SURFACE PHOTOMETRY OF EDGE-ON GALAXIES - IC-5249 AND ESO-404-G18

We present the results of BRI CCD surface photometry of two late type edge-on galaxies, IC 5249 and ESO 404-G18, which are very thin and alm ost perfectly edge-on. Surface brightness and color profiles along the major and minor axes, and vertical profiles at various distances from the galactic center are examined. Unlike most other edge-on spirals, both galaxies show no sign of a dust lane. From the color profiles, th e overall contribution of dust turns out to he very weak in these syst ems. The vertical profiles have been found to demonstrate clearly an e xcess of light at small z over the isothermal model suggested by van d er Kruit and Searle. A simple exponential distribution model seems to give a better fit for the overall trend of the z dependence of light. The scale height of their disks does not change with distance from the galactic center like other spirals. However a thick disk component fo und in earlier type disk galaxies is not seen in either of these syste ms. The major axis profile of IC 5249 demonstrates a peculiar two-comp onent structure with an exponential inner disk where the change of sur face brightness is slow and an exponential outer disk with a steep cha nge of surface brightness. The very large scale length of the inner di sk is considered in relation to its low surface brightness. A systemat ic further study of low surface brightness disk galaxies is required f or a firm conclusion regarding the correlation between large disk scal e length and overall surface brightness.