The large catalog of quasars and the LQAC-3 compilation
Résumé
Due to their point-like aspect and to their lack of significant proper motion, quasars represent the ideal objects for modeling quasi-inertial directions in space. For that reason the present primary conventional reference frame, the ICRF-2, is constructed from the set of the celestial coordinates of 3,414 extra-galactic objects, most of them being quasars. Thus each newly discovered quasar must be considered as a potential ideal astrometric marker. Therefore it looks interesting to compile in a regular basis all the recorded quasars at a given epoch. This constitutes the aim of the LQAC (Large Quasar Astrometric Catalogue). We present here the third release of this catalog named as the LQAC-3, insisting on the related strategy of compilation and on the various items it contains in the fields of astrometry, redshift, photometry, morphology and magnitude.