We analyse the spatial distribution and colour of the intracluster light ( ICL ) in 683 clusters of galaxies between z = 0.2 and 0.3 , selected from \sim 1500 deg ^ { 2 } of the first data release of the Sloan Digital Sky Survey ( SDSS-DR1 ) .
Surface photometry in the g , r and i bands is conducted on stacked images of the clusters , after rescaling them to the same metric size and masking out resolved sources .
We are able to trace the average surface brightness profile of the ICL out to 700 kpc , where it is less than 10 ^ { -4 } of the mean surface brightness of the dark night sky .
The ICL appears as a clear surface brightness excess with respect to an inner R ^ { 1 / 4 } profile which characterises the mean profile of the brightest cluster galaxies ( BCG ) .
The surface brightness of the ICL ranges from 27.5 mag arcsec ^ { -2 } at 100 kpc to \sim 32 mag arcsec ^ { -2 } at 700 kpc in the observed r -band .
This corresponds SB in the range 26.5 to 31 in the rest-frame g -band .
We find that , on average , the ICL contributes only a small fraction of the total optical emission in a cluster .
Within a fixed metric aperture of 500 kpc , this fraction is 10.9 \pm 5.0 per cent for our clusters .
A further 21.9 \pm 3.0 per cent is contributed on average by the BCG itself .
The radial distribution of the ICL is more centrally concentrated than that of the cluster galaxies , but the colours of the two components are identical within the statistical uncertainties .
In the mean the ICL is aligned with and more flattened than the BCG itself .
This alignment is substantially stronger than that of the cluster light as a whole .
We find the surface brightness of the ICL to correlate both with BCG luminosity and with cluster richness , while the fraction of the total light in the ICL is almost independent of these quantities .
These results support the idea that the ICL is produced by stripping and disruption of galaxies as they pass through the central regions of clusters .
Our measurements of the diffuse light also constrain the faint-end slope of the cluster luminosity function .
Slopes \alpha < -1.35 would imply more light from undetected galaxies than is observed in the diffuse component .