deviations from the standard dispersion curve that are inconsistent with the data and likely rule out the model independently of the argument of Luan (2014). The problem is then turned around and higher-order dispersion terms are connected to the moments of the density distribution along the line of sight. The deviations quantified in three observed bursts are analysed and a lower limit on the maximum electron density is obtained in one case, although with considerable uncertainty. Selection effects are then discussed and shown to be non-restrictive in relation to plasma density, except at the lowest frequencies.
A. Tuntsov
Fri, 28 Feb 14
3/54