Abstract
From B and V photographic surface photometry we have obtained isophote maps, photometric parameters, luminosity profiles and B-V color indices for the group of the spiral galaxies NGC 6769, 6770 and 6771. The observations were made with the 1.6 m telescope of Observat6rio Astrofisico Brasileiro using the combination of 103a-0 or IIa-0 plate plus GG385 filter for the B system and IIa-D plate plus GG495 for the V system. The reductions were made using the Zeiss-Jena microdensitometer of Instituto de Fisica - UFRGS, Porto Alegre and the method of Sersic (1968) or the PDS microdensitometer of Observatorio Nacional, Rio de Janeiro, and the software developed in that observatory by da al. (1982). The values obtained for the total apparent magnitudes (mB), total color indices (mB-m ), absolute magnitudes (MB), major (0) and minor (d) diameters are listed in the table below, together with the isophotal level where these values were obtained. TABLE 1. Photometric Parameters NGC mB MB 0(") d(") kpc kpc 6769 12.70 0.65 -21.27 130.0 93.0 24.86 28.1 20.1 6770 12.91 0.71 -20.97 174.0 128.0 24.86 36.7 27.0 6771 13.76 0.90 -20.25 143.0 34.5 25.17 33.4 8.1 In general, the color indices vary from about 1.1 nag in the nuclear regions to about 0.3 mag in the blue regions. Exponential and r1 / laws have been adjusted to the luminosity profiles.
