K- (or K′-) band detection limits (5σ) for companions. Individual curves are shown as gray curves, with solid (dashed) lines indicating very low mass (low mass) targets, respectively. The red curve shows the median detection limit for very-low mass targets. All curves are smoothed using a 3-pixel running median filter for separations larger than 08 for visual purposes. Blue and green diamonds represent candidate companions to very low-mass and low-mass targets identified in our survey, respectively. Orange symbols indicate companions which are confirmed or suspected unrelated background stars based on astrometric (circle symbols) and/or photometric (square symbols) arguments. The magnitude difference to the bright visual companion to UKIDSS 10 has been inverted and is shown as the open diamond.