Luminosity distribution in galaxies. I. The elliptical galaxy NGC 3379 as a luminosity distribution standard

A standard mean luminosity profile in the B band of the El galaxy NGC 3379 along its east-west x-axis is derived from four sets of medium- and low-resolution photographic and photoelectric McDonald data. The 154 mean points cover a range in excess of 11 mag down to ..mu../sub B/=27.8 mag arcsec/sup -2/ (x=7'.3), with possible detection out to x=16'.3 (..mu../sub B/approx. =30.9).The profile is presented within +- 0.08 mag at all x>10'' by ..mu../sub 1/=14.076+3.0083 x/sup 1/4/ (x in arcsec). Near the center the galaxy is brighter than ..mu../sub 1/ by up to 0.35 mag; the excess can be represented by a Gaussian core ..mu../sub II/=18.565+0.03965 r/sup 2/ (r in arcsec) contributing 19.8% of the integrated magnitude B=11.97 within r* =12'' and 4.0% of the total magnitude B/sub T/=10.225 of the galaxy.This two-component model convolved by the appropriate point spread function represents the data within a standard deviation of 0.04 mag over the whole range. Other analytical formulae give generally poorer fits. There is no evidence for a tidal cutoff or a tidal extension.The integrated magnitudes derived from the model agree with aperture photometry (47 values) within 0.05 mag (s.d.).