IXPE Data Analysis

Update 2022 April 8: The IXPE team have replaced the initial processing of Cas A and Cen X-3 data with corrected versions (see below update from March 18). If you downloaded these data before April 8 2022, you will need to replace them with the current version on the archive. You can also check the DATE keywords in your FITS files; the correct versions have April 4th (Cas A) or 5th (Cen X-3).

Update 2022 March 23: The IXPE team have discovered a bug in HEASoft's barrycor routine in HEASoft 6.30 or before. See the HEASoft known issues for a work-around or update your build to HEASoft 6.30.1 for a fix.

Update 2022 March 18: The IXPE team have discovered an error in the processing of the Q,U data. The significance of any detection measured in a single detector is correct, but the implied angle is effectively meaningless. Further if you add data from all 3 detectors, any true polarization will effectively cancel out. We are working on fixing this problem and will regenerate the level 2 event lists (the only files impacted) and replace the observations on the archive.

IXPE Data

On the IXPE archive are released the processed (level 2) event files for each observation. These can be analyzed with the standard multi-mission HEASARC software tools such as ximage and xselect. These can be used to create spectra, images, and light curves for science analysis.

Note that the archive also contains raw (level 1) event files as well as housekeeping data that allows an advanced user to reprocess the data with the IXPE pipeline tools. But this is not needed for most users, since the level 2 events are already highly processed by the IXPE team.

IXPE Software Package

The IXPE software package has been included in HEASoft and first released with HeaSoft 6.30 (March 2022) The package includes software routines that process level 1 event data with various corrections and selections to create science-ready level 2 event files. The package also includes several tools to generate related products.

The current version of the IXPE software package is distributed with the latest HEAsoft distribution.

IXPE Support Documentation

The IXPE team have also provided several documents about the instrument and observatory as well as about using the data and software.

Documents Release Date Description
IXPE Observatory June 2022 The IXPE Team description of the observatory and guide for users.
IXPE Data Formats June 2022 The IXPE Team description of the data formats for level 1, level 2, and calibration data products.
IXPE Software User Guide March 28 2022 Software analysis guide including a description of the pipeline as well as help for each tool (pdf)
IXPE Instrument June 2022 The IXPE Team description of the instrument.

IXPE Proposal Tools

HEASARC WebPIMMS

WebPIMMS on MSFC IXPE site

Latest News

  • IXPE Caldb Updated (17 Nov 2022)
    The IXPE Caldb has been updated for the XRT (version 20221021) and the GPD (version 20221020). Downloads are available from the IXPE Calibration page. Users can also access the HEASARC caldb remotely.
  • A New Slant on Cas A (17 Nov 2022)
    IXPE image of magnetic fields in Cas A hits the HEASARC Picture of the Week
  • 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.