First Detection of the Doppler Shift of X-ray Photons Due to a Telescope's Orbital Motion
Abstract
We have detected for the first time the redshifting and blueshifting of X-ray photons due to the orbital motion of an X-ray telescope around the Earth. Current and planned X-ray telescopes like XRISM/Resolve and NewAthena can achieve energy resolutions R = E / ΔE ≈ 1000, requiring spectroscopic calibration of physical effects such as the local standard of rest and the orbit of the Earth around the Sun. We construct an a priori method for detecting a heretofore unexamined effect: the modulation of redshift due to the motion of an X-ray telescope around the Earth. We apply this pipeline to several XRISM/Resolve observations of narrow iron Kα emission lines from galactic center molecular clouds, and we detect evidence of orbital redshift modulation in the Kα emission at the 95% confidence level. Our findings suggest that orbital redshift modulation is already present and detectable in X-ray data and motivates reexamination of how X-ray photon data is packaged in the emerging era of high-resolution X-ray spectroscopy.
Versions
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BibTeX
@misc{dikerby2026first,
title = {{First Detection of the Doppler Shift of X-ray Photons Due to a Telescope's Orbital Motion}},
author = {Stephen DiKerby and Shuo Zhang},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.36042},
eprint = {2609.36042},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.36042},
note = {CC BY-NC-SA 4.0},
}
RIS
TY - UNPB
TI - First Detection of the Doppler Shift of X-ray Photons Due to a Telescope's Orbital Motion
AU - Stephen DiKerby
AU - Shuo Zhang
PY - 2026
DA - 2026/09/28
PB - arXiv
DO - 10.48550/arxiv.2609.36042
UR - https://arxiv.org/abs/2609.36042
AB - We have detected for the first time the redshifting and blueshifting of X-ray photons due to the orbital motion of an X-ray telescope around the Earth. Current and planned X-ray telescopes like XRISM/Resolve and NewAthena can achieve energy resolutions R = E / ΔE ≈ 1000, requiring spectroscopic calibration of physical effects such as the local standard of rest and the orbit of the Earth around the Sun. We construct an a priori method for detecting a heretofore unexamined effect: the modulation of redshift due to the motion of an X-ray telescope around the Earth. We apply this pipeline to several XRISM/Resolve observations of narrow iron Kα emission lines from galactic center molecular clouds, and we detect evidence of orbital redshift modulation in the Kα emission at the 95% confidence level. Our findings suggest that orbital redshift modulation is already present and detectable in X-ray data and motivates reexamination of how X-ray photon data is packaged in the emerging era of high-resolution X-ray spectroscopy.
ER -