A posteriori correction of Gaia CRF proper motions using conditional probability and zero-parallax prior
Abstract
The formal precision of Gaia CRF proper motions, and in principle positions, can be statistically improved by introducing conditional probability based on the zero-parallax prior for these extremely distant sources. The method developed in this study produces statistically conditioned proper-motion estimates under the assumed per-source Gaussian covariance model. It is demonstrated that thus corrected proper motion vectors of 1.2 million CRF objects in Gaia DR3 show a tighter distribution around zero and a general reduction in the rate of outliers by approximately 15\%. A general vector spherical harmonic fit to degree 4 is produced with the corrected data for a filtered subset of CRF quasars with redshifts between 1 and 1.5. This application, predicated on the unknown stochastic component of the global parallax field, shows a 3-sigma change in the estimated magnitude of the Galactocentric acceleration of the solar system barycenter, quantifying the sensitivity of this fundamental determination to the proposed conditioning of proper motions.
Versions
Related
- A Hierarchical Bayesian Differential Calibration of the Gaia DR3 Parallax Zero Point Using Galactic Globular Clusters
- First Trigonometric Parallax Measurements with the KVN and VERA Array (KaVA)
- Spectroscopic follow-up of compact object binary candidates from Gaia DR3: White dwarfs, neutron stars, black holes, and the parallax zeropoint
- Spectroscopic follow-up of compact object binary candidates from Gaia DR3: White dwarfs, neutron stars, black holes, and the parallax zeropoint
- Deconvolved IXPE Polarization Maps of the Crab Nebula in a Maximum-a-Posteriori Framework
BibTeX
@misc{makarov2026posteriori,
title = {{A posteriori correction of Gaia CRF proper motions using conditional probability and zero-parallax prior}},
author = {Valeri V. Makarov},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2608.16767},
eprint = {2608.16767},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2608.16767},
}
RIS
TY - UNPB
TI - A posteriori correction of Gaia CRF proper motions using conditional probability and zero-parallax prior
AU - Valeri V. Makarov
PY - 2026
DA - 2026/10/29
PB - arXiv
DO - 10.48550/arxiv.2608.16767
UR - https://arxiv.org/abs/2608.16767
AB - The formal precision of Gaia CRF proper motions, and in principle positions, can be statistically improved by introducing conditional probability based on the zero-parallax prior for these extremely distant sources. The method developed in this study produces statistically conditioned proper-motion estimates under the assumed per-source Gaussian covariance model. It is demonstrated that thus corrected proper motion vectors of 1.2 million CRF objects in Gaia DR3 show a tighter distribution around zero and a general reduction in the rate of outliers by approximately 15\%. A general vector spherical harmonic fit to degree 4 is produced with the corrected data for a filtered subset of CRF quasars with redshifts between 1 and 1.5. This application, predicated on the unknown stochastic component of the global parallax field, shows a 3-sigma change in the estimated magnitude of the Galactocentric acceleration of the solar system barycenter, quantifying the sensitivity of this fundamental determination to the proposed conditioning of proper motions.
ER -