Gaia is the high accuracy astrometric survey mission of ESA, successfully launched into an Earth-Sun L2 orbit on 19 December 2013. Gaia is surveying the entire sky down to a magnitude of about G=20, which includes or order one billion stars, or about 1% of the Galactic stellar population. Together with the stellar sample, several million galaxies, perhaps half a million quasars and thousands of solar system objects will also be detected. In addition to astrometric information, radial velocities will be measured for the brightest objects, and astrophysical parameters will be determined from low resolution spectra.
The Data Processing and Analysis Consortium (DPAC) is responsible for the data handling from the mission. DPAC is divided into nine subgroups, called coordinating units, each of which is responsible for a different aspect of the Gaia data processing.
The MPIA hosts one of two Gaia teams in Heidelberg (the other is at ARI), funded primarily by the German space agency, the DLR. This team plays a leading role in CU8 "Astrophysical Parameters", by developing algorithms to classify and interpret the Gaia data. We are building the Gaia classification machine - the "Discrete Source Classifier (DSC)" - a probabilistic classifier to identify all Gaia sources. We also provide the algorithm for inferring the physical parameters for single stars (called "GSP-Phot") and for binary stars (called "MSC") using the BP/RP spectra and parallaxes. The group additionally maintains the CU8 data model and contributes to another coordination unit, CU9. In parallel to Gaia we are involved in related projects involving the application of statistical data analysis methods to large data sets.