The GRB Investigations by ESA Satellite Gaia

The ESA satellite in development Gaia to be launched in 2011 will focus on highly precise astrometry of stars and all objects down to limiting magnitude 20. Albeit focusing on astrometry related matters, the satellite will also provide photometric and spectral information and hence important inputs for various branches of astrophysics. Within the Gaia Variability UnitCU7 and related work package Specific Object Studies there has been a sub‐work package accepted for optical counterparts to celestial high‐energy sources, a category which includes the optical counterparts (i.e. optical transients and optical afterglows, including counterparts of XRFs and yet hypothetical orphan afterglows) of GRBs, and also microquasars. Although the sampling of photometric data will not be optimal for this type of work, the strength of Gaia in such analyses is the fine spectral resolution (spectro‐photometry) which will allow the correct classification of related triggers. The possibilities to detect and to analyze optical ...