  Active galactic nuclei are the most luminous persistent (non-transient, even
if often variable) objects in the Universe. They are bright in the entire
electromagnetic spectrum. Blazars are a special class where the jets point
nearly to our line of sight. Because of this special geometry and the bulk
relativistic motion of the plasma in the jet, their radiation is enhanced by
relativistic beaming. The majority of extragalactic objects detected in
gamma-rays are blazars. However, finding their counterparts in other wavebands
could be challenging. Here we present the results of our 5-GHz European VLBI
Network (EVN) observation of the radio source J1331+2932, a candidate blazar
found while searching for possible gamma-ray emission from the stellar binary
system DG CVn (Loh et al. 2017). The highest-resolution radio interferometric
measurements provide the ultimate tool to confirm the blazar nature of a radio
source by imaging compact radio jet structure with Doppler-boosted radio
emission, and give the most accurate celestial coordinates as well.
