SDSS J160531.84+174826.1: A Dwarf Disk Galaxy with an Intermediate-Mass Black Hole
Yuan, Weimin; Zhou, Hongyan; Wang, Huiyuan; Fan, Lulu; Dou, Liming; Wang, Tinggui; Wang, Junxian; Dong, Xiaobo; Shan, Hongguang; Lu, Honglin
China, United States
Abstract
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-1 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 7×104 Msolar. The host galaxy appears to be a disk galaxy with a boxy bulge or nuclear bar. With an absolute magnitude of MR=-17.8 (MB=-16.4), it is among the least luminous host galaxies ever identified for a Seyfert 1.