Colour and stellar population gradients of galaxies in poor groups of galaxies

We studied the color distribution of satellite galaxies in three groups of galaxies and found that nearly a half of galaxies show statistically significant radial color gradients, which are indicative of changing stellar ages and metallicities. We found that the disk-dominated satellite galaxies with positive color and age gradients (i.e., evolving in outside-in fashion) are residing, predominantly, in the inner, dense group regions, within the characteristic radius R ₂₀₀, while those galaxies, residing in the outer group in-fall region, show typically zero or negative gradients.