Gaia Data Release 3 (GDR3)
Gaia Data Release 3 (Gaia DR3) was released on 13th of June 2022. The data are available through the Gaia Archive (and through the partner data centres). The Gaia DR3 catalogue builds upon the Early Data Release 3 (released on 3 December 2020) and combines, for the same stretch of time and the same set of observations, these already-published data products, with numerous new data products such as extended objects and non-single stars.
The contents of Gaia DR3 is described below.
Gaia DR3 Content overview (EDR3 + DR3)
The Gaia Early Data Release 3 (Gaia EDR3) enhances the DR2 catalogs by 118.79 million objects. It includes five-parameter astrometric solutions – positions on the sky, parallaxes, and proper motions – for more than 585 million sources, an additional pseudo-colour parameter for 800 million further sources (called six-parameter solution), and an additional 400 million sources with only positions, for a total of more than 1.8 billion sources with a mean G magnitude.
Additionally from the 13th of June 2022, the full Gaia DR3 adds radial velocities for more than 33 million sources (about 4 times more than Gaia DR2). Followed by about 200 millions BP/RP spectra and about 1 million high resolution spectra from the radial velocity spectrometer (RVS). Finally Gaia DR3 publish a huge catalog of objects classification of more than 1.59 billion sources, and a large variaty of smaller specifica catalogs like non-single stars, variable sources, galaxy and QSO candidates, solar system objects, and more.
The Gaia EDR3 release delivers an overall improvement in sky-coverage (almost complete down to 19 mag) and a great improvement in precision of both astrometric and photometric measurements. It spans 34 month of data collection by the Gaia satellite.
Gaia early data release - The Gaia Sky in colour - Image credit: ESA/Gaia/DPAC Image - license: CC-BY-SA 3.0 IGO - Acknowledgement: created by A. Moitinho, University of Lisbon, Portugal
Gaia DR3 in numbers
The below table gives an overview of Gaia Early Data Release 3 in numbers:
| # sources in Gaia (E)DR3 | # sources in Gaia DR2 | # sources in Gaia DR1 | |
| Total number of sources | 1,811,709,771 | 1,692,919,135 | 1,142,679,769 |
| Number of 5-parameter sources | 585,416,709 | 1,331,909,727 | 2,057,050 |
| Number of 6-parameter sources | 882,328,109 | ||
| Number of 2-parameter sources | 343,964,953 | 361,009,408 | 1,140,622,719 |
| Sources with mean G magnitude | 1,806,254,432 | 1,692,919,135 | 1,142,679,769 |
| Sources with mean GBP-band photometry | 1,542,033,472 | 1,381,964,755 | - |
| Sources with mean GRP-band photometry | 1,554,997,939 | 1,383,551,713 | - |
| Gaia-CRF sources | 1,614,173 | 556,869 | 2,191 |
| Sources with radial velocities | 33,812,183 | 7,224,631 | - |
| Variable sources | 10,509,536 | 550,737 | 3,194 |
| Known asteroids with epoch data | 158,152 | 14,099 | - |
| Sources with astrophysical parameters from BP/RP spectra | 470,759,263 | 161,497,595 | - |
| Sources with object classifications | 1,590,760,469 | - | - |
| Mean BP/RP spectra | 219,197,643 | - | - |
| Mean RVS spectra | 999,645 | - | - |
For the full content, please refer to ESAC's documentation: Gaia DR3
Background of the data
Gaia (E)DR3 data is based on data collected between 25 July 2014 and 28 May 2017, spanning a period of 34 months of data collection. As a comparison, Gaia DR2 was based on 22 months of data and Gaia DR1 was based on observations collected in the first 14 months of Gaia's routine operational phase.
The reference epoch for Gaia DR3 (both Gaia EDR3 and the full Gaia DR3) is 2016.0. Remember that the reference epoch is different for each Gaia data release, and that the reference epoch for Gaia DR2 was J2015.5 and for Gaia DR1 was J2015.0.
Positions and proper motions are referred to the ICRS, to which the optical reference frame defined by Gaia DR3 (Gaia-CRF3) is aligned. The time coordinate for Gaia DR3 results is the barycentric coordinate time (TCB).