Radio Emission on Sub-parsec Scales from the Intermediate-mass Black Hole in Ngc4395

The Seyfert 1 nucleus of NGC4395 is energized by a black hole of mass 3.6× 10M⊙ (Peterson et al.), making it one of only two nuclear black holes of intermediate mass, 10−10M⊙, detected in the radio regime. Building upon UV and X-ray evidence for outflows from this Seyfert nucleus, the VLBI High Sensitivity Array was used at 1.4 GHz to search for extended structure on scales greater than 5 mas (0.1 pc). Elongated emission was discovered, extending over 15 mas (0.3 pc) and suggesting an outflow on sub-parsec scales from this intermediate-mass black hole. The Seyfert nucleus is located at the center of an elliptical star cluster, and the elongation position angle of the sub-parsec radio structure is only 19 from the star cluster’s minor axis. Subject headings: galaxies: active — galaxies: individual (NGC 4395) — galaxies: nuclei — galaxies: Seyfert — radio continuum: galaxies