7 Comparison with other samples

The derived parameters viz. the scale lengths and the central disk surface brightnesses were computed with those derived by de Jong ([1996]) for normal spiral galaxies. The plot of the blue scale length versus the corrected central disk brightness (Fig. 11) shows that the Markarian starburst galaxies in our sample have scale lengths less than about 2 kpc in the B band. These are shorter compared to those derived for normal spirals by de Jong using a bulge-disk decomposition. The central disk surface brightness is also brighter than that observed in normal spirals by other workers. Bothun et al. ([1989]) report a mean value of 2 kpc for the scale lengths derived using "marking the disk" based on the study of the Wasilewski sample of emission-line galaxies in the Gunn R band. They also find the mean central surface brightness of exponential disks to be about 1.5 mag brighter than that for normal spirals in Gunn R. However, Courteau ([1996]) cautions against the comparison of scale lengths derived by different workers due to the subjective nature of the measurements. He argues that "marking the disk" approach would lead to smaller scale lengths over the bulge-disk decomposition fits. In the (B/D) decompositions, the inclusion of a bulge reduces the amount of light contributed by the inner disk and thus leads to a shallower slope for the disk profiles. Knapen & van der Kruit ([1991]) find discrepancies up to a factor of two in the scale lengths measured by various workers.