The construction of the large quasar astrometric catalogue (LQAC)

We gather the 12 largest quasar catalogues (4 from radio interferometry programs, 8 from optical survey) and we carry out systematic cross-identifications of the objects to obtain their best position estimates, and to provide physical information at both optical and radio wavelengths. This catalogue compilation designated LQAC, gives equatorial coordinates of 113666 quasars with magnitudes at 9 bandwidths, 5 radio fluxes, redshift and absolute magnitude. We made use of VO tools like Aladin for preliminary studies. For cross idenfication, data processing and validation, we made use of two different software packages with the same parameters and strategy : VO Topcat with Stilts and homemade Fortran programs.