HEAPOW: Extreme Polarization (2016 Oct 17)
A wave of electromagnetic radiation is characterized by its wavelength (or frequency, or energy) and its orientation, or polarization. A linearly polarized wave of radiation oscillates in a single plane (up-and-down or side-to-side). Determining the polarization of electromagnetic radiation helps determine the geometry of the source of the radiation, difficult information to obtain otherwise for astronomical sources residing at cosmic distances. Studies of polarization are routinely done at optical and lower energies, but determining the polarization of high-energy radiation like X-rays is technologically challenging. Arising to meet that challenge is X-Calibur, a balloon-borne telescope which uses a combination of high-energy X-ray mirrors and solid-state detectors to determine the orientation of X-rays produced by neutron stars, black holes and other sources. X-ray polarization measurements can show how spinning black holes affect space-time, or what happens in the super strong magnetic fields near pulsars and magnetars. X-Calibur was launched from Fort Sumner, New Mexico on September 17, 2016 and landed on September 19 on the New-Mexico/Arizona border. X-Calibur targets during this flight included the Crab Nebula and its pulsar, the microquasar Sco X-1, and the black hole binary system Cyg X-1. We may be entering a golden age of high-energy polarization studies: NASA has two X-ray polarimeter missions, PRAXyS and IXPE on the drawing board, and others are under consideration.
WUSTL: X-Ray and Gamma-Ray Astroparticle Physics
| << Previous HEAPOW | High Energy Astrophysics Picture of the Week | Next HEAPOW >> |