We measure the luminosity function of morphologically selected E/S0 galaxies from z = 0.5 to z = 1.0 using deep high resolution Advanced Camera for Surveys ( ACS ) imaging data .
Our data extend 2 magnitudes deeper than the Deep Groth Strip Survey ( DGSS ) .
At 0.5 < z < 0.75 , we find M _ { B } ^ { * } -5 \log h _ { 0.7 } = -21.1 \pm 0.3 and \alpha = -0.53 \pm 0.2 , and at 0.75 < z < 1.0 , we find M _ { B } ^ { * } -5 \log h _ { 0.7 } = -21.4 \pm 0.2 .
Our morphologically selected luminosity functions are similar in both shape and number density to other morphologically selected luminosity functions ( e.g. , DGSS ) , but we find significant differences to the luminosity functions of samples selected using morphological proxies like colour or SED .
The difference is due to incompleteness from blue E/S0 galaxies , which make up to \sim 30 \% of the sample and contamination from early-type spirals .
Most of the blue E/S0 galaxies have similar structural properties to the red E/S0s and could passively evolve to form giant red ellipticals at z = 0 .
However , the bluest , ( U - V ) _ { 0 } < 1.2 , have much smaller Sersic parameters and would evolve into much fainter galaxies .
These may be the progenitors of dwarf ellipticals .
We demonstrate the need for both morphological and colour information to constrain the evolution of E/S0 galaxies .