Gaia: The Galaxy in six (and more) dimensions

Abstract

The ESA cornerstone mission Gaia was successfully launched in 2013, and is now scanning the sky to accurately measure the positions and motions of about two billion point-like sources of 3 V 20.5 mag, with the main goal of reconstructing the 6D phase space structure of the Milky Way. The typical uncertainties in the astrometry will be in the range 30-500 µas. The sky will be repeatedly scanned (70 times on average) for five years or more, adding the time dimension, and the Gaia data are complemented by mmag photometry in three broad bands, plus line-of-sight velocities from medium resolution spectroscopy for brighter stars. This impressive dataset is having a large impact on various areas of astrophysics, from solar system objects to distant quasars, from nearby stars to unresolved galaxies, from binaries and extrasolar planets to light bending experiments. This invited review paper presents an overview of the Gaia mission and describes why, to reach the goal performances in astrometry and to adequately map the Milky Way kinematics, Gaia was also equipped with state-of-the-art photometers and spectrographs, enabling us to explore much more than the 6D phase-space of positions and velocities. Scientific highlights of the first two Gaia data releases are briefly presented.

The Gaia spectrophotometric standard stars survey – V. Preliminary flux tables for the calibration of Gaia DR2 and (E)DR3

“…The ESA astrometric mission Gaia 1 (Gaia Collaboration 2016a) has revolutionized our view of the Milky Way and its data are bringing progress in almost every area of astrophysical research (Perryman et al 2001;Gilmore 2018;Pancino 2020). Three data releases were published so far, 2 with a constant increase in the data quality and in the quantity of data products (Gaia Collaboration 2016b, 2020.…”

“…The ESA astrometric mission Gaia 1 (Gaia Collaboration 2016a) has revolutionized our view of the Milky Way and its data are bringing progress in almost every area of astrophysical research (Perryman et al 2001;Gilmore 2018;Pancino 2020). Three data releases were published so far, 2 with a constant increase in the data quality and in the quantity of data products (Gaia Collaboration 2016b, 2020. Several thousand publications in different areas of astrophysical research cite or use Gaia data, from Solar system objects and fundamental physics to the study of stars, stellar clusters, the Milky Way, and the Local Group.…”

Understanding the evolution of radiation damage on the Gaia CCDs after 72 months at L2

“…Given the amount of fuel on board, Gaia could continue operating into 2024, over ten years since its launch date and double the original mission time, all due to the current exemplary levels of performance. 26 Figure 15 shows an idea of how much the pre-flight predictions influenced the testing. Due to the earlier launch date and the 90% confidence levels for testing, pre-flight testing occurred with high irradiations of protons on comparative energy levels to solar protons.…”

The Gaia spectrophotometric standard stars survey -- V. Preliminary flux tables for the calibration of Gaia DR2 and (E)DR3

“…The ESA astrometric mission Gaia 1 (Gaia Collaboration et al 2016a) has revolutionized our view of the Milky Way and its data are bringing progress in almost every area of astrophysical research (Perryman et al 2001;Gilmore 2018;Pancino 2020). Three data releases were published so far 2 , with a constant increase in the data quality and in the quantity of data products (Gaia Collaboration et al 2016bCollaboration et al , 2018Collaboration et al , 2020.…”