Radio and millimeter spectral properties of newly identified high-energy gamma-ray sources

We have conducted a variability study of several radio/millimeter sources t hat are possible counterparts of high-energy gamma-ray sources detected by EGRET. Some sources were possibly variable during this period. The radio so urce with the highest spectral and temporal coverage, PMN J0850-1213, behav es in a manner consistent with the shocked-jet models for extragalactic rad io sources proposed in the literature. In addition, GB 105536.5 + 564424 is an X-ray-selected BL Lac object, and, if the identification with the EGRET source is correct, it would be the most distant such object detected at en ergies > 100 MeV (z = 0.41). A future detection in the TeV range, as well, could provide an important constraint on absorption of very high energy gam ma rays by the intergalactic infrared photon held. We also discuss the poss ibility that this object is a gravitationally microlensed active galactic n ucleus, with the foreground lensing object at z = 0.144.