xAbout IXPE

About IXPE

IXPE's two-year baseline IXPE mission will measure the x-ray polarization of cosmic sources, using three identical telescopes, each comprising an x-ray mirror assembly and a polarization-sensitive detector. The mission, a collaboration between NASA and the Italian Space Agency (ASI), is led by the Principal Investigator (PI), Dr. Martin C. Weisskopf at NASA's Marshall Space Flight Center (MSFC). MSFC manages the project and is responsible for the x-ray optics and the Science Operations Center (SOC). Italy's National Institute for Astrophysics (INAF) and National Institute for Nuclear Physics (INFN) are responsible for the x-ray instrument. Ball Aerospace is the primary industry partner, responsible for the spacecraft, integration, and testing, as well as managing the Mission Operations Center (MOC) at the University of Colorado’s Laboratory for Atmospheric and Space Physics (LASP). In addition to funding the Instrument at INAF, INFN, and industrial partner OHB-Italia, ASI provides IXPE use of its Malindi ground station and software support by its Space Science Data Center (SSDC). The SOC will archive IXPE science data products at the High-Energy Astrophysics Science Archive Research Center (HEASARC) at NASA's Goddard Space Flight Center (GSFC), for release to the international scientific community.

The IXPE Science Team comprises investigators from MSFC, INAF, INFN, and three universities---Roma Tre University, Stanford University, and the Massachusetts Institute of Technology---plus over 80 collaborators from more than a dozen countries. During the first two years of the mission, the IXPE Science Team develops and executes the IXPE observing program. If the mission extends beyond two years, the HEASARC will administer a General Observer (GO) program for IXPE.

IXPE science

IXPE accomplishes new science with new capabilities

  • Opens a new window on the universe -- imaging (30'') X-ray polarimetry
    • Is the science driver that advances and impacts high-energy astrophysics
    • Increases information space and lifts modeling degeneracies
  • Addresses key questions, providing new scientific results and constraints
    • What is the spin of a black hole?
    • What are the geometry and magnetic-field strength in magnetars?
    • Was our Galactic Center an Active Galactic Nucleus in the recent past?
    • What is the magnetic field structure in synchrotron X-ray sources?
    • What are the geometries and origins of X-rays from pulsars (isolated and accreting)?
  • Provides powerful and unique capabilities
    • Reduces integration time by a factor of 100 compared to the OSO-8 experiment
    • Simultaneously provides imaging, spectral, timing, and polarization data
    • Is free of false-polarization systematic effects at less than a fraction of a percent
    • Enables meaningful polarization measurements for many sources of different classes

IXPE observatory

IXPE spacecraft structure

IXPE mirrors

Parameter Value
Number of mirror modules 3
Number of shells per mirror module 24
Focal length 4000 mm
Total shell length 600 mm
Range of shell diameters 162-272 mm
Range of shell thicknesses 0.18-0.25 mm
Shell material Electroformed nickel-cobalt alloy
Effective area per mirror module 502 cm2 (@ 2.3 keV); 590 cm2 (@ 4.5 keV)
Angular resolution (HPD) <= 25 arcsec
Field of view (detector limited) 12.9 arcmin square

The polarization sensitive detectors

Parameter Value
Sensitive area 15 mm x 15 mm
Fill gas and composition DME @ 650 mbar
Detector window 50 µm thick beryllium
Absorption and drift region depth 10 mm
GEM (gas electron multiplier) copper-plated 50 µm liquid-crystal polymer
GEM hole pitch 50 µm triangular lattice
Number ASIC readout pixels 300 x 352
ASIC pixelated anode Hexagonal @ 50 µm pitch
Spatial resolution (FWHM) <= 123 µm (6.4 arcsec) @ 2 keV
Energy resolution (FWHM) 0.54 keV @ 2 keV (∝ √E)

For more information, see:

Latest News

  • IXPE archive is open! (14 Mar 2022)
    The HEASARC has opened the IXPE data archive. Currently, Cas A and Cen X-3 datasets are available.
  • IXPE first light image of Cas A! (14 Feb 2022)
    IXPE has released its first light image of supernova remnant Cassiopeia A using data taken in January.
  • IXPE begins science operations. (13 Jan 2022)
    IXPE begins science operations with an observation of the supernova remnant Cassiopeia A.
  • IXPE boom successfully deployed. (16 Dec 2021)
    The IXPE spacecraft successfully deployed, positioning the mirrors 13 feet (4 meters) away from the instruments and is now ready for commissioning.
  • IXPE launch! (9 Dec 2021)
    The IXPE spacecraft successfully launched aboard a SpaceX Falcon 9 rocket from NASA's Kennedy Space Center in Florida.