IXPE

The Imaging X-ray Polarimetry Explorer (IXPE) measures the polarization of X-rays from cosmic sources, a property no previous dedicated satellite mission was built to observe systematically. Polarization measurements reveal the geometry and magnetic field structure of extreme objects like black holes and neutron stars. IXPE complements the imaging and spectroscopic capabilities of NASA's Chandra X-ray Observatory, which has no polarimetry instrument.

IXPE was launched on December 9, 2021, aboard a SpaceX Falcon 9 rocket from Kennedy Space Center in Florida. The mission is led by NASA, with the Italian Space Agency (ASI) providing the polarization-sensitive X-ray detectors. It is part of NASA's Small Explorers (SMEX) program for cost-effective scientific missions.

IXPE observes stellar-mass and supermassive black holes, neutron stars, pulsars, magnetars, supernova remnants, and active galactic nuclei. Its polarization measurements of objects like the Crab Nebula and the supermassive black hole in galaxy M87 provide unique data about the geometry of emission regions and magnetic field orientation. These observations complement the imaging data from telescopes like Chandra and XMM-Newton.

IXPE's polarization measurements allow astronomers to map the geometry of the accretion disks and relativistic jets around black holes in ways that imaging alone cannot achieve. By measuring the angle and degree of X-ray polarization from objects like the supermassive black hole in galaxy M87, IXPE provides direct evidence about the magnetic field structures that drive jet formation. This data helps test predictions of general relativity in the strong-gravity regime near event horizons.