Disc scalelengths of non‐active and active spiral galaxies

摘要: Disc scalelengths rD are determined for a sample of 32 non-active and 28 active spiral galaxies from optical CCD images. For 21 the 20 B, V, R I data have been obtained, while remaining only B images taken. 18 galaxies, which measured in all four passbands, decreases systematically to I, whereas such decrease is found with BVRI data. ratios rD(B)/rD(I),rD(V)/rD(I) rD(R)/rD(I) increase increasing apparent ellipticity e galaxies. no systematic variation any found. The rD(B)/rD(I) compared model calculations. represented best by stellar disc that has an intrinsic colour gradient central depth band face-on view τ0B=3. For agreement between models dust. The best-fitting does not reproduce galaxies. The main conclusion this work structural differences seem exist discs show significant gradients within their discs, do not. These probably caused combination disc, dust extinction. Furthermore, measurements indicate extinction centre, but they optically thin outer regions. throughout disc.