Poster Presentation

Transient Blurring of the Scintillation Arc of B1737+13

Author(s): Yen-Hua Chen(ASIAA), Sammy Siegel(Department of Astronomy, Boston University, Boston, US), Daniel Baker(ASIAA), Dan Stinebring(Department of Physics and Astronomy, Oberlin College, Oberlin, US), Ue-Li Pen(ASIAA)

Presenter: Yen-Hua Chen (Academia Sinica Institute of Astronomy and Astrophysics/ASIAA)

For many pulsars, the scattering structures responsible for scintillation appear to be dominated by a single thin screen along the line of sight that persists over years to decades. Recently, we have begun to see more examples where a secondary lens passes near the line of sight and adds to or distorts the scintillation arc on the secondary spectrum over the course of days to months. In this work we report on such a transient event for pulsar B1737+13, where the secondary spectrum goes from clear parabolic structures to a blurry state and then back again to sharply defined inverted arclets over 270 days. Using phase retrieval techniques to separate the two screens in the wavefield, we report a curvature and rate of motion of features in the wavefield consistent with a second screen passing though the line of sight. Using simulations of the scattering screens, we propose a potential configuration of screens that could explain the observed feature.