1ST 7-MM VLBI OBSERVATIONS OF THE PECULIAR SUPERLUMINAL RADIO-SOURCE 4C-39.25

On sub-milliarcsecond to milliarcsecond scales the quasar 4C 39.25 consists of two ''stationary'' jet components a and c between which a component b is moving superluminally eastward towards a. From global VLBI observations at 7 mm we have obtained the first image of 4C 39.25 at this wavelength. The high angular resolution of 7 mm-VLBI maps allows us to follow the motion of b towards a to separations not resolvable by VLBI-observations at longer wavelengths. The present observations also confirm the existence of a new jet component d detected recently with VLBI at 1.3 cm wavelength. The component is located approximately 2.7 mas west of a and seems to have an inverted spectrum between 1.3 cm and 7 mm. We suggest that d is either the ''core'' of 4C 39.25 or is a recently ejected new jet component with a time-evolving spectrum.