Unexplained discrepancy in folded TESS light curves relative to Luna (2023)

Determine the cause of the discrepancy between the folded and binned TESS Sector 12 light curve of IGR J16194-2810 reported in this study and the folded light curve presented by Luna (2023), specifically why Luna’s folded curve appears significantly less noisy and more coherent despite analysis of the same temporal region.

Background

The authors reanalyzed TESS photometry to assess a previously reported neutron-star spin period near 4.06 hours. While a weak, transient signal is detected, the folded light curve in this work differs noticeably from the version reported by Luna (2023), appearing noisier and less coherent.

This discrepancy remains unresolved and potentially affects the robustness of the proposed spin-period detection, motivating clarification of data processing, detrending, and folding procedures or instrumental/systematic effects.

References

The shape of our folded and binned TESS light curve from the second half of sector 12 does not match that provided by \citet{luna_2023}. The folded light curve shown in his Figure 1 appears significantly less noisy and more coherent than the one yielded by our analysis. We were unable to determine the reason for this discrepancy (Luna, private communication).

— The Symbiotic X-ray Binary IGR J16194-2810: A Window on the Future Evolution of Wide Neutron Star Binaries From Gaia  (2405.17560 - Nagarajan et al., 2024) in Section 5.7 (Spin Period Analysis)