Identification of the Early Fermi /Lat Gamma-Ray Bright Objects With Extragalactic Vlbi Sources

A list of 205 γ-ray strong objects was reported recently as a result of a three-month integration with the Large Area Telescope on board the Fermi Gamma-Ray Space Telescope . We attempted identification of these objects, cross-correlating the γ-ray positions with very long baseline interferometry (VLBI) positions of a large all-sky sample of extragalactic radio sources selected on the basis of their parsec-scale flux density. The original associations reported by the Fermi team are confirmed, and six new identifications are suggested. A Monte Carlo analysis shows that the fraction of chance associations in our analysis is less than 5%, and confirms that the vast majority of γ-ray bright extragalactic sources are radio-loud blazars with strong parsec-scale jets. A correlation between the parsec-scale radio and γ-ray flux is supported by our analysis of a complete VLBI flux-density-limited sample of extragalactic jets. The effectiveness of using a VLBI catalog to find associations between γ-ray detections and compact extragalactic radio sources, especially near the Galactic plane, is demonstrated. It is suggested that VLBI catalogs should be used for future identification of Fermi /LAT objects.