Surface Photometry of the Dwarf Elliptical Galaxies NGC 185 and NGC 205

Abstract

We present BVRI CCD surface photometry for the central (6&#39;.35 X 6&#39;.35) regions of the dwarf elliptical galaxies NGC 185 and NGC 205 in the Local Group. Surface brightness profiles of NGC 185 (R < 225&#34;) and NGC 205 (R < 186&#34;) show excess components in the central regions. The colors of NGC 185 get bluer inward at R < 25&#34;, while they remain constant at R >= 25&#34;. The colors of NGC 205 get bluer inward at 1&#34; < R < 50&#34;, and remain flat outside. Our photometry, supplemented by the photometry based on the far-ultraviolet and visual images of the HST archive data, shows that there is an inversion of color at the very nucleus region (at about 1&#34;). The implications of the redder color of the core part of the nucleus compared with neighboring regions are discussed. The amount of the excess components in the central regions of these galaxies is estimated to be ~10^5 solar luminosity. Distributions of dust clouds in the central regions of the two galaxies are also investigated.