Radio and Gamma-ray Properties of Extragalactic Jets from the TANAMI Sample
Résumé
The TANAMI program has been observing parsec-scale radio jets of southern (declinationsouth of - 30deg.)gamma-raybright AGN, simultaneously with Fermi/LAT monitoring of theirgamma-rayemission, via high-resolution radio imaging with Very Long Baseline Interferometrytechniques. We present the radio and gamma-rayproperties of the TANAMI sources based on oneyear of contemporaneous TANAMI and Fermi/LAT data. A large fraction (72%)of the TANAMI sample can be associated with bright gamma-ray sources for this timerange. Association rates differ for different optical classes with all BLLacs, 76% ofquasars, and just 17% of galaxies detected by the LAT. Upper limits were established onthe gamma-rayflux from TANAMI sources not detected by LAT. This analysis led to the identification ofthree new Fermi sources whose detection was later confirmed. Thegamma-ray andradio luminosities are related by L_gamma ∝ L_r^0.89+-0.04. The brightness temperatures of the radio coresincrease with the average gamma-ray luminosity and the presence of brightnesstemperatures above the inverse Compton limit implies strong Doppler boosting in thosesources. The undetected sources have lower gamma/radio luminosity ratios and lower contemporaneousbrightness temperatures. Unless the Fermi/LAT-undetected blazars are muchgamma-ray-fainter than theFermi/LAT-detected sources, their gamma-ray luminosity should notbe significantly lower than the upper limits calculated here.