IXPE event detection and event reconstruction

The Gas Pixel Detectors (GPD) are innovative gas detectors able to simultaneously perform polarimetry, imaging, timing and spectroscopy in the soft X-ray band (2-8 keV). They do so by imaging individual ionization tracks produced by photoelectrons emitted after the absorption of incident X-rays. The Imaging X-ray Polarimetry Explorer (IXPE) mission, a NASA-ASI mission launched in December 2021 and dedicated to the study of objects with extreme magnetic and gravitational fields, such as Black Holes, Neutron Stars, Supernova Remnants and Pulsar Wind Nebulae, hosts three GPDs in its focal plane. I will describe how IXPE data are reduced to retrieve the information about source polarization, focusing on the reconstruction algorithms used to analyze the raw photoelectron images produced by the GPDs.