Gaia in the UK

Taking the Galactic Census


Gaia data releases

The Gaia data accumulation is split into segments of roughly one year in length. The processing of the data is taking place in cycles, where each cycle covers all completed data segments up to an agreed date. The Gaia data is self-calibrating, in other words, it defines its own "system". Such systems are created for the astrometric as well as the photometric data. In each cycle the system is re-defined, getting rapidly closer to the final fully converged system. The next steps then involve connecting these internal Gaia systems to ground-based systems.  For the astrometric data this amounts to establishing the celestial reference system, in the photometric data this involves the detailed calibration of the Gaia pass bands. The great advantage of this approach is that a system is obtained with well-defined internal accuracy, and a clear transformation is established to define the external (or absolute) accuracies.

Gaia Data Release 1

Release date: 14 September 2016.

Gaia DR1 catalogue contains astrometric and photometric data for over 1 billion sources brighter than magnitude 20.7 in Gaia's photometric G-band (white light - from about 350 to 1000 nanometres). Gaia DR1 is based on observations collected between 25 July 2014 and 16 September 2015. See Gaia Data Release 1 for more information.

Gaia Data Release 1 data

Gaia DR1 data is available from the ESA Gaia Archive and from the main partner data centres:

Gaia Data Release 2

Release date: 25 April 2018.

Gaia DR2 data is based on data collected between 25 July 2014 (10:30 UTC) and 23 May 2016 (11:35 UTC), spanning a period of 22 months of data collection (or 668 days), as compared to Gaia DR1 which was based on observations collected in the first 14 months of Gaia's routine operational phase.
The reference epoch for Gaia DR2 is J2015.5 (with respect to the J2015.0 epoch for Gaia DR1). Positions and proper motions are referred to the ICRS, to which the optical reference frame defined by Gaia DR2 is aligned. The time coordinate for Gaia DR2 results is the barycentric coordinate time (TCB).

See Gaia Data Release 2 for more information.

Gaia DR2 data

The Gaia DR2 data can be accessed at:

Direct data downloads

Gaia data can also be downloaded directly in CSV format from .

Gaia data release schedule

Visit Gaia Data Release Scenario for more information about Gaia data release schedule.

Gaia Photometric Science Alerts

The Gaia Science Alerts (GSA) project is searching for transient events (a transient is anything in the sky which appears, disappears or changes) in the data from Gaia, and publishes transient alerts to the world in real time on the Gaia Photometric Science Alerts website.

Extensive background information about each transient is also available from GSA website. This information includes light curves and light curve data for all transients, and spectra obtained with Gaia's blue and red photometers (BP/RP spectra) are available for most of the alerts. The spectra are uncalibrated – see Gaia spectra for information on how to interpret these spectra and some examples.

More information about the Gaia Photometric Science Alerts project, including observing advice, can be found in Alerts section of this website.

Solar System Objects

Gaia Follow-Up Network for Solar System Objects (Gaia-FUN-SSO)

The Gaia Follow-Up Network for Solar System Objects (Gaia-FUN-SSO) has been set up to coordinate ground-based observations on alert triggered by the data processing system during the mission for the confirmation of newly detected moving objects or for the improvement of orbits of some critical targets. Gaia scans the sky following a predefined scanning law and such ground-based observations are required to avoid the loss of newly detected Solar System objects and to facilitate their subsequent identification by the satellite.

The alerts, including the ephemeris to help finding the targets, are published on Gaia-FUN-SSO  website, where they can be accessed by the registered members of the Gaia Follow-up network. The network currently consists in about 80 observers in 27 observing sites, spread all over the world (November 2016).

Gaia Groundbased Observational Service for Asteroids (Gaia-GOSA)

The Gaia Groundbased Observational Service for Asteroids (Gaia-GOSA) is a web service to coordinate observers with small to medium size telescopes (so mainly amateur astronomers) with the goal of gathering photometric light curves of a selection of asteroids.
As an observer you can register for free at the Gaia-GOSA website. After providing instrument setup and location, the website will compute what asteroids are visible to the entered observer for a given date, and results will be displayed while giving priority to two kinds of targets:

  • Hot targets: these are targets that are scientifically interesting targets being observed by Gaia within the next 24 hours.
  • Follow-up targets: asteroids with existing observations but with missing segments of the lightcurves, and thus with a need for follow-up observations.

After a successful observation, users can submit their raw frames, which are then processed and analysed by the Gaia-GOSA team. First observations of the Gaia-GOSA service were obtained in 2016. So far (as of November 2017) more than 300 light curves have been gathered by Gaia-GOSA users and data are now being processed. The data gathered through this service will be used to validate Gaia measurements of asteroids but will also enhance their scientific exploitation.
The service was developed by Adam Mickiewicz at the University of Poznań and a Polish IT company iTTi, with collaboration of Gaia DPAC members at the Observatoire de la Côte d'Azur and from the University of Barcelona, under the ESA Contract "Gaia-GOSA: An interactive service for asteroid follow-up observations". Read more about Gaia-GOSA.

Gaia Object Generator and Gaia Universe Model Snapshot

Gaia Object Generator (GOG) 18 and a new version of the Gaia Universe Model Snapshot (GUMS-18) are now available from Gaia Simulations.


Page last updated: 09 August 2018