Tsukuba Uchu Forum

136th Uchu Forum

X-ray polarisation observations: A new means of exploring the high-energy universe

Toru Tamagawa


X-rays are emitted from many astrophysical objects, including black holes, neutron stars, galaxies, and galaxy clusters. The Imaging X-ray Polarimeter Explorer (IXPE) satellite was launched by NASA in December 2021 to observe polarization with high sensitivity, which is the only field of X-ray astrophysics that has not yet been tackled. NASA launched the IXPE in December 2021. X-ray photons carry four independent types of physical information (position, time, energy, and polarization), but polarization provides us with new information about celestial objects that cannot be obtained from the other three alone. For example, IXPE has been used to measure the spin of black holes, to investigate the distribution of coronal gas in the vicinity of black holes, and to examine the effect of the powerful magnetic field of neutron stars (up to 10^10 T) on the vacuum. In this talk, I will explain X-ray polarimetry and describe IXPE, and introduce the latest results of X-ray polarimetry observations by IXPE. Image