2007ApJ...657..700D

We report the discovery of a dwarf Seyfert 1 active galactic nucleus (AGN) with a candidate intermediate-mass black hole, hosted by the dwarf galaxy SDSS J160531.84+174826.1 at z=0.032. A broad component of the Hα line with FWHM=781 km/s is detected in its optical spectrum, and a bright, pointlike nucleus is evident from a Hubble Space Telescope (HST) imaging observation. Nonthermal X-ray emission is also detected from the nucleus. The black hole mass, as estimated from the luminosity and width of the broad Hα component, is about 7x10⁴ M_☉. The host galaxy appears to be a disk galaxy with a boxy bulge or nuclear bar. With an absolute magnitude of M_R=-17.8 (M_B=-16.4), it is among the least luminous host galaxies ever identified for a Seyfert 1.