When Can Pulsar Timing Distinguish a Propagation Mass from a Weak Longitudinal Background?
Abstract
A weak longitudinal background can imitate the angular response of a gravitational-wave propagation mass. We quantify this ambiguity in a compressed Gaussian experiment constructed from the NANOGrav 15-year timing data. At a false-alarm probability of 10−3, allowing a weak longitudinal component in a massless background costs at least 16.29 percentage points of optimal rejection power for a specified source in a 20-pulsar subarray. Expanding the array to 40 pulsars at the same background level recovers at least 7.62 points. In a separate low-background experiment, we allow the same continuous range of longitudinal amplitudes at zero and positive mass. Across that range and three injected background levels, one test rejects zero mass with at least 97.38\% power at either of two masses separated by 1.08\%. With false assignment limited to 10−3 at the other mass, the power to identify either mass is at most 1.584\%. A cutoff can thus be identifiable before its position within a frequency cell can be resolved.
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BibTeX
@misc{zhou2026when,
title = {{When Can Pulsar Timing Distinguish a Propagation Mass from a Weak Longitudinal Background?}},
author = {Kun Zhou and Jin Li},
howpublished = {arXiv},
year = {2026},
month = nov,
doi = {10.48550/arxiv.2611.08382},
eprint = {2611.08382},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2611.08382},
}
RIS
TY - UNPB
TI - When Can Pulsar Timing Distinguish a Propagation Mass from a Weak Longitudinal Background?
AU - Kun Zhou
AU - Jin Li
PY - 2026
DA - 2026/11/05
PB - arXiv
DO - 10.48550/arxiv.2611.08382
UR - https://arxiv.org/abs/2611.08382
AB - A weak longitudinal background can imitate the angular response of a gravitational-wave propagation mass. We quantify this ambiguity in a compressed Gaussian experiment constructed from the NANOGrav 15-year timing data. At a false-alarm probability of 10^−3, allowing a weak longitudinal component in a massless background costs at least 16.29 percentage points of optimal rejection power for a specified source in a 20-pulsar subarray. Expanding the array to 40 pulsars at the same background level recovers at least 7.62 points. In a separate low-background experiment, we allow the same continuous range of longitudinal amplitudes at zero and positive mass. Across that range and three injected background levels, one test rejects zero mass with at least 97.38\% power at either of two masses separated by 1.08\%. With false assignment limited to 10^−3 at the other mass, the power to identify either mass is at most 1.584\%. A cutoff can thus be identifiable before its position within a frequency cell can be resolved.
ER -