Neighbors came to the aid of a University of Pennsylvania archeology professor who was robbed at gunpoint earlier tonight, police sources said. The 52-year-old professor, whose name was not released, was approached by two thieves – ages 12 and 15 – near his car on Windsor Avenue near 47th Street at about 7:45 p.m. The older crook aimed a handgun at the professor, which is when several residents on Windsor Avenue came out of their houses and shouted at the young robbers, the sources said. The suspects ran off, but were apprehended minutes later by 18th District cops who responded to neighbors’ 9-1-1 calls. They were charged with robbery and weapons offenses, sources said.