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 Re = 490 pc and a brightness of Mr = −18.08 mag. Optical spectroscopy available from the Sloan Digital Sky Survey (SDSS) reveals the presence of prominent broad-line emissions with the Hα broad component width of FWHM=2400 km/s. The black hole (BH) mass, as estimated from the luminosity and width of the broad Hα emission, is 2.1×106 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.
@article{arxiv.1603.07832,
title = {SDSS J085431.18+173730.5: The First Compact Elliptical Galaxy Hosting an Active Nucleus},
author = {Sanjaya Paudel and Michael Hilker and Change Hee Ree and Minjin Kim},
journal= {arXiv preprint arXiv:1603.07832},
year = {2016}
}