High-velocity line emission in the narrow-line region of NGC 4151

Narrowband imaging of the nuclear region of NGC 4151 with the Hubble Space Telescope is presented. The filter bandpasses isolate line emission in vari ous high-velocity ranges in several ions. Slitless and long-slit spectra of the region with the Space Telescope Imaging Spectrograph also indicate the locations of high-velocity gas. These emission regions are faint and inter spersed among the bright emission clouds seen in direct images. They have r adial velocities up to 1400 km s(-1) relative to the nucleus and are found in both approach and recession on both sides of the nucleus. This contrasts strongly with the bright emission-line clouds, which have been discussed p reviously as showing bidirectional outflow with velocities within 400 km s( -1) of the nucleus. We discuss the possible connections of the high-velocit y material with the radio jet and the nuclear radiation.