Gaia Calibration and Relativity Tests

Principal Investigators:
Prof. Dr. habil. Sergei A. Klioner
Project Manager:
Prof. Dr. habil. Sergei A. Klioner
additional Affiliation:
HPC Platform used:
Date published:
Dr.-Ing. Enrico Gerlach, Dipl. Inf. Robin Geyer, Dipl. Inf. Hagen Steidelmüller
The ESA Gaia satellite mission delivers ultra-high precision data for astronomy and fundamental physics. Converting the raw data to a usable form is one of the largest computational challenges ever solved in observational astronomy. The local astronomy group at TUD is responsible for the core computations, calibration and relativistic modeling of the data and part of the European Gaia data consortium. The usage of the local HPC system is absolutely essential for this work.

The ESA cornerstone satellite mission Gaia -- launched in December 2013 -- delivers high-precision astrometric, photometric and spectroscopic data of around two billion celestial objects. The main goal of the mission is to generate a map of our Galaxy: a catalog of positions, proper motions and parallaxes with an unique accuracy of up to a few microarcseconds (about 10 picoradians). The catalog is a result of the so-called astrometric global iterative solution (AGIS). The AGIS solution is a least-squares fit of over 10 billion scientific parameters using about 1000 billions of observations. A multitude of calibrations and nuisance parameters have to be taken into account. The quality and stability checks should be also routinely made. The size of the problem makes it indispensable to use the most efficient implementations of all algorithms.
Lohrmann-Observatory at TU Dresden hosts one of two research groups in the Data Processing and Analysis Consortium (DPAC) which are able to run the AGIS software and produce some parts of the resulting Gaia catalog. Furthermore, the group is responsible for some special sorts of instrumental calibrations as well as for tests of fundamental physical laws (in particular laws which are related to general relativity) using observational data of the Gaia mission. One part of the workload are tests using artificial data to understand and simulate a multitude of physical effects and their detectability by Gaia. The other part of the workload are the computations of the AGIS solutions with different calibrations and the interrelation of those calibrations with the astrometric solution and its accuracy. The usage of the ZIH HPC systems has strongly supported these activities and has enabled significant improvements in the final Gaia data products.
The results of Early Data Release 3 can be found here: 

Institute / Institutes:
TU Dresden
Sky density of the largest and cleanest quasar catalog constructed by the team in Dresden based on the Gaia data.