Determining the nature of the unassociated Fermi-LAT gamma-ray sources

The Fermi satellite opened new horizons in gammaray astronomy with thedetection of already 1451 sources in the first 11 months of science operationsof the LAT instrument. While some of them are identified as gammaray pulsarsand AGNs, other are just associated with potential gammaray emitters. However,many of the LAT sources have no potential association yet. Their nature isunknown and can only be investigated through multiwavelength observations. Herewe propose to map the error boxes of selected LAT sources in Xrays with XMM andin the optical with the VLT. On the basis of their Xray/optical properties, foreach LAT source we will then be able to single out the Xray source which is apotential gammaray emitter. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]