The 2dF-SDSS LRG and QSO survey: Evolution of the Luminosity Function of Luminous Red Galaxies to z=0.6

We present new measurements of the luminosity function (LF) of Luminous Red Galaxies (LRGs) from the Sloan Digital Sky Survey (SDSS) and the 2dF-SDSS LRG and Quasar (2SLAQ) survey. We have carefully quantified, and corrected for, uncertainties in the K and evolutionary corrections, differences in the colour selection methods, and the effects of photometric errors, thus ensuring we are studying the same galaxy population in both surveys. Using a limited subset of 6326 SDSS LRGs (with 0.17<z<0.24) and 1725 2SLAQ LRGs (with 0.5 <z<0.6), for which the matching colour selection is most reliable, we find no evidence for any additional evolution in the LRG LF, over this redshift range, beyond that expected from a simple passive evolution model. This lack of additional evolution is quantified using the comoving luminosity density of SDSS and 2SLAQ LRGs, brighter than M_r - 5logh = -22.5, which are 2.51+/-0.03 x 10^-7 L_sun Mpc^-3 and 2.44+/-0.15 x 10^-7 L_sun Mpc^-3 respectively (