Colloquium on Jul. 2, 2020

Reopening the window of astronomical soft X-ray polarimetry

Speaker: Feng Hua (Qinghua Univ.)

Venue: Video Conference

Time: 15:00 PM, Thursday, Jul. 2, 2020

Abstract: 

Polarimetry in the standard X-ray band is argued to be a powerful and sometimes unique tool in diagnosing the magnetic field, geometry and emission mechanism in astrophysics. However, this window has remained closed for more than 40 years since the OSO-8 experiment in 1970s. In this talk, I will introduce the space program PolarLight, which is a miniature X-ray polarimeter based on a novel technique that enables high-sensitivity X-ray polarimetry. PolarLight was launched into a low-Earth orbit in October 2018 onboard a CubeSat. With the first-year data, polarization in the soft X-ray band from the Crab nebula ha been detected, consistent with the results obtained with OSO-8. A possible variation in polarization after a glitch of the Crab pulsar i revealed at a significance of 3 sigma, suggesting that the magnetosphere of the pulsar may have altered due to the glitch.  I will also share some thoughts about  how CubeSats can be used for space astronomy.