Gaia Early Data Release 3
By L. Lindegren, U. Bastian, M. Biermann, A. Bombrun, A. Torres, E. Gerlach, R. Geyer, J. Hernández, T. Hilger, D. Hobbs and 7 more. Astronomy & Astrophysics, 2020
384 citations recorded by the source corpus.
Context. Gaia Early Data Release 3 (Gaia EDR3) gives trigonometric parallaxes for nearly 1.5 billion sources. Inspection of the EDR3 data for sources identified as quasars reveals that their parallaxes are biased, that is, they are systematically offset from the expected distribution around zero, by a few tens of microarcseconds. Aims. We attempt to map the main dependences of the parallax bias in EDR3. In principle, this could provide a recipe for correcting the EDR3 parallaxes. Methods. Quasars provide the most direct way for estimating the parallax bias for faint sources. In order to extend this to brighter sources and a broader range of colours, we used differential methods based on physical pairs (binaries) and sources in the Large Magellanic Cloud. The functional forms of the dependences were explored by mapping the systematic differences between EDR3 and DR2 parallaxes. Results. The parallax bias is found to depend in a non-trivial way on (at least) the magnitude, colour, and ecliptic latitude of the source. Different dependences apply to the five- and six-parameter solutions in EDR3. While it is not possible to derive a definitive recipe for the parallax correction, we give tentative expressions to be used at the researcher’s discretion and point out some possible paths towards future improvements.
Subfields: Astronomy and Astrophysics, Instrumentation
View Paper: https://www.semanticscholar.org/paper/272dd0745999920539173ff126388ea9ff899f02
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Citations in the corpus
- Cosmic Distances Calibrated to 1% Precision with Gaia EDR3 Parallaxes and Hubble Space Telescope Photometry of 75 Milky Way Cepheids Confirm Tension with ΛCDM (2020, background): “The improvements result from an increase in the sampling (34 versus 22 months), improved analysis of the data (Lindegren et al. 2020a, 2020b, hereafter L20a, b), and an improved characterization of the leading systematic uncertainty in DR2: the parallax offset term.”
- A million binaries from Gaia eDR3: sample selection and validation of Gaia parallax uncertainties (2021, methodology): “0.7 arcsec; not shown in Figure 9), theGaia eDR3 catalog contains only equal-brightness pairs (Lindegren et al. 2020b, their Figure 6).”