SDSS J160531.84+174826.1: A Dwarf Disk Galaxy with an Intermediate-Mass Black Hole

• Published in: The Astrophysical journal Vol. 657; no. 2; pp. 700 - 705
• Main Authors: Dong, Xiaobo, Wang, Tinggui, Yuan, Weimin, Shan, Hongguang, Zhou, Hongyan, Fan, Lulu, Dou, Liming, Wang, Huiyuan, Wang, Junxian, Lu, Honglin
• Format: Journal Article
• Language: English
• Published: Chicago, IL IOP Publishing 10.03.2007; University of Chicago Press
• Subjects: Astronomy; Earth, ocean, space; Exact sciences and technology; Active galaxies; Seyfert galaxies; galaxies: Seyfert; galaxies: dwarf- galaxies: individual (SDSS J160531.84+174826.1); Dwarf galaxies; Black holes; galaxies: active; Disk galaxies; Galaxy nuclei; Cosmology; galaxies: nuclei
• ISSN: 0004-637X; 1538-4357
• DOI: 10.1086/510899

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 Ha line with FWHM = 781 km s super(-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 Ha component, is about7 x 10 super(4)M sub( ). The host galaxy appears to be a disk galaxy with a boxy bulge or nuclear bar. With an absolute magnitude of M sub(R) = -17.8 (M sub(B) = -16.4), it is among the least luminous host galaxies ever identified for a Seyfert 1.