Quantification of flux uncertainties introduced by the correction procedure

Derive a straightforward estimate of how stellar-atmosphere-model selection and interpolation and magnitude-grid corrections affect the flux errors of corrected Gaia XP spectra.

Background

The catalogue reports empirical medians and standard deviations of magnitude residuals as proxies for magnitude uncertainties because the correction procedure introduces additional sources of uncertainty. These include the selection and interpolation of Kurucz stellar-atmosphere models and the empirical corrections derived on the magnitude–magnitude grid. The paper states that the effect of these operations on flux errors is not straightforward to determine, leaving the propagation and quantification of correction-induced uncertainties unresolved.

References

However, our correction procedure introduces uncertainties that are difficult to quantify, e.g. those related to the selection and interpolation of the stellar atmosphere models or those related to the corrections on the mag-mag grid itself. It is hard to determine a straightforward estimate of how these operations affect flux errors.

— Vera C. Rubin LSST Synthetic Magnitudes derived from Gaia XP Spectra  (2608.17922 - Razim et al., 18 Aug 2026) in Section 5.1, “Run catalogue”