We have derived detailed R band luminosity profiles and structural parameters for a total of 430 brightest cluster galaxies ( BCGs ) , down to a limiting surface brightness of 24.5 magarcsec ^ { -2 } .
Light profiles were initially fitted with a Sérsic ’ s R ^ { 1 / n } model , but we found that 205 ( \sim 48 \% ) BCGs require a double component model to accurately match their light profiles .
The best fit for these 205 galaxies is an inner Sérsic model , with indices n \sim 1 - 7 , plus an outer exponential component .

Thus , we establish the existence of two categories of the BCGs luminosity profiles : single and double component profiles .
We found that double profile BCGs are brighter ( \sim 0.2 mag ) than single profile BCG .
In fact , the Kolmogorov-Smirnov test applied to these subsamples indicates that they have different total magnitude distributions , with mean values M _ { R } = -23.8 \pm 0.6 mag for single profile BCGs and M _ { R } = -24.0 \pm 0.5 mag for double profile BCGs .
We find that partial luminosities for both subsamples are indistinguishable up to r = 15 kpc , while for r > 20 kpc the luminosities we obtain are on average 0.2 mag brighter for double profile BCGs .
This result indicates that extra-light for double profile BCGs does not come from the inner region but from the outer regions of these galaxies .

The best fit slope of the Kormendy relation for the whole sample is a = 3.13 \pm 0.04 .
However , when fitted separately , single and double profile BCGs show different slopes : a _ { single } = 3.29 \pm 0.06 and a _ { double } = 2.79 \pm 0.08 .
Also , the logarithmic slope of the metric luminosity \alpha is higher in double profile BCGs ( \alpha _ { double } = 0.65 \pm 0.12 ) than in single profile BCGs ( \alpha _ { single } = 0.59 \pm 0.14 ) .
The mean isophote outer ellipticity ( calculated at \mu \sim 24 mag arcsec ^ { -2 } ) is higher in double profile BCGs ( e _ { double } = 0.30 \pm 0.10 ) than in single profile BCGs ( e _ { single } = 0.26 \pm 0.11 ) .
Similarly , the mean absolute value of inner minus outer ellipticity is also higher in double profile BCGs

On the other hand , we did not find differences between these two BCGs categories when we compared global cluster properties such as the BCG-projected position relative to the cluster X-ray center emission , X-ray luminosity , or BCG orientation with respect to the cluster position angle .