(Technical Astrium France in Toulouse, working on the assembly of mosaic CCD on the satellite ‘Gaia’. Image: Astrium.)

The human eye can see at a glance several thousand stars on a clear night. Gaia will be able to study one billion stars within the Milky Way and neighboring galaxies, over the five year duration of its mission . This way, you create a catalog record which specify the brightness, spectral characteristics and three-dimensional position and displacement of each object observed.

To study the most distant stars, whose brightness is about a million times smaller than the human eye can detect, Gaia has a CCD detector consists of 106, an advanced version of the sensors can be found in the conventional digital cameras. The detector designed for the mission Gaia is formed by 106 CCD developed specifically for this mission by the company e2v Technologies, Chelmsford, UK. Each of them is a bit smaller than a credit card (4.7 x 6 cm) and thinner than a human hair.

Thus, the focal plane of Gaia , which collects the light captured by telescopes, is formed by a mosaic of CCD 0.5 x 1.0 m, which has just been assembled in the premises of the prime contractor for the mission, Astrium France in Toulouse. The full mosaic has seven rows of CCD to increase the sensitivity of the sensors will be maintained at a temperature of -110 ° C. Gaia will operate at a million miles from Earth in the direction opposite the Sun, the so-called point Lagrange, in which the Earth-Sun gravitational forces are balanced by creating a stable point in space.

As telescopes Gaia made ​​a sweep of the sky, the light of each star will reach the focal plane to map its position and movement in three dimensions, color and intensity and their emission spectrum. The launch of Gaia is scheduled for 2013. This mission will obtain three-dimensional map of the 1% of the stars in our Galaxy, which will help reveal the composition, formation and evolution of the Milky Way. Gaia will also study a number of other celestial bodies, from small objects in our own solar system to distant quasars and galaxies near the limits of the observable universe.

The Gaia space catalog

The Gaia mission of ESA will generate about a petabyte of information, that is a million gigabytes, which must be processed and analyzed to obtain results. Therefore, the Consortium has been formed of Analysis and Data Processing (CAPD). This consortium is responsible for processing satellite data during the mission and, once finished, will continue its work for three years to transform information into astrophysical data to be published in several catalogs.

Specifically, a team led by Professor Department of Astronomy and Meteorology of the UB Jordi Torra will process and manage the first science data from the satellite. Also of UB, Prof. Carme Jordi leads the group involved in the treatment of photometric data and the controller module simulations of the mission is Professor Xavier Luri the same department.

With the mission simulator test the validity of the proposed scientific solutions and approaches are assessed techniques that have made the industries that built the satellite. The simulator makes heavy use of MareNostrum. In parallel data processing, and following the traditional lines of research group, Professor Francesca Figueras directs the preparation of the scientific exploitation of the data for the understanding of the Milky Way.

Source: UB