Criteria for galaxy classification in SDSS

We considered the sample of galaxy pairs collected from SDSS DR5. At first we made a morphological classification of approximately 1100 galaxies by visual inspection. As it is known the galaxy morphological types strongly depend on the color indices, the concentration parameters, galaxy magnitudes, de Vaucouleurs and exponential fit scale radii. Thus we used pairs of these parameters and found the universal criteria which can be used for galaxy morphological classification with the help of our "by-eye" classification. According to our criteria we can select early type galaxies with 90% probability.