We make use of the images from the Sloan Digital Sky Survey Stripe 82 to present an analysis of r band surface brightness profiles and radial color gradients (g - r, u - r) in 111 nearby early-type galaxies (ETGs). With Stripe 82 images, we are able
to pay special attentions to the low-surface-brightness areas (LSB areas) of the galaxies. The LSB areas make a difference to the Sersic fittings and concentration indices, making both the indices less than the typical values for ETGs. There are about 60% negative color gradients (red-core) within 1.5Re , much more than the approximately 10% positive ones (blue-core) within the same radius. However, taking into account of the LSB areas, we find that the color gradients are not necessarily monotonic: about one third of the red-core (or blue-core) galaxies have positive (or negative) color gradients in the outer areas. So LSB areas not only make ETGs Sersic profiles deviate from de Vaucouleur ones and shift to the disk end, but also reveal that quite a number of ETGs have opposite color gradients in inner and outer areas. These outcomes remind us the necessity of double-Sersic fitting. These LSB phenomena may be interpreted by mergers and thus different metallicity in the outer areas. Isophotal parameters are also discussed briefly in this paper: more disky nearby ETGs are spotted than boxy ones.
We present the {it Spitzer} Space Telescope InfraRed Array Camera (IRAC) and Multiband Imaging Photometer (MIPS) observations of the elliptical galaxy NGC 315. After removal of the host galaxys stellar emission, we detected for the first time an infr
ared-red nucleus in NGC 315. We measured the spectral energy distribution (SED) for this active nucleus with wavelength range covering from radio to X-ray, and obtained the bolometric luminosity of $rm L_{bol} approx 1.9 times 10^{43} ergs s^{-1}$, corresponding to an extremely low Eddington ratio (L/L$_{rm Edd}$) of 4.97 $times$ 10$^{-4}$. Our results confirm that the physical nature of the nucleus of NGC 315 is a low-luminosity AGN, consistent with the recent optical and {it Chandra} X-ray observations.
