Wenbin Lu from the Division of Physics, Mathematics and Astronmy at Caltech will be the featured speaker at an upcoming Department of Physics and Astronomy colloquium. His talk is titled, "Fast Radio Burst Source Properties from Polarization Measurments."
Fast radio bursts (FRBs) are bright millisecond-duration transient events, which were the major unexpected astronomical discovery in decades. There are thousands of bright (> 1 Jy ms) FRBs per day coming from random directions across the entire sky. One source, FRB 121102, was found to generate numerous bursts. This allowed follow-up observations to pin-point its host galaxy, which is at a distance of ~1 Gpc. Recent polarization measurements show that the bursts from FRB 121102 are nearly 100% linearly polarized and that their polarization position angles vary within a small confined range. Lu shows that these two properties can be explained by propagation effects through the magnetosphere of a strongly magnetized neutron star, provided that its rotation period is longer than 0.3 seconds and its magnetic inclination is less than about 20 degrees. In the future, when more bursts from the repeater are detected with polarization measurements, it should be possible to measure the rotation period of the progenitor and test its neutron star nature. He also will present a prediction of the maximum luminosity Lmax for FRBs under the coherent curvature emission model. The existence of this Lmax is because the electric field responsible for accelerating the emitting particles becomes close to the quantum critical strength and is then quickly shielded by Schwinger pairs within a nano-second.