Spatially resolved ultraviolet spectroscopy of the liner NGC 3998

Results of IUE observations of the Liner NGC 3998 are reported. Spatial structure in the long wavelength emission is apparent; the spatial profiles from the LWP line-by-line images show a two-component structure, with an unresolved central component superimposed on extended underlying emission. The LWP emission was separated into component spectra. The unresolved component spectrum is considerably flatter than the extended component spectrum, which is dominated by fairly late type stars (late F to early G). The unresolved component also shows strong C II) 2326 A and broad Mg II 2800 A emission.The width of the Mg II emission is 8600 km/sec, and its profile agrees quite well with the broad wings of the H alpha emission. The results support the idea that NGC 3998 may contain a dwarf Seyfert nucleus.