Gaia Early Data Release 3

Abstract

Context. We present the early installment of the third Gaia data release, Gaia EDR3, consisting of astrometry and photometry for 1.8 billion sources brighter than magnitude 21, complemented with the list of radial velocities from Gaia DR2. Aims. A summary of the contents of Gaia EDR3 is presented, accompanied by a discussion on the differences with respect to Gaia DR2 and an overview of the main limitations which are present in the survey. Recommendations are made on the responsible use of Gaia EDR3 results. Methods. The raw data collected with the Gaia instruments during the first 34 months of the mission have been processed by the Gaia Data Processing and Analysis Consortium and turned into this early third data release, which represents a major advance with respect to Gaia DR2 in terms of astrometric and photometric precision, accuracy, and homogeneity. Results. Gaia EDR3 contains celestial positions and the apparent brightness in G for approximately 1.8 billion sources. For 1.5 billion of those sources, parallaxes, proper motions, and the (G BP − G RP ) colour are also available. The passbands for G, G BP , and G RP are provided as part of the release. For ease of use, the 7 million radial velocities from Gaia DR2 are included in this release, after the removal of a small number of spurious values. New radial velocities will appear as part of Gaia DR3. Finally, Gaia EDR3 represents an updated materialisation of the celestial reference frame (CRF) in the optical, the Gaia-CRF3, which is based solely on extragalactic sources. The creation of the source list for Gaia EDR3 includes enhancements that make it more robust with respect to high proper motion stars, and the disturbing effects of spurious and partially resolved sources. The source list is largely the same as that for Gaia DR2, but it does feature new sources and there are some notable changes. The source list will not change for Gaia DR3. Conclusions. Gaia EDR3 represents a significant advance over Gaia DR2, with parallax precisions increased by 30 per cent, proper motion precisions increased by a factor of 2, and the systematic errors in the astrometry suppressed by 30-40% for the parallaxes and by a factor ∼2.5 for the proper motions. The photometry also features increased precision, but above all much better homogeneity across colour, magnitude, and celestial position. A single passband for G, G BP , and G RP is valid over the entire magnitude and colour range, with no systematics above the 1% level

All-sky analysis of astrochronometric signals induced by gravitational waves

“…The white noise amplitude is set such that the effective angular resolution for each star is 10 µas. A conservative estimate for N lies within this range for stateof-the-art surveys, such as the results expected by the final data release for the GAIA mission [21]. We also show the angular spectra obtained from the realisations which agree with the input values.…”

“…This suggests that a survey of some 10 9 stars, over several years at angular precision of a few µas, would achieve upper bounds on the cosmological background of GWs comparable to limits currently imposed by LIGO-VIRGO observations [20] at higher frequencies. Today, the GAIA [21] satellite survey is already operating with a few orders of magnitude of this baseline, and similar missions in the future may go well beyond this [22]. Different approaches have been adopted in defining the formalism through which the signal of isotropic GWs is imprinted in both timing residual and astrometric observations, including their induced anisotropies.…”

Multi-messenger parameter inference of gravitational-wave and electromagnetic observations of white dwarf binaries

“…In the future, we aim to adapt our framework to enable population level studies to bring us closer to the goal of being capable of simulating realistic gravitational-wave data for existing binary systems to make as accurate projections for LISA as possible. Additionally, we will aim to incorporate more sophisticated simulations of spectroscopic data as well as simulated distance estimates such as those provided by Gaia (Brown et al 2021) into the parameter recovery portion of our pipeline, with the goal of automating the process for the white dwarf binaries that experiments such as ZTF are finding (Burdge et al 2020).…”

Gravity or turbulence V: Star forming regions undergoing violent relaxation

“…We have derived stellar masses and ages for a sample of kinematic candidates selected using the astrometric observables of parallax (𝜛) and proper motions (𝜇 𝛼 , 𝜇 𝛿 ) from GAIA-EDR3 (Gaia Collaboration et al 2021) in the chosen studied region (hereafter, the ONC region: 83.0 • ≤ 𝛼 𝐽 2000 ≤ 84.5 • and −6.5 • ≤ 𝛿 𝐽 2000 ≤ −4.0 • ). We apply the selection criteria used by Hernandez et.…”

“…In brief, the MassAge code uses spectral types (or effective temperatures), photometry (𝐺 𝑝 , 𝑅 𝑝 , and 𝐵 𝑝 ) and parallaxes from GAIA-EDR3 (Gaia Collaboration et al 2021), and the 𝐽 and 𝐻 magnitudes from 2MASS (Cutri et al 2003). The uncertainties in the estimated values are obtained using the Monte Carlo method of error propagation (Anderson 1976).…”