Letters of Intent received in 2014

LoI 2016-231
Unveiling the Gaia sky: science from the first data release

Topics

- The Gaia mission: presentation of the status and performances after the first 2.5 years of scientific observations
- The first Gaia Data Release and the Hundred Thousand Proper Motions catalogue
- First scientific results of the Gaia mission expected on:
(i) Astrometry and Reference frames
(ii) Solar system objects & Gaia alerts
(iii) Galactic and stellar physics & the Hundred-Thousand-Proper-Motion project for the Hipparcos stars

Rationale

The ESA Gaia mission is astrometrically, photometrically and spectroscopically surveying the full sky since july 2014. This survey will be complete to magnitude 20 for the astrometry and photometry and to magnitude 16 for the spectroscopy (~1 billion and ~150 millions sources expected, respectively).
The Gaia astrometry will allow stellar distance measurements with unprecedented accuracy, and with the complement of radial velocities, it will provide the full kinematic information of the targets. Moreover, the photometric and spectroscopic data will be used to classify objects and astrophysically characterize stars.

The first Gaia data release (GDR1) is foreseen for mid 2016. It will consist of: (i) positions and magnitudes for about 900,000,000 single-stars, (ii) ecliptic-pole data collected during the commissioning phase, (iii) the catalogue of the Hundred Thousand Proper Motion (HTPM) project, containing for the Hipparcos stars highly accurate proper motions derived from the combination of Gaia and Hipparcos positions. Moreover, since the beginning of the mission, photometric science alerts will have been released and near-Earth-asteroid
information communicated at short notice.

This symposium will be organised in late 2016. It will be the occasion to review the first 2.5 years of Gaia activities and to present and discuss the first scientific results derived from GDR1, about six months after its delivery. The symposium will also prepare the astronomical community for the scientific exploitation of the second data release, planned a couple of months after the symposium.

We plan a five day symposium, with about 10 sessions, focussing on different aspects of Gaia. First, the overall status of the mission will be detailed with an emphasis on the operational/calibration aspects impacting the different data releases and the expected final accuracies. This will be
followed by a detailed description of GDR1 and the expected contents of GDR2. Subsequently the meeting will focus on the science results based on GDR1 data, and in particular on studies related to solar system objects and Galactic and
stellar physics. These fields should be primarily impacted by the GDR1 data. A specific session will be also dedicated to the ground-based spectroscopic surveys that benefit from and have been partly motivated by Gaia (Gaia-ESO Survey, HERMES,...). As usual, we plan to have both review and summary talks, as well as contributed talks and posters.

In summary, this symposium will mark the first step of the Gaia revolution in our understanding of Solar system bodies, stellar astrophysics, the Milky Way and many other research topics. Finally, the conference will also be a tribute to François Mignard, chair of the Gaia Data Processing and Analysis Consortium since its formation until the end of 2012.