Constraints on the amplitude A of the intrinsic alignment model. The black solid curve corresponds to using the full MegaZ-LRG sample. The constraints from the individual MegaZ-LRG redshift bins are shown as red dashed lines (z > 0.529) and orange dotted lines (z < 0.529). For comparison we also show the constraints on A for the SDSS L4 sample as green solid line and for the SDSS LRG medium luminosity samples with z < 0.27 (dark blue dotted line) and z > 0.27 (purple dashed line).