http://arxiv.org/abs/1903.00426
Context. Variations in pulsar dispersion measures have been observed since shortly after the discovery of pulsars. As early as 2006, frequency-dependent dispersion measures have been observed and attributed to several possible causes. Cordes et al. (2016) demonstrated that ray-path averaging over different effective light-cone volumes through the turbulent ionized interstellar medium must contribute to this effect. Aims. We assess the frequency-dependent dispersion measures and reported extreme scattering event(s) in Donner et al. (2019) seen in the direction of PSR J2219+4754 to determine if the observations are consistent with such an event. Methods. We examine the observations of Donner et al. (2019) in the context of the recent literature on interstellar medium propagation effects and observations. Results. We find that the frequency dependence of the dispersion measure timeseries for PSR J2219+4754 is consistent with being due solely to turbulence in the ionized interstellar medium and that there is no evidence for an extreme scattering event.
M. Lam, T. Lazio, T. Dolch, et. al.
Mon, 4 Mar 19
16/48
Comments: 10 pages, 5 figures, submitted to A&A