http://arxiv.org/abs/1406.3977
Anomalous orbits are found when minimum-chi^{2} estimation is applied to synthetic Gaia data for weak orbital signals – i.e., orbits whose astrometric signatures are comparable to the single-scan measurement error (Pourbaix 2002). These orbits are nearly parabolic, edge-on, and their major axes align with the line-of-sight to the observer. Such orbits violate the Copernican principle (CPr) and as such could be rejected. However, the preferred alternative is to develop a statistical technique that incorporates the CPr as a fundamental postulate. This can be achieved in the context of Bayesian estimation by defining a Copernican prior. With this development, Pourbaix’s anomalous orbits no longer arise. Instead, orbits with a somewhat higher chi^{2} but which do not violate the CPr are selected.
Other areas of astronomy where the investigator must analyse data from ‘imperfect experiments’ might similarly benefit from appropriately- defined Copernican priors.
L. Lucy
Tue, 17 Jun 14
8/63
Comments: 9 pages, 9 figures. Research Note. Submitted to Astronomy and Astrophysics
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