English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

CONTEXT. Gaia EDR3 has produced parallaxes for 1.468x10^9 sources but thereare calibration issues that require corrections to the published values anduncertainties. AIMS. We want to characterize the behavior of the uncertaintiesof the Gaia EDR3 parallaxes. We also aim to provide a procedure for thecalculation of distances to stars and stellar clusters. METHODS. We reanalyzesome of the data in the calibration papers for QSO and LMC parallaxes andcombine those results with measurements for six bright GCs. We calculate theangular covariance of EDR3 parallaxes at small separations based on the LMCresults and combine it with the results for larger angles using QSOs to obtainan analytical formula for the angular covariance over the whole sky. Theresults for the six GCs are used to validate the parallax bias correction as afunction of magnitude, color, and ecliptic latitude and to determine theconstant used to convert internal uncertainties to external ones. RESULTS. Theangular covariance at zero separation is 106.2 muas^2, yielding a minimumuncertainty for EDR3 parallaxes of 10.3 muas for individual stars. That valuecan be only slightly reduced for GCs after considering the behavior of theangular covariance of the parallaxes for small separations. The Lindegren etal. parallax bias correction works quite well, except for the brightermagnitudes, suggesting improvements may be possible there. The value of k is1.1-1.7 and depends on G. Stars with moderately large values of RUWE can stillprovide useful parallaxes albeit with larger values of k. We give accurate andprecise Gaia EDR3 distances to the six GCs and for the specific case of 47 Tucwe are able to beat the angular covariance limit and derive a high-precisiondistance of 4.53+-0.06 kpc. Finally, a recipe for the derivation of distancesto stars and stellar clusters using Gaia EDR3 parallaxes is given. [ABRIDGED]

Validation of the accuracy and precision of Gaia EDR3 parallaxes with globular clusters