SDSS J085431.18+173730.5: The First Compact Elliptical Galaxy Hosting an   Active Nucleus
  We report the discovery of a rare compact early-type galaxy, SDSS J085431.18+173730.5 (hereafter cE\_AGN). It has an half light radius of R$_{e}$ = 490 pc and a brightness of M$_{r}$ = $-$18.08 mag. Optical spectroscopy available from the Sloan Digital Sky Survey (SDSS) reveals the presence of prominent broad-line emissions with the H$\alpha$ broad component width of FWHM=2400 km/s. The black hole (BH) mass, as estimated from the luminosity and width of the broad H$\alpha$ emission, is 2.1$\times$10$^{6}$ M$_{\sun}$. With the help of surface photometry, we perform a detailed analysis of the structural properties. The observed light distribution is best modeled with a double S\'ersic function. Fixing the outer component as an exponential disk, we find that the inner component has a S\'ersic index of n = 1.4. Considering the inner component as bulge/spheroidal we find that cE\_AGN remains consistent in both BH mass -- bulge mass relation and BH mass -- bulge S\'ersic index relation. Given these observational properties, we discuss its possible origin investigating the surrounding environment where it is located. 
Sanjaya Paudel, Michael Hilker, Change Hee Ree and Minjin Kim
astro-ph.GA