2024ApJ...962..183D -
Astrophys. J., 962, 183 (2024/February-3)
Polarization Leakage and the IXPE Point-spread Function.
DINSMORE J.T. and ROMANI R.W.
Abstract (from CDS):
By measuring photoelectron tracks, the gas pixel detectors of the Imaging X-ray Polarimetry Explorer satellite provide estimates of the photon detection location and its electric vector position angle (EVPA). However, imperfections in reconstructing event positions blur the image, and EVPA-position correlations result in artificial polarized halos around bright sources. We introduce a new model describing this “polarization leakage” and use it to recover the on-orbit telescope point-spread functions, useful for faint-source detection and image reconstruction. These point-spread functions are more accurate than previous approximations or ground-calibrated products (Δχ2 ≈ 3 × 104 and 4 × 104 respectively for a bright 106-count source). We also define an algorithm for polarization leakage correction substantially more accurate than existing prescriptions (Δχ2 ≈ 1 × 103). These corrections depend on the reconstruction method, and we supply prescriptions for the mission-standard “Moments” methods as well as for “Neural Net” event reconstruction. Finally, we present a method to isolate leakage contributions to polarization observations of extended sources and show that an accurate PSF allows the extraction of sub-PSF-scale polarization patterns.
Abstract Copyright:
© 2024. The Author(s). Published by the American Astronomical Society.
Journal keyword(s):
Pulsar wind nebulae - X-ray astronomy - Polarimetry - Open source software - X-ray detectors
Status at CDS
:
Large table(s) will be appraised for possible ingestion in VizieR.
Simbad objects:
7
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