Exploring the Radio and γ-Ray Connection in the 1FHL AGN Sample

<p>The first Fermi-LAT catalog of sources above 10 GeV (1FHL) is providing us for the first time with a large, deep and unbiased sample to gather gamma-ray data in the energy range 10-500 GeV, ideal for addressing both the connection between radio and VHE emission and the characterization of the most extreme gamma-ray sourcesIn this talk we focus our attention on the 1FHL blazars in the northern hemisphere, by providing new 5 GHz VLBA observations for the faintest members of the sample, for which we reveal compact radio emission (mas scale angular resolution), and brightness temperature values of the order of 2x10^10 K, which are close to the expected value for equipartition. Moreover, we propose new low-frequency counterparts for 14 unsassociated gamma-ray sourcesWe gather a final sample of 231 1FHL sources with high resolution radio observations. We find that overall the radio VLBI and hard gamma-ray emission (E>10 GeV) appears to be uncorrelated (r=‚àí0.02), even when BL Lacs and FSRQs are considered separately, which is in contrast with what found when lower gamma-ray energies (E>0.1 GeV) are considered. However, when we take into account the single SED classes, high synchrotron peaked objects are the only blazar sub-class showing a strong and significant correlation (r = 0.60, p = 0.0032). We interpret and explain this correlation behavior within the framework of the blazar SED properties.