Color of Bright Galaxies

The colors are computed using a procedure outlined in the Third Reference Catalogue of Bright Galaxies (RC3) whereby standard color curves approximated by Laplace-Gauss integrals are fitted to observed photoelectric multiaperture photometry. 11 sources of such photometry were used for our analysis, each source being assigned an appropriate weight according to a rigorous analysis of residuals of the data from the best-fitting standard color curves.

Together with the integrated B-V and U-B colors provided in RC3, our analysis widens the range of wavelength of homogeneously defined colors of normal galaxies of all Hubble types. We present color-color and color-type relations that can be modeled to understand the star formation history of galaxies.