Final Report Summary - GAIA-ESO-MW (The Gaia-ESO Milky Way Survey)
The primary ambition of this project was to deliver the Gaia-ESO Public Spectroscopic Survey. This Survey is the first large-telescope spectroscopic stellar survey ever implemented, is the largest large-telescope project ESO has attempted, and is a Europe-wide collaboration of 500 scientists in 100 Institutes. It is jointly led by the ERC PI (Gerry Gilmore) and Prof Sofia Randich (Arcetri Observatory Italy). The science ambition was to sample all stellar populations in the Milky Way, young star clusters to the oldest field stars, targeting up to 100,000 stars with up to 200,000 spectra. We achieved 115,000 stars and 202,000 spectra. The optimistic second goal was to bring together the European-wide community of stellar spectroscopists to share and enhance their techniques, identify and improve their common assumptions, and build a collaborative Europe-wide partnership ready for the next generation facilities. Amazingly, that has been achieved.
Stellar spectroscopy of high formal precision has often been limited in its impact by systematic scale differences between techniques and different stellar types. These differences are often of the same amplitude as the differences between competing astrophysical interpretations of the data, limiting progress. They are particularly important in major spectroscopic surveys, where calibration issues can limit huge project investments. In the current era of Gaia, where the first all-sky studies are viable, ensuring follow-up studies in different regions and hemispheres becomes especially important. The Gaia-ESO Survey was designed to mitigate these systematic limitations, and so to enhance the long-term impact of the project. We achieved this by including all the major European stellar spectroscopy groups in the project, using all suitable for stars of a given type, and combining and homogenising the outputs on to a consistent calibrated scale. Given the size of Gaia-ESO, this leaves a legacy which can be implemented world-wide. We additionally invested considerable effort to identify and mitigate the cause of these systematics, developing and publishing new lists of the fundament inputs to processing systems.
In addition to that methodological legacy astrophysical (temperature, gravity) and physical (radial velocity, rotation velocity) parameters, stellar abundances from all the main nucleosynthetic families for many elements, and systemic properties of many star clusters covering a wide range in position and age have been derived. All this information will be published open-source and maintained in the ESO archive a a legacy data set. At the end of the ERC grant nearly 200 project papers have been published, with many more to follow, while a cohort of excellent young scientists have been trained and are building their own academic careers.
Stellar spectroscopy of high formal precision has often been limited in its impact by systematic scale differences between techniques and different stellar types. These differences are often of the same amplitude as the differences between competing astrophysical interpretations of the data, limiting progress. They are particularly important in major spectroscopic surveys, where calibration issues can limit huge project investments. In the current era of Gaia, where the first all-sky studies are viable, ensuring follow-up studies in different regions and hemispheres becomes especially important. The Gaia-ESO Survey was designed to mitigate these systematic limitations, and so to enhance the long-term impact of the project. We achieved this by including all the major European stellar spectroscopy groups in the project, using all suitable for stars of a given type, and combining and homogenising the outputs on to a consistent calibrated scale. Given the size of Gaia-ESO, this leaves a legacy which can be implemented world-wide. We additionally invested considerable effort to identify and mitigate the cause of these systematics, developing and publishing new lists of the fundament inputs to processing systems.
In addition to that methodological legacy astrophysical (temperature, gravity) and physical (radial velocity, rotation velocity) parameters, stellar abundances from all the main nucleosynthetic families for many elements, and systemic properties of many star clusters covering a wide range in position and age have been derived. All this information will be published open-source and maintained in the ESO archive a a legacy data set. At the end of the ERC grant nearly 200 project papers have been published, with many more to follow, while a cohort of excellent young scientists have been trained and are building their own academic careers.