Morphology, kinematics, and dynamics of bulges of spirals .2. Surface photometry of the central part of NGC 5055

The morphological properties of the central 1.9x2.8 arcmin region of NGC 5055 have been studied on the basis of BVRI and H alpha CCD imaging and photometry. Intensity and color profiles, together with isophotal contours have been analyzed and compared with kinematical data from high spatial resolution spectroscopy which was presented in a previous paper. A study is carried out on the extinction by dust in the galaxy. It is found that the extinction law can be obtained from the examination of the colors of a set of 18 OB associations distributed across the galaxy. In particular, we found that dust absorption along the spiral structure can be roughly reproduced by a linear outward decreasing law, with a central value of A(v) similar or equal to 3-4 mag. (C) 1996 American Astronomical Society.