Kavli Affiliate: Roger W. Romani
| First 5 Authors: Jack T. Dinsmore, Roger W. Romani, , ,
| Summary:
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 ($Delta chi^2approx 3times
10^{4}$ and $4 times 10^4$ respectively for a bright $10^6$-count source). We
also define an algorithm for polarization leakage correction substantially more
accurate than existing prescriptions ($Delta chi^2approx 1times 10^{3}$).
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.
| Search Query: ArXiv Query: search_query=au:”Roger W. Romani”&id_list=&start=0&max_results=3