We perform photometric analyses for a bright early-type galaxy ( ETG ) sample with 2949 galaxies ( M _ { r } < -22.5 mag ) in the redshift range of 0.05 to 0.15 , drawn from the SDSS DR7 with morphological classification from Galaxy Zoo 1 .
We measure the Petrosian and isophotal magnitudes , as well as the corresponding half-light radius for each galaxy .
We find that for brightest galaxies ( M _ { r } < -23 mag ) , our Petrosian magnitudes , and isophotal magnitudes to 25 { mag / arcsec ^ { 2 } } and 1 % of the sky brightness are on average 0.16 mag , 0.20 mag , and 0.26 mag brighter than the SDSS Petrosian values , respectively .
In the first case the underestimations are caused by overestimations in the sky background by the SDSS PHOTO algorithm , while the latter two are also due to deeper photometry .
Similarly , the typical half-light radii ( r _ { 50 } ) measured by the SDSS algorithm are smaller than our measurements .
As a result , the bright-end of the r -band luminosity function is found to decline more slowly than previous works .
Our measured luminosity densities at the bright end are more than one order of magnitude higher than those of Blanton et al .
( 2003 ) , and the stellar mass densities at M _ { \ast } \sim 5 \times 10 ^ { 11 } M _ { \odot } and M _ { \ast } \sim 10 ^ { 12 } M _ { \odot } are a few tenths and a factor of few higher than those of Bernardi et al .
( 2010 ) .
These results may significantly alleviate the tension in the assembly of massive galaxies between observations and predictions of the hierarchical structure formation model .