Detailed isophotometry of NGC 253 in the Sculptor Group in blue light to a limiting surface brightness of 29 mag arcsec-2 has been obtained from a combination of photographic and photoelectric photometry. The standard photometric parameters have been derived; in particular, the total magnitude is BT = 8.05, and the maximum detected dimensions are 60' × 26', or 44 x 19 kpc at the assumed distance of 2.5 Mpc. The absolute luminosity of NGC 253, corrected for galactic and internal extinction is LT = 2.65 × 1010 Lsun. A three component luminosity model of NGC 253 is derived consisting of a r1/4 spheroid, an exponential disk, and the spiral arms, which contribute, respectively, 15, 59, and 26% of the total B luminosity.
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W. D. Pence (1980) studied this question.