ASCA observations of the unidentified EGRET source 2EGS J1418-6049

In a 40 ks ASCA exposure of the GeV EGRET error box of the unidentified source 2EGS J1418-6049, we observe diffuse emission surrounding several unusual hard spectrum X-ray sources. Two of these sources have plausible identifications as absorbed active galactic nuclei (AGNs). Our best candidate for the EGRET source counterpart is an extended nonthermal object, which we argue to be a wind nebula surrounding a pulsar with characteristic age tau similar to 10(4.5) yr. We also discuss optical and radio data supporting the proposal that the GeV source is a young energetic pulsar. This analysis demonstrates how hard X-ray observations can significantly constrain the nature of GeV gamma-ray sources.