Mass-luminosity distribution and physical conditions of ionized gas in NGC 4575

Photographic photometry and spectroscopic observations of NGC 4575 suggest it to be a galaxy of reduced dimensions Dxd=14.4x13.5 kpc and of high luminosity M=-20.7. The rotation curve was also determined. Assuming a model of three homogeneous similar spheroids, we derived the density and mass distribution, and their total mass was found to be Msub(T)=2.33x1010Msub(Sun). The mass luminosity ratio does not vary within r=24seconds of arc, indicating that the stellar composition is similar within it, and the ratio Msub(T)/Lsub(T)approximately1 suggests that this object contains a high proportion of young stars. From the emission lines it is found that the electronic density Ne approximately 100cm-3 is relatively low in the H II regions. The abundance ratios N(N)/N(S) and N(N)/N(H) for the nucleus and two emission regions were also derived. (Auth.)