GaiaEarly Data Release 3

Abstract

Context. Gaia Early Data Release 3 (Gaia EDR3) contains results for 1.812 billion sources in the magnitude range G = 3–21 based on observations collected by the European Space Agency Gaia satellite during the first 34 months of its operational phase. Aims. We describe the input data, the models, and the processing used for the astrometric content of Gaia EDR3, as well as the validation of these results performed within the astrometry task. Methods. The processing broadly followed the same procedures as for Gaia DR2, but with significant improvements to the modelling of observations. For the first time in the Gaia data processing, colour-dependent calibrations of the line- and point-spread functions have been used for sources with well-determined colours from DR2. In the astrometric processing these sources obtained five-parameter solutions, whereas other sources were processed using a special calibration that allowed a pseudocolour to be estimated as the sixth astrometric parameter. Compared with DR2, the astrometric calibration models have been extended, and the spin-related distortion model includes a self-consistent determination of basic-angle variations, improving the global parallax zero point. Results. Gaia EDR3 gives full astrometric data (positions at epoch J2016.0, parallaxes, and proper motions) for 1.468 billion sources (585 millionwith five-parameter solutions, 882 million with six parameters), and mean positions at J2016.0 for an additional 344 million.Solutions with five parameters are generally more accurate than six-parameter solutions, and are available for 93% of the sources brighter than the 17th magnitude. The median uncertainty in parallax and annual proper motion is 0.02–0.03 mas at magnitude G = 9–14, and around 0.5 mas at G = 20. Extensive characterisation of the statistical properties of the solutions is provided, including the estimated angular power spectrum of parallax bias from the quasars.

Optimized modelling of Gaia–Hipparcos astrometry for the detection of the smallest cold Jupiter and confirmation of seven low-mass companions

“…The stellar mass errors contribute 7%, 67%, 36%, 5%, 82%, 95%, 27%, and 84% to the uncertainty of the masses of HD 131664 B, HD 16160 C, HD 161797 Ab, HD 190360 b, HD 190406 B, HD 39587 B, HD 4747 B, and HIP 2552 C, respectively. Second, because the five-parameter astrometry model used in Gaia EDR3 (Lindegren et al 2021) does not account for companion-induced nonlinear motion of a star, the longer baseline of Gaia EDR3 does not improve the fit much for stars with massive companions. In particular, the Gaia EDR3 astrometry is more uncertain than the DR2 astrometry for HD 131664, HD 16160, and HIP 2552.…”

Blue extreme disk-runaway stars with Gaia EDR3

“…Consequently, the high observed ejection velocities of disk runaways call for an as yet mostly neglected mechanism possibly involving very massive stars (Gvaramadze 2009;Gvaramadze et al 2009) or intermediate-mass black holes (Fragione & Gualandris 2019), see Irrgang et al (2018a) for a more detailed discussion. With proper motions of significantly improved accuracy and precision from the Gaia early data release 3 (EDR3, Gaia Collaboration 2021; Lindegren et al 2021), it is now possible to determine whether this trend continues.…”

Cataclysmic Variables in the Second Year of the Zwicky Transient Facility

“…The EDR3 Gaia parallaxes (Lindegren et al 2021) were used to calculate the distances and absolute magnitudes shown in Tables 1 and 2. Paper I, which used the DR2 Gaia parallaxes, showed that the majority of CVs from ZTF had absolute magnitudes at quiescence between 10 and 12, near the faint end of previous results in the literature (Warner 1987(Warner , 1995.…”