An identification for "Geminga" (2CG 195+04) : The optical counterpart of 1E 0630+178, a unique object in the gamma-ray source error box.

The results of a deep CCD search for the counterpart of the Einstein Observatory X-ray source 1E 0630+178, itself the probable counterpart of the COS B high-energy gamma source 2CG 195+04 ('Geminga'), are reported. An object has been found as the only candidate in the approximately 30-sq arcsec error box. Its magnitude, mv = about 21.3 + or - 0.2, yields a high fx/fv ratio which, coupled with other properties of the X-ray source, renders this an object of unique interest, especially if it is responsible for the high gamma flux.